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以大型土工离心机为技术依托,采用离心模型试验,研究开挖和降雨对滑面为折线型的大型滑坡变形破坏和稳定性的影响。试验中采用变形标志点、颗粒图像测速技术(PIV)和可承受高离心力的传感器,在获取坡体土压力、孔隙水压力和位移矢量场的基础上,综合分析开挖和降雨诱发大型滑坡变形破坏的特征及失稳模式。试验结果表明,在滑面形态变化大的部位开挖卸荷容易引起折线型滑面大型滑坡的局部复活;受开挖卸荷和降雨影响,滑坡后缘的开挖斜坡位移最大且最先失稳;受降雨的影响,滑坡前部位移较大,坡体表面变形破坏严重,开挖斜坡下部发育一条次级滑裂面,滑坡后缘和开挖平台前沿滑面坡度突变处各形成一条潜在主滑裂面。离心模型试验显示折线型滑面的滑坡受开挖和降雨的影响可表现出分级分块滑动的变形破坏特征。稳定性分析表明,降雨使折线型滑面的大型滑坡不同滑段稳定性系数不同程度降低,滑坡后缘、开挖斜坡和滑坡前缘处于不稳定状态。
Based on the technical support of large-scale geocentrifugal centrifuge, the centrifugal model test is used to study the effect of excavation and rainfall on the deformation, failure and stability of large-scale landslide with sliding surface. In the experiment, deformation marker points, particle image velocimetry (PIV) and sensors capable of withstanding high centrifugal force were used to obtain the slope soil pressure, pore water pressure and displacement vector field. Based on the comprehensive analysis of large-scale landslide deformation induced by excavation and rainfall Damage characteristics and instability mode. The test results show that the excavation and unloading at the site where the sliding surface morphology changes greatly can easily lead to the local revival of the large-scale landslide with the fold-line sliding surface. Due to the influence of excavation unloading and rainfall, the displacement of the landslide trailing edge has the largest displacement and the first loss Stable. Due to the influence of rainfall, the displacement of front of landslide is large, and the deformation of surface of the slope is serious. A secondary slip surface develops in the lower part of excavation slope. The main slip surface. Centrifuge model tests show that the landslide of the polyline sliding surface can show the deformation and failure characteristics of the block sliding by the excavation and rainfall. Stability analysis shows that the rainfall causes the stability coefficients of different landslides of the fold line slip surface to decrease in varying degrees, and the landslide, excavation slope and landslide front are unstable.