ACTIVITY REPORTS
A group of 14 keen members of the HKIE Geotechnical Division were fortunate to participate
in an over-subscribed technical visit to MTR Contract 708 West Island Line (WIL)
Underground Magazine held on 20th March 2010. Kindly hosted by the Engineer’s Representative
Kristian Murfitt (MTR) and Contractor’s Representative Terry Chan (Gammon Construction
Limited), participants had an invaluable first hand view of the design and construction
aspects of the site for storing explosives to support high blasting demand anticipated
during WIL construction. Visitors were briefed on the scope of works, construction
methods being adopted and challenges being overcome during the ongoing construction
works including some challenging geological conditions.
The West Island Line is a 3.3km extension of the MTR Island Line linking Sheung Wan to Sai Ying Pun, The University of Hong Kong and Kennedy Town. Construction works mainly comprise underground excavation for the railway tunnels, stations and pedestrian adits. Whilst tunnel boring machines will be used for the section between Sheung Wan and Sai Ying Pun, the majority of underground works will be excavated by drill and blast method. Therefore reliable delivery of explosives for blasting is the key to the project success. Centralized supply of blasting explosives from Mines Department of CEDD is limited to one delivery per day and requires three days advance pre-ordering. Therefore constructing a temporary underground magazine for safe storage of blasting explosives will speed up the construction process and enhance the reliability and flexibility of explosives delivery to meet the tight programme of WIL construction.
A lively question and answer session followed the presentations with participants expressing particular interest in the design and construction obstacles encountered. This included geotechnical aspects such as the need to mine through both boulders and soft ground whilst maintaining traffic flow on Victoria Road, maintaining the environmental conditions of the steep and heavily vegetated terrain, restricted site access and tight works schedule. HKIE attendees were then escorted to the tunnel opening for a closer inspection of the ongoing construction works.
HKIE Geotechnical Division would like to express gratitude to the WIL 708 team for their gracious hospitability and making the event successful.
The West Island Line is a 3.3km extension of the MTR Island Line linking Sheung Wan to Sai Ying Pun, The University of Hong Kong and Kennedy Town. Construction works mainly comprise underground excavation for the railway tunnels, stations and pedestrian adits. Whilst tunnel boring machines will be used for the section between Sheung Wan and Sai Ying Pun, the majority of underground works will be excavated by drill and blast method. Therefore reliable delivery of explosives for blasting is the key to the project success. Centralized supply of blasting explosives from Mines Department of CEDD is limited to one delivery per day and requires three days advance pre-ordering. Therefore constructing a temporary underground magazine for safe storage of blasting explosives will speed up the construction process and enhance the reliability and flexibility of explosives delivery to meet the tight programme of WIL construction.
A lively question and answer session followed the presentations with participants expressing particular interest in the design and construction obstacles encountered. This included geotechnical aspects such as the need to mine through both boulders and soft ground whilst maintaining traffic flow on Victoria Road, maintaining the environmental conditions of the steep and heavily vegetated terrain, restricted site access and tight works schedule. HKIE attendees were then escorted to the tunnel opening for a closer inspection of the ongoing construction works.
HKIE Geotechnical Division would like to express gratitude to the WIL 708 team for their gracious hospitability and making the event successful.
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Ir David Sein (HKIE GE Division) presenting souvenirs to the speakers of MTR Engineer’s
Representative, Kristian Murfitt
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Ir David Sein presenting souvenirs to Mr. Terry Chan of Gammon Construction Limited
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| Participants of the technical visit at the site of MTR Contract 708 WIL Underground Magazin |
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An HKIE Geotechnical Division site visit to CEDD Contract No. CV/2007/03, Anderson
Road Development, was conducted on 6 March 2010 with 27 participants in attendance.
Visitors were able to view large scale site formation and associated infrastructure
work. The site visit was kindly organized by CEDD and supported by Ove Arup & Partners
Hong Kong Limited and China State Construction Engineering (Hong Kong) Limited.
A warm welcome was provided by the Resident Site Staff and the Contractor including Ms Julia Ho (RE), Mr Michael Wright (SE), and Mr Y K Lau (ARE) from Arup and Mr Kingsley Chiang (Site Agent) from China State. Mr Lau gave an informative presentation on various aspects of the project including the slope works, reinforced earth retaining walls, junction improvement works, drainage systems and landscape works. Corrugated plastic sheathing as specified in Geoguide 7 is being adopted to protect the soil nails from corrosion due to the soil aggressivity at this site. The engineering and town planning aspects of constructing the 20ha platform and associated infrastructure facilities were also conveyed to the visitors. The development will facilitate future housing and other community use including the relocation of existing temples. A deeper understanding of the geotechnical blasting was conveyed through the question and answer session including explanations of the instrumentation systems and trigger levels being adopted to monitor sensitive receivers against air overpressure and vibration.
The discussions continued during the site walk and the hosts shared their valuable experience with the visitors. Participants visited various locations around the site including a blasting area where protective blast screens were being erected, reinforced earth retaining wall construction, and the on-site rock crushing machine. Blasting work was not scheduled during the HKIE site visit because blasting is not allowed on the weekends. Nevertheless, video examples of the Anderson Road Development blasting works were shown to visitors in addition to visiting the blasting zone. The site staff shared their first hand experience with all participants who were able to gain a clear picture on the site formation and the associated infrastructure work at Anderson Road.
HKIE Geotechnical Division expressed its sincere gratitude to CEDD, Arup and China State and the hosts were presented with souvenirs in appreciation of their efforts.
A warm welcome was provided by the Resident Site Staff and the Contractor including Ms Julia Ho (RE), Mr Michael Wright (SE), and Mr Y K Lau (ARE) from Arup and Mr Kingsley Chiang (Site Agent) from China State. Mr Lau gave an informative presentation on various aspects of the project including the slope works, reinforced earth retaining walls, junction improvement works, drainage systems and landscape works. Corrugated plastic sheathing as specified in Geoguide 7 is being adopted to protect the soil nails from corrosion due to the soil aggressivity at this site. The engineering and town planning aspects of constructing the 20ha platform and associated infrastructure facilities were also conveyed to the visitors. The development will facilitate future housing and other community use including the relocation of existing temples. A deeper understanding of the geotechnical blasting was conveyed through the question and answer session including explanations of the instrumentation systems and trigger levels being adopted to monitor sensitive receivers against air overpressure and vibration.
