scholarly journals Determining the Critical Slip Surface of Three-Dimensional Soil Slopes from the Stress Fields Solved Using the Finite Element Method

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Yu-chuan Yang ◽  
Hui-ge Xing ◽  
Xing-guo Yang ◽  
Jia-wen Zhou

The slope stability problem is an important issue for the safety of human beings and structures. The stability analysis of the three-dimensional (3D) slope is essential to prevent landslides, but the most important and difficult problem is how to determine the 3D critical slip surface with the minimum factor of safety in earth slopes. Basing on the slope stress field with the finite element method, a stability analysis method is proposed to determine the critical slip surface and the corresponding safety factor of 3D soil slopes. Spherical and ellipsoidal slip surfaces are considered through the analysis. The moment equilibrium is used to compute the safety factor combined with the Mohr-Coulomb criteria and the limit equilibrium principle. Some assumptions are introduced to reduce the search range of center points and the radius of spheres or ellipsoids. The proposed method is validated by a classical 3D benchmark soil slope. Simulated results indicate that the safety factor of the benchmark slope is 2.14 using the spherical slip surface and 2.19 using the ellipsoidal slip surface, which is close to the results of previous methods. The simulated results indicate that the proposed method can be used for the stability analysis of a 3D soil slope.

2012 ◽  
Vol 446-449 ◽  
pp. 1905-1913
Author(s):  
Mo Wen Xie ◽  
Zeng Fu Wang ◽  
Xiang Yu Liu ◽  
Ning Jia

The Various methods of optimization or random search have been developed for locating the critical slip surface of a slope and the related minimum safety factor in the limit equilibrium stability analysis of slope. But all these methods are based on a two-dimensional (2D) method and no one had been adapted for a search of the three-dimensional (3D) critical slip surface. In this paper, a new Monte Carlo random simulating method has been proposed to identify the 3D critical slip surface, in which assuming the initial slip to be the lower part of an ellipsoid, the 3D critical slip surface in the 3D slope stability analysis is located by minimizing the 3D safety factor of limit equilibrium approach. Based on the column-based three-dimensional limit equilibrium slope stability analysis models, new Geographic Information Systems (GIS) grid-based 3D deterministic limit equilibrium models are developed to calculate the 3D safety factors. Several practical examples, of obtained minimum safety factor and its critical slip surface by a 2D optimization or random technique, are extended to 3D slope problems to locate the 3D critical slip surface and to compare with the 2D results. The results shows that, comparing with the 2D results, the resulting 3D critical slip surface has no apparent difference only from a cross section, but the associated 3D safety factor is definitely higher.


2011 ◽  
Vol 255-260 ◽  
pp. 1926-1929
Author(s):  
Da Kun Shi ◽  
Yang Song Zhang

Based on geologic condition of one tunnel surrounding rock mass, systematic numerical tests had been carried out to study the stability of surrounding rock mass with different distributions of weak intercalated rock by the FEM software ABAQUS and strength reduction finite element method. Some quantificational results about the stability of surrounding rock mass were summarized. And the safety factor and latent slip surface were worked out. The stability of surrounding rock mass was judged by strength reduction finite element method. According to the analysis above, it’s known that the discrepancy of two rules is small; the safety factor is the lowest when weak intercalated rock in vault, and when at bottom, it’s higher than that of in vault. The conclusion can be used to guide the procedure of construction and ensure the safety.


2018 ◽  
Vol 10 (10) ◽  
pp. 168781401880347 ◽  
Author(s):  
Ji Zhou ◽  
Duan-Wei Shi ◽  
Zhi-Lin Sun ◽  
Tao Bi ◽  
Xiong-Hao Cheng ◽  
...  

Taking the hydraulic cylinder for the miter gate in Dateng Gorges Water Conservancy Project as the object, a large slenderness ratio test hydraulic cylinder was designed based on the similarity theory. The buckling analysis of the test hydraulic cylinder was carried out by the finite element method, considering the friction at the supports, the misalignments between piston rod and cylinder tube, and gravity. The results indicate that the stability safety factor is 10.55. A buckling experimental system was established, and the buckling stability of the test hydraulic cylinder was tested for the sliding bearing support and the rolling bearing support at the piston-rod end, respectively. The stability safety factor is over 9.01 and 6.82 relevantly. The similarities and differences among the results of the finite element method, experimental method, NB/T 35020-2013, and two-sections pressure bar method were analyzed. Experimental and analytical results clearly show that the friction at the supports is a key factor in determining the magnitude of the stability safety for large slenderness ratio horizontal hydraulic hoist and utilizing the sliding bearing can effectively improve the stability safety factor.


2014 ◽  
Vol 685 ◽  
pp. 217-223
Author(s):  
Peng Lan ◽  
Teng Fei Wang ◽  
Nian Li Lu

The objective of this study is to develop an analytical method for the out-of-plane stability of combined boom system with main jib and fly jib. Boundary conditions and deformation compatibility equations are introduced to get the analytical expression of out-of-plane buckling characteristic equation by establishing the bending and torsional deformation differential equations of jibs and the strut under the instability critical state. The analytical results obtained agree well with the finite element method (FEM) results. The influence of the dip angle between the main jib and the fly jib on the stability of the boom system is discussed. And the comparison between the combined boom system and the bending beam-column in the stable bearing capacity is made. It is shown that the upwards-bend boom system is much stronger than the downwards-bend boom system. There exists a certain dip angel between the main jib and the fly jib that makes the stable bearing capacity biggest. By comparing the stable bearing capacity of boom system with that of the bending beam-column, it is obtained that the flexible tension system will significantly improve the stable bearing capacity of the bending beam-column.


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