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1、成都理工大学 硕士学位论文 汶川5.12地震诱发大光包巨型滑坡形成机理与运动特征研究 姓名：李世贵 申请学位级别：硕士 专业：地质工程 指导教师：黄润秋;裴向军 20100601 摘 要 I 汶川汶川 5.12 地震诱发大光包巨型滑坡地震诱发大光包巨型滑坡 形成机理及运动特征研究形成机理及运动特征研究 作者简介：李世贵，男，1980 年 9 月出生，师从成都理工大学黄润秋教授， 裴向军教授，2010 年 6 月毕业于成都理工大学地质工程专业，获得工学硕士学 位。 摘摘 要要 2008 年 5 月 28 日 14 时 28 分，四川汶川发生 Ms8.0 级地震，由于震级高， 持续时间长，释放能量
2、大，震区地质环境脆弱，地震诱发了大量崩塌、滑坡等次 生地质灾害，其中四川安县大光包滑坡是规模最大，初步估算滑坡体积在 7.42 亿 m 3左右，成因机理最为复杂的地质灾害体。 通过现场详细地质调查测绘及定性分析，运用三维离散元软件，对坡体动力 作用进行全过程数值模拟再现，得到如下基本结论及认识： （1）大光包巨型滑坡是在地震过程中，一次性整体溃裂滑动破坏后高速运动 产生，不存在次级或多级大规模滑塌破坏迹象； （2）大光包滑坡具有多项典型独特地质现象，主要有主滑体运动 1.6km 后 任未完全解体；未完全解体滑体前端逆冲推覆变形，形成鼓丘及岩层反翘，产 生强烈挤压剪切缝及长大拉张裂缝； 门槛石沟
3、南侧坡面一定高度范围内的植被 及浅层土层“不翼而飞” ，变形破坏原因独特；滑坡北侧断壁背坡发育多条长 大拉张裂缝，多处见深宽拉陷槽，后壁背坡却完好无损。 （3）滑坡动力形成机制及运动特征具有以下特点和阶段：坡体震裂松弛， 产生微张裂缝并不断向深部扩展；后缘破裂面和滑面及北侧破裂边界贯通，滑 床底部岩体在上覆厚重山体及地震竖向应力的反复拉压作用下被碾碎， 由于摩擦 产生的高温作用，已变成近似炭状颗粒；坡体由静摩擦向动摩擦状态转变，处 于不断被加速启动过程；当坡体被加速超过滑动临界值，发生整体溃屈式滑动破 坏， 滑体进入高速运动阶段； 滑体高速冲过黄洞子沟过程中， 发生 “气垫效应” ； 高速运动
4、滑体的前端与迎面山体强烈冲撞，岩体溃喷式解体形成碎屑流，整体 刚性骤然降低，主滑体中段及后段岩体产生逆冲推覆变形，缓冲减速，顺利实现 “软着陆” ，保持整体完整。 （4）数值模拟分析结果表明：滑坡形成及运动特征与定性分析及现场实际 地质现象基本吻合； 各监测点位移动力响应及速度和加速度动力响应时程曲线 成都理工大学硕士学位论文 II 形态特征及变化趋势具有整体一致性特点，这一点可以证明滑坡是一次性发生 的；坡体高高程及特殊地形位置地震动力响应强烈，尤其是条形单薄山脊端部 较为明显；地形起伏大及高程较高的位置加速度放大系数明显增大，沟谷放大 不明显。 关键词：关键词：地震诱发 巨型滑坡 地震动力
5、响应 形成机理 运动特征 Abstract III Study of the formation mechanism and dynamic characteristics of Daguangbao massive landslide induced by 5.12 wenchuan earthkuake Introduction of the author: Lishigui, male, was born in Sep, 1980 whose tutor are Professor Runqiu-Huang and Professor Xiangjun-Pei. He graduated
6、 from Chengdu University of Technology in geological engineering major and was granted the Master Degree in June, 2010. Abstract At 2:28 p.m. on May 28, 2008, Ms8.0 earthquake occurred in Wenchuan Sichuan， Because of high magnitude, long duration, large energy release, seismic zero vulnerability of
7、the geological environment, the earthkuake induced a large number of fallings 、landslides and other secondary geological disasters，in the ological disasters， Da guang bao landslide lying in An County Sichuan province is the largest and most complex mechanism body of geological disasters. the volume
8、of landslide is preliminarily estimated about at 742 million m3. Detailed geological mapping by field survey and qualitative analysis, The use of 3D discrete element software is to reach the role of slope dynamic numerical simulation of the whole process of reproduction, Obtain the following basic c
9、onclusions and the knowledge: (1) In the earthquake process Daguangbao massive landslide is the one-time production after the shattering for high speed movement, there is no large-scale secondary or several level collapse or failure phenomena; (2) Da guangbao landslide has typical and unique geologi
10、cal phenomenon:they are :The main landslide body after its movement 1.2km is not fully disintegrated; The front sliding body of incomplete disintegration reached to thrust deformation, rock drumlin formation and anti-Alice Produced a strong extrusion shear fractures and raised tension fracture;The s
11、outh slope plane of vegetation within a certain height and the shallow soil are “missing“,the reason of Deformation and failure are perfect unique;The back slope of the north failure surface develope a number of tension fracture, many see pull trapped deep groove width, but the back slope of landsli
12、de 成都理工大学硕士学位论文 IV back scarp is intact. (3) Landslide dynamic formation mechanism and the movement characteristics has the following characteristics and stages:Stage of slope shatering cracking and loosing, slightly open cracks starts to appear and to continue to produce more deep cracks extended;P
13、osterior fracture surface、south skid surface and north side of failure surface break through the border,Rock in the bottom of Sliding bed were crushed, after the overlying heavy mountain and seismic vertical stress produce repeated tension and compression, As the high temperature generated by fricti
14、on，the rack have become a near carbon-like particles;Slope from the static friction to dynamic friction state changes, at the start of the process of constantly being accelerated, When the slope is accelerated over the threshold,Daguangbao slope overally produced shattering-sliding rupture;During th
15、e process of the landslide High-speedly crossing huangdongzi valley, “Air-cushion effect” occurred;High speed front-end landslide body strongly collides the face of the mountain，the rock collapse jet and are broken up debris flow ； the overall stiffness suddenly reduce,because of the process the mid
16、dle and back rock of landslide body produce thrust deformation, the buffer reduction speed, successfully realize “soft landing“ to maintain the overall integrity. (4)Numerical simulation results show that:Landslide formation and sporting characteristics and qualitative analysis and field geological phenomenon are actually in good agreement;the displacement、 speed and acceleration dynamic response curves of changes are basicly consistent in morphological characteristics a