The discussions continued during the site walk and the hosts shared their valuable experience with the visitors. Participants visited various locations around the site including a blasting area where protective blast screens were being erected, reinforced earth retaining wall construction, and the on-site rock crushing machine. Blasting work was not scheduled during the HKIE site visit because blasting is not allowed on the weekends. Nevertheless, video examples of the Anderson Road Development blasting works were shown to visitors in addition to visiting the blasting zone. The site staff shared their first hand experience with all participants who were able to gain a clear picture on the site formation and the associated infrastructure work at Anderson Road.
HKIE Geotechnical Division expressed its sincere gratitude to CEDD, Arup and China State and the hosts were presented with souvenirs in appreciation of their efforts.
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Ir David Sein (left) from HKIE Geotechnical Division presenting souvenirs to Ms
Julia Ho, Mr Michael Wright, and Mr Y K Lau (right) from Arup
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Group photo of HKIE Geotechnical Division Visitors at Anderson Road Development
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On 16 January 2010, the HKIE Geotechnical Division organized a successful technical
visit to Lai Chi Kok Transfer Scheme with 25 participants attending. The technical
visit included presentations by the Resident Site Staff (AECOM) and the Contractor
(Leighton-John Holland Joint Venture) followed by a site tour.
The project was commenced on 17 November 2008 and is scheduled for completion by the end of 2012. The contract sum is about HK$1.7 billion. Due to urbanization and increasing stormwater runoff, the capacity of the existing drainage system in Lai Chi Kok, Cheung Sha Wan and Sham Shui Po areas are susceptible to flooding during heavy rainstorms. The aim is to alleviate flooding of the low lying, developed areas of Kowloon. The project includes the construction of 3.7km of 4.9m diameter drainage tunnel which will intercept and capture stormwater runoff from the upper catchment in West Kowloon and discharge it into Victoria Harbour near Stonecutters Island. Temporary works challenges to construct six intakes, a stilling basin and an outfall were also discussed.
The main tunnels will be constructed by Tunnel Boring Machine (TBM). A slurry type TBM was adopted to maintain face stability under bentonite in order and cope with the anticipated geological conditions including hard rock, mixed ground and soft ground conditions. Drill and blast techniques in rock will be adopted in the construction of the connecting adits between the intakes and the tunnels.
An interactive Q&A session was held immediate after the presentations. The participants raised questions relating to the detailed operations of the TBM, the ground treatment methods at the temporary tunnel portal and the ground monitoring system during the tunneling works. After the Q&A session, the HKIE GE Division presented souvenirs of appreciation to the hosts and thanked them for their generous invitation and delivering such informative presentations.
The hosts then guided participants on a site tour. The hosts provided an on site explanation of the slurry treatment plant, the assembly and launch preparations of the TBM and the temporary works at the tunnel portal. Participants expressed keen interest in the detailed TBM operations which were further elaborated by the hosts during the site walk. The group finished the site visit with a group photo in front of the tunnel portal area.
The project was commenced on 17 November 2008 and is scheduled for completion by the end of 2012. The contract sum is about HK$1.7 billion. Due to urbanization and increasing stormwater runoff, the capacity of the existing drainage system in Lai Chi Kok, Cheung Sha Wan and Sham Shui Po areas are susceptible to flooding during heavy rainstorms. The aim is to alleviate flooding of the low lying, developed areas of Kowloon. The project includes the construction of 3.7km of 4.9m diameter drainage tunnel which will intercept and capture stormwater runoff from the upper catchment in West Kowloon and discharge it into Victoria Harbour near Stonecutters Island. Temporary works challenges to construct six intakes, a stilling basin and an outfall were also discussed.
The main tunnels will be constructed by Tunnel Boring Machine (TBM). A slurry type TBM was adopted to maintain face stability under bentonite in order and cope with the anticipated geological conditions including hard rock, mixed ground and soft ground conditions. Drill and blast techniques in rock will be adopted in the construction of the connecting adits between the intakes and the tunnels.
An interactive Q&A session was held immediate after the presentations. The participants raised questions relating to the detailed operations of the TBM, the ground treatment methods at the temporary tunnel portal and the ground monitoring system during the tunneling works. After the Q&A session, the HKIE GE Division presented souvenirs of appreciation to the hosts and thanked them for their generous invitation and delivering such informative presentations.
The hosts then guided participants on a site tour. The hosts provided an on site explanation of the slurry treatment plant, the assembly and launch preparations of the TBM and the temporary works at the tunnel portal. Participants expressed keen interest in the detailed TBM operations which were further elaborated by the hosts during the site walk. The group finished the site visit with a group photo in front of the tunnel portal area.
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Ir David Sein of HKIE GE Division
presented souvenirs to the speakers AECOM |
Ir David Sein of HKIE GE Division presented souvenirs to Leighton-John Holland Joint
Venture
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| The hosts introduced the setup of the slurry treatment plant |
Group photo at tunnel portal
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On 5 December 2009, HKIE Geotechnical Division arranged a technical visit to the
project a HKU Student Hostel at Lung Wah Street with 25 participants attending.
The visit to this site formation and foundation project was jointly organized by
the HKIE with the kind assistance from Chun Wo Construction & Engineering Co. Ltd
and Meinhardt (Hong Kong) Ltd being the Main Contractor and Structural Engineer
of the project respectively.
Chun Wo’s project manager, Mr Gary Lo, gave a lively presentation of the project background. The project involves site formation and foundation works for four tower blocks for the student hostel. The site is located in very congested, narrow and steeply sloping ground. The project includes construction of large diameter bored piles the tower foundations and also a bored pile wall and ELS system to retain the slope and adjacent existing bored pile wall during excavation and construction. The large scale foundation works in such congested and steep site presented an enormous challenge to the site team. A haul road was constructed to facilitate easy mobilization of machinery rather than establish a temporary working platform. The site was arranged to concurrently accommodate as many construction plant as possible in order to achieve a faster construction programme.
A lively question and answer session was held following the presentations with attendees expressing particular interest in the geotechnical aspects of the project including the rockhead determination for the bored pile sockets with ground conditions identifying considerable depth of interbedded soil/rock stratum. Other topics discussed included the construction method for creating an opening at the bored pile wall for the future entrance of the hostel and encountering of unforeseen underground structures during construction of the large diameter bored piles.
