基于FLAC3D的抗滑桩抗震加固机理及模式研究

Study on Seismic Reinforcement Mechanism and Model of Anti-slide Piles Based on FLAC3D

以典型工程断层带边坡为原型,选择FLAC3D数值模拟方法建立三维边坡模型,分析地震作用下边坡和抗滑桩动力响应特征、抗震加固机理以及抗滑桩加固模式。结果表明,地震波对断层带边坡岩体产生振荡作用,导致岩体松弛进而向临空面滑动;边坡采用抗滑桩支护后,改善了桩周岩土体的力学性能;地震波中面波部分直接到达抗滑桩桩身位置,另一部分先到达桩间土拱处,再由土拱传播到桩身;纵波和横波传播到弹性好的抗滑桩处,能量损失较少,经反射后对边坡产生加固效用;坡高30 m、坡比1∶ 1时,不同桩支护不同位置的最优锚固长度为10、 12 m ,最优桩间距为6、7 m。

Taking typical engineering slope in fault zone as the prototype,the FLAC3D software is utilized to build a model of three-dimensional slope. The dynamic response characteristics of slope and anti-slide pile under the earthquake,anti-slide pile reinforcement mechanism and anti-slide pile strengthening mode are analyzed by the model. The results show that,(a) the seismic wave creates oscillating effect on slope rock mass,which causes the rock mass to relax and slide to the free surface;(b) the mechanical properties of rock and soil around piles are improved after the slope is supported by anti-slide piles;(c) part of surface wave directly reaches the position of anti-slide pile body,and other part first reaches the soil arch between piles,and then propagates from soil arch to pile body;(d) the P-wave and S-wave propagate to anti-slide pile with good elasticity and less energy loss,and after reflection,they have reinforcement effect on the slope;and (e) when the slope height is 30 m and the slope ratio is 1∶ 1,the optimal anchoring length for different positions of pile supporting are 10 m and 12 m respectively,and the optimal pile spacing are 6 m and 7 m respectively.