scholarly journals The application of the strength reduction shortest path method to the stability analysis of shallow buried tunnel

2021 ◽  
Author(s):  
Wei Wang ◽  
Jiaqi Zhang ◽  
Ao Liu
Keyword(s):  
Stability Analysis ◽  
Internal Friction ◽  
Shortest Path ◽  
Limit Equilibrium ◽  
Friction Angle ◽  
Strength Reduction ◽  
Surrounding Rock ◽  
Internal Friction Angle ◽  
The Stability ◽  
Shallow Buried Tunnel

Abstract In order to improve the theoretical analysis of surrounding rock stability of shallow buried tunnel. The strength reduction shortest path theory is applied to the stability analysis of shallow buried tunnel surrounding rock, combined with the ultimate equilibrium strength reduction theory. We discussed the influence of the depth and span ratio of tunnel, cohesion, and internal friction angle on the shortest path of the strength reduction, and studied the effects of various factors on shallow buried tunnel safety relationship by using strength reduction factor of safety and the shortest path of the shallow buried tunnel surrounding rock and the grey relational analysis theory. The results show that: In the analysis of shallow buried tunnel in strength reduction, the approximate distribution obeys parabolic between reduction path length and the reduction ratio. When the strength reduction of cohesion is the shortest path the reduction rate is greater than the internal friction angle. The internal friction angle and cohesive force have a great influence on the stability of shallow tunnel under the method of shortest path of strength reduction. Finally, the comprehensive safety factor of shallow buried tunnel calculated by the finite element strength reduction shortest path method is greater than that calculated by the limit equilibrium method.

Stability Analysis of Dam Slope by Double Safety Factors of Dynamic Local Strength Reduction Method

2015 ◽  
Vol 744-746 ◽  
pp. 593-596
Author(s):  
Yuan Meng
Keyword(s):  
Internal Friction ◽  
Reduction Method ◽  
Failure Process ◽  
Friction Angle ◽  
Strength Reduction ◽  
Internal Friction Angle ◽  
Material Strength ◽  
Strength Reduction Method ◽  
Strength Parameters ◽  
Local Strength

When calculating the dam slope failure process, traditional strength reduction method doesn't consider the difference of decay rate between cohesion and internal friction angle and discount the strength parameters for all elements. This paper uses two different reduction factors for material strength parameters, slope cohesion and internal friction angle. Based on the yield approach index criterion, we change the reduction region in time and put forward a double safety factor of dynamic local strength reduction method for engineering analysis of dam slope stability.

scholarly journals A New Unified Solution for Circular Tunnels Based on Generalized SMP Criterion considering the Strain Softening and Dilatancy

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Qifeng Guo ◽  
Jiliang Pan ◽  
Xinghui Wu ◽  
Xun Xi ◽  
Meifeng Cai
Keyword(s):  
Internal Friction ◽  
Plastic Zone ◽  
Strain Softening ◽  
Friction Angle ◽  
Surrounding Rock ◽  
Internal Friction Angle ◽  
Plastic State ◽  
Circular Tunnel ◽  
Dilatancy Angle ◽  
Elastic Plastic

According to the strain-softening characteristics of rock mass, an ideal elastic strain-softening model is developed, and the surrounding rock of tunnels is subdivided into the plastic broken zone, plastic strain-softening zone, and elastic zone. Based on the generalized spatially mobilized plane criterion, an elastic-plastic analytical solution of a circular tunnel is derived. The effects of intermediate principal stress, strain softening, and dilatancy are considered in the unified solution. The stress, displacement, and plastic zone radius of surrounding rock based on the SMP criterion are compared with those based on the Mohr–Coulomb criterion. Furthermore, the effects of parameters such as the softening modulus, dilatancy angle, and internal friction angle on the deformation and stress of tunnels are discussed. It has been found that the larger the dilatancy angle is, the larger the plastic zone displacement and the radius of the broken zone are. The larger the internal friction angle, the smaller the sizes of the plastic zone, the strain-softening zone, and the broken zone are. The deformation of surrounding rock in the broken zone is more sensitive to the internal friction angle than that in the strain-softening zone. The unified solution based on the SMP criterion provides a well understanding for the elastic-plastic state of tunnels, which can be the guidance for tunnel excavations and support designs.

Study on the Development of Plastic Zone Based on Strain Expressed Mohr- Coulomb Yield Condition

2014 ◽  
Vol 580-583 ◽  
pp. 195-200
Author(s):  
Cai Yang ◽  
Tu Gen Feng
Keyword(s):  
Internal Friction ◽  
Plastic Zone ◽  
Poisson’S Ratio ◽  
Yield Condition ◽  
Friction Angle ◽  
Strength Reduction ◽  
Internal Friction Angle ◽  
Slope Instability ◽  
Poisson's Ratio ◽  
Material Parameters

At present, there is a lot of research for slope stability, the inherent reason of slope instability is geotechnical material will get plastic deformation under load. In this paper, Mohr- Coulomb yield condition is transformed strain expressed to stress expressed.Based on this, analysis the effects that geotechnical material parameters internal friction angle ,cohesion c and Poisson's ratio to Mohr- Coulomb yield condition and the development of soil plastic zone.In addition, using the strength reduction FEM simulating the change of plastic zone distribution caused by change of the geotechnical materials parameters .The results show that the internal friction angle , cohesion c are reducted, the plastic zone expand;Increasing the Poisson’s ratio , narrowing the slope’s plastic zone;Plastic zone’s different distribution is caused by different material parameters affect the yield surface.