HKIE members were able to get a close view of the challenging site conditions and the discussions with the hosts continued during the site inspection. Further explanation was provided of the ongoing bored pile construction activities including close liaison with adjoining residents during construction.
HKIE GE Division thanked Chun Wo and Meinhardt for their generous invitation, informative presentations and warm hospitality. The hosts were presented with souvenirs by HKIE.
Chun Wo’s project manager, Mr Gary Lo, gave a lively presentation of the project background. The project involves site formation and foundation works for four tower blocks for the student hostel. The site is located in very congested, narrow and steeply sloping ground. The project includes construction of large diameter bored piles the tower foundations and also a bored pile wall and ELS system to retain the slope and adjacent existing bored pile wall during excavation and construction. The large scale foundation works in such congested and steep site presented an enormous challenge to the site team. A haul road was constructed to facilitate easy mobilization of machinery rather than establish a temporary working platform. The site was arranged to concurrently accommodate as many construction plant as possible in order to achieve a faster construction programme.
A lively question and answer session was held following the presentations with attendees expressing particular interest in the geotechnical aspects of the project including the rockhead determination for the bored pile sockets with ground conditions identifying considerable depth of interbedded soil/rock stratum. Other topics discussed included the construction method for creating an opening at the bored pile wall for the future entrance of the hostel and encountering of unforeseen underground structures during construction of the large diameter bored piles.
HKIE members were able to get a close view of the challenging site conditions and the discussions with the hosts continued during the site inspection. Further explanation was provided of the ongoing bored pile construction activities including close liaison with adjoining residents during construction.
HKIE GE Division thanked Chun Wo and Meinhardt for their generous invitation, informative presentations and warm hospitality. The hosts were presented with souvenirs by HKIE.
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Ir David Sein and Ir Arthur So (HKIE GE Division)
presenting souvenirs to the speakers of Chun Wo and Meinhardt team |
Participants at the site of HKU Student Hostel at Lung Wah Street
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On 24th October 2009, HKIE Geotechnical Division successfully organized a technical
site visit to Central Reclamation Phase 3 (CR3) with 29 participants attending.
The visit was kindly hosted by the Engineer’s Resident Site Staff (Atkins China
Ltd) and provided a rare opportunity for participants to gain valuable insights
into the design and construction of this large scale civil reclamation project including
complex geotechnical elements.
Ir Stephen Cheung (SRE) introduced the delegation with a brief background to the overall project. This was followed by two separate presentations to provide participants with an understanding of the design aspects for various elements of the project including the reclamation, seawalls and deep excavations for the future trunk road and railway overrun tunnel. The CR3 team then shared some of the difficult construction challenges and explained how they were overcome, including the off-site construction and placement of precast units of seawall caissons. Central Reclamation Phase 3 covers an area of 23 hectares and was reclaimed in four main stages to facilitate the relocation and re-provisioning of major construction constraints including the Star Ferry pier, Queen’s pier, stormwater culverts and cooling water pumping stations. Reclamation works commenced at the end of 2004 with the reclamation being substantially completed in May 2009.
A lively question and answer session was held following the presentations with attendees expressing particular interest in the geotechnical aspects of the project including the dredging and reclamation works and the deep vibro-densification method used to compact the sand fill. HKIE attendees were then escorted to a number of selected locations across the site to view the ongoing works on the site. During the site tour, enthusiastic discussions continued with Atkins engineers providing further explanations about a wide range of construction issues. The attendees were able to view site construction works including diaphragm wall, completed reclamation, seawall works and pre-bored H-pile.
HKIE GE Division thanked Atkins CR3 team for their generous invitation, informative presentations and warm hospitality. The hosts were presented with souvenirs by HKIE.
Ir Stephen Cheung (SRE) introduced the delegation with a brief background to the overall project. This was followed by two separate presentations to provide participants with an understanding of the design aspects for various elements of the project including the reclamation, seawalls and deep excavations for the future trunk road and railway overrun tunnel. The CR3 team then shared some of the difficult construction challenges and explained how they were overcome, including the off-site construction and placement of precast units of seawall caissons. Central Reclamation Phase 3 covers an area of 23 hectares and was reclaimed in four main stages to facilitate the relocation and re-provisioning of major construction constraints including the Star Ferry pier, Queen’s pier, stormwater culverts and cooling water pumping stations. Reclamation works commenced at the end of 2004 with the reclamation being substantially completed in May 2009.
A lively question and answer session was held following the presentations with attendees expressing particular interest in the geotechnical aspects of the project including the dredging and reclamation works and the deep vibro-densification method used to compact the sand fill. HKIE attendees were then escorted to a number of selected locations across the site to view the ongoing works on the site. During the site tour, enthusiastic discussions continued with Atkins engineers providing further explanations about a wide range of construction issues. The attendees were able to view site construction works including diaphragm wall, completed reclamation, seawall works and pre-bored H-pile.
HKIE GE Division thanked Atkins CR3 team for their generous invitation, informative presentations and warm hospitality. The hosts were presented with souvenirs by HKIE.
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Ir David Sein and Ir Kenneth Chan (HKIE GE Division)
presenting souvenirs to the speakers of Atkins CR3 team |
Participants at the site of Central Reclamation Phase 3
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On 28th April 2009, HKIE Geotechnical Division arranged a site visit to Anderson
Road Quarry. The visit was kindly hosted by CEDD and the Contractor, KWP Quarry
Company, providing a rare opportunity for participants to understand more about
quarry activities and gain valuable insights into the approach toward quarry rehabilitation.
Mr Brian Kwok of CEDD provided an informative presentation on the history of Anderson Road Quarry together with an explanation of the current works being carried out under the quarry rehabilitation contract. Since the 1950s, Anderson Road Quarry was formed into a major landscape scar visible from Victoria Harbour. The Hong Kong government initiated a rehabilitation programme for the quarry in a bid to restore the damaged landscape. The quarry rehabilitation contract was signed in January 1997 with rehabilitation works scheduled for completion in December 2013. The objectives of the rehabilitation are to re-contour the degraded old quarry face and create a final landform that will blend in with the surrounding natural ground. Mr Brian Kwok explained that the quarry rehabilitation contract was structured so as to produce sufficient rock products to finance the rehabilitation works. Geologically, the quarry is formed in both granites and volcanics and the final quarry profile will have an overall height of about 210m. The final face will be formed with a series of benches and intermediate rock cut slopes up to 20m height and angles ranging from 54o to 65o depending on the local quality of the insitu rock.
