剪胀和破坏耦合的节理岩体本构模型的研究  

A STUDY OF CONSTITUTIVE MODEL COUPLING DILATANCY AND DEGRADATION FOR JOINTED ROCK

作　　者：肖卫国[1] 兑关锁[1] 陈铁林[1] 任青文[2] 

机构地区：[1]北京交通大学土木建筑工程学院,北京100044 [2]河海大学土木工程学院,江苏南京210098

出　　处：《岩石力学与工程学报》2009年第12期2535-2543,共9页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(50539030)

摘　　要：根据节理岩体切向加载作用下的变形机制,把微凸体在磨损破坏过程中引起的剪胀软化现象和伴随的强化现象分开考虑,提出一种新的本构模型。试验结果表明,在法向和切向载荷共同作用下,由于微凸体的爬坡和啃断作用,节理岩体均会发生一定程度的剪胀和磨损,累积