有限元确定沟谷岸坡桥基位置的应用

Application of Finite Element Method in Determination of Bridge Foundation Position on Valley Slope

高陡边坡桥基位置的确定,应遵循桥基荷载对地质体扰动最小的设计原则,即沟谷临空面最大应力影响系数趋于稳定时的桥基位置为最合理位置:先用有限元法计算桥梁布设前后边坡的应力场,求出桥基荷载作用下的应力影响系数,再计算沟谷临空面最大应力影响系数随桥基位置的变化曲线,当曲线趋于稳定时的桥基位置为最合理。通过FLG特大桥实例分析表明,计算结果与该区其他桥梁桥基位置的选择较吻合,验证了基于应力分析法确定高陡边坡的桥基水平安全距离是可行的。

Determination of bridge foundation position on high steep slope shall follow the design principle ofthe minimum geological disturbance caused by abutment load,which means the most reasonable position of bridge foundation is where the maximum stress factor of valley free surface trends to stable.First,the slope stress field for arrangement of front and back slopes of FLG super-large bridge shall be calculated with finite element method to find out stress factor under bridge foundation load;then calculate the curve of the maximum stress factor of valley free surface changing with bridge foundation position.When the curve trends to be stable,bridge foundation is in the most reasonable position.It is shown from analysis through FLG Bridge example that calculation result is in accordance with the location of other bridge foundation in this region,which verifies that it is feasible to determine horizontal safety distance of bridge foundation on high steep slope based on stress analysis.