A lively question and answer session was held following the presentation. Of interest to HKIE participants was the innovative construction method to excavate a vertical “glory hole” which shortened the transportation route for excavated rock materials and minimized the generation of dust and environmental disturbance during transportation to the lower rock processing areas. The discussions also covered the design approach to rock slope stability and vibration monitoring to safeguard the quarry face during blasting.
HKIE attendees were then treated to rides in a 4WD convoy to a number of selected locations across the quarry. The foggy weather somewhat hampered the surrounding view, however it didn’t detract from the enthusiasm of the visitors who continued the lively discussion with the hosts throughout the site tour. The group visited the upper restored portion of the quarry face where quarry greening and planting had already been completed and a new eco-system had been re-established. At one of the blast face locations, the Contractor KWP explained the blasting sequence and how the blast direction and sequence was always planned so it did not face the sensitive residential developments below. Residential buildings have been developed in the area below the quarry and extensive measures are being implemented to mitigate the environmental impacts of the quarrying operation. This includes dust suppression by water spraying and enclosed conveyer belts to suppress both noise and dust respectively.
HKIE GE Division thanked CEDD and the Contractor KWP for their generous invitation, informative presentations and warm hospitaility. The hosts were presented with souvenirs by HKIE.
Mr Brian Kwok of CEDD provided an informative presentation on the history of Anderson Road Quarry together with an explanation of the current works being carried out under the quarry rehabilitation contract. Since the 1950s, Anderson Road Quarry was formed into a major landscape scar visible from Victoria Harbour. The Hong Kong government initiated a rehabilitation programme for the quarry in a bid to restore the damaged landscape. The quarry rehabilitation contract was signed in January 1997 with rehabilitation works scheduled for completion in December 2013. The objectives of the rehabilitation are to re-contour the degraded old quarry face and create a final landform that will blend in with the surrounding natural ground. Mr Brian Kwok explained that the quarry rehabilitation contract was structured so as to produce sufficient rock products to finance the rehabilitation works. Geologically, the quarry is formed in both granites and volcanics and the final quarry profile will have an overall height of about 210m. The final face will be formed with a series of benches and intermediate rock cut slopes up to 20m height and angles ranging from 54o to 65o depending on the local quality of the insitu rock.
A lively question and answer session was held following the presentation. Of interest to HKIE participants was the innovative construction method to excavate a vertical “glory hole” which shortened the transportation route for excavated rock materials and minimized the generation of dust and environmental disturbance during transportation to the lower rock processing areas. The discussions also covered the design approach to rock slope stability and vibration monitoring to safeguard the quarry face during blasting.
HKIE attendees were then treated to rides in a 4WD convoy to a number of selected locations across the quarry. The foggy weather somewhat hampered the surrounding view, however it didn’t detract from the enthusiasm of the visitors who continued the lively discussion with the hosts throughout the site tour. The group visited the upper restored portion of the quarry face where quarry greening and planting had already been completed and a new eco-system had been re-established. At one of the blast face locations, the Contractor KWP explained the blasting sequence and how the blast direction and sequence was always planned so it did not face the sensitive residential developments below. Residential buildings have been developed in the area below the quarry and extensive measures are being implemented to mitigate the environmental impacts of the quarrying operation. This includes dust suppression by water spraying and enclosed conveyer belts to suppress both noise and dust respectively.
HKIE GE Division thanked CEDD and the Contractor KWP for their generous invitation, informative presentations and warm hospitaility. The hosts were presented with souvenirs by HKIE.
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Ir Kenneth Chan (HKIE GE Division) presenting a souvenir to Mr Brian Kwok (CEDD) |
Group photo of the delegation
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On 26 February 2009, the Hong Kong Geotechnical Society, Geotechnical Division and
the Young Members Committee jointly organised a technical seminar on the application,
design, material specification and construction of reinforced soil walls (RE Wall).
The seminar was delivered by Ir Dr Nehemiah Lee Chee Hai, Managing Director of Nehemiah
Reinforced Soil Sdn Bhd who was flying from Malaysia. Over 100 participants attended
this seminar.
The seminar began with an introduction on the development of RE Wall and material used for the reinforcement such as geosynthetic and anchor reinforcement. Ir Dr Lee then described the basic concept of RE Wall by showing human load acting on a little sand bund with and without twigs which acted as reinforcement. He revealed that RE Wall was widely used in residential, industrial and infrastructure projects due to its technical and economical advantages over conventional forms of construction. Ir Dr Lee presented photos of RE Wall with impressive facing panels which showed that RE Walls not only provide solution on stability but also give aesthetics and landscaping design to the environment.
After the introduction, Ir Dr Lee explained the design of RE Wall with reference to the BS8006:1995. The design is to safeguard against the occurrence of ultimate limit state (ULS) and the serviceability state (SLS). Ir Dr Lee advised that mode of failures including overall instability, sliding failure, overturning failure and bearing failure, known as the external instability must be checked during design. Internal instability such as rupture and pull-out of reinforcements should also be checked. He also mentioned that the Geoguide 6 published by the GEO is a good design guide for the design of RE Wall.
In the second part of the seminar, Ir Dr Lee presented the findings of some recent research studies including centrifuge model test to model the failure mechanism of RE Wall and field pull-out test for reinforcement. Comparison between the predicted and field data of the lateral displacements of RE Wall was also presented. Finally, Ir Dr Lee briefly described the construction method and sequence for constructing RE Wall.
The seminar was ended with a question-and-answer session and a number of questions related to drainage and RE Wall stability were asked. On behalf of all co-organizers, we would like to express our sincere gratitude to Ir Dr Lee for his informative presentation.
The seminar began with an introduction on the development of RE Wall and material used for the reinforcement such as geosynthetic and anchor reinforcement. Ir Dr Lee then described the basic concept of RE Wall by showing human load acting on a little sand bund with and without twigs which acted as reinforcement. He revealed that RE Wall was widely used in residential, industrial and infrastructure projects due to its technical and economical advantages over conventional forms of construction. Ir Dr Lee presented photos of RE Wall with impressive facing panels which showed that RE Walls not only provide solution on stability but also give aesthetics and landscaping design to the environment.
