Rainfall induced shallow landslides are known to be extremely dangerous since the sliding mass can propagate quickly and travel far from the source. Although the sliding mechanism in sloping ground is simple to unders...Rainfall induced shallow landslides are known to be extremely dangerous since the sliding mass can propagate quickly and travel far from the source. Although the sliding mechanism in sloping ground is simple to understand, the problem may be complicated by unsaturated transient water flow. The flow behavior of rainwater in unsaturated sloping ground and the consequent factor of safety must be clearly understood to assess slope stability under rainfall conditions. A series of laboratory experiments was conducted to examine the critical hydrological states so that assessment of slope stability under rainfall condition can be performed. Based on the test results, a unique relationship between critical hydrological states, rainfall intensity, and soil properties was formulated. Sequential stability analysis provided insights into the stability of slopes subjected to variations in soil properties, slope angles and rainfall intensities, and the consequent variation in the depth of the failure plane, vital in landslide risk assessment, was determined through this analysis.The variation of rainfall intensity was found to strongly affect the depth of the failure plane in cohesionless sloping ground. Furthermore, the influence of rainfall intensity on the depth of the failure plane may be alleviated by a small magnitude of cohesive strength. The results of this study will reinforce knowledge of landslide behavior and help to improve mitigation measures in susceptible areas.展开更多
This paper presents an analysis of a tunnel failure accident during shield tunnel construction on Foshan Metro Line 2 in China.The failure is caused by the leakage of the multilayer seal system,which consists of sever...This paper presents an analysis of a tunnel failure accident during shield tunnel construction on Foshan Metro Line 2 in China.The failure is caused by the leakage of the multilayer seal system,which consists of several brush seals at the tail of the shield.Four different failure modes for the multilayer seal system are discussed.A simple structural analysis of the brush seals is then conducted,and failure mode 4(failure due to brush seal deformation)is identified as a major reason for the Foshan tunnel accident.A finite element method(FEM)analysis is employed to validate the conclusions drawn from the simple structural analysis of the brush seals.展开更多
This paper presents a case study on groundwater control and environmental protection during a deep excavation of the foundation pit for the Liyang Road Station of Metro Line 10 in Shanghai.A three-dimensional finite e...This paper presents a case study on groundwater control and environmental protection during a deep excavation of the foundation pit for the Liyang Road Station of Metro Line 10 in Shanghai.A three-dimensional finite element simulation model was constructed to quantify the effects of a dewatering process on the environment around the excavation pit.To understand the decrease in the groundwater level around the foundation pit,the ground settlement and groundwater level were studied.During the excavation,environmental protection methods were used in the design of the optimal watering system to check its detrimental environmental effects.The effects of the diaphragm wall and horizontal barrier system were analyzed by varying their insertion depths and the resulting changes in the ground settlement and groundwater level were studied.It was found that increasing the insertion depth of the diaphragm wall reduced settlement near the excavation site but increased the construction costs.The diaphragm wall used in combination with a horizontal barrier was found to be effective in arresting the decrease in groundwater level and reducing settlement around the excavation site.展开更多
基金the financial support from the Thailand Research Fund under the TRF Senior Research Scholar program (Grant No. RTA6080055)Suranaree University of Technologythe Office of Higher Education Commission under NRU project of Thailand
文摘Rainfall induced shallow landslides are known to be extremely dangerous since the sliding mass can propagate quickly and travel far from the source. Although the sliding mechanism in sloping ground is simple to understand, the problem may be complicated by unsaturated transient water flow. The flow behavior of rainwater in unsaturated sloping ground and the consequent factor of safety must be clearly understood to assess slope stability under rainfall conditions. A series of laboratory experiments was conducted to examine the critical hydrological states so that assessment of slope stability under rainfall condition can be performed. Based on the test results, a unique relationship between critical hydrological states, rainfall intensity, and soil properties was formulated. Sequential stability analysis provided insights into the stability of slopes subjected to variations in soil properties, slope angles and rainfall intensities, and the consequent variation in the depth of the failure plane, vital in landslide risk assessment, was determined through this analysis.The variation of rainfall intensity was found to strongly affect the depth of the failure plane in cohesionless sloping ground. Furthermore, the influence of rainfall intensity on the depth of the failure plane may be alleviated by a small magnitude of cohesive strength. The results of this study will reinforce knowledge of landslide behavior and help to improve mitigation measures in susceptible areas.
基金The research work described herein was funded by the National Basic Research Program of China(973 Program:2015CB057806).This financial support is gratefully acknowledged.
文摘This paper presents an analysis of a tunnel failure accident during shield tunnel construction on Foshan Metro Line 2 in China.The failure is caused by the leakage of the multilayer seal system,which consists of several brush seals at the tail of the shield.Four different failure modes for the multilayer seal system are discussed.A simple structural analysis of the brush seals is then conducted,and failure mode 4(failure due to brush seal deformation)is identified as a major reason for the Foshan tunnel accident.A finite element method(FEM)analysis is employed to validate the conclusions drawn from the simple structural analysis of the brush seals.
基金This research was funded by the Innovative Research Funding of the Science and Technology Commission of Shanghai Municipality(Grant No.18DZ1201102).This financial support is greatly appreciated.
文摘This paper presents a case study on groundwater control and environmental protection during a deep excavation of the foundation pit for the Liyang Road Station of Metro Line 10 in Shanghai.A three-dimensional finite element simulation model was constructed to quantify the effects of a dewatering process on the environment around the excavation pit.To understand the decrease in the groundwater level around the foundation pit,the ground settlement and groundwater level were studied.During the excavation,environmental protection methods were used in the design of the optimal watering system to check its detrimental environmental effects.The effects of the diaphragm wall and horizontal barrier system were analyzed by varying their insertion depths and the resulting changes in the ground settlement and groundwater level were studied.It was found that increasing the insertion depth of the diaphragm wall reduced settlement near the excavation site but increased the construction costs.The diaphragm wall used in combination with a horizontal barrier was found to be effective in arresting the decrease in groundwater level and reducing settlement around the excavation site.
