基于滑体与受灾体共同作用的冲击能计算模型

CALCULATION MODEL OF IMPACT ENERGY BASED ON INTERACTION OF LANDSLIDE MASS AND DISASTER-AFFECTED BODIES

滑坡冲击能计算是准确评估受灾体易损性的重要依据。对滑坡致灾过程能耗机制分析发现,滑体在下滑及冲击受灾体过程中,由于内部崩解碰撞将会耗散部分能量。基于滑体与受灾体冲击过程能耗机制提出冲击能计算方程组。结合实际,采用斜率为滑体变形模量的斜线逼近滑体真实变形曲线,将受灾体简化为弹性悬臂梁,从而在冲击能计算方程的基础上推导出滑体冲击能简化计算模型。同时提出一种能直观反映冲击能大小的指标,称之为冲击效应系数。该系数反映出冲击能和滑体内部耗能是由受灾体与滑体变形特性共同决定的。受灾体相对滑体越坚固,冲击效应系数越大,则冲击能越小,滑体内部耗能越大;受灾体相对滑体越脆弱,冲击效应系数越小,则冲击能越大,滑体内部耗能越小。结合工程实例,介绍冲击能简化计算步骤。最后通过实例表明冲击过程中滑体内部将会耗散绝大部分能量,与前期模型实验反映的规律在定性上是一致的。

Impact energy is an important basis for landslide vulnerability assessment. Internal collapse of landslide mass dissipates part of the kinetic energy in the process of landslide. Calculation equations of impact energy are proposed based on the study of interaction mechanism between landslide mass and disaster-affected bodies. Based on the equations, a simplified model for impact energy calculation is put forward. At the same time, a coefficient of impact effect is defined, which can reflect the impact energy intuitively. The coefficient of impact effect indicates that the impact energy and internal energy dissipation of landslide mass are determined together by the characteristics of landslide and disaster-affected bodies. Increment in the coefficient of impact effect means that the impact energy decreases and the internal energy dissipation of landslide mass increases： and vice versa. The results of case study show that the impact energy calculated by the simplified model is consistent with those obtained by experiments, and it is more accurate than the result calculated by the method without consideration of the internal energy dissipation.