Deformation Mechanism and Reinforcement Effect for Slope Excavated in Complex Accumulative Formation
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摘要: 针对某电力工程换流站高挖方边坡，分别采用极限平衡法和强度折减法对边坡的稳定性和变形特征进行分析。分析结果表明，边坡的稳定性受降雨和地震作用影响显著，两种工况下边坡均处于不稳定状态，地震作用对斜坡地带堆积体结构形成损伤，不但使边坡整体稳定性下降，还促使坡体内裂隙大量发育，利于降雨入渗，进一步恶化边坡的水文地质条件，导致坡体孔隙水压力增加、有效应力降低。边坡加固设计采用桩板墙+坡面格构锚杆支护措施，加固后边坡稳定性系数达到1.406，最大总位移由加固前的425 mm降至9 mm，大幅提高边坡稳定性，表明防护方案能保障边坡安全性，达到防治和风险管控的目的。Abstract: For a high excavation slope of a converter station in a power engineering project, the stability and deformation characteristics of the slope were analyzed using the limit equilibrium method and the strength reduction method, respectively. The results showed that the stability of the slope is significantly affected by rainfall and earthquakes. The slope was in an unstable state under both working conditions. Earthquake induced damage to the accumulation structure of slope zones. Not only does it reduce the overall stability of the slope, but it also promotes the extensive development of cracks within the slope. It was beneficial for rainfall infiltration and further deteriorating the hydrogeological conditions of the slope, and it caused an increase in pore water pressure and a decrease in effective stress in the slope. The slope reinforcement design adopted the support measures of pile sheet wall and lattice anchor rod. The stability coefficient of the reinforced slope reached 1.406, and the maximum total displacement decreased from 425 mm before reinforcement to 9 mm. It significantly improved slope stability and indicated that the protection plan can ensure the safety of the slope and achieve the purpose of prevention and risk control.
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表 1 岩土物理力学参数
岩土名称 天然重度
γ/（kN·m−3）饱和重度
γsat/（kN·m−3）天然抗剪
强度饱和抗剪
强度c/kPa φ/(°) c/kPa φ/(°) ②1松散碎石层 19.0 20.0 5 25 2 21 ②2稍密碎石层 20.0 21.0 10 28 8 24 ②3中密–密
实碎石层21.0 22.0 15 31 12 25 ④层强风化
片岩、千枚岩22.0 22.0 28 30 20 28 
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表 2 极限平衡法计算结果
计算工况 稳定性系数 稳定状态 安全系数 天然 1.001 欠稳定 1.35 暴雨 0.727 不稳定 1.25 地震 0.667 不稳定 1.15 地震+暴雨 0.660 不稳定 1.05
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表 3 边坡稳定性系数对比
计算工况 稳定性系数
（极限平衡法）稳定性系数
（Geo-Studio）天然工况 1.001 1.121 暴雨工况 0.727 0.881 地震工况 0.667 0.846 暴雨+地震 0.660 0.713
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