龙门山断裂带及附近区域地貌形成与地应力演化机制研究  

Geomorphic formation and crustal stress evolution mechanism in the Longmenshan fault zone and its adjacent regions

作　　者：师皓宇[1,2] 马念杰[1] Shi Haoyu;Ma Nianjie(School of Resources and Safety Engineering, China University of Mining and Technology, Beijing, Beijing 100083, China;School of Safety Engineering, North China Institute of Science and Technology, Beijing 101601, China)

机构地区：[1]中国矿业大学(北京)资源与安全工程学院,中国北京100083 [2]华北科技学院安全工程学院,中国北京101601

出　　处：《地震学报》2018年第3期332-340,共9页Acta Seismologica Sinica

基　　金：国家自然科学基金重点资助项目(51434006)资助

摘　　要：以龙门山附近区域水平运动特性以及深部岩体力学特性为基本条件,采用FLAC模拟软件计算分析了龙门山断裂带及附近区域的地貌形成过程和地应力演化机制。研究结果认为:区域板块运动是龙门山地貌形成的重要原因,龙门山3条断层在62万年内的相对滑移速率分别为1.53,0.245和0.458 mm/a,与实际监测结果基本吻合;龙门山断裂带左侧呈抬升趋势,右侧四川盆地的垂向运动保持稳定;随着区域板块的运动,3条断裂带附近主应力的变化均经历了3个阶段,即应力低态稳定阶段,应力增高阶段和应力高态稳定阶段,最终形成应力积聚—应力释放的平衡局面;断裂带附近的最大、最小主应力比值介于2.94—3.71之间,平均为3.3,与实际监测结果基本吻合。由此可以推断,龙门山及附近区域将长期处于高偏应力环境,即长期处于"应力累积—进入临界状态—发震—新的应力累积"的地震周期。Took Longmenshan regional kinematic characteristics and mechanical characteristics of deep rock mass as basic condition,we used FLAC simulation software to analyze geomorphic process of Longmenshan fault and the crustal stress evolution mechanism of its adjacent area. The results show that regional plate motion was the important reason of the Longmenshan landforms formation,and the relative slip velocities of three faults in Longmenshan are1.53,0.245 and 0.458 mm/a respectively,which basically coincide with the actual monitoring results. The left region of Longmenshan fault zone is uplifted,while the right region that is the Sichuan basin remains stable. With the regional plate motion,there are three stages in the development of principal stress near the fault zone,which are the low-state stability stage,the increase stage and the high-state stability stage,and balance of stress accumulation-stress release is finally formed. The ratio of maximum and minimum principal stress near the fault zone is in a range of 2.94—3.71,and the average value is 3.3,basically coincide with the actual monitoring results. The following conjecture can be obtained that Longmenshan fault and its vicinity area will be in a high deviatoric stress environment for a long time,and will under the seismic period of ＂stress accumulation-entering the critical state-earthquake generation-new stress accumulation＂ for a long time.

关 键 词：区域构造运动 龙门山断裂带 数值模拟 地貌形成 地应力演化 

分 类 号：P313.4[天文地球—固体地球物理学]