鄂北调水工程膨胀土渠道滑坡破坏机理及处置措施研究

发布时间：2018-12-19 17:46

【摘要】：基于鄂北调水工程109+620—109+800段典型膨胀土渠道滑坡现场调研资料与试验数据,从裂隙、大气降雨、施工及防护措施等方面对膨胀土渠道滑坡原因进行了探讨,研究了膨胀土滑坡的破坏机理,同时采用刚体极限平衡法(M-P法)对优化设计施工前后的边坡抗滑稳定安全系数进行了模拟分析验证。结果表明:该膨胀土渠道滑坡主要受土体裂隙控制,雨水的劈裂作用起到连通贯穿裂隙的作用;上部弱膨胀土在大气降雨影响下发育陡倾角裂隙,往往形成滑坡体后缘下挫变形;坡脚及基底中等膨胀土发育无规则缓倾角长大裂隙,为边坡滑动提供软弱滑动面或滑动带,形成滑坡前缘;久强降雨软化边坡表层土体,降低其强度,同时雨水进入裂隙中对土体起到破裂作用;多次干湿循环贯通土体各向异性裂隙,生成深层软弱滑动面或滑动带;施工不当与防护措施不足是导致此次膨胀土滑坡的人为因素。为保障工程后期膨胀土边坡稳定,应遵循快速施工、地质预测、动态设计、及时封闭、尽早回填的原则,选择合理边坡坡比,建设有效排水系统并硬化顺延覆盖一级边坡,对边坡垮塌或滑动进行实时监控量测。
[Abstract]:Based on the field investigation data and test data of typical expansive soil channel landslide in 109620-109,800 section of water transfer project in northern Hubei, the causes of expansive soil channel landslide are discussed from the aspects of cracks, atmospheric rainfall, construction and protection measures, etc. The failure mechanism of expansive soil landslide is studied, and the stability safety factor of slope before and after optimization design and construction is simulated and verified by rigid body limit equilibrium method (M-P method). The results show that the landslide of the expansive soil channel is mainly controlled by the soil fissures, and Rain Water's cleavage plays the role of connecting through the fissures. Under the influence of atmospheric rainfall, the upper weakly expansive soil develops steep dipping fissures, which often result in the collapse and deformation of the back edge of the landslide body. At the foot of the slope and the medium expansive soil of the basement, the long cracks with irregular slowly inclined angle are developed, which provide the weak sliding surface or the slip zone for the slope slide, and form the landslide front edge. The surface soil of the slope is softened by heavy rainfall and its strength is reduced, at the same time Rain Water enters into the fissure to break the soil, and dry-wet circulation penetrates through the anisotropic fracture of the soil for many times, forming deep weak sliding surface or sliding zone. Improper construction and inadequate protective measures are the human factors leading to the expansive soil landslide. In order to ensure the stability of expansive soil slope in the later stage of engineering, we should follow the principles of rapid construction, geological prediction, dynamic design, timely closure and early backfilling, select a reasonable slope ratio, build an effective drainage system and harden and cover the first grade slope. Real-time monitoring and measurement of slope collapse or slippage.
【作者单位】：湖北省水利水电规划勘测设计院;
【分类号】：TV698

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