Recovery Execution in Landslide at the Portal of Highway Tunnel

2011 ◽  
Vol 250-253 ◽  
pp. 1823-1826 ◽  
Author(s):  
Kai Wang ◽  
Hai Gui Kang ◽  
Hai Tao Wang
Keyword(s):  
Stability Analysis ◽  
Limit Equilibrium ◽  
Limit Equilibrium Method ◽  
Surrounding Rock ◽  
Landslide Stability ◽  
Highway Tunnel ◽  
Design Requirements ◽  
The Stability ◽  
Ground Condition

The main feature of NATM is to utilize all available means to develop the maximum self-supporting capacity of the surrounding rock or soil itself, and to undertake investigation and monitoring during construction to provide the stability of the tunnel. If undetected worse ground condition is encountered, the strengthening works will be carried out to ensure safety. In this case study, taking the Wangkeng tunnel portal engineering of the Jiyuan-Shaoyuan Expressway in Henan Province as an example, the calculation and evaluation of landslide stability are performed by limit equilibrium method and FEM. Based on the results of stability analysis, the anti-slide piles and ground drainage are adopted as the harnessing measures of landslide. Comparison of stability analysis before/after landslide harnesses was made by FEM. The results show that these treatments can satisfy the design requirements. It could be a useful reference to the design and construction of tunnels with soil entrance.

The Stability Analysis of Underwater Slopes Based on Strength Reduction Method

2011 ◽  
Vol 243-249 ◽  
pp. 2690-2693
Author(s):  
Lin Yan Li ◽  
Yin Liu ◽  
Hao Chen ◽  
Heng Bin Wu
Keyword(s):  
Rock Mass ◽  
Stability Analysis ◽  
Reduction Method ◽  
Limit Equilibrium ◽  
Limit Equilibrium Method ◽  
Strength Reduction ◽  
Strength Reduction Method ◽  
Equilibrium Method ◽  
Erosion Effect ◽  
The Stability

Present methods for stability analysis of underwater slopes are mostly confined to laboratory experiments and limit equilibrium method. This paper is based on strength reduction method, considering the deformation parameters of rock mass to discuss the stability of underwater slopes. Comparing the consequences, the sliding planes and safety factors agreed well with the result of limit equilibrium method. The applicability of strength reduction method for underwater slopes stability was well proved. When analyzing after changing the water depth, it was showed that there are more erosion effect induced and reduction for the parameters of rock mass, but little influence on the safety factor of underwater slopes.

scholarly journals Slope Stability Analysis of “Vorobyovy Gory” Landslide in Moscow

2019 ◽  
Vol 11 (2) ◽  
pp. 90-94
Author(s):  
D. Tao ◽  
O.S. Barykina ◽  
K. Kang
Keyword(s):  
Sensitivity Analysis ◽  
Stability Analysis ◽  
Internal Friction ◽  
Slope Stability ◽  
Limit Equilibrium ◽  
Soil Layer ◽  
Friction Angle ◽  
Limit Equilibrium Method ◽  
Mechanical Parameters ◽  
Moscow River

 There are many engineering-geological problems in Moscow, including seepage deformation, karst and landslide. Among them, landslides develop along the Moscow River and its branches. This paper aims to analyze the slope stability of “Vorobyovy Gory” landslide with the help of the program GeoStudio. According to the limit equilibrium method, we can know the slope stability. In addition, we can know the internal friction angle among in the physical and mechanical parameters of soil layer has the greatest influences on its stability by sensitivity analysis. Finally, we can get the probability of damage by probabilistic analysis.

scholarly journals Mechanism of Embankment Reinforced with Back Berm in Road Engineering

2014 ◽  
Vol 8 (1) ◽  
pp. 853-860
Author(s):  
Wang Qi-Hu
Keyword(s):  
Internal Friction ◽  
Lateral Displacement ◽  
Boundary Value ◽  
Friction Angle ◽  
Nonlinear Finite Element ◽  
Internal Friction Angle ◽  
Nonlinear Finite Element Method ◽  
Road Engineering ◽  
The Stability ◽  
Rock And Soil

Based on the nonlinear finite element method, the mechanism of embankment reinforced with back berm in road engineering reinforced has been studied. It is found there is almost no influence on the value of vertical settlement at the scope of original embankment by back berm. Only the vertical settlement under the location of back berm has been influenced lightly by back berm. The lateral displacement of embankment could be reduced or restrained by back berm. The stability of embankment enhanced when width of back berm enlarged. But the stability of embankment would not be increased any more when the width of back berm achieved its boundary value, so the width of back berm should not be bigger than the boundary value. The stability of embankment enhanced when the value of cohesion or internal friction angle of back berm increased. So rock and soil with big cohesion and internal friction angle should be used to fill back berm preferentially.

Stability Analysis of the Cutting Slope Considering the Influence of Water Content of Soil

2012 ◽  
Vol 204-208 ◽  
pp. 115-118 ◽  
Author(s):  
Qiang Ma ◽  
Heng Lin Xiao ◽  
Qi Zhi Hu ◽  
Li Hua Li
Keyword(s):  
Internal Friction ◽  
Water Content ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Safety Factors ◽  
Strength Parameters ◽  
Direct Shear Tests ◽  
Cutting Slope ◽  
Influence Of Water ◽  
The Stability

Based on the method of strength reduction, numerical simulations were carried out to analyze the stability of the cutting slope. The direct shear tests of slope soil samples with different water content were carried out, and the safety factors of stability of the cutting slope were investigated with different cohesions and internal friction angles. At last, displacements and safety factors of stability of the slope with drains and without drains were calculated, and the observations of displacement of the cutting slope in field were also carried out. The results show that: The water content of the slope soil has great effects on the strength parameters, the cohesion and the internal friction angle decrease with the increase of the water content, and the effect is more significant on the cohesion than that on the internal friction angle. The safety factor of stability for the slope increases with the increase of the strength parameters, hence it increases with the decrease of the water content. The section of the slope without drains in the field is unstable, while the section with drains maintains stable.

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