CHINA will propose the inscription of karst landscapes in Wulong County （Chongqing Municipality）, Libo County （Guizhou Province） and Shilin City （Yunnan Province） on the prestigious World Heritage List during th...CHINA will propose the inscription of karst landscapes in Wulong County （Chongqing Municipality）, Libo County （Guizhou Province） and Shilin City （Yunnan Province） on the prestigious World Heritage List during the 31st UNESCO World Heritage Comittee session in Christchurch, New Zealand, from June 23 to July 2.展开更多
In the design of shield tunnels,it is expected that a design can be more economical as more site investigation data are available.Nev-ertheless,the cost of site investigation will also increase as more site investigat...In the design of shield tunnels,it is expected that a design can be more economical as more site investigation data are available.Nev-ertheless,the cost of site investigation will also increase as more site investigation data are required.It is thus important to assess the potential benefit of a site investigation program before it is conducted considering the uncertainty in the soil properties and the site inves-tigation outcomes.In this paper,a probabilistic framework is suggested to assess the effectiveness of a site investigation program for the design of shield tunnels through the random field theory.An efficient method based on the generalized extreme value distribution is used to calculate the failure probability of the tunnel,through which the expected benefit from a site investigation program can be estimated conveniently.The result shows that a site investigation program is more valuable when a greater target design reliability index is needed.The expected benefit from a site investigation program increases as the borehole intensity increases,and it also increases as the scale of fluctuation of the soil properties increases.The method suggested in this paper provides a useful tool for planning borehole layout for the design of shield tunnels,which is promising for the optimization of site investigation.展开更多
文摘CHINA will propose the inscription of karst landscapes in Wulong County （Chongqing Municipality）, Libo County （Guizhou Province） and Shilin City （Yunnan Province） on the prestigious World Heritage List during the 31st UNESCO World Heritage Comittee session in Christchurch, New Zealand, from June 23 to July 2.
基金supported by the National Key Research and Development Program of China(Grant No.2021YFB2600500)the National Natu-ral Science Foundation of China(Grant No.42072302),and the Fundamental Research Funds for the Central Universities.
文摘In the design of shield tunnels,it is expected that a design can be more economical as more site investigation data are available.Nev-ertheless,the cost of site investigation will also increase as more site investigation data are required.It is thus important to assess the potential benefit of a site investigation program before it is conducted considering the uncertainty in the soil properties and the site inves-tigation outcomes.In this paper,a probabilistic framework is suggested to assess the effectiveness of a site investigation program for the design of shield tunnels through the random field theory.An efficient method based on the generalized extreme value distribution is used to calculate the failure probability of the tunnel,through which the expected benefit from a site investigation program can be estimated conveniently.The result shows that a site investigation program is more valuable when a greater target design reliability index is needed.The expected benefit from a site investigation program increases as the borehole intensity increases,and it also increases as the scale of fluctuation of the soil properties increases.The method suggested in this paper provides a useful tool for planning borehole layout for the design of shield tunnels,which is promising for the optimization of site investigation.
