三峡库区高切坡破坏模式分析及防护对策

受三峡水库蓄水影响,大量基础设施工程重建而形成了大量的高切坡,暴露出日益增多的地质灾害隐患.以湖北省宜昌市某高切坡为例,采用现场地质调查、工程经验类比和力学计算等手段,结合高切坡的地形地貌、地质结构及构造、地层岩性、岩体风化等特征,分析了该高切坡可能的破坏模式主要有整体滑移、局部剥落掉块、块体滑移、水砂流冲蚀、风化球滚落等.稳定性计算结果显示,桩号K0＋000～0＋040、K0＋214～0＋280、K0＋420～0＋642段,在暴雨工况下该段坡面稳定性较差,不满足规范要求;桩号K0＋040～K0＋214、K0＋280～0＋420段平面滑移计算安全系数小于1.35,安全储备不够.针对分析结果分段采用格构、锚喷治理措施,同时辅以排水、护脚墙及植被恢复等,形成安全、经济、绿色边坡.

Failure models and protective measures of highly incised slopes in area of three gorges reservoir

Affected by the Three Gorges Project,reconstruction of a large number of infrastructure projects resulted in a large number of high cutting slopes,which exposed the growing risks of geological disasters.We took a high slope in Yichang resident as a case,combing with its characteristics of high cut slope topography and geological structure and lithology,rock weathering,and used survey of field geological,analogy of engineering experience and mechanical calculations for the paper study.The possible overall slippage,partial peeling,block slipping,water sand erosion and weathered ball rolling are the possible failure modes of high cut slope.And the calculations shows the poor stability in Section K0＋000 to 0＋040,K0＋214 to 0＋280 and K0＋420 to 0＋642 in heavy rain conditions,which does not meet the regulatory;the safety factor of plane slipping calculation is less than 1.35 in Section K0＋040to K0＋214 and K0＋280 to 0＋420 with the low security margin.According to the above results,segmented protective measures of trellis and shotcrete are taken,supplemented by drainage,retaining walls and vegetation restoration to form a safe,economical and green slope.