Advanced Materials Research Vols. 1065-1069

Abstract: Many efforts have been focused on stability problems of geotechnical structures with the limit analysis method. A key advance of this present method is that the problem is described only in terms of nodes and discontinuities connecting those nodes rather than element or bodies. The alternative approximation procedure might involve discretization of a given body using a suitably large number of nodes laid out on a grid, with the failure mechanism comprising the most critical subset of potential discontinuities interconnecting these nodes. The method using Mohr-Coulomb failure criterion to formulate the objective function is developed and the safety factor is determined from optimization. In order to evaluate the applicability and validity of the proposed method numerical results of some examples are presented and compared with the solutions obtained using other well-known techniques. The comparisons show that the proposed method is an effective method and can be applied to evaluate the safety factor in the analyses of slope stability problems.

Abstract: In order to analyze the stability of surrounding rock accurately and effectively, a rock classification method based on QGA (quantum genetic algorithm)-SVM (support vector machine) is put forward. QGA was used for global search in the solution space to optimize the kernel function parameters of SVM. And this method improved the classification accuracy of SVM in rock classification. Finally, a rock classification model based on QGA-SVM was established and applied to practical engineering. The result shows that the improved SVM has a higher accuracy in stability analysis of surrounding rock.

Abstract: Roscoe and Burland set the yield surface of the Cambridge model to elliptic and concluded modified Cambridge model. In this paper, the model has been improved and got the accuracy of the elastic-plastic matrix improvement model, by using the Cambridge model to calculate the volumetric strain and shear strain of soil theoreically and inculcating CU triaxial tests to measure the corresponding soil volumetric strain and shear strain and applying least squares theory to simulate the ratio of theoretical calculations and experimental results.

Abstract: The advantage outward joints connectivity rate (CR) which extend along the slope plays an important role to overall stability of the high rock slope, but less research on it has been done. In order to research the 180m high rock slope at water inlet of Wudongde hydropower station at Jinsha River, qualitative and quantitative analysis methods have been used. Based on the statistics of the outward joints CR which extend along the slope, and the weighted average parameters of the “bottom sliding surface” combined with the rock bridge, the stability factor of slope has been calculated by rigid body limit equilibrium method. According to the CR sensitivity analysis and calculation, the effect degrees of the joint connectivity rate to the slope stability, and the effect degrees of the bandwidth selection to the CR and stability factors in the bandwidth projection method of linear CR have been demonstrated in paper.

Abstract: For studying on the effects of loading rate on modulus and strength of sandstone, uniaxial compression experiment of the samples, from Balikun mine, was performed at different loading rates. The influence of loading rate on average modulus, uniaxial compressive strength and post-peak strength degradation angle was analyzed, and the results indicate that:: The average modulus of sandstone samples increases with loading rate increasing; the both almost obey linear relationship. The peak strength of sandstone grows with the increase of loading rate; there is an approximately exponential relationship between the two. With loading rate increasing, the post-peak strength degradation angle decreases; the relationship between the both is approximately exponential.

Abstract: This paper introduced to the low viscous loess liquefaction problem by acid modification method. The liquefaction test showed that after the modification, the modified loess’s pore water pressures is very smaller then unmodified samples under 50-65Kpa dynamic stress. The modified loess almost no stress reduced after the liquefaction test. It showed that the method can effectively reduce low viscous loess liquefaction potential, and enhance the loess strength.

Abstract: For high-rise buildings piled raft foundation reinforcement, use ANSYS to establish the piled raft foundation complement pile reinforcement model which is called long-short-piled raft foundation. Parameters of complement pile respectively from the aspects of pile length and pile diameter for change, study its effect on piled raft foundation vertical bearing performance. Provide certain reference value for practical engineering.

Abstract: Failure of slope generally sites along the slope of the stress concentration, while there are too many factors affecting stress distribution of slope, including the geometry of the slope, the strength parameters, the boundary conditions and constraints, etc. In this paper, considering the edge affect the elastic modulus of rock and soil slope, Poisson's ratio, shear strength parameters and other characteristics factors, by using finite element modeling to analyze the distribution forms of stress of the different slope, every factors affecting on the stress distribution of the different slope can be obtained. Through in-depth analysis, getting some understanding of regularity, it can be used to guide the engineering practice and has some promotional value.

Abstract: The stability of the soil slop is influenced by many factors. In this paper, the influence of cross section geometric shape on the slope stability is analyzed by establishing a reasonable calculation model and using finite element strength reduction method. Results indicate that the slope stability of stepped excavation surface is higher than that of linear excavation surface, and the stability is better with larger and more platforms, the designers should make a choice in design by comparing cost and ease of construction. Slope table form also has affections, the stability of concave linear and convex slope type decreases in turn.

Abstract: Limit equilibrium method is commonly used earth-rock fill dams stability calculation method in engineering, this article simply introduces the basic principle of limit equilibrium method, and through a practical project introduced the methods in the application of earth-rock fill dams reinforcement, and achieved good effect.