Face Stability Analysis of Rectangular Tunnels Driven by a Pressurized Shield

2011 ◽  
Vol 378-379 ◽  
pp. 461-465 ◽  
Author(s):  
Xiao Ming Tu ◽  
Yu You Yang ◽  
Gui He Wang
Keyword(s):  
Stability Analysis ◽  
Failure Mechanism ◽  
Upper Bound ◽  
Limit Analysis ◽  
Underground Space ◽  
Face Stability ◽  
Upper Bound Method ◽  
Analysis Theory ◽  
Development And Utilization ◽  
Rectangular Tunnel

With the development and utilization of underground space, some new tunnel forms are emerging, such as the rectangular tunnel, double tunnels, treble tunnels and so on. The aim of this paper is to determine the collapse face pressure of a rectangular tunnel driven by a pressurized shield. The calculation is based on the upper-bound method of the limit analysis theory. A translational kinematically admissible failure mechanism consists a sequence of truncated rigid cones are considered for the calculation schemes. The numerical results obtained by the calculation are presented.

Upper-bound solutions of three-dimensional passive earth pressures

2005 ◽  
Vol 42 (5) ◽  
pp. 1449-1460 ◽  
Author(s):  
S Škrabl ◽  
B Macuh
Keyword(s):  
Failure Mechanism ◽  
Upper Bound ◽  
Limit Analysis ◽  
Central Body ◽  
Three Dimensional ◽  
Failure Surface ◽  
Outer Side ◽  
Soil Pressure ◽  
Upper Bound Method ◽  
The Cross

This paper presents a novel approach to the determination of passive soil pressures: using the upper-bound method within the framework of limit analysis theory. It is based on a three-dimensional, kinematically admissible, rotational, hyperbolical failure mechanism. The failure mechanism is composed of the central and two lateral bodies, which are connected by a common velocity field. This approach is similar to two-dimensional stability analyses, where the log spiral potential failure surface is considered. The front surface of the central body interacts with the retaining wall; the upper surface can be loaded by surcharge loading; and the log spiral segment defines the curved failure surface of the central part. The cross sections of the lateral bodies are in agreement with the cross section of the central body. On the outer side, they are laterally bounded by a curved and kinematically admissible hyperbolic surface, which is defined by enveloping the hyperbolical half cones and part of the case surface of the leading half cone. The results give values for the passive soil pressure coefficients that are for most cases lower than the values determined by the upper-bound method of limit analysis for a translational failure mechanism, as published in the literature.Key words: limit analysis, earth pressure, passive pressure, failure surface, soil–structure interaction.

scholarly journals Static and seismic passive earth pressure coefficients on rigid retaining structures

2000 ◽  
Vol 37 (2) ◽  
pp. 463-478 ◽  
Author(s):  
A -H Soubra
Keyword(s):  
Failure Mechanism ◽  
Upper Bound ◽  
Limit Analysis ◽  
Earth Pressure ◽  
Numerical Results ◽  
Passive Earth Pressure ◽  
Pressure Coefficients ◽  
Passive Pressure ◽  
Analysis Theory ◽  
Earthquake Effects

The passive earth pressure problem is investigated by means of the kinematical method of the limit analysis theory. A translational kinematically admissible failure mechanism composed of a sequence of rigid triangles is proposed. This mechanism allows the calculation of the passive earth pressure coefficients in both the static and seismic cases. Quasi-static representation of earthquake effects using the seismic coefficient concept is adopted. Rigorous upper-bound solutions are obtained in the framework of the limit analysis theory. The numerical results of the static and seismic passive earth pressure coefficients are presented and compared with the results of other authors.Key words: limit analysis, passive pressure, earthquake.

Three-dimensional face stability analysis of shallow tunnels using numerical limit analysis and material point method

2021 ◽  
Vol 112 ◽  
pp. 103904
Author(s):  
Fabricio Fernández ◽  
Jhonatan E.G. Rojas ◽  
Eurípedes A. Vargas ◽  
Raquel Q. Velloso ◽  
Daniel Dias
Keyword(s):  
Stability Analysis ◽  
Limit Analysis ◽  
Three Dimensional ◽  
Material Point Method ◽  
Material Point ◽  
Point Method ◽  
Face Stability ◽  
Shallow Tunnels ◽  
Dimensional Face

scholarly journals Comparative study of material point method and upper bound limit analysis in slope stability analysis

