叠瓦状逆断层的变形规律和力学机理物理模拟试验——以龙门山断裂带为例  

Physical Simulation Experimental Research on the Deformation Law and Mechanical Mechanism of Imbricated Thrust Fault: with Longmenshan Fault as an Example

作　　者：苏生瑞[1] 李鹏[1] 王琦[1] 苏卫卫[1] 张莹[1] 

机构地区：[1]长安大学地质工程与测绘学院,西安710054

出　　处：《吉林大学学报（地球科学版）》2014年第1期249-258,共10页Journal of Jilin University：Earth Science Edition

基　　金：国家自然科学基金重点项目(41030749);国家自然科学基金项目(41072223);中国地质调查局项目(1212010914205)

摘　　要：为了揭示叠瓦状逆断层在地质过程中的变形和应力变化规律,为地震预报和地质灾害防治提供参考,以龙门山断裂带为研究背景,采用大型物理模拟试验,再现了叠瓦状逆断层的演化过程。通过对模型内部位移和应变的实时监测,得出了叠瓦状逆断层的变形和应力分布规律:1)除下伏断层的下盘局部斜向下外,整个构造区的变形以沿断层带斜向上为主;断层带同侧,变形量深部大于浅表层;水平向变形随与挤压端距离的增大而逐渐减小,并伴有瞬间的跳跃性增大。2)研究区除在断层上盘的浅层出现局部的拉应力外,其余都处在压应力状态,深部应力及其释放量都大于浅层;应力不是线性的增大或减小,而是随挤压端位移的增大沿某个趋势上下震荡。地应力在下伏断层带附近更容易发生聚积和释放,在变化时间上深部先于浅层。浅层地应力呈现出先增大后减小再增大再减小的规律;深部地应力的释放在上覆断层两侧出现了跳跃性的减小,而下伏断层的两侧先出现瞬时的增大,然后才逐渐减小。3)浅层变形量和应力变化具有相同的规律和同步性,但均滞后于深部应力的变化。Adopting the large physical simulation experiment with the Longmenshan fault zone as the research background ,it reproduced the imbricated thrust fault evolution process .By the real-time monitoring of displacement and strain in inside of the model ,it was concluded the deformation and stress distribution law of imbricate thrust fault as follows ：1）The deformation of the whole tectonic region is inclined up along the fault zone except partly inclined down of underlying fault footwall ;the deep deformation is greater than shallow surface at the same side of fault zone ;the horizontal deformation＆amp;nbsp;gradually decreases with the increase of the distance from the extrusion end , and accompanied by instaneous jumping increase .2）T he research area is in compressive stress state except local tensile stress in the shallow of the upper wall ,and the deep stress and its release quantity are much greater than the shallow ;the stress does not increase or decrease linearly , but with the increasing displacement of extrusion end along a trend shocks up and down .The crustal stress near the underlying fault zone is more likely to appear accumulation and release .In the changing time ,the deep is jumping decrease ,but the both side of the underlying fault zone instantly increase at first then decrease gradually .3）The deformation and stress of shallow changes with the same rule ,but all are lagging behind the deep .

关 键 词：叠瓦状逆断层 龙门山 地应力 模拟试验 

分 类 号：P554[天文地球—构造地质学] P56[天文地球—地质学]