Analysis on the safe distance between shield tunnel through sand stratum and underlying karst cave

2018 ◽  
Vol 22 (2) ◽  
pp. 81-90 ◽  
Author(s):  
Wei Wang ◽  
Shiming Gao ◽  
Lingfeng Liu ◽  
Wushuang Wen ◽  
Ping Li ◽  
...  
Keyword(s):  
Shield Tunnel ◽  
Karst Cave ◽  
Safe Distance ◽  
Sand Stratum

Numerical Simulation of Safe Distance between Concealed Karst Cave and Tunnel Based on Shear Strength Reduction Method Safety Factor Catastrophe

2014 ◽  
Vol 501-504 ◽  
pp. 1753-1756
Author(s):  
Yong Biao Lai ◽  
Mang Shu Wang ◽  
Xin Hua You
Keyword(s):  
Numerical Simulation ◽  
Safety Factor ◽  
Reduction Method ◽  
Strength Reduction ◽  
Karst Cave ◽  
Strength Reduction Method ◽  
Safe Distance ◽  
Shear Strength Reduction Method ◽  
Concealed Karst Cave ◽  
Shear Strength Reduction

The numerical simulation method of safe distance between concealed karst cave and tunnel based on shear strength reduction method safety factor catastrophe is proposed. The safety factor of different distance between concealed karst cave and tunnel can be obtained using strength reduction finite element method numerical calculation with the finite element solution non convergence as the standard rock damage, then compare the safety factor of different distance, the catastrophe of safety factor corresponding to the distance is the safe distance between concealed karst cave and tunnel, and the plastic zone of rock stratum between concealed karst cave and tunnel is reaching run-through state, which is verified by engineering example.

Predicting Model of Safe Distance between Tunnel and Karst Cave

2013 ◽  
Vol 470 ◽  
pp. 862-865
Author(s):  
Yong Biao Lai ◽  
Meng Shu Wang ◽  
Cheng Uang Bai
Keyword(s):  
Poisson Ratio ◽  
Pressure Coefficient ◽  
Influence Factors ◽  
Friction Angle ◽  
Support Vector ◽  
Karst Cave ◽  
Safe Distance ◽  
Predicting Model ◽  
Rock Density ◽  
Concealed Karst Cave

A method of predicting safe distance between tunnel and karst cave based on support vector machine was proposed, 10 parameters (rock density,elasticity modulusE, poisson ratio, friction angle, cohesionC, lateral pressure coefficient , the karst cave spanL,rate between height and span of the Karst caveR, tunnel deepH,cave position) were chosen for safe distance influence factors, then an intelligent predicting model of safe distance between tunnel and karst cave was built, this predicting model can predict 7 kinds position of safe distance between tunnel and concealed karst cave and was feasible and high prediction precision, which was verified by engineering example.

Research of Safe Distance between Concealed Karst Cave and Tunnel

2013 ◽  
Vol 405-408 ◽  
pp. 1283-1287
Author(s):  
Yong Biao Lai ◽  
Chun Sheng Qiao ◽  
Chen Guang Bai
Keyword(s):  
Catastrophe Theory ◽  
Total Potential Energy ◽  
Karst Cave ◽  
Safe Distance ◽  
Rock Stratum ◽  
Distance Calculation ◽  
Total Potential ◽  
Concealed Karst Cave ◽  
The Stability ◽  
Rock Strata

Based on the catastrophe theory, a research method of safe distance between concealed karst cave and tunnel is put forward. The stability of rock stratum between concealed karst cave and tunnel is evaluated by the catastrophe theory, the catastrophe mode of rock strata system destabilization is established through the research of rock stratum total potential energy between karst cave and tunnel, then the safe distance calculation formula between concealed karst cave and tunnel are deduced, which is veried by an engineering example.

Study of Safe Distance Criterion between Concealed Karst Cave and Tunnel

2014 ◽  
Vol 556-562 ◽  
pp. 849-852 ◽  
Author(s):  
Yong Biao Lai ◽  
Meng Shu Wang ◽  
Xin Hua You
Keyword(s):  
Surrounding Rock ◽  
Karst Cave ◽  
Instability Mechanism ◽  
Safe Distance ◽  
Rock Stratum ◽  
Safety Coefficient ◽  
Concealed Karst Cave ◽  
Comparison And Analysis ◽  
Simulation Results ◽  
The Stability

On the basis of analysis of the stability criterion of surrounding rock and instability mechanism of the rock stratum between concealed karst cave and tunnel, the rock stratum energy catastrophe and safety coefficient catastrophe as safe distance criterion between concealed karst cave and tunnel were put forward, then the comparison and analysis of numerical simulation results based on the run-through of plastic zone criterion, energy catastrophe criterion and safety coefficient catastrophe criterion were carried out with engineering examples, the results showed that energy catastrophe criterion was more reasonable.

