汶川地震震裂山体裂缝变形特征与动力机制研究

Study on Deformation Characteristics and Dynamic Mechanism of Shattered Mountain Fractures in Wenchuan Earthquake

介绍了地震裂缝的类别、基本特征、分布规律,从发育规模和失稳机制对各类地震裂缝的特点和破坏特征进行了理论分析,探讨了地震裂缝的展布、发育特征、变形迹象,并利用岩石断裂力学机理,结合应力强度因子方法分析结构面的震裂损伤机制。研究结果表明：1根据斜坡地震裂缝的形态特征和变形迹象分为表面型、贯穿型、走向型、倾向型、闭合型、扩展型6种基本类型;2斜坡上地震裂缝总体走向在N30°~60°E;3地震裂缝主要分布在发震断层附近或者山脊位置以及斜坡陡缓交界部位,裂缝延伸性好、张开程度高,充填较少或者无充填;4地震裂缝力学机制主要属于拉张裂缝,岩体结构面在动力作用下的变形破坏过程分为破裂、扩展、贯通3个阶段。

The categories,basic characteristics and distribution law of seismic fracture were introduced,theoretical analysis study on the features and failure characteristics of various types of seismic fractures was conducted from their development scale and instability mechanism,the distribution,development characteristics,deformation signs of seismic fractures were explored and combined with the stress intensity factor method,the shattering injury mechanisms of structure surface was analyzed by use of rock fracture mechanics mechanism.The research results show：（1）The seismic fractures are divided into six types：surface type,transfixing type,strike type,tendency type,closure type and extension type from its morphological characteristics and deformation signs;（2）On the whole the Seismic fractures has 30°N-60°E trend;（3）The seismic fractures mainly distributed in seismogenic faults area or ridge and steep with slow border area,high open degree,fillings less or no.（4）The mechanism of seismic fractures belongs to tensile crack,the deformation and failure process of structural planes of rock mass under dynamic action is divided into rupture,expansion and penetration three stages.