Applied Mechanics and Materials Vols. 353-356

Abstract: On basis of limit equilibrium analysis methods for theory of unsaturated soil mechanics, silt subgrade slope stability under the condition of rainfall infiltration is analyzed and the factors affecting the stability of subgrade slope are presented in this article, which provides theoretical basis and technical support for future subgrade construction.

Abstract: On the background of rock masses and field engineering geology of a mine, the feature of rock mechanics and rock mass structure of surrounding rock at mining district are analyzed. Based on the finite difference theory and block theory, FLAC3D program (Fast Lagrangian Analysis for Continuum), rock mechanic and rock mass structure results are used to construct the finite difference mechanical model, which reflected the surrounding rock stability when mining. By the numerical simulation, the mechanical effect is studied by the process of mining and its results can be used to produce some theory and actual basis.

Abstract: The mining coal in the front of long wall face consists of elastic zone, plastic zone and fracture zone. Based on the research of zonaldisintegration of surrounding rock mass in deep tunnel, the zonal disintegration phenomenon of deep coal mine was analyzed by using the theoretical analysis method. On the basis of the Griffith theory, the internal and external boundary formulas of fracture zone and the mechanical criteria of zonal disintegration were obtained. The research shows that the essence of zonal disintegration is the tensile failure and brittle tension crack failure under the abutment pressure, the main influence factors of the width variation of fracture zone are original rock stress and un-axial tensile strength of coal.

Abstract: The high-rise towers and podium of the Shandong Provincial Center for Culture and Art adopt post-grouting drilling bored pile (pressure loaded pile) and compaction-under reamed bored pile (uplift pile) respectively. Based on an off-site self-balanced static-load test of the two kinds of piles, the bearing capacity, displacement, technology for pile-forming, construction period, and engineering cost are presented in detail, and the design basis for the two piles obtaining high bearing capacity on soft soil is also preliminarily put forward. The results of this study provides a design reference for the similar projects in the western new district of Jinan City.

Abstract: Non-linear stress-strain characteristics and strain dependency of stiffness of saturated soils at small strain level have been reported by many researchers. However, the non-linear stiffness of unsaturated soils is not fully studied. The aim of this study is to clarify main factors affecting the non-linear stiffness of unsaturated soil at small strain range for a precise prediction of various ground deformations. Experiments were conducted with both sand and cohesive soil, by using a triaxial apparatus developed for small strain measurement. As the important factors for mechanical behaviour of unsaturated soils under small strain range, the effects of suction and mean net stress, which introduce the decrease of void ratio and degree of saturation, were discussed in the study.

Abstract: The landslide forecasting study is one of the hot problems in landslide research. Based on the actual observation data, the exponential smoothing and nonlinear regression analysis are integrated. According to the criteria of displacement and displacement velocity, the dynamic track prediction about the slippage time of landslide is introduced. In light of the practical landslide conditions, a model was established for the special displacement of some monitoring points£¬ and the prediction based on this model was obtained with high accuracy. Therefore, the method can be used in practical engineering.

Abstract: A few solutions for stone column composite ground consolidation have been presented which ignoring the nonlinear characteristic of surrounding soil or the variation of upper load with time. Considering the nonlinear characteristic of surrounding soil, variation of upper load with time, distribution of permeability coefficient in smear zone, the governing equation for consolidation of composite ground is obtained. The equation is solved using separation of variables method. Finally, the influence of parameters on consolidation rate is discussed.

Abstract: The portable falling weight deflectometer (PFWD) test, bearing plate test, beckman beam test, and compaction test were carried out in this study. The relation of dynamic modulus and static modulus, dynamic modulus and deflection, dynamic modulus and compaction ratio, dynamic modulus and water content (consistency) was built. It turns out that there are good power function regression relationship between dynamic modulus and static modulus, dynamic modulus and deflection, dynamic modulus and compaction ratio, dynamic modulus and water content and consistency. Key words: red sandstone; dynamic modulus; resilient modulus; deflection; compaction ratio; water content

Abstract: The article takes tailings dam material as study object. A series tests, including particles analysis test, density test, seepage test, static treaxial test and compression test were conducted to analyze the physical and mechanical properties of heap dam materials. The characteristic curve and data were received. The result can system analysis the deformation laws of dam material. Experiments show that the compression coefficient of tailings is sensitive to void ratio. Through analysis of the strength parameters of the tailings in static triaxial test, it is known that the tailings cohesion can be neglected as 0 and the change of dry density has a larger influence on strength of tailings material.

Abstract: Geothermal resource is a very clean source of energy, and its exploration and development has a history of almost one hundred years. In this paper, the mathematical model of multi-physical field on the platform of Comsol Multiphysics software was set up about the flow-solid-Thermal numerical model. During the analysis, rock porosity and permeability of stratum were taken into consideration to study change state of the temperature of export wells and injection wells. Besides, porosity-temperature curve fitting and permeability-temperature curve fitting were made respectively to study the relationship between the stratum temperature and permeability and porosity.