scholarly journals Prediction of the Collapse Region Induced by a Concealed Karst Cave above a Deep Highway Tunnel

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Fu Huang ◽  
Di Wang ◽  
Yuan Feng ◽  
Min Zhang
Keyword(s):  
Rock Mass ◽  
Karst Cave ◽  
Favorable Result ◽  
Safe Distance ◽  
Upper Bound Theorem ◽  
Analytical Expression ◽  
Highway Tunnel ◽  
Concealed Karst Cave ◽  
Collapse Region ◽  
Minimum Safe Distance

The presence of a concealed karst cave above a deep highway tunnel may cause the collapse of the rock mass between the karst cave and tunnel during excavation. Rock mass collapse threatens the safety of tunnel construction personnel. A prediction method of the collapse region induced by a concealed karst cave above a deep highway tunnel is proposed on the basis of the upper bound theorem of limit analysis. An analytical expression of the collapse surface is derived from the variational principle. Using the analytical expression of the collapse surface, the shapes of the collapse surfaces are plotted for different rock mass parameters. Moreover, the minimum safe distance between the karst cave and tunnel is defined, and the computational equation of the minimum safe distance is derived. The proposed method is applied in a highway tunnel excavated in a karst terrain as a case study. Based on geological survey report parameters, the shape of the collapse surface and the minimum safe distance between the karst cave and tunnel are obtained. Finally, the collapse surface of the rock mass provided by the proposed approach is compared with that provided by numerical simulation, and the favorable result comparison shows that the proposed method is valid.

scholarly journals Pore Water Pressure Responses in Sand Stratum during Shield Tunnelling: A Case Study

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Yu Liang ◽  
Yufei Xiao ◽  
Yuexiang Lin
Keyword(s):  
Pore Water ◽  
Large Scale ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Fine Sand ◽  
Element Model ◽  
Shield Tunnel ◽  
Support Pressure ◽  
Shield Tunnelling ◽  
Sand Stratum

When shield tunnelling is in a water-rich sand stratum with poor bearing capacity, instability is easily generated, and even ground collapses may occur. The variation of pore water pressure in a water-rich sand stratum during shield tunnelling was analyzed based on a large-scale cross-river shield tunnel in China, which was also investigated by a three-dimensional fluid-solid coupling finite element model. The results show that the influence range of the pore water pressure in front of the excavation face is approximately 2.0 times the excavation diameter and 1.5 times on both sides of the shield. The tunnelling steps would cause obvious variation in the pore water pressure and lead to great disturbance to the surrounding fine sand stratum. The quality of filter cake and the set of support pressure imposes an important impact on the nonlinear variation in the pore pressure, which could cause great disturbance to the stratum. To ensure the safety of the subsequent tunnelling in the fine sand layer, effective treatment should be taken.

Numerical Simulation Method of Safe Distance between Concealed Karst Cave and Tunnel Based on Energy Catastrophe

2013 ◽  
Vol 353-356 ◽  
pp. 1470-1474
Author(s):  
Yong Biao Lai ◽  
Meng Shu Wang ◽  
Cheng Guang Bai
Keyword(s):  
Numerical Simulation ◽  
Catastrophe Theory ◽  
Simulation Method ◽  
Karst Cave ◽  
Safe Distance ◽  
Rock Stratum ◽  
Catastrophe Model ◽  
Numerical Simulation Method ◽  
Concealed Karst Cave ◽  
Distance Change

Stability of rock stratum between concealed karst cave and tunnel is evaluated by the catastrophe theory. The numerical simulation method of safe distance between concealed karst cave and tunnel is proposed based on catastrophe theory energy catastrophe. Through array of rock stratum energy change and distance change between concealed karst cave and tunnel, a cusp catastrophe model of safe distance between concealed karst cave and tunnel is built. The simulation of safe distance between concealed karst cave and tunnel can be finished by Ansys program and Matlab, and automatically calculates the safe distance by a compile interface program, which is verified by engineering example.

scholarly journals Karst cave treatment technology for a subsea shield tunnel

2021 ◽  
Vol 861 (7) ◽  
pp. 072111
Author(s):  
Shuobiao Li ◽  
Wenqi Ding ◽  
Yitao He ◽  
Qingzhao Zhang
Keyword(s):  
Shield Tunnel ◽  
Karst Cave ◽  
Treatment Technology
Sign in / Sign up

Export Citation Format

Share Document