An attribute recognition model for safe thickness assessment between a concealed karst cave and a tunnel is established based on the attribute mathematic theory.The model can be applied to carrying out risk classifica...An attribute recognition model for safe thickness assessment between a concealed karst cave and a tunnel is established based on the attribute mathematic theory.The model can be applied to carrying out risk classification of the safe thickness between a concealed karst cave and a tunnel and to guarantee construction’s safety in tunnel engineering.Firstly,the assessment indicators and classification standard of safe thickness between a concealed karst cave and a tunnel are studied based on the perturbation method.Then some attribute measurement functions are constructed to compute the attribute measurement of each single index and synthetic attribute measurement.Finally,the identification and classification of risk assessment of safe thickness between a concealed karst cave and a tunnel are recognized by the confidence criterion.The results of two engineering application show that the evaluation results agree well with the site situations in construction.The results provide a good guidance for the tunnel construction.展开更多
A section of the Nanliang high speed railway tunnel on Shijiazhuang-Taiyuan high-speed passenger railway line in China was instrumented and studied for its mechanical properties and performances. The cross section for...A section of the Nanliang high speed railway tunnel on Shijiazhuang-Taiyuan high-speed passenger railway line in China was instrumented and studied for its mechanical properties and performances. The cross section for the tunnel was300 m2and is classified as the largest cross section for railway tunnels in China. Through in situ experimental studies, mechanistic properties of the tunnel were identified, including the surrounding rock pressure, convergences along tunnel perimeter and safety of primary support and lining structure.Based on the field measured data, the surrounding rock pressure demand for large-span deep tunnel in hard rock is recommended as double peak type in the vertical direction and fold line type was recommended for horizontal pressure. The results suggested that Promojiyfakonov's theory was most close to the monitored value. Specific recommendations were also generated for the use of bolts in tunnel structures.Numerical simulation was used to evaluate the safety of the tunnel and it confirmed that the current design can satisfy the requirement of the current code.展开更多
The objective of this work is to obtain the seismic safety coefficient and fracture surface and proceed with the seismic safety evaluation for the rock mass or soil mass surrounding a tunnel,and the limitation of eval...The objective of this work is to obtain the seismic safety coefficient and fracture surface and proceed with the seismic safety evaluation for the rock mass or soil mass surrounding a tunnel,and the limitation of evaluating seismic stability is considered using the pseudo-static strength reduction.By using the finite element software ANSYS and the strength reduction method,new methods of seismic safety evaluation for the rock mass or soil mass surrounding a tunnel are put forward,such as the dynamic finite element static shear strength reduction method and dynamic finite element shear strength reduction method.In order to prove the feasibility of the proposed methods,the results of numerical examples are compared with that of the pseudo-static strength reduction method.The results show that 1) the two methods are both feasible,and the plastic zone first appears near the bottom corners; 2) the safety factor of new method Ⅱ is smaller than that of new method I but generally,and the difference is very small.Therefore,in order to ensure the safety of the structure,two new methods are proposed to evaluate the seismic stability of the rock mass or soil mass surrounding a tunnel.A theoretical basis is provided for the seismic stability of the rock mass or soil mass and the lining surrounding a tunnel and also provided for the engineering application.展开更多
基金Projects(51509147,51879153) supported by the National Natural Science Foundation of ChinaProjects(2017JC002,2017JC001) supported by the Fundamental Research Funds of Shandong University,China
文摘An attribute recognition model for safe thickness assessment between a concealed karst cave and a tunnel is established based on the attribute mathematic theory.The model can be applied to carrying out risk classification of the safe thickness between a concealed karst cave and a tunnel and to guarantee construction’s safety in tunnel engineering.Firstly,the assessment indicators and classification standard of safe thickness between a concealed karst cave and a tunnel are studied based on the perturbation method.Then some attribute measurement functions are constructed to compute the attribute measurement of each single index and synthetic attribute measurement.Finally,the identification and classification of risk assessment of safe thickness between a concealed karst cave and a tunnel are recognized by the confidence criterion.The results of two engineering application show that the evaluation results agree well with the site situations in construction.The results provide a good guidance for the tunnel construction.
基金sponsored by projects (Grant Nos. 50978172, 51078318) of the National Natural Science Foundation of ChinaProject (Grant No. 10-0667) supposed by the New Century Excellent Talents in University
文摘A section of the Nanliang high speed railway tunnel on Shijiazhuang-Taiyuan high-speed passenger railway line in China was instrumented and studied for its mechanical properties and performances. The cross section for the tunnel was300 m2and is classified as the largest cross section for railway tunnels in China. Through in situ experimental studies, mechanistic properties of the tunnel were identified, including the surrounding rock pressure, convergences along tunnel perimeter and safety of primary support and lining structure.Based on the field measured data, the surrounding rock pressure demand for large-span deep tunnel in hard rock is recommended as double peak type in the vertical direction and fold line type was recommended for horizontal pressure. The results suggested that Promojiyfakonov's theory was most close to the monitored value. Specific recommendations were also generated for the use of bolts in tunnel structures.Numerical simulation was used to evaluate the safety of the tunnel and it confirmed that the current design can satisfy the requirement of the current code.
基金Project(2011CB013600) supported by State Key Program for Basic Research of ChinaProject(20136201110003) supported by the Education Ministry Doctoral Tutor Foundation of China+1 种基金Project(51368039) supported by the National Natural Science Foundation of ChinaProject(2013-4-94) supported by the Program of Science and Technology Research in Lanzhou City,China
文摘The objective of this work is to obtain the seismic safety coefficient and fracture surface and proceed with the seismic safety evaluation for the rock mass or soil mass surrounding a tunnel,and the limitation of evaluating seismic stability is considered using the pseudo-static strength reduction.By using the finite element software ANSYS and the strength reduction method,new methods of seismic safety evaluation for the rock mass or soil mass surrounding a tunnel are put forward,such as the dynamic finite element static shear strength reduction method and dynamic finite element shear strength reduction method.In order to prove the feasibility of the proposed methods,the results of numerical examples are compared with that of the pseudo-static strength reduction method.The results show that 1) the two methods are both feasible,and the plastic zone first appears near the bottom corners; 2) the safety factor of new method Ⅱ is smaller than that of new method I but generally,and the difference is very small.Therefore,in order to ensure the safety of the structure,two new methods are proposed to evaluate the seismic stability of the rock mass or soil mass surrounding a tunnel.A theoretical basis is provided for the seismic stability of the rock mass or soil mass and the lining surrounding a tunnel and also provided for the engineering application.
