高速岩质滑坡启动弹冲加速机制及弹冲速度计算——以武隆县鸡尾山滑坡为例

高速岩质滑坡启动弹冲加速机制是开展高速岩质滑坡全过程动力学研究的基础。系统阐述了高速岩质滑坡启动弹冲加速机制,着重分析了岩质滑坡启程中的滑带释能和锁固体释能加速效应。基于岩石循环加、卸载试验,探讨了岩石弹性应变能释放规律,并将得到的规律用于确定滑带可释放弹性应变能。鉴于目前确定滑坡启动弹冲速度所存在的诸多问题,重新推导了滑坡启动弹冲速度计算公式,并对鸡尾山滑坡启动弹冲规律进行了研究。研究表明,鸡尾山滑坡启动弹冲速度为1.261 1 m/s,滑体初始动能主要源于滑带弹性应变能的释放。最后通过一个滑坡概化模型计算得到了岩质滑坡启动弹冲的极限速度范围为2.6⁴.4 m/s。

Starting-elastic-impulsive acceleration mechanism of high-speed rockslide and elastic-impulsive velocity calculation: Taking Jiweishan rockslide in Wulong,Chongqing for example

Starting-elastic-impulsive acceleration mechanism of high-speed rockslide is the foundation of carrying out the research of full course dynamics mechanism of high-speed rockslide. The starting-elastic-impulsive acceleration mechanism of high-speed rockslide is systematically expounded and attributed to two acceleration effects of energy release of sliding zone and energy release of locking block. In order to explore the releasing law of elastic strain energy in rock, cyclic loading and unloading tests of rock are carried out. Meanwhile, the results are applied to calculate the releasable elastic energy for determining elastic-impulsive velocity. Considering the problems in determining the elastic-impulsive velocity in current methods, a new formula for calculating starting-elastic-impulsive velocity is deduced based on the constitutive equation of the sliding zone and the releasing law of elastic strain energy in rock. Jiweishan rockslide is studied using this new method. The results show that starting kinetic energy is mainly provided by the elastic energy of sliding zone rather than the elastic energy of locking block. The total starting-elastic-impulsive velocity of Jiweishan rockslide is 1.261 1 m/s. Finally, the extreme velocity ranges from 2.6 to 4.4 m/s obtained by a generalized sliding model.