| 汶川八级地震触发何家沟碎屑流滑坡基本特征及形成机理 |
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| 引用本文： | 郑勇,韩刚,赵其华.汶川八级地震触发何家沟碎屑流滑坡基本特征及形成机理[J].地质灾害与环境保护,2009,20(4):86-90. |
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| 作者姓名： | 郑勇 韩刚 赵其华 |
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| 作者单位： | 1. 四川省地质环境监测总站,成都,610081
2. 成都理工大学环境与土木工程学院,成都,610059 |
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| 摘 要： | 汶川地震造成大量次生斜坡地质灾害，包含崩塌、滑坡及泥石流等灾种，其中以滑坡分布最为广泛、破坏力最强，且多以高速碎屑流为表现形式，何家沟滑坡即是其中典型例证。滑坡距发震断裂——映秀-北川南枝断裂不足5km，震前斜坡为双向临空的单薄山脊，其走向与断裂走向小角度相交，岩层走向与坡面斜交，中风化基岩结合紧密，结构面延伸性较好，强风化基岩较破碎，浅表部残坡积物较为松散。调查分析表明：残坡积物与强风化基岩是碎屑流滑坡的物质基础；中风化基岩面构成碎屑流滑坡滑床；斜坡临空面是滑坡产生的地形条件；高强度、长历时强震是导致滑坡产生的根本因素。滑坡的形成经历以下4个阶段：强震导致坡体表层残坡积物与强风化基岩松弛和解体；在强震作用下滑体从高位整体下错；松散物质沿中风化基岩面溃滑形成碎屑流和碎屑流堆积阶段。碎屑流产生后，受地形限制，停积于沟床内，在随后的“9．24”特大暴雨过程中进一步转化为泥石流次生灾害。
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| 关 键 词： | 汶川地震 碎屑流滑坡 形成机理 次生灾害 |
BASIC CHARACTERTISTIC AND FORMATION MECHANISM OF CLASTIC FLOW LANDSLIDE AT HEJIAGOU OCCURRED DURING THE WENCHUAN EARTHQUAKE |
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| ZHENG Yong,HAN Gang,ZHAO Qi-hua.BASIC CHARACTERTISTIC AND FORMATION MECHANISM OF CLASTIC FLOW LANDSLIDE AT HEJIAGOU OCCURRED DURING THE WENCHUAN EARTHQUAKE[J].Journal of Geological Hazards and Environment Preservation,2009,20(4):86-90. |
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| Authors: | ZHENG Yong HAN Gang ZHAO Qi-hua |
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| Institution: | ZHENG Yong , HAN Gang , ZHAO Qi-hua (1. General Geo-environmental Monitoring Station of Sichuan Province, Chengdu 610081 China; 2. College of Environment and Civil Engineering,Chengdu University of Technology,Chengdu 610059 China) |
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| Abstract: | Wenchuan Earthquake caused a large number of secondary slopes, geological hazards; including collapse, landslide, debris flow and other kinds of disasters, of which the landslides is the most widely distributed and caused the most damaging, and often manifested as high-speed clastic flow. The Hejiagou landslide is a typical example. The distance of the landslide and the triggering seismic fault, Yingxiu-Beichuan fault is less than 5 km. The slope is bidirectional empty tenuity ridge, its small angle toward the intersection with the fault trend, rock trend and slope surface skew. Medium weathering bedrock is linked closely together, and structural planes extend long. Strong weathering bedrock is crushing, superficial talus material and residual deposit is loose. Investigation indicates that., talus material, residual deposit and strong weathering bedrock are material base of clastic flow landslide; medium weathering bedrock face is landslide bed; The empty face of slope is terrain condition, high strength; long time strong earthquake is the basic factor of landslide. The formation of landslide can be divided into the four stages as follow：Strong earthquake leads to superficial talus material and residual deposit and strong weathering bedrock disintegrate, he materials slipped from the high overall under the action of the strong earthquake, loose materials slide along medium weathering bedrock face forming clastic flow, and clastic flow accumulated. Subjected to terrain constraints, clastic flow accumulated in ditch bed, in the subsequent ＂9.24＂ torrential rain, and became further into a debris flow during the secondary disasters. |
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| Keywords: | Wenchuan Earthquake elastic flow landslide formation mechanics secondary disaster |
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