Applied Mechanics and Materials Vols. 256-259

Abstract: In order to search for the control factors of slope stability containing weak layers, combining with the methods of the finite element and the limit equilibrium to simulate the slope stability problems. From the numerical simulation results, the stress field distribution and displacement field distribution internal the slope could be got. According to the finite element analysis results and the safety factor of slope stability got with the limit equilibrium method, evaluate the slope stability. By the simulation analysis of slope which contains a number of weak structural surfaces, the conclusion we got is that the existence of weak structural plane like weak layers and faults are the main factors of slope instability.

Abstract: The construction of main shaft No.2 in Wutong coal mine is the key project of energy expansion and technological innovation. It started in December 2008 and jointed commissioning in the end of July 2010.Engineering capacity,a tight schedule and the difficulty of construction are the tough points. So if according with conventional construction methods,the project would have difficulty in completing on schedule.After repeated demonstration ,the researches of Wutong coal mine break the routine. The construction technology of segmented parallel operations is adopted to accelerate the construction schedule.This technology not only makes main shaft No.2 in advance of two months to complete construction and installation works, but also achieves difficult precisely through in both upper and lower segments.Totally plane error is only 80mm in through point.The project hits a good example for future wellbore rapid construction.

Abstract: Through the permeability leach test,this paper analyzed the change rule of the strength parameters of the saline soil with salt content. The results show that the more salt the saline soil had before leached,the more cohesive force and internal friction angle is reduced after it was leached, and the relationship between them can be explained through hyperbolic function.According to the soil shear strength theory, deduced the calculation formula of the strength after leached. Through the verification, the calculation values of the strength parameter and measured values were very close. Shear strength calculation formula offers a theoretical basis for the design and the foundation stability calculation of buildings in saline soil areas.

Abstract: The masses, elastic wave velocities of sandstone specimens under chemical corrosion and pH values of solutions soaking specimens are tested in different soak time. It is indicated that elastic wave velocity can be utilized to perform time-dependent test research on the same specimen with the advantage of being highly sensitive to micro void and without damage on specimen in the testing process. The test results show that the relationships between the masses and the chemical solutions are small.The chemical erosion action on rock will reach a relative equilibrium status in a certain time in the closed chemical environment and pH value will reach ultimately one stable value which will be decided by the rock characteristics. The alkalescence of sandstone decides that the solutions of soaking specimen will turn to alkalescence.

Abstract: Research the structure changes before and after collapsible experiment of loess microstructure. Using artificial preparation methods prepared different moisture samples of Liaoxi loess. Do collapsible test and Scanning electron microscope test with the prepared samples. According to Digital Terrain Model theory, three-dimensional porosities were calculated based on gray scale information from the SEM images extracted by MATLAB. The results are shown following as: the microstructure of loess samples is getting dense, the average number of pore of samples obviously increases and the pore area decreases after the sample is collapsed. The distribution before and after the collapsibility of gray value has certain regularity. The before one has double peaks, large distribution. The after one has single peak, concentrate distribution and meets normal distribution.

Abstract: The hybrid finite-discrete element method Y-2D/3D IDE is applied to model the dynamic fracture of rock specimens with various geometries during impacting a fixed rigid surface. It is found that the modelled primary fractures are highly dependent on the rock geometry determining the weakest plane for a given impact, which agrees well with others' experimental and SPH numerical results. Compared with others' SPH results, Y-2D/3D IDE better simulates the actinomorphic pattern of primary fractures around the impact area and the secondary & tertiary fractures observed in the dynamic fracture experiments. It is concluded that the proposed Y-2D/3D IDE is a valuable tool to model rock dynamic fracture compared with FEM and DEM.

Abstract: Based on the hierarchical summation method of elasticity theory, the comprehensive template model of land subsidence induced by dewatering of pit is put forward. According to the soils experience range of conversion relationship β (between deformation modulus E0 and compression modulus Es ), we can calculate upper and lower limits of Es. When the compression modulus Es is respectively taken upper and lower limit, the curve between falling groundwater values and sedimentation values can be taken in conditions of unit thickness different soils of different pore ratio. So the comprehensive template model is built. The example shows that the comprehensive template model can be effectively calculated land subsidence induced by dewatering of pit.

Abstract: Based on mining area end slope stability evaluation engineer- ing of Pingshuo East open pit coal mine in Shanxi Province, ac- cording to the status quo of the North Slope of the first mining district of the East open pit coal mine as well as engineering g- eological investigation results, this article selected a represen- tative cross-section of the North Slope,adopted processing fu- nctions of finite element analysis software MIDAS/GTS, and re- spectively analyze slope stability under three conditions of the mining area of the initial excavation,backfilling and disposal,a- nd follow-up excavation.The paper concluded that Initial exca- vation caused slope instability; backfill slope is stable after di- sposal; follow-up excavation has essentially no effect on slope stability. The establishment and analysis are much closer to t- he real situation, objectively reflect the distribution of slope s- tability of the East open pit coal mine, and provide a design for open pit production safety.

Abstract: Based on the background of a foundation pit slope of the tertiary strong weathered basalt(TSWB), a quantitative analysis of the slope stability is proposed by combination of the limit equilibrium and the numerical analysis. The analysis also considers the effects of the natural state and soaking state Then, as an example, an ultra-deep foundation pit slope (UFPS) is analyzed under the background of TSWB. The Janbu method is used in the limit equilibrium because it can meet all the equilibrium conditions, including the force and moment equilibrium equation. The Lagrangian difference method which based on shear strength reduction is adopted in numerical analysis. Some meaningful conclusions can be obtained through comparing analysis the calculation results of Janbu method with finite difference method. These conclusions can be given a reference to similar projects.

Abstract: Joint roughness coefficient (JRC) is an important factor in the evaluation of the shear strength and deformation parameters of rock joints. This paper presents a method for measuring JRC of rock fractures based on digital image progressing technique. Though preprocessing of the rock fracture image, the skeleton of the fracture was got, the rough degree were analyzed and quantized by geometric parameters of the skeleton. By establishing the relationship between JRC and the rough degree, JRC will be got though the rough degree. This method improves automation degree and accuracy comparing to the previous methods. Finally this method was used to get the JRC of rock fracture in Jijicao, Beishan, Gansu province, where may be the high-radiation nuclear waste repository.