偏压隧道边坡桩锚支护加固效果的数值分析

Numerical Analysis of the Effect of Bolt and Pile Support on Slope in Unsymmetrical Pressure Tunnel

为分析锚拉桩与抗滑桩组成的桩锚支护对偏压隧道边坡的加固效果,以某软弱围岩隧道为背景,建立三维弹塑性有限元模型进行分析,重点分析了桩锚加固与无加固状态下的边坡剪应变,水平与竖直位移,坡底抗滑桩轴力。结果表明,坡体剪应变在岩层交界面上最大,桩锚加固使得边坡的剪应变减小了42.8%;右线隧道拱脚的水平位移最大,桩锚加固使得边坡"U"形区范围明显缩小;竖直位移随着岩层深度的增加逐渐减小,桩锚加固使得坡底到坡中心的竖直位移减小了63%;桩锚加固状态下,坡底靠近临空面的抗滑桩轴力最小,其余抗滑桩轴力大小接近。

To analyze the reinforcement effect of bolt and pile support which serves as the protective measures on slope in unsymmetrical pressure tunnel, taking a tunnel in soft rock as the background, using FEM to establish three-dimensional elastic-plastic model for numerical simulation, analysis focuses on the shear strain of slope on bolt and pile foundation, the horizontal and vertical displacement, as well as the axial force of the pile along the bottom of the slope. The results show that bolt and pile support makes the slope shear strain decreased by 42.8 % in rock interface; the horizontal displacement reaches the maximum in the arch foot of right line tunnel, bolt and pile support makes the ＂U＂ type area reduced significantly; the vertical displacement decreases with the increase of the rock depth, bolt and pile support makes vertical displacement reduced by 63% from the center position to the bottom of the slope; and axial force of the pile emerge the minimum near the free face, the rest is close to the number under the condition of the bolt and pile support.