RESEARCHES ON THE GEO-HAZARDS TRIGGERED BY WENCHUAN EARTHQUAKE,SICHUAN
RESEARCHES ON THE GEO-HAZARDS TRIGGERED BY WENCHUAN EARTHQUAKE,SICHUAN
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发表时间：
2008
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通讯作者：
Yin Yueping
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作者：
Yin Yueping
汶川地震引发山体滑坡、岩崩、泥石流15000多处，直接造成约20,000人死亡。潜在地质灾害点10,000多处，其中斜坡崩塌增加最为明显，表明地震对山区陡坡有明显异常作用。特别是，对地震形成的堰塞湖水量、滑坡坝高及其碎屑物成分和结构进行了综合分析，并对33个坝高大于10 m的滑坡坝进行了评价，结果表明，将滑坡坝分为极高、高、中、低4种溃坝潜势类型，地震诱发滑坡的滑床多为不连续的平坦滑床。“尖点碰撞”是滑坡的主要特征。滑床可分为勺形、隆起形和阶梯形。现场调查表明，滑坡附近被地震摧毁的建筑物的垂直振动明显。滑坡分为三个阶段：甩出地面震荡、碰撞坍塌破碎、高速滑动流动，在高速滑动流动过程中，会产生三种效果：（1）高速气床效应，滑坡体由较大的岩块和土体组成，有足够的厚度，飞行距离1 ~ 3 km。(2)破碎的泥石流作用，碰撞破碎的土石处于流动状态，特别是其中含有丰富的水分，形成长距离的流滑。(3)铲刮、巨大的碰撞力使下部岩石崩塌，形成新的滑坡和崩塌，它们的厚度并不大，滑动床也不是，以北川县西部和青川县东河口两个滑坡为例，分析了高速长距离滑动的机理和地震灾害的形成滑坡。北川县西部的滑坡掩埋了1,600人，摧毁了数百间房屋和建筑物，这是地震引发的最严重的滑坡灾害，也是世界上最大的滑坡灾害。青川东河口滑坡：泥石流是一种典型的地震诱发的高速、长距离滑坡，其分布范围约为2，泥石流高速冲至清江左岸形成滑坡坝，造成7个村庄被埋，近400人死亡。
Wenchuan Earthquake triggered landslides,rock collapses and debris flows at more than 15000 sites,which directly caused about 20,000 fatalities.There are more than 10,000 sites of potential geo-hazards,where an increase in slope collapses is mostly noticeable,which shows the earthquake has substantially abnormal actions on steep slopes in the mountains.In particular,the amplifications at mountain peaks is extremely evident.A comprehensive analysis of quake lake volumes,landslide dam heights and their debris compositions and structures was carried out.An assessment on the 33 landslide dames of dam heights great than 10 m formed by the earthquake was further conducted.Consequently,the landslide dams were classified into four types of the dam burst potential : extremely high,high,intermediate and low.The sliding beds of the landslides induced by the earthquake usually have non-continuous flat sliding beds."Sharp point collision" is a common and major characteristic.The sliding beds can be classified into spoon-shaped,raised-shaped and staircase-shaped.Site investigations demonstrate that the vertical vibrations in buildings destroyed by the earthquake adjacent to the landslides were evident.The landslides have three stages: throwing out of ground shocking,collision and collapsing and broken,and high-speed sliding flow.During the high-speed sliding flow,three effects were occurring:(1) high-speed air-bed effect,landslide debris were comprised with larger rock blocks and soils,had enough thickness and the flying distance of 1 to 3 km.(2) Broken debris flow effect,collision broken soils and rocks were in a flowing state,especially they contained abundant water,forming long distance flow sliding.(3) Shovel and scraping,huge collision forces induced collapse of rocks at lower portion,which formed new landslides and collapses,however,their thicknesses are not large and the sliding beds were non-smooth and irregular.The two landslides at western Beichuan county and Dongheko of Qingchuan county were analyzed in detail.They are used as examples to analyze the mechanism of the high speed and long distance sliding and hazard formation of earthquake landslides.The landslide at western Beichuan county buried 1,600 people and destroyed several hundreds houses and buildings,which is the severest landslide disaster triggered by the earthquake and is a rear event in the world.The Donghekou landslide at Qingchuan: Debris flow is a typical high speed and long distance landslide triggered by the earthquake.Its distrace is about 2,400 m.Its high-speed debris flew to the left bank of Qingjiang river and formed landslide dam,resulted 7 villages buried and about 400 fatalities.