After the introduction, Ir Dr Lee explained the design of RE Wall with reference to the BS8006:1995. The design is to safeguard against the occurrence of ultimate limit state (ULS) and the serviceability state (SLS). Ir Dr Lee advised that mode of failures including overall instability, sliding failure, overturning failure and bearing failure, known as the external instability must be checked during design. Internal instability such as rupture and pull-out of reinforcements should also be checked. He also mentioned that the Geoguide 6 published by the GEO is a good design guide for the design of RE Wall.
In the second part of the seminar, Ir Dr Lee presented the findings of some recent research studies including centrifuge model test to model the failure mechanism of RE Wall and field pull-out test for reinforcement. Comparison between the predicted and field data of the lateral displacements of RE Wall was also presented. Finally, Ir Dr Lee briefly described the construction method and sequence for constructing RE Wall.
The seminar was ended with a question-and-answer session and a number of questions related to drainage and RE Wall stability were asked. On behalf of all co-organizers, we would like to express our sincere gratitude to Ir Dr Lee for his informative presentation.
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| A full house of audience |
Ir Dr Eric Li, immediate past chairman of GE Division, (R)
presenting souvenir to Ir Dr Nehemiah Lee (L) |
It was a fine and warm Saturday morning. A team of 24 HK engineers paid a cross-border
visit to Shenzhen Metro Railway construction sites at Qian Hai and Lin Hua Shan.
The team was led by Prof Tham, the chairman of Geotechnical Division of HKIE as
well as Ir. Arthur So, the committee member responsible for technical site visits.
The team arrived at Lok Ma Chau Border Control at 9:00 a.m. and received on the
other side of the border, a very warm welcome by the representative of Shenzhen
Institution of Civil Engineering and Architecture (ICEA, SZ). The first stop of
the visit was at the site of Qian Hai interchange where two metro lines, namely
line No. 1 and Line No.3, will meet at the centre of Qian Hai- the proposed CBD
of the new town, about 7 km2 in area for commercial and residential use. It will
also be the transportation centre of Shenzhen where transportation links and infrastructures
will be available to bring passengers to Shenzhen CBD, or across border to Tuen
Mun and HK International Airport, or to SZ airport all within 10 minutes.
Construction of Qian Hai Interchange involved a deep excavation of about 16 m from ground through a new reclamation into the thick, untreated underlying fish-pond deposit. The excavation was retained by 3-levels of struts against the diaphragm walls on both sides, each 80 cm thick with 8m embedment beneath the formation level in pond deposit and in situ material. At the time of visit, the excavation had been brought down to formation level. From the site staff, it was noted that there were site difficulties including local collapse of diaphragm wall during excavation in the untreated fish-pond deposit.
The second stop of the site visit was at Lin Hua Shan Station in Shenzhen city where the Metro station construction required a deep excavation of about 16m from existing ground by the side of a busy commuter road where the excavation works involved complicated works of utility and traffic diversion.
After site visit, the representatives of HKIE GD met with their counterparts from ICEA, SZ to exchange information about activities of both institutions. Both sides agreed to keep close contact with each other in future.
Construction of Qian Hai Interchange involved a deep excavation of about 16 m from ground through a new reclamation into the thick, untreated underlying fish-pond deposit. The excavation was retained by 3-levels of struts against the diaphragm walls on both sides, each 80 cm thick with 8m embedment beneath the formation level in pond deposit and in situ material. At the time of visit, the excavation had been brought down to formation level. From the site staff, it was noted that there were site difficulties including local collapse of diaphragm wall during excavation in the untreated fish-pond deposit.
The second stop of the site visit was at Lin Hua Shan Station in Shenzhen city where the Metro station construction required a deep excavation of about 16m from existing ground by the side of a busy commuter road where the excavation works involved complicated works of utility and traffic diversion.
After site visit, the representatives of HKIE GD met with their counterparts from ICEA, SZ to exchange information about activities of both institutions. Both sides agreed to keep close contact with each other in future.
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Prof George Tham, Chairman of the Geotechnical Division
presenting souvenir to Mr. Liu Qiong Xiang, the general manager of Shenzhen General Institute of Architectural Design and Research Co., Ltd |
Photo of the group visiting the Shenzhen Metro Railway work sites
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A technical seminar organized by the Cavern Working Group of the Geotechnical Division
was held at the HKIE Headquarters on 17 December 2008. The two speakers from Maunsell
AECOM, Ir Bob Frew and Ir Eddie Wong, presented the design and construction of the
Chong Ming Tunnel in Shanghai. The seminar was well attended by over 100 members.
The Chong Ming Tunnels are 7.5 km twin bored tunnels which form part of the 25 km Shanghai – Chong Ming Expressway under the Yangzi River in Shanghai. The construction cost was estimated to be RMB 12.6 billion. Upon completion in 2011, the travelling time from downtown Shanghai to Chong Ming Island will be greatly reduced from almost 2 hours to only 30 minutes.
In this project, the Herrenknecht S317 & S318 Mixshield Tunnel Boring Machines (TBMs) manufactured in Germany were employed. The TBMs, both with a diameter of 15.43 m, were the largest TBMs in the world to date. These machines are designed for soft ground tunneling works. It had taken the contractor 17 months from design to final site assembly of the giant machines.
Each 2 m permanent lining ring weighed 16 tons and was composed of 11 pieces of precast reinforced concrete segments. Upon completion, the tunnel will provide 3 traffic lanes for each direction. One single tunnel box is reserved for light rail transit as well as a cavity is designed to hold utilities. The tunnel construction works had been one year ahead of schedule with an average progressing rate of 44 rings (88 m) installed per week. The fastest record was 65 rings (130 m) per week at the East Tunnel.
In addition to the twin tunnels, the project involved the construction of 2 m diameter cross passage tunnels at regular intervals as well as low point sumps. Since the tunnels were constructed through a very thick silty stratum under the riverbed of the Yangzi river with a water depth of 65 m, ground freezing technique was considered the best solution in controlling possible water ingress during excavation. Prior to ground freezing, temporary steel access doors were first constructed at each cross passage point at the tunnel lining followed by the installation of packer drill holes and ground freezing tubes at specified orientations. Calcium Chloride Brine was supplied at a temperature of -35 degree Celsius for freezing and solidifying the surrounding soil mass during each excavation cycle. At a later stage, steel tunnel ribs will be installed as a means of temporary tunnel support before the placing and casting of the reinforced concrete permanent tunnel lining.
