Papers by Keyword: Strength Reduction Method

Abstract: The slopes reinforced by anti-slide piles were simulated in this paper. The setting position, pile spacing and anchorage depth of integrated piles were discussed with strength reduction method. The results show that the pile position should depart slope into two stages, and the further strain would be limited. When the spacing of the anti-slide piles is 2-3 times of pile diameter, it has a soil arching effect to wedge the soil. The anchorage depth can affect the form of the potential sliding surface. Three kinds of defective piles were studied to research deformation of slope reinforced by defective piles. The defective piles were namely expanded pile, necking pile and segregationpile. The equivalent plastic strain zone was used to judge the slope failure, and then the stability and deformation process of the three-dimensional slope were simulated. By comparing the plastic strain, safety coefficient curve and pile-soil stress curve, between the defective pile and integrated pile, the progressive failure process of the reinforced slope was analyzed, including the formation process of the macroscopic shear zone.

Abstract: 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.

Abstract: Piles are used widely for stabilization of landslides. To stabilize a slope settled on bedrock with piles the required factor of safety must be checked, and pile should be designed properly. Piles should be socketed into firm rock to prevent uprooting or overturning .In this research it is aimed to look into the socketed length of pile in bedrock. Therefore the parameters that affect the factor of safety of slope/pile system such as location, length, spacing and diameter of piles are analyzed. The effect of socketed length of pile in rock on pile behavior is investigated by plotting the shear force and bending moment diagrams along pile. The optimal pile position is found to be located slightly upper of the middle of the slope. The minimum socketed length after which the factor of safety will be remained constant is found to be 0.12L where L is pile length.FLAC3D computer code based on finite difference method is used to simulate the slope/pile system.

Abstract: To the problem of slope stability analysis and slope-cutting of rock slope, the traditional method Limit Equilibrium Method has many shortcomings as assuming the position and shape of the slip plane first. However, with the new theory of Strength Reduction Method, the problem can be easily solved. By selecting the appropriate criterion of instability and failure of sliding surface of slope, the Strength Reduction Method simulates the gradual development process of slope-cutting. By this method, we can simulate the failure process of slope and obtain the safety factors and slipping surface. This paper put forward the process of cutting slop by Strength Reduction FDM (Finite Difference Method) which had new insights into the choice of instability criterion, flow rule and slip plane.

Abstract: So far, due to the complexity of underground engineering, a mature and proper method used to determine rock pressure is not for sure. For now, method to design lining structure mainly adopts empirical design, assisted by load structure method. The paper assesses the safety of lining structure from two aspects, that is, from load structure method and from strength reduction method. The results indicate that compared with strength reduction method to evaluate safety of the lining structure, load structure method is relatively conservative.

Abstract: Stability analysis of steep rock bedding slope with weak structure planes using strength reduction method was simulated in this paper. The post processing function can display the development condition of the plastic zone, which is the criterion for instability of the slope. Analysis with working conditions of natural circumstance, after excavation, and the slope reinforced by anchor shank after excavation were put forward. Failure modes and safety coefficients of the slope proved that weak plane is the main factor controlling slope failure. Simulation results shown that strength reduction method is appropriate in predict the shape and position of the potential failure surface of steep rock bedding slope.

Abstract: According to the actual progress of a certain Surface Mine and based on strength reduction method, the deformation and fracture processes of the high dip bedded soft rock slope was simulated with RFPA-SRM, the stability of the slope was calculated. By analyzing the numerical simulation results, the characters of the deformation of high dip bedded soft rock slope and the landslide mode were demonstrated, which could provide a scientific basis for reasonable landslide control measures.

Abstract: A nonlinear procedure for coupled elastoplastic analysis of the dam seismic stability was presented in this paper. The soil nonlinear dynamic behavior was modeled using by a multiple yield surface model based on the numerical framework of u-p formulation. The strength reduction method was used to determine the factor of safety of dam slope and the location of failure surface. A case study of a 293.5 m high clay core rockfill dam was used to demonstrate the application of the method. Based on the computed results, it is founded that the maximum acceleration amplification coefficient is 1.72, which is almost 20% less than that obtained from the equivalent linear analysis. The most dangerous slip surface was at the shallow zone of the lower part of the upstream slope, which was different from the predicted location from the equivalent linear analysis. The earthquake induced pore water pressure and permanent deformation were also studied in detail.

Abstract: This paper focuses on stability analysis of an artificial rock mass slope by a nonlinear finite element method (FEM). For a long time, rock slope stability problem is always an important research issue in the field of geotechnical engineering, which is related to human life and property safety as well as engineering security and efficiency. Therefore, the stability analysis and evaluation on rock slope is of great significance. The static and dynamic stability analysis on the artificial rock mass slope of WuAn power plant in China is carried on respectively in this paper by using the strength reduction method and FLAC3D software. In this analysis, static and dynamic instability criterions are enumerated, and the static and dynamic safety factors are calculated with the developed criterions of the displacement mutation, respectively. The analysis results show that the artificial rock mass slope is basically stable. It indicates that analyzing slope stability with strength reduction method is feasible.

Abstract: Taking the slope of K178+500-K178+550 of Beian-Heihe expressway as example, based on the steady saturated-unsaturated seepage theory and simplified the seepage force of groundwater into equivalent nodal load, then using the strength reduction finite element method to analysis the stability and potential slide area of roadbed slope which has no engineering measures; the interaction between slide-resistant pile and weathered rock can be reasonably considered by using the contact surface element, the result shows that, the safety factor of roadbed slope can be improved and the shearing strength of roadbed slope can be evenly dispersed by the reinforcement measure. The result can be used for the stability evaluation and reinforcement of subgrade slope of weathered rock area.