束口式锁固型滑坡演化失稳机理试验研究

Experimental Study on Failure Mechanism of Arch Locked Segment Landslides

锁固型滑坡演化失稳机理对滑坡预警预报具有十分重要的意义,物理模型试验是研究滑坡变形演化的有效方法之一。通过自制的束口式锁固型滑坡物理模型试验装置,利用三维激光扫描仪、微型土压力传感器、高清相机等对滑坡形态、应力、位移等进行高精度监测,开展了束口式锁固型滑坡的演化失稳机理试验研究。利用竖向位移云图、坡面形态变化、土压力、深部位移,监测束口式锁固型滑坡应力响应特征及变形特征,分析了束口式锁固型滑坡演化失稳过程,进一步揭示了束口式锁固型滑坡失稳机理。试验结果表明:锁固段有着明显的锁固效应,束口锁固段对滑坡的稳定性起到重要的控制作用;束口式锁固型滑坡的失稳过程可分为初始变形阶段、匀速变形阶段和加速变形阶段;根据束口式锁固型滑坡失稳过程,其演化机理可概括为:后缘推移—束口锁固效应—中部挤压堆积—锁固段压剪断裂—滑坡整体失稳。

The failure mechanism of locked segment landslides is of great significance to the early warning and prediction of landslides.Physical model tests are one of the effective methods to study the evolution of landslides.Through the self-made physical model test device for landslides with an arch locked segment failure mechanism,the landslide morphology,stress and displacement are monitored with high precision by using three-dimensional laser scanner,micro earth pressure sensor and high-definition camera,and the evolution failure mechanism test of arch locked segment landslide is carried out.The stress response characteristics and deformation characteristics of arch locked segment landslide are monitored by using vertical displacement cloud map,slope shape change,earth pressure and deep displacement.The evolution and failure mechanism of arch locked segment landslide is analyzed,and the failure mechanism of beam mouth locked landslide is further clarified.The results are as follows.Firstly,the locking section has an obvious locking effect,and arch locked segment plays an important role in controlling the stability of the landslide.Secondly,the instability process of arch locked segment landslide can be divided into the initial deformation stage,the constant deformation stage and the accelerated deformation stage.Thirdly,according to the instability process of arch locked segment landslides,the evolution mechanism can be summarized as follows:rear edge of sliding mass shifting-locking effect-squeezing action accumulates at the middle of the sliding mass-compressive and shear fracture occurs in the locked segment-complete landslide failure occurs.