The Stability Analysis Of Pile On Loess Slope

With the rapid development of national economy and the West Development, public facilities and infrastructure will flourish, consisting of highway, railway and subway. So the stability of loess slope and structures on loess slope is urgent to study.Taking ZhuangKeZui Bridge0abutment as the engineering background, the stability of loess slope and the abutment-pile-foundation system has been analysed by finite element software MIDAS-GTS to establish three-dimensional finite element model on typical working condition, and then taking the loess collapsibility and loess slope reinforcement into account, quantitative analysis has been done to measure the stability.The main research contents and conclusions are as follows:(1) According to the "Code for design on special roadbed of railway"(TB10035-2006) and "Code for seismic design of Railway Engineering"(GB50111-2006), basing on the data of geology survey and research conclusion, the loess slope material parameters has been set. The finite element model is in accordance with the design of1:1ratio of loess slope, the10m height of each level and the2m width platform. The loess collapsibility and earthquake force cannot be ignored, which bring the reduce of loess slope stability coefficient and the change of displacement and plastic strain zone to threaten the stability of loess slope and the abutment-pile-foundation system.(2) The stability of abutment-pile-foundation system has been analysed from three dimensional finite model by MIDAS-GTS on typical working condition. The maximum longitudinal-displacement occurs in front of abutment; and the maximum vertical-displacem-ent occurs in the back of abutment. The typical plastic zones occur in different working condition, which are strain plastic zone in front of loess slope and extruded plastic zone in backfill of abutment. The main stress range of pile is form pile top to2/3pile range, and the overall stress is more obvious in loess foundation the mudstone layer.(3) The seismic force has more effect on longitudinal-displacement of the loess slope and the pile, at the same time, the two plastic zones has a trend to link up, according to the finite element analysis.(4) The effect of loess collapsibility to the stability of loess slope and the abutment-pile-foundation has been taken through the finite element software MIDAS-GTS. The effect of loess collapsibility is more on longitudinal-displacement than vertical-displacement, which can bring the instability of loess slope, and the two plastic zone has a trend to expand and link up. The vertical-stress of pile has more effect than the longitudinal-stress of pile from the loess collapsibility. (5) The slope reinforcement effect on the stability of loess slope and the abutment-pile-foundation system has been analysed by the finite element software MIDAS-GTS. The slope reinforcement has a great effect on bearing capability. The effect of slope reinforcement is more on longitudinal-displacement than vertical-displacement, at the same time, the two plastic zone has a trend to lessen. The vertical-stress of pile has more effect than the longitudinal-stress of pile from the slope reinforcement.