The initial design, post-tender re-design of the tunnel section for the addition of a light rail reserve, the design modification of cross passage tunnels, waste water recycle system and many innovative ideas in overcoming construction problems were addressed by the two speakers. The seminar finished with a Question & Answer session. On behalf of the Division, we would like to thank Ir Bob Frew and Ir Eddie Wong for the informative and interesting presentation.
The Chong Ming Tunnels are 7.5 km twin bored tunnels which form part of the 25 km Shanghai – Chong Ming Expressway under the Yangzi River in Shanghai. The construction cost was estimated to be RMB 12.6 billion. Upon completion in 2011, the travelling time from downtown Shanghai to Chong Ming Island will be greatly reduced from almost 2 hours to only 30 minutes.
In this project, the Herrenknecht S317 & S318 Mixshield Tunnel Boring Machines (TBMs) manufactured in Germany were employed. The TBMs, both with a diameter of 15.43 m, were the largest TBMs in the world to date. These machines are designed for soft ground tunneling works. It had taken the contractor 17 months from design to final site assembly of the giant machines.
Each 2 m permanent lining ring weighed 16 tons and was composed of 11 pieces of precast reinforced concrete segments. Upon completion, the tunnel will provide 3 traffic lanes for each direction. One single tunnel box is reserved for light rail transit as well as a cavity is designed to hold utilities. The tunnel construction works had been one year ahead of schedule with an average progressing rate of 44 rings (88 m) installed per week. The fastest record was 65 rings (130 m) per week at the East Tunnel.
In addition to the twin tunnels, the project involved the construction of 2 m diameter cross passage tunnels at regular intervals as well as low point sumps. Since the tunnels were constructed through a very thick silty stratum under the riverbed of the Yangzi river with a water depth of 65 m, ground freezing technique was considered the best solution in controlling possible water ingress during excavation. Prior to ground freezing, temporary steel access doors were first constructed at each cross passage point at the tunnel lining followed by the installation of packer drill holes and ground freezing tubes at specified orientations. Calcium Chloride Brine was supplied at a temperature of -35 degree Celsius for freezing and solidifying the surrounding soil mass during each excavation cycle. At a later stage, steel tunnel ribs will be installed as a means of temporary tunnel support before the placing and casting of the reinforced concrete permanent tunnel lining.
The initial design, post-tender re-design of the tunnel section for the addition of a light rail reserve, the design modification of cross passage tunnels, waste water recycle system and many innovative ideas in overcoming construction problems were addressed by the two speakers. The seminar finished with a Question & Answer session. On behalf of the Division, we would like to thank Ir Bob Frew and Ir Eddie Wong for the informative and interesting presentation.
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Ir Joseph Lo, chairman of the Cavern Working Group
presenting souvenir to one of the speakers, Ir Bob Frew. |
From Right to Left, Ir Professor George Tham,
Ir Joseph Lo, Ir Eddie Wong, Ir Bob Frew, and Ir Dr Eric Li |
On the 6th December 2008, the GE Division arranged a technical visit to the Hong
Kong West Drainage Tunnel with some 20 members participating. This Drainage Services
Department (DSD) project involves upgrading the flood protection standards in northern
Hong Kong by building a main drainage tunnel of about 11km length extending from
Tai Hang to Cyberport. There will be 34 stormwater intakes and a total of about
8km of adits connecting the intakes with the drainage tunnel. The drainage tunnel
will intercept stormwater collected from Mid-levels and discharge it into the sea
directly, to alleviate flooding in the lower catchment of Northern Hong Kong Island.
The Contractor, Dragages-Nishimatsu Joint Venture (DNJV) presented the project to GE Division members. Mr David Clayton (DNJV Geotechnical Manager) provided the group with an informative project overview including discussion of the proposed TBM construction methods, the intake shafts and the monitoring systems. Mr Hans Sundstrom (DNJV Construction Manager) followed up with an interesting presentation of the construction challenges to build the tunnel portals and connecting adit tunnels.
The works commenced in November 2007 and are due for completion in 2012. The main tunnel will be constructed by two hard rock TBMs driven from the eastern portal at Tai Hang Road (in granitic rock) and the western portal at Cyberport (in volcanic rocks) which are 6.25 m and 7.5 m diameter respectively. The TBMs are equipped with capability for advanced probing to investigate envisaged fault zones during the TBM drives. One of DSD’s primary objectives during construction is to minimize impact to the environment as well as daily lives of the public. To contain the construction’s impact below the ground, most of the intakes shaft boring works will employ the use of raise boring machines which minimizes the disturbance at ground level. GE Division attendees were also introduced to state of the art monitoring systems being implemented at this project including the Tunnel Data Monitoring System (TDMS) and Permanent Scatterer Interferometric Synthetic Aperture Radar (PSInSAR).
There was a lively question and answer session after the presentations followed by a site visit to the Western Portal where cavern excavation works were in progress using non-blasting rock splitting techniques. The GE Division group also viewed the western portal slope stabilization works and temporary works construction for TBM launch. HKIE GE Division thanked Mr Clayton and Mr Sundstrom for their generous invitation and informative presentations and presented them with a souvenir.
At last, the group thanked Mr Clayton and Mr Sundstrom for their generous invitation and informative presentations. The organizer of the site visit, Ir David Sein presented a souvenir to DNJV.
The Contractor, Dragages-Nishimatsu Joint Venture (DNJV) presented the project to GE Division members. Mr David Clayton (DNJV Geotechnical Manager) provided the group with an informative project overview including discussion of the proposed TBM construction methods, the intake shafts and the monitoring systems. Mr Hans Sundstrom (DNJV Construction Manager) followed up with an interesting presentation of the construction challenges to build the tunnel portals and connecting adit tunnels.
