高陡横坡段桥梁双桩结构计算方法研究

Study on Calculation Method of Bridge Double Piles Structure in High-steep Transverse Slope

针对山区高陡横坡地段桥梁双桩基础的结构与荷载特征,建立了桩基与边坡及桩间土相互作用新模式:后桩承受推力以滑动面为界简化为滑坡推力与主动土压力;前桩与后桩所承受的侧土抗力则服从(mz+C)的线性增长规律;并假定桩间土对前桩的作用力q\-a是桩间距、桩宽(桩径)及滑坡体宽度的函数,由此可充分反映桩间土及滑坡体对土压力传递的影响。在此基础上,导得不同特征桩段的微分方程,并基于有限差分解进行了求解,从而提出了高陡横坡段桥梁双桩结构内力位移计算方法。理论计算与室内模型试验实测数据的对比表明,该方法误差可满足工程要求。

According to the structure and load characteristics of bridge double-pile foundation in high-steep transverse slope,a new model of pile-soil-slope interaction was established：The back pile born thrust was simplified as slope sliding thrust and active earth pressure at critical sliding surface,lateral soil resistance of the double piles obeys the linear growth rule（mz＋C）,and the acting force of inter-pile soil to front pile was assumed as the function of pile space,pile width（diameter） and sliding body width,which can fully reflect the effect of inter-pile soil and sliding body on the soil pressure transmission.Then,the differential equations of pile sections with different characteristics were deduced,and the displacement calculation method of the structure was obtained by finite difference solution.The comparison between theoretical solutions and laboratory model test data shows that the error of this method meets the requirements of practical engineering.