考虑分级开挖卸荷下岩质高边坡变形演化机制与支护效应研究

Research on the Deformation Evolution Mechanism and Support Performance of High Rock Slopes Considering Progressive Excavation Unloading

摘要: 本文以华中地区某公路岩质高边坡为工程背景，采用数值模拟方法研究其在分级开挖与支护过程中的稳定性演变规律。基于Abaqus有限元分析软件，建立考虑开挖卸荷效应的边坡二维模型，选用Mohr-Coulomb本构模型表征岩土体力学行为，并通过强度折减法系统评价边坡安全系数。研究分析了边坡在逐级开挖过程中的位移场演化、应力场演化、塑性区发展及安全系数的变化特征，对比了锚杆框架梁支护措施实施前后边坡稳定性的响应差异。结果表明：边坡位移随开挖深度增加而显著增大，位移集中区由坡脚逐渐向中上部扩展；边坡拉应力随开挖级数不断增大，拉应力集中区由坡面逐渐向坡内扩展；支护结构可有效抑制塑性区贯通，显著提升边坡安全系数；“开挖一级、加固一级”的施工策略能有效控制边坡变形，保障施工期稳定。本研究为该类岩质高边坡工程的稳定性分析与控制提供了理论依据与方法参考。

Abstract: This paper investigates the stability evolution of a high rock slope in a highway located in central China during staged excavation and support, using numerical simulation methods. Based on the Abaqus finite element analysis platform, a two-dimensional slope model considering excavation unloading effects is established, with the Mohr-Coulomb constitutive model adopted to characterize the mechanical behavior of the rock and soil. The strength reduction method is employed to systematically evaluate the slope safety factor. The evolution of the displacement field, the development of plastic zones, and the variation of the safety factor during graded excavation are analyzed. The differences in slope stability response before and after the implementation of anchor rod-frame beam support measures are compared. Results indicate that slope displacement increases significantly with excavation depth, and the displacement concentration zone gradually expands from the slope toe to the mid-upper part. The support structure effectively inhibits the connection of plastic zones and significantly improves the safety factor. The construction strategy of “excavate one level, reinforce one level” proves effective in controlling slope deformation and ensuring stability during construction. This study provides a theoretical basis and methodological reference for the stability analysis and control of similar high rock slope engineering.