Analysis On Affection Factors Of Settlement Composite Soil Nailing Support

With the increase in high-rise buildings and underground space development, there has been more and more deep excavation projects in our field of vision. The most deep excavation projects are constructed in the built-up areas of the city, so the construction site is extremely narrow. The original design strength theory can not accurately predict the deformation, resulting in large deformation, and it seriously affects the surrounding environment and the normal use of the building. Because soil nailing structure is a kind of supporting structure that active only after the soil start deforming. Therefore, the slope deformation has become an important factor what limited this supporting structure development. Although in recent years academics and engineers have focused on studying deformation control of composite soil nailing supporting, but there are still many issue to be solved in the calculation of soil nailing and composite soil nailing and the surrounding ground settlement.In this paper, a relevant data of composite soil nailing engineering examples and large-scale engineering software FLAC-3D numerical simulation of its analysis were used to compare the simulation results with the measured results, and the affect of adding the micro-pile to soil nailing was analyzed in the settlement of slope roof. The main work in the following areas:(1) Describes the soil nailing and composite soil nailing the relevant theory and introduces FLAC-3D software’s basic features and principles of calculation.(2) According to the project to created different model, compared numerical simulation data with measured data, it is feasible that the numerical model simulates soil nailing and composite soil nailing slope settlement.(3) By comparing soil subsidence curves of stress and plastic zone of soil nailing and composite soil nailing in certain conditions (excavation depth, soil parameters), and concluded: micro piles can be very effective to improve the soil stresses and plastic zone, reduce the slope settlement.(4) The effects of slope settlement of composite soil nailing in different factors (soil nail length, soil nail inclination, micro pile embedment depth, micro piles diameter, prestress) were analyzed in this paper, and the method of orthogonal experiment is used in this analysis in order to research on the sensitivity of five factors of the slope settlement with composite soil nailing, and the following conclusions:the greatest impact factor is prestress, and then followed by soil nail length, soil nail inclination, micro pile diameter, micro pile embedment depth; the largest settlement point appears at a distance of about1m～3m slope position; at a distance slope of about H (H is the excavation depth) meters range excavation settlement was less affected.Because there is little research about soil nailing and composite soil nailing slope settlement at this stage, the research project will be guided to the soil nailing and composite soil nailing numerical analysis of slope settlement or relevant research.