The Loess High Slope Stability Analysis And The Pile Group Study

Soil slope stability analysis is one of the three classical mechanics, It is also an important subject in geotechnical engineering. In Northwest China loess is all the type,widely distributed,large thickness, in the loess area which road and rail are constructing, it will face with a lot of high slope problems, such as how to ensure high loess slope stability, it is also the key to road and railway construction of which the problems. At the same time, the high slope on the bridge pier foundation, which force is more complex. In addition, come from the under the pile of the upper vertical and lateral loads, the pile side also bear the thrust of the role of the slope, it is that both active and passive pile characteristics.This paper lies in the city of guyuan's new railway projects area background, it is lies on typical of loess cut slope, high slope on the bridge abutments and piers for the object, through the material nonlinear finite element based numerical simulation, the system The stability of the slope, abutments-pile-slope system and pier cap-pile-slope system stability under the worst load and mechanical behaviorFinite element-based multi-level strength reduction of high slope stability loess cutting research, arrive at different degree of slope stability collapsible capacity there is a big influence, thus affecting the high loess slope stability, the key to loess depression caused by strength reduction. While multi-level damage Loess Slope first start from the bottom foot of the slope, toe stress concentration caused the shear strength of soil and destruction of the first peak, which leads to cracking and its slope can not afford to shoulder the shear stress near the point of delivery to make reduce its intensity; with shear stress were passed, then finally the strength of the slip plane is reduced, as the result,the overall slump and started sliding surface damage。Through the bridge abutment on the high loess slope-pile-the slope system, it based on nonlinear finite element analysis derived in the normal use of the most unfavorable loading conditions, the bridge abutment-pile-instability of the slope system mainly due to the destruction of the soil pile; Slope-abutment-pile system to the maximum load carrying capacity in the process, the slope of the soil without significant slip surface, indicating that as long as the deviation from the slope of a certain distance from abutment which can guarantee the stability of the slope. When the pile has a clear hierarchical nature of the soil, the pile of soil boundaries in the part of a larger is stressing, prone to the plastic yield region, reflecting the high slope on the pile soil behind abutment to withstand greater thrust force characteristics.Through the high loess slope pier cap on-pile-the slope system which based on nonlinear finite element analysis derived, the normal use of the slope under the most adverse load-pile-pile system is the main reason for instability loess pile damage, pile and soil slip separation, loss of vertical bearing capacity of pile. For all of the soil pile pier loess pile, pile foundation under the most unfavorable load stress in the pile at the top bit larger, and the first to crack, with recommendations to strengthen the pile top and cap connected parts of the reinforcement and structural design. Meanwhile, pile the stress and displacement results show that different parts along the vertical and horizontal pile there is a big difference in the force, reflecting the strong force of pile groups and pile of non-synchronous effect of the soil thrust the role of soil mass.