Applied Mechanics and Materials Vols. 580-583

Abstract: On the basis of engineering project in coastland, this article analyzes the construction technology and reinforcement mechanism of vacuum preloading reinforces soft soil foundation. By indoor soil test of Reinforcement of soil before and after processing, comparing the change of the physical and shear strength index, verify vacuum preloading method underwater is effective means in handing soft ground and provide some experience for regional development and promotion of underwater application of vacuum preloading technology.

Abstract: This paper takes some sections of Tianjin coast for example, explore the microstructure morphology and index-load combination in the condition of different settling time with load combination about reclaimed soil on the basis of sampling and testing of original state reclaimed soil. Including apparent form, size, directionality gap , formation of the skeleton and bulk density changes of the flocculation body aggregate. It found the characteristics and regularities of microstructure of reclaimed soil in the initial settlement. The research claims the structure of reclaimed soil is enhanced and the change of soil microstructure has positive significance to the engineering geological properties. in the process of consolidation Keyword: reclaimed soil; microstructure; Consolidation settlement

Abstract: The mean spacing of rock fracture is a very important parameter base to evaluate rock mass,a number of rock studies base on it. Object of this paper is Beishan preselected area in Gansu Province, China. A uthor use GPS-RTK to measure the fracture’s endpoints and inflection, then process the resulting coordinate, building a three-dimensional model of rock fracture by using three-dimensional software and meshing the three-dimensional model, Through the analysis of fractures in each grid to calculate the linear density of rock fracture, after the orientation and inclination correction on linear density, it can be converted to an mean spacing of rock fractures. The mean spacing of rock fracture can be directly used for rock mass classification in GSI rock systems, and has a great significance in rock engineering studies.

Abstract: Underground continuous wall has received more and more attention in the construction field as the important part in the foundation engineering. Pointing at the deformation characteristic of continuous wall, the factors which influent the deformation of continuous including the intrinsic mechanical characteristic and time effect in the construction area. The main calculation methods and various of calculation models are concluded as well as the construction technology, which concludes the research production in the continuous wall field and pointing the direction for the following research.

Abstract: In order to determine the concentration range of high-density slurry with coarse sands for suiting pipeline transportation in Jinchuan mine, at the same time find a suitable model to predict yield stress. In this paper, based on the coarse sand of Jinchuan mine as material to prepare high-density slurry, studied on the rheological properties. Through two-factor variance analysis, qualitative and ration analysis of the effect was conducted on the cement content and mass concentration to rheological parameters. The results show that the rheological model of the coarse sand is similar to that of Bingham plastic fluid, the mass concentration has a significant effect on viscosity and yield stress, and the viscosity is significantly affected by the cement content. The mass concentration of 82%-84% is suitable gravity transportation in pipeline. Meanwhile the relation model is established between yield stress and water-cement ratio, aggregate volume concentration, the model has high precision. These provide technical basis for designing filling system and ensuring the stability of slurry transportation, and a new idea for the research of rheological properties.

Abstract: Mechanical behaviors of pile-soil effect and anchor-soil effect are significantly important in supporting engineering activities of foundation pit. In this paper, finite difference method (FDM) was utilized to perform the numerical simulation of pile-anchor system, composed of supporting piles and pre-stressed anchor cables. Numerical simulations were on the basis of the foundation pit of Jinan’s West Railway Station, and 3D simulation analysis of foundation pit has been prepared during the whole processes of excavation, supporting and construction. The paper also analyzed the changes of bending moments of piles and axial forces of cables, and discussed mechanical behaviors of pile-anchor system, through comparisons with field monitoring. The results show that the parameters concluding vertical gridding’s number, cohesion of pile and soil, and pile stiffness have robust influences on supporting elements’ behaviors. Mechanical behaviors of supporting pile and axial forces of anchor cable changed dramatically, indicating that the potential failure form was converted from toppling failure to sliding failure.

Abstract: A failure criterion is proposed for complex rocks and soils. Their anisotropic and nonlinear behavior is analyzed theoretically and experimentally. The influence of the intermediate principal stress is taken into account. The nonhomogeneous strength and the effect of geological temperature are also discussed. Many classical failure criteria are special cases of the proposed condition. The criterion is applied in the analysis of the bedrock of Ankang Dam in China. The case study illustrates the potential of the proposed general model in engineering application.

Abstract: Rock mass mechanical parameters play a significant role in geotechnical engineering design, slope stability evaluation and numerical simulation, which is commonly determined by GSI method. The simplified method using P-velocity to determine GSI (Geological Strength Index) values is proposed in this study, avoiding the limitations of Hoek-Brown method. The relationship between GSI and P-velocity is established through data collected from several projects in China. Then the dam site of Rumei hydropower station, Tibet, China has been taken as a case study to validate this relationship. This method can be utilized directly in engineering projects since it can meet with the engineering accuracy requirement and reduce the cost.

Abstract: The mold bag cement soil was used to be as the material of dike core while building cofferdam. So the engineering characteristics of cement soil with low mix additions were analyzed in this paper. It was pointed out the unconfined compressive strength of cement soil is mainly related to the property of soil, water content, cement mixing content and degree of mixing uniformity, but has little to do with curing condition, cement adding way and the property of mixing water.

Abstract: Energy transformation in rock failure process is a complicate process, especially in the high geostress conditions. First from the point of energy, analysis and study on the rock deformation and failure process under uniaxial compression and triaxial compression condition. Based on the test results, the deformation failure characteristics and its energy in triaxial compression are analyzed. Reveal the energy dissipation and energy release characteristics in the process, and found the internal causes is stored elastic in rock mass unit can release suddenly and cause rock damaged. Especially in the high geo-stress condition, the compressed engineering rock mass are often faced with the risk of unloading damage. After add anchor, the mechanics performance of specimen after peak period is significantly improved, and can absorb more of the release of strain energy, which is helpful for maintaining the overall stability of surrounding rock.