推移式滑坡演化过程模型试验与数值模拟研究

利用MTS电液伺服加载与控制系统对推移式滑坡物理模型后缘进行了分级推力加载，完成了推移式滑坡演化全过程的模拟。基于三维激光扫描技术对滑体表面的位移和变形进行了高精度、全方位、非连续性监测。采用多重分形基本理论对监测点云数据进行了系统分析，从试验的角度探讨了推移式滑坡演化过程中位移多重分形维数的变化特征。模型试验结果表明：推移式滑坡变形破坏以沿滑带发生的整体滑移为主，并表现出明显的演化阶段性特征，大致可划分为3个阶段：（1）后缘压缩阶段：滑坡模型表面变形体现为后缘土体的局部前移与隆起，整体变形小，多重分形维数成降维的特征，降维过程中未发生突变、有序性好；（2）匀速变形阶段：滑坡模型表面产生了明显的位移，变形不断向前和向两侧发展，前缘、中部滑体发生隆起现象，多重分形维数表现出先减后增的趋势；（3）加速变形阶段：滑坡模型表面体现出持续、快速、变化鲜明的整体变形特征，伴随出现滑坡模型中前部隆起带及横向、纵向的隆胀裂缝，多重分形维数成增维趋势。基于模型试验，利用FLAC3D进行了推移式滑坡演化过程的动态数值模拟，验证了滑坡演化的阶段性特征，揭示了推移式滑坡演化过程中稳定性系数非线性递减的规律。

Model testing and numerical simulation study of evolutionary process of thrust load caused landslide

A physical model has been developed to study the whole evolutionary process of thrust load caused landslide under the multi-stage loading of MTS electro-hydraulic servo loading and analysis system. The displacement and deformation of the thrust load caused landslide model’s top surface are non-consecutively monitored with advanced 3D laser scanning technology. On the basis of multi-fractal theory, the variation of multi-fractal dimension of displacement in the evolutionary process of thrust load caused landslide is studied through the experiment. The experimental results show that the deformation and failure mode of thrust load caused landslide are dominated by general shear failure and it presents explicit developing phased characteristics. When the slope is in margin compressing stage, the deformation on the surface of the landslide is formed as some parts moving forward and uplift on the margin of the landslide, and the multi-fractal dimensions of displacement are decreasing orderly. When the slope is in uniform deformation stage, obvious displacement can be seen on the surface of the landslide model and the deformation keeps spreading to the front and sides of it. Uplift phenomenon can be seen in some parts in the front and center. During this stage, the multi-fractal dimensions of displacement decrease firstly, and then increase. When the slope is in accelerating deformation stage, landslide model surface presents sustained, rapid and obvious deformation associated with horizontal, vertical expansion cracks in the front and center part of it. During this stage, the multi-fractal dimensions of displacement are increasing gradually. Based on the landslide physical model test, FLAC3D numerical software is used to simulate the evolutionary process of thrust load caused landslide. It is verified that evolutionary process of landslide can be divided into the above three stages. Also the simulation discloses that the attenuation of the stability coefficient of landslide is nonlinear and the attenuation rate is decreasing.