转折型沟谷对地震崩塌体块石拦截效果分析

INTERCEPTION EFFECT OF STREAM VALLEY BENDS TO ROCK FALL BLOCKS IN WENCHUAN EARTHQUAKE

在现场调查和统计的基础上,分析了青川县东河口地震型崩塌体200余块块石沿转折型沟谷的分布特征和各不同体积组块石的分布特征。提出块石拦截率概念,并据此从数量和体积2个角度定量分析了沟谷拐弯段对块石的拦截效果。分析认为:转折型沟谷在控制块石的运移方面具有积极作用;相比小体积块石,沟谷拐弯段对大体积块石具有更好的拦截效果;从数量上来看,沟谷内靠近崩塌堆积体后壁的拐弯拦截块石相对较少。本文的分析思路及方法为认识和研究转折型构筑物及其拐弯在控制崩塌体运移等方面提供参考,所得结论为人类防治崩塌灾害等方面提供借鉴。

On the basis of the investigation and the statistics on site,this paper studies the distribution characters of the whole and different volume groups＇ rockfall of more than 200 blocks along the bended valley at Donghekou in Qinchuan town.The rockfalls happened during the 2008 Wenchuan Earthquake.The concept of rock blocks interception rate are given on the basis of statistical information.Then,the interception effect of the turning point and the rock blocks＇ distribution in the valley are analysed quantitatively from the point of the rock block number and the rock block volume.The conclusions are given as follows： the valley bend has the positive effect on controlling the following of the rockfall blocks;the larger the rock block,the bigger possibility intercepted at the point.From the view of the number,the bend turning point near the rockfall resource intercepted more rock blocks than that near the foot of the mountain.The method and the conclusions give the support to research bended valley and its turning point controlling the migration of the rockfall deposits,and also give some reference for preventing the rockfall hazards.