2020 ◽  
Vol 2 (1) ◽  
pp. 44-57
Author(s):  
Lianheng Zhao ◽  
Nan Qiao ◽  
Zhigang Zhao ◽  
Shi Zuo ◽  
Xiang Wang
Keyword(s):  
Stability Analysis ◽  
Upper Bound ◽  
Limit Analysis ◽  
Slope Failure ◽  
Slip Surface ◽  
Material Point Method ◽  
Material Point ◽  
Critical Slip Surface ◽  
The Stability ◽  
Upper Bound Limit Analysis

Abstract The upper bound limit analysis (UBLA) is one of the key research directions in geotechnical engineering and is widely used in engineering practice. UBLA assumes that the slip surface with the minimum factor of safety (FSmin) is the critical slip surface, and then applies it to slope stability analysis. However, the hypothesis of UBLA has not been systematically verified, which may be due to the fact that the traditional numerical method is difficult to simulate the large deformation. In this study, in order to systematically verify the assumption of UBLA, material point method (MPM), which is suitable to simulate the large deformation of continuous media, is used to simulate the whole process of the slope failure, including the large-scale transportation and deposition of soil mass after slope failure. And a series of comparative studies are conducted on the stability of cohesive slopes using UBLA and MPM. The proposed study indicated that the slope angle, internal friction angle and cohesion have a remarkable effect on the slip surface of the cohesive slope. Also, for stable slopes, the calculation results of the two are relatively close. However, for unstable slopes, the slider volume determined by the UBLA is much smaller than the slider volume determined by the MPM. In other words, for unstable slopes, the critical slip surface of UBLA is very different from the slip surface when the slope failure occurs, and when the UBLA is applied to the stability analysis of unstable slope, it will lead to extremely unfavorable results.

scholarly journals Upper-Bound Multi-Rigid-Block Solutions for Seismic Performance of Slopes with a Weak Thin Layer

2017 ◽  
Vol 2017 ◽  
pp. 1-11
Author(s):  
Gang Zheng ◽  
Xinyu Yang ◽  
Haizuo Zhou ◽  
Da Ha ◽  
Tianqi Zhang
Keyword(s):  
Thin Layer ◽  
Failure Mechanism ◽  
Seismic Performance ◽  
Upper Bound ◽  
Limit Analysis ◽  
Slope Angle ◽  
Rigid Block ◽  
Acceleration Coefficient ◽  
Critical Yield ◽  
Yield Acceleration

The presence of a weak layer has an adverse influence on the seismic performance of slopes. The upper-bound solution serves as a rigorous method in the stability analysis of geotechnical problems. In this study, a multi-rigid-block solution based on the category of the upper-bound theorem of limit analysis is presented to examine the seismic performance of nonhomogeneous slopes with a weak thin layer. Comparison of the static factors of safety is conducted with various solutions (i.e., limit analysis with a different failure mechanism, limit equilibrium solution, and numerical method), and the results exhibit reasonable consistency. An analytical solution in estimating the critical yield acceleration coefficient is derived, and the influence of slope angle, slope height, and soil strength on the critical yield acceleration coefficient and failure mechanism is analyzed. Subsequently, Newmark’s analytical procedure is employed to evaluate cumulative displacement with various real earthquake acceleration records as input motion. Results show that the strength and geometric parameters have a remarkable influence on the critical yield acceleration coefficient, and the cumulative displacement increases with the increasing slope angle.

scholarly journals Upper Bound Solution for the Face Stability of Shield Tunnel below the Water Table

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Xilin Lu ◽  
Haoran Wang ◽  
Maosong Huang
Keyword(s):  
Upper Bound ◽  
Limit Analysis ◽  
Fe Simulation ◽  
Shield Tunnel ◽  
Support Pressure ◽  
Seepage Force ◽  
Tunnel Face ◽  
Face Stability ◽  
The Face ◽  
Upper Bound Limit Analysis

By FE simulation with Mohr-Coulomb perfect elastoplasticity model, the relationship between the support pressure and displacement of the shield tunnel face was obtained. According to the plastic strain distribution at collapse state, an appropriate failure mechanism was proposed for upper bound limit analysis, and the formula to calculate the limit support pressure was deduced. The limit support pressure was rearranged to be the summation of soil cohesionc, surcharge loadq, and soil gravityγmultiplied by their corresponding coefficientsNc,Nq, andNγ, and parametric studies were carried out on these coefficients. In order to consider the influence of seepage on the face stability, the pore water pressure distribution and the seepage force on the tunnel face were obtained by FE simulation. After adding the power of seepage force into the equation of the upper bound limit analysis, the total limit support pressure for stabilizing the tunnel face under seepage condition was obtained. The total limit support pressure was shown to increase almost linearly with the water table.

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