2001年昆仑山口西8.1级地震区的冻土及地震破坏特征

The Frozen Soils and Devastating Characteristics of West Kunlun Mountains Pass M_s8.1 Earthquake Area in 2001

通过对 2 0 0 1年昆仑山口西 8 1级地震区冻土震害考察研究表明 ,震区主要存在冰碛、冲积、洪积和湖积等成因的冻土 ,沿地震破裂带冻土厚度变化较大。震区冻土变形破坏主要包括地震构造成因的地震破裂带和由地震振动引起的裂缝、液化、震陷和崩塌等。冻土中地震破裂带在地表主要以脆性变形为主 ,在地震断裂左旋走滑运动作用下 ,主要由剪切裂缝、张裂缝和开裂的挤压鼓包等组成。裂缝、液化、震陷和崩塌等变形破坏的展布特征及其组合形式与震区岩土与环境条件密切相关 ;本次地震震害具有地震破裂带规模大、有建筑物分布的青藏公路一线地震烈度衰减较快和震害分布受岩土条件影响大等特点。

The investigation and study of seismic hazard in frozen soils deposit region by the West of Kunlun mountain pass M S 8.1 earthquake in 2001 shows that there is frozen soils distribution in the region, which mainly result from the glacial deposit, alluvial deposits, deluvial deposits, lacustrine deposits, and of which the depth varies greatly along the rupture. The forms of devastation mainly include earthquake surface ruptures, caused by structure factor, fractures, liquefaction, seismic subsidence, collapse, caused by seismic shaking. The earthquake rupture in frozen soils mainly shows brittle deformation, and is composed of shear fractures, tension fractures and seismic ridges caused by the left-lateral motion of the seismic fault. The displaying features and composition forms of the fractures, liquefactions, subsidences and collapses are closely related to rock and environment. The devastation of this earthquake characterizes huge surface deformation,fast decline of intensity along the rupture belt on the Qinghai-Xizang road where there are buildings on, and distribution of seismic hazard influenced by geotechnical engineering's.