Stability Analysis of Narrow and Long Excavation in Soft Soil Area

2015 ◽  
Vol 723 ◽  
pp. 372-376
Author(s):  
Shi Chong Zhou ◽  
Li Li Gao ◽  
Dong Hui Wu ◽  
Yang Liu ◽  
Dong Yue Wang ◽  
...  

At the present stage of excavation design,the embedded depth of braced structure should meet the requirement of circular sliding stability when the bottom is soft soil. By increasing the embedded depth of support structure, the requirements of stability could be meet. In the normal design, the support structure must penetrate the soft soil layer when the bottom exist soft soil. While when the excavation is narrow and long, because of the obviously spatial effect, there is no need to determine the embedded depth based on the general circular sliding stability. In this paper, based on one the project example, calculate and analyze the similar stability using strength reduction method through the finite element software Plaxis and Midas.

2013 ◽  
Vol 639-640 ◽  
pp. 593-597
Author(s):  
Lin Chen ◽  
Yong Yao ◽  
Jiong Yang ◽  
Zhao Qiang Zhang

According to finite element strength reduction method,the article has discussed the failure mechanism of anti-sliding pile by using finite element software MIDAS /GTS ,exploration report and anti-sliding pile design data.The comparative analysis shows that the failure of anti-siding pile is contributed by the slope excavation and rainwater.The analysis method and results can provide reference significance to other anti-sliding pile design.This paper also provide a feasible method for prediction of consequence in slope excavation.


2014 ◽  
Vol 580-583 ◽  
pp. 805-811
Author(s):  
Mao Yin Shi ◽  
Fu Gui Song

A synthesized investigation is conducted of trench formation machine’s effect on trench wall in soft soil area. The failure pattern of the slurry-trench is analyzed by means of 3D FEM based on strength reduction method. The investigation shows that the global instibility occurs in the superficial layers and speads along the trench segment. The grab movement in slurry has an instant impact on the trench wall and may cause local instability. The overload and construction technique of trench formation equipment are both important concerns during trench construction to ensure safetry.


2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Li Wang ◽  
Shimei Wang ◽  
Gao Li ◽  
Lin Wang

Landslide deformations have predictable rheological properties, but, when using finite element analysis, only the elastoplastic constitutive equation of soil is considered. Soil creep properties are not considered, often rendering inaccurate results. In this paper, the three-dimensional state equation of the extended Burgers model is derived based on the creep test results of slip-surface soil and the Mohr–Coulomb elastoplastic model. This paper uses FLAC3D, a finite-element software platform, for secondary development and to verify the accuracy of the model and program. A strength reduction method that considers rheological properties is proposed. A numerical simulation of rheological properties is conducted on a landslide and compared with conventional viscoelastic constitutive results. It can be found that the landslide displacement calculation is significantly smaller when the rheological properties are not considered. The stability coefficient of the landslide calculated by the strength reduction method, considering the rheological properties, is smaller than the coefficient calculated without considering rheological properties.


2016 ◽  
Vol 858 ◽  
pp. 73-80
Author(s):  
Ying Kong ◽  
Hua Peng Shi ◽  
Hong Ming Yu

With the slope unstable rock masses of a stope in Longsi mine, Jiaozuo City, China as the target, we computed and analyzed the stability of unstable rock masses using a limit equilibrium method (LEM) and a discrete element strength reduction method (SRM). Results show that the unstable rock masses are currently stable. Under the external actions of natural weathering, rainfall and earthquake, unstable rock mass 1 was manifested as a shear slip failure mode, and its stability was controlled jointly by bedding-plane and posterior-margin steep inclined joints. In comparison, unstable rock mass 2 was manifested as a tensile-crack toppling failure mode, and its stability was controlled by the perforation of posterior-margin joints. From the results of the 2 methods we find the safety factor determined from SRM is larger, but not significantly, than that from LEM, and SRM can simulate the progressive failure process of unstable rock masses. SRM also provides information about forces and deformation (e.g. stress-strain, and displacement) and more efficiently visualizes the parts at the slope that are susceptible to instability, suggesting SRM can be used as a supplementation of LEM.


2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Ruili Lu ◽  
Wei Wei ◽  
Kaiwei Shang ◽  
Xiangyang Jing

In order to study the failure mechanism and assess the stability of the inlet slope of the outlet structure of Lianghekou Hydropower station, the strength reduction method considering the ubiquitous joint model is proposed. Firstly, two-dimension numerical models are built to investigate the influence of the dilation angle of ubiquitous joints, mesh discretization, and solution domain size on the slope stability. It is found that the factor of safety is insensitive to the dilation angle of ubiquitous joints and the solution domain size but sensitive to the mesh discretization when the number of elements less than a certain threshold. Then, a complex three-dimension numerical model is built to assess the stability of the inlet slope of the outlet structure of Lianghekou Hydropower station. During the strength reduction procedure, the progressive failure process and the final failure surface of the slope are obtained. Furthermore, the comparison of factors of safety obtained from strength reduction method and analytical solutions indicates that the effect of vertical side boundaries plays an important role in the stability of jointed rock slope, and the cohesive force is the main contribution to the resistant force of vertical side boundaries.


2015 ◽  
Vol 744-746 ◽  
pp. 593-596
Author(s):  
Yuan Meng

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.


2012 ◽  
Vol 170-173 ◽  
pp. 1238-1242
Author(s):  
Xue Wei Li ◽  
Xin Yuan ◽  
Xiao Wei Li

Abstract. Combined the strength reduction method with ABAQUS, the development of the slope plastic strain of different reduction coefficient is obtained by constantly adjusting reduction coefficient to change the strength index of the soil. The reduction coefficient is obtained from the criterion of numerical convergence and displacement mutation and plastic zone breakthrough. Through the analysis and comparison with the results, the reduction coefficient by the criterion of displacement mutation is consistent with the result of the criterion of plastic zone breakthrough. The reduction coefficient is the safety coefficient of the slope, and compared and analyzed with the slope factor of limit equilibrium method Bishop. The result shows that the displacement mutation and the plastic zone breakthrough as criterions to judge the slope instability are reasonable.


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