考虑滑动过程内部崩解耗散的滑坡体运动模型

滑坡体运动模型是计算滑速、滑距及滑体动能等运动特征参数的基础,是滑坡致灾范围及致灾强度评估的关键技术,现有运动模型将滑体作为质点或刚性块体,没有考虑下滑过程中内部崩解摩擦耗散的能量,而实际滑坡中这部分能量对滑坡致灾强度指标有较大影响,为此,基于滑体下滑运动机理提出了一种考虑内部耗能的运动模型,该模型将滑体下滑运动抽象为变形体平面运动问题,并将滑体简化为内部变形受力服从滑体土直剪实验破坏后应力应变关系的质点黏壶系统,从而建立其运动学控制方程。还推导了黏阻力计算公式,与运动方程联立得出滑速、滑体动能、滑体重力势能、滑体内部耗能及滑距的计算公式。结合实际滑坡工程进行计算分析得出,该模型一定程度上反映了滑体运动过程中内部崩解摩擦耗能的规律,计算结果与离散单元模拟结果及模型试验规律相近,比传统的运动模型更贴近实际,且比数值模拟更简捷,为滑体运动模型理论研究和工程推广提供了一种新的途径。

Mobility assessment model for landslide mass considering disintegration energy consumption in slipping process

The mobility assessment model for landslide mass can be used in calculating the speed, sliding distance, impact energy and affected area of landslide. It’s the key technology for risk assessment of landslide. In the conventional methods, the landslide mass is usually assumed as the mass point or rigid block, and the dynamic assessment process does not take the disintegration energy consumption into account. An assessment model for landslide mass in slipping process considering the disintegration energy consumption is proposed. In the model, the landslide mass is assumed as a system consisting of two mass points and a dashpot, and the slipping process is simplified as a deformation body in plan motion. Furthermore the stress-strain characteristics of landslide mass follow the rules of soil residual strength from repeated direct shear tests. The motion equations of the mobility assessment model and the relevant formula for calculating viscosity resistance force of the dashpot are established. The equation is used to deduce the formula for intensity indexes (including slipping velocity, impact energy and sliding distance). As a case study, a landslide project is analyzed to illustrate this mobility assessment model. The results show that the proposed model conforms to the energy transformation rules of landslide mass, and its results are closer to the reality than those of the conventional methods. It is more convenient than the numerical methods.