The works commenced in November 2007 and are due for completion in 2012. The main tunnel will be constructed by two hard rock TBMs driven from the eastern portal at Tai Hang Road (in granitic rock) and the western portal at Cyberport (in volcanic rocks) which are 6.25 m and 7.5 m diameter respectively. The TBMs are equipped with capability for advanced probing to investigate envisaged fault zones during the TBM drives. One of DSD’s primary objectives during construction is to minimize impact to the environment as well as daily lives of the public. To contain the construction’s impact below the ground, most of the intakes shaft boring works will employ the use of raise boring machines which minimizes the disturbance at ground level. GE Division attendees were also introduced to state of the art monitoring systems being implemented at this project including the Tunnel Data Monitoring System (TDMS) and Permanent Scatterer Interferometric Synthetic Aperture Radar (PSInSAR).
There was a lively question and answer session after the presentations followed by a site visit to the Western Portal where cavern excavation works were in progress using non-blasting rock splitting techniques. The GE Division group also viewed the western portal slope stabilization works and temporary works construction for TBM launch. HKIE GE Division thanked Mr Clayton and Mr Sundstrom for their generous invitation and informative presentations and presented them with a souvenir.
At last, the group thanked Mr Clayton and Mr Sundstrom for their generous invitation and informative presentations. The organizer of the site visit, Ir David Sein presented a souvenir to DNJV.
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Ir David Sein presenting a souvenir to
Mr David Clayton (L) and Mr Sundstrom (R) |
Group photo of the delegation |
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| Schematic layout of DSD Hong Kong West Drainage Tunnel |
The Asia-Pacific Seminar on Geological Conservation and Sustainable Development
2008 which was jointly organized by the Geotechnical Division and YMC of the HKIE,
The Chinese University and the Association for Geoconservation Hong Kong, was successfully
held on 13 August 2008 at the Hong Kong Convention and Exhibition Centre. We had
the great honour to have invited Mr Edward T W Yau, JP, Secretary for the Environment
of the HKSAR Government as the Guest of Honour and to officiate the opening ceremony.
The prime objective of the seminar was to bring together local and overseas experts to impart on the geological conservation in consideration for the rising public concerns on sustainability. Four international speakers, Dr Patrick McKeever of the Geological Survey of Northern Ireland, Dr Werner Janoschek of the International Year of Planet Earth, Prof Anze Chen of the Chinese Academy of Geological Science and Prof Kuiyuan Tao of the Nanjing Institute of Geology and Mineral Resources, joined with six other local experts and professionals to discuss and share on the development of geological conservation as well as engineering and sustainability both in Hong Kong and throughout the world.
Particular interest of the seminar had been drawn to the merits of establishing geoparks, the balance between conservation and economic issue of a geosite, raising public awareness to the geological conservation through public engagement, the setting up of a geosite inventory and classification system and the application of geological sustainable concepts in local construction projects. Common vision was shared by all of the speakers on the importance of raising public awareness and educating the public on geological conservation as well as encouraging public appreciation on the geological beauties.
The seminar was concluded by a 45-minute discussion forum with enthusiastic audience bringing in wide range of questions and opinions towards the current status and future proceeding of geological conservation and sustainable development and how these could be applied in Hong Kong. All the technical papers on public education and geological conservation were published in the proceedings of the seminar. It was very encouraging to seeing this one-day seminar well received by near 200 local professionals as well as over 10 local media bodies.
The detailed activity report can be found here.
The prime objective of the seminar was to bring together local and overseas experts to impart on the geological conservation in consideration for the rising public concerns on sustainability. Four international speakers, Dr Patrick McKeever of the Geological Survey of Northern Ireland, Dr Werner Janoschek of the International Year of Planet Earth, Prof Anze Chen of the Chinese Academy of Geological Science and Prof Kuiyuan Tao of the Nanjing Institute of Geology and Mineral Resources, joined with six other local experts and professionals to discuss and share on the development of geological conservation as well as engineering and sustainability both in Hong Kong and throughout the world.
Particular interest of the seminar had been drawn to the merits of establishing geoparks, the balance between conservation and economic issue of a geosite, raising public awareness to the geological conservation through public engagement, the setting up of a geosite inventory and classification system and the application of geological sustainable concepts in local construction projects. Common vision was shared by all of the speakers on the importance of raising public awareness and educating the public on geological conservation as well as encouraging public appreciation on the geological beauties.
The seminar was concluded by a 45-minute discussion forum with enthusiastic audience bringing in wide range of questions and opinions towards the current status and future proceeding of geological conservation and sustainable development and how these could be applied in Hong Kong. All the technical papers on public education and geological conservation were published in the proceedings of the seminar. It was very encouraging to seeing this one-day seminar well received by near 200 local professionals as well as over 10 local media bodies.
The detailed activity report can be found here.
by Ir Dr Eric SF Li
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| Chairlady of YMC speaking at the Seminar | Group Photo of the Organising Committee |
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| Group Photo of all the Speakers |
Guest of Honour Mr Edward Yau
and the Chairman of the Seminar |
A foundation contract for a stormwater pumping station in Sheung Wan (SWSPS) was
commissioned by Drainage Services Department. A part of the contract required the
construction of a monolithic large-size base slab at 11m below ground surface at
the deepest location. To facilitate the deep excavation, the contractor was required
to design and construct an excavation and lateral support (ELS) retaining wall system.
The design aspects of the ELS were presented in a seminar held on 18 June 2008 by Ir Dr Eric Li, the Immediate past Chairman of the Geotechnical Division. In his presentation, he noted that the ELS design was complicated by the pumping station being located in closely to the seawall. Geotechnical challenges in the design included the presence of large size boulders below ground surface, high permeability of the rock and reclamation sand fills, and the soft marine deposits left un-dredged during the reclamation. The design also had to consider the nearby structures surrounding the site.
Dr Li presented the audiences the types of retaining walls that had been considered in the design and construction. In the process, the involvement of contractor and specialist contractor was important. A hydraulically push-in sheetpiling system was finally adopted. He opined that this kind of sheetpiling system would be suitable to conditions where tight vibration limit was required and he noted the ground settlements measured during the sheetpiling at SWSPS was relative small. Moreover, to overcome the large size boulder/rock obstruction, Dr Li showed the audiences how an innovative rock cutter had been used for the project. The audiences expressed keen interests in the system and were impressed by the quality of the completed sheetpile retaining wall.
To improve the ground and to provide an effective water cut-off curtain, the design adopted two types of grouting, namely the Tube-a-Manchet cement-bentonite grout and the jet grout. The former type of grouting was commonly used in Hong Kong for grouting soils of more granular nature. However, for more cohesive soils, the TAM grouting could only permeable to a limited distance and hence the use of jet grouting had to be used, which cuts insitu soft clay and mixes that with injected cement. The jet grout parameters adopted in the design and some precautionary measures to minimise ground disturbance were provided during the presentation. Dr Li noted particularly the importance on the quality control and the workmanship of the grouting in order to have successful results.
The seminar was well received with over 120 audiences attended and attracted considerable follow up questions.
The design aspects of the ELS were presented in a seminar held on 18 June 2008 by Ir Dr Eric Li, the Immediate past Chairman of the Geotechnical Division. In his presentation, he noted that the ELS design was complicated by the pumping station being located in closely to the seawall. Geotechnical challenges in the design included the presence of large size boulders below ground surface, high permeability of the rock and reclamation sand fills, and the soft marine deposits left un-dredged during the reclamation. The design also had to consider the nearby structures surrounding the site.
Dr Li presented the audiences the types of retaining walls that had been considered in the design and construction. In the process, the involvement of contractor and specialist contractor was important. A hydraulically push-in sheetpiling system was finally adopted. He opined that this kind of sheetpiling system would be suitable to conditions where tight vibration limit was required and he noted the ground settlements measured during the sheetpiling at SWSPS was relative small. Moreover, to overcome the large size boulder/rock obstruction, Dr Li showed the audiences how an innovative rock cutter had been used for the project. The audiences expressed keen interests in the system and were impressed by the quality of the completed sheetpile retaining wall.
To improve the ground and to provide an effective water cut-off curtain, the design adopted two types of grouting, namely the Tube-a-Manchet cement-bentonite grout and the jet grout. The former type of grouting was commonly used in Hong Kong for grouting soils of more granular nature. However, for more cohesive soils, the TAM grouting could only permeable to a limited distance and hence the use of jet grouting had to be used, which cuts insitu soft clay and mixes that with injected cement. The jet grout parameters adopted in the design and some precautionary measures to minimise ground disturbance were provided during the presentation. Dr Li noted particularly the importance on the quality control and the workmanship of the grouting in order to have successful results.
The seminar was well received with over 120 audiences attended and attracted considerable follow up questions.
by Ir Dr Eric SF Li
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| Sheetpiling by hydraulic push-in method | Excavation in progress at SWSPS |
The 5.12 earthquake in Sichuan (四川) killed nearly 70,000 lives and made devastating
damages.
On the request of Sowers Action, a charity organisation focusing on improving foundation education in poorer parts of China, the Geotechnical Division joined their field inspections in June and July 2008 to southern Gansu (甘肅); the area having very little media coverage and public attention but the damages being equally serious. Helps in rebuilding damaged schools were desperately needed. Our members provided valuable specialist engineering advice to assist them in evaluating funding applications and retrofitting damaged schools.
Several members of the division, including Eric Li, Albert Ho, Rupert Leung, Alex Ho, Tim Lai and Eddie Wong, volunteered to participate in the field missions and were separated into five working groups to visit different towns of Gansu. Amongst the various teams, the working group of our Immediate Past Chairman Eric Li was specially followed by the RTHK “HK Connection”(鏗鏘集). They left Hong Kong on 24 June 2008 and landed in Lanzhou (蘭州). They started the torturous land journey in early morning on 25 June and finally arrived the earthquake-damaged Wenxian (文縣), a town approximately 20km from Sichuan border, late on 26 June after some 14 hours of travelling on a 4-wheel drive jeep. On the way, they witnessed many damaged buildings, as well as many large scale landslide and debris flow trails. Also, they could experience the effects of several aftershocks, reported to be exceeding Richter scale 4.
On the way back to Lanzhou in treacherous rain, the group encountered life-threatening event. Their jeep was first stopped when the road ahead was completely blocked by a major debris flow occurred hours before. Noting that the debris would require considerable time to be cleared, they decided to retreat to the nearest village to take shelter. However, the backward journey was also stopped after 2km of travelling as the road was again blocked by falling rocks weighing over 30 tonnes occurred minutes ago. They were extremely lucky that they were not travelling pass the scenes at the times of debris or rock falling.
Members participated in the field inspections all considered the works being very meaningful and their experience would be presented to all HKIE members soon. It is expected that the collaborations of the Division with Sowers Action will continue. Members willing to help shall contact the Chairman of the Division.
On the request of Sowers Action, a charity organisation focusing on improving foundation education in poorer parts of China, the Geotechnical Division joined their field inspections in June and July 2008 to southern Gansu (甘肅); the area having very little media coverage and public attention but the damages being equally serious. Helps in rebuilding damaged schools were desperately needed. Our members provided valuable specialist engineering advice to assist them in evaluating funding applications and retrofitting damaged schools.
Several members of the division, including Eric Li, Albert Ho, Rupert Leung, Alex Ho, Tim Lai and Eddie Wong, volunteered to participate in the field missions and were separated into five working groups to visit different towns of Gansu. Amongst the various teams, the working group of our Immediate Past Chairman Eric Li was specially followed by the RTHK “HK Connection”(鏗鏘集). They left Hong Kong on 24 June 2008 and landed in Lanzhou (蘭州). They started the torturous land journey in early morning on 25 June and finally arrived the earthquake-damaged Wenxian (文縣), a town approximately 20km from Sichuan border, late on 26 June after some 14 hours of travelling on a 4-wheel drive jeep. On the way, they witnessed many damaged buildings, as well as many large scale landslide and debris flow trails. Also, they could experience the effects of several aftershocks, reported to be exceeding Richter scale 4.
On the way back to Lanzhou in treacherous rain, the group encountered life-threatening event. Their jeep was first stopped when the road ahead was completely blocked by a major debris flow occurred hours before. Noting that the debris would require considerable time to be cleared, they decided to retreat to the nearest village to take shelter. However, the backward journey was also stopped after 2km of travelling as the road was again blocked by falling rocks weighing over 30 tonnes occurred minutes ago. They were extremely lucky that they were not travelling pass the scenes at the times of debris or rock falling.
Members participated in the field inspections all considered the works being very meaningful and their experience would be presented to all HKIE members soon. It is expected that the collaborations of the Division with Sowers Action will continue. Members willing to help shall contact the Chairman of the Division.
by Ir Dr Eric SF Li
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| Sowers Action CEO getting interviewed | Debris flow blocking the road to Lanzhou |