地震型砾岩崩塌体运动学特征分析

An analysis of the kinematics characteristics of the gravel rockfall deposit induced by earthquake

汶川地震在工程区诱发了大量的崩塌灾害,提供了大量的"天然崩塌试验"现象。本文以汶川地震诱发的都江堰青城后山红岩度假区的大型砾岩崩塌体作为研究对象,主要分析了它的运动学特征。通过测量获得崩塌体最大位移块石运移边界角(reach of angle)。结合现场调查和数值模拟,得出坡体植被及人工构筑物的遮挡作用是导致研究对象运移边界角数值偏大的主要因素。统计该崩塌堆积体沿沟谷延伸方向的块石分布情况,并分析沟谷拐点处块石大小比例及各大小块石数占统计区相应大小块石总数的比例。得出大块石(>1m3)在滚落过程中,平均约有总数量的1/4被截留在了拐点处。作者认为,充分分析自然力作用下的典型崩塌体的分布及运移等特征对于崩塌的运动学研究及人类的防灾减灾工程具有重要的参考和指导。

The Wenchuan earthquake caused lots of rockfall in the engineering area,supplying many phenomena of the＂natural rockfall tests.＂ The huge gravel rockfall deposit that was caused by the Wenchuan earthquake in the Hongyan holiday resort of Du Jiangyan,Qing Chenghou mountain is analyzed and the focus of this paper is mainly on analyzing its kinematics characteristics.The value of the reach of angle of the rockfall deposit was measured in the site.The reasons leading to the number of the angle larger than the obstruction of the plants and the building over the original slope are analyzed with the methods of investigation and numerical simulation.Statistics of the distribution of the rockfall deposit along the valley were gained by analyzing the portion of different sizes of the rock blocks at the turning of the gravel,and the portion of the numbers of different sizes of the rock blocks at the turning at the whole statistical region.By the analysis,1 / 4 of the number of the whole rock blocks（ 〉1 m3）were trapped at the turning of the gravel on average.The results show that it is of great significance to research the kinematics of the rockfall deposits and to decrease the rockfall hazards by analyzing the characteristics of distribution and migration of the rockfall deposit caused by natural forces.