大型高速滑坡锁固段破裂震动触发启程剧动机理研究

The mechanism of large high-speed landslide has long been a worldwide and advanced topic since 1960s. A large high-speed landslide always has a big locked segment whose sudden rupture always triggers a big quake. This quake is considered to be the main mechanism for initial intense departure of a high-speed landslide in this proposal. The properties of the quake and the triggering mechanism for initial intense departure are studied with the compounded use of instance analysis, model experiment and numerical simulation. The formation, spectrum characteristics and transferring mechanism will be firstly studied by the use of instance analysis and model experiments. Then three mechanisms for the initial intense departure will be then studied, including the ejection of the rock mass under the coupling of gravity and the seismic force, dramatic increasing of pore pressure due to the quake, and the thixotropic behavior of clay because of the quake. The results will help in the understanding, prediction and control of large high-speed landslides. Also, they will provide some theoretical references for large hydraulic engineering, urban and rural constructions, railways, road survey and designs. The overall objectives of disaster prevention and mitigation can be then targeted.

二十世纪六十年代以来，大型高速滑坡高速滑动机理已成为滑坡研究的世界性前沿课题。但关于滑坡锁固段破裂震动触发自身启程剧动方面的研究不多。大型高速滑坡锁固段规模大，其剪切破裂会产生剧烈震动，震动力可能以抛射方式触发滑体启动；锁固段的裂隙岩体可能充水或夹泥，震动作用下的孔隙水压力剧增及饱和黏土触变也会对滑坡的启程剧动有重要影响。基于此，本课题以锁固段破裂震动为主线，采用理论分析、模型试验和数值模拟相结合的研究方法，首先研究锁固段破裂震动的形成、波谱特征及传播特性；在此基础上研究其触发滑体启程剧动的机理，包括重力和地震力耦合条件下滑体向坡外的斜抛效应、滑带饱水孔隙水压力剧增效应、黏土触变效应。研究结果可为大型高速滑坡的预测和防治，为大型交通及水利工程、城乡建设的勘察设计提供理论依据，达到防灾减灾的总目标。

大型高速滑坡高速滑动机理是滑坡研究的世界性前沿课题，经过半个多世纪的研究，取得了诸多研究成果，但关于滑坡锁固段破裂震动触发自身启程剧动方面的研究不多。本课题从锁固段破裂震动效应出发，采用理论分析、模型试验相结合的研究方法，首先研究锁固段破裂震动的形成、波谱特征及传播特性；在此基础上研究其触发滑体启程剧动的机理，即重力和地震力耦合条件下滑体向坡外的斜抛效应。探索了锁固段破裂震动特征参数与岩性、剪切方向、锁固段面积占比（锁固段与整个滑面的面积比）等因素间的关系，提出滑坡震动力的估算方法；研究了锁固段破裂震动对滑体的影响，研究表明锁固段附近滑体在强大的震动力作用下，不但会发生节理岩体破碎，而且会在震动力和重力的耦合作用下发生向坡外的斜抛，即滑体的弹射（抛射）；在此基础上，研究大型高速滑坡启动过程及启动加速度、启程速度计算方法。研究结果可为山区重点基础建设工程沿线大型高速滑坡预测和防治提供理论依据。