Advanced Materials Research Vols. 838-841

Abstract: At present, the most direct and extensive research method which in the field of engineering geology and rock soil mechanics is a numerical analysis method .But the numerical analysis method is developing from two-dimensional to three-dimensional . The slope stability not only has something to do with engineering geological condition , but also with the concave and convex extent of the slope. The text tries to present the three-dimensional effect of the slope by the three-dimensional model, and takes the example of Jilinguole 2 strip mine irregular three-dimensional slope, researching the three-dimensional model method of the irregular slope stability by AUTOCAD and ANSYS, founding the FLAC^3D.This paper analyzes the stability of the Jilinguole 2 strip mine south slope by numerical simulation analysis.

Abstract: Based on the direct shear tests of schist and shale at dry and water-saturated states, combed with the advantages and disadvantages of models for rock mass and structure surface, we proposed shear stress-displacement constitutive model of schistose rock mass. The model is in the form of piecewise exponential function and its advantages are as follows: Piecewise function can reasonably describe the nonlinear pre-peak shear hardening and post-peak shear softening characteristics; Regard peak strength, peak displacement and residual strength as critical points, so it can accurately describe the strength characteristics of the material; The fitting degree is high with direct shear tests both at dry and water-saturated states; Only one parameter value is needed to obtain by fitting experimental curves while others are convenient to determine. All of those are benefit to applications in engineering practice.

Abstract: To analyze the damage evolution characteristics of Liaoxi frost sand soil on dynamic load , firstly in the foundation of frozen soil damage theory,micro-strength and dynamic modulus are introduced to analyze the damage evolution characteristics of Liaoxi frost sandy soil .Then ,based on the dynamic triaxial test ,respectively analyze the influences made to dynamic modulus by confining pressure and initial water content . Some regular patterns are summarized .The greater the confining pressure, the greater the dynamic modulus of frost sand soil is ,and with the increase of dynamic strain the dynamic modulus under different confining pressure trend to be same .The bigger quantity of initial water content ,the greater the dynamic modulus is and the change rate of frost sand soil`s dynamic modulus with different initial water content are approximately equal .That initial water content has more significant effects on the dynamic modulus is found by the comparison of the effects caused by confining pressure and initial water content .

Abstract: The non-linear finite element program Ls-DYNA/ANSYS is applied to simulate numerically the capacity for the geo-materials to dissipate the energy induced by the falling objects. The calculation results for the crushed stone coincide well with those recommended by the current Code of《DNV-rp-f107_2010》, which is on the basis of experiment data, implying the feasibility of using this program to estimate the energy dissipating capacity of the geo-materials. Because little research has been performed with clay soil, the program Ls-DYNA/ANSYS is used to predict the energy dissipating capacity of clay layers.

Abstract: Different excavation methods present different influence on the deformation of foundation pit.Combining with engineering example,it analyzes and researches the excavation way of the reserved soil after foundation pit excavation.And through the application of the finite element software MIDAS GTS,it carries on the numerical simulation for the impact of section excavation sequence and different section length on the deformation.Ultimately it determines the optimal excavation sequence and length,and achieves the purpose of control deformation during construction.

Abstract: The main reason of expansive soil embankment slope landslide is the infiltration of rainwater. Analyzing engineering characteristics and failure mechanism of expansive soil embankment slope, considering the force of expansion under the infiltration of rainwater, and choosing the appropriate constitutive model, simulate expansive soil embankment slope under humidification state. According different conditions of the expansive soil and different depth of infiltration, and simplifying the swelling force, establish a simple and reasonable model of expansion force changes. Expansive soil embankment slope stability is mainly affected by the moisture of expansive soil slope after analyzing the calculation results. The safety of expansive soil slope after immersion in rainwater decreases significantly. It shows designers should choose reasonable slope ratio and consider the embankment slope protection and drainage measures.

Abstract: At present, the research is not enough for the correlation of structure and stress-strain characters in domestic.The paper aims how the change of water content and confining pressure influence the stress-strain characters of intact loess and remolded loess by consolidated drained triaxial shear test for the Shanxi loess.The results showed that: the intact loess have structure, and the strength of intact loess is larger than remolded loess in the same condition. With the increasing of water content or confining pressure, the stress-strain of intact loess and remolded loess will tend to coincide and the impact of structure feature for loess strength will weaken.

Abstract: Sidewall pressure is important to open caisson design. However, FEM simulation for the sinking process of open caisson is quite difficult due to extremely large deformation including soil flow and solid boundary movement. In order to overcome this problem, Particle Flow Code (PFC), which is based upon discrete element method (DEM), was applied to simulate the whole sinking process of an open caisson using proposed load servo mechanism, and the variations of the sidewall pressure with sinking depth and elevation were investigated. The outcomes agree well with the in-situ observation data and the indoor experiment data, which verifies the feasibility of modeling the sinking process of open caissons using PFC and further studying their soil-structure interaction mechanisms from the microscopic prospect.

Abstract: In this paper, slope stability considering non-probabilistic reliability analysis based on interval analysis was discussed. We can get safety factor, safety factor interval, non-probabilistic reliability by slope stability computation based on interval analysis. Based on the hypothesis that interval variable of structural performance function numerical value obeys uniform distribution, failure probability based on interval analysis was put forward. These form plural evaluation system about slope stability; it perfects safety evaluation for slope stability.

Abstract: Based on the engineering properties of red sandstone, especially hydraulic mechanical properties, red sandstone slopes are taken as examples. Polarized microscope, powder X-ray diffraction and several general experimental analyses are conducted to get some basic physical indices and microstructure parameters. By summarizing and comparing to other scholars research results, this paper analyzes the disintegration mechanism and failure mechanism of the red sandstone Slope. Several examples of slopes reinforcement projects of Changji highway in Hunan province are taken for the analysis of red sandstone rock properties deeply. Meanwhile, a comprehensive analysis is carried out between three red sandstone slopes instability mechanisms. Finally, some more practical reinforcement methods will be discussed in this article which would do favor to provide scientific basis for disaster prevention and mitigation.