基于FLAC3D路桥不稳定边坡治理工程的动力响应研究

抗滑桩广泛应用于边坡支护工程，但路桥不稳定边坡抗滑桩对其进行加固时，其在地震作用下的动力响应问题仍未定论。以道真至瓮安高速公路河槽大桥不稳定边坡治理工程为依托，以SIMQKE_GR软件拟合地震设计反应谱，利用FLAC3D有限差分软件建立数值模型，对比地震作用下抗滑桩等支挡结构设立与否对路桥不稳定边坡的动力响应变化规律的影响。结果表明:（1）加速度放大系数无论是沿坡内还是抗滑桩，其值沿竖向均存在一定的震荡变化，但在抗滑桩支护情况下，其震荡幅度明显变小，加速度放大系数变化更平稳。（2）速度放大系数随着高度的增加逐渐减小，未加抗滑桩时速度放大系数在顶层附近出现大幅度波动，添加了抗滑桩的情况下其震荡幅度明显趋缓，变化更稳定。（3）坡体在施加抗滑桩后，治理效果明显，残余位移最大值由无抗滑桩的16.9 cm变为有抗滑桩的1 cm，但最大值均位于边坡表层碎石土和粉质黏土附近。

Research on dynamic response of highway bridge unstable slope treatment project based on FLAC3D

Anti-slide piles are widely used in slope support engineering. However, when anti-slide piles are used to reinforce unstable slope of highway bridges, the dynamic response of it under earthquake action is still uncertain. Based on the unstable slope treatment project of channel bridge of Daozhen-Weng’an expressway, the seismic design response spectrum is fitted by SIMQKE_GR software, and the numerical model is established by FLAC3D finite difference software. The influence of anti-slide piles and other retaining structures on the dynamic response of unstable slope under earthquake is studied. The results show that:(1) The magnification coefficient of acceleration varies along the slope and anti-slide pile, but the magnitude of vibration decreases obviously and the magnification coefficient of acceleration varies more smoothly under the condition of anti-slide pile support; (2) The velocity amplification coefficient decreases gradually with the increase of height. Without anti-slide piles, the velocity amplification coefficient fluctuates greatly near the top floor. When anti-slide piles are used, the vibration amplitude slows down and the change is more stable. (3) After the application of anti-slide piles, the treatment effect is obvious. The maximum residual displacement of the slope changes from 16.9 cm without anti-slide piles to 1 cm with anti-slide piles, but the maximum value is located near the gravel soil and silty clay on the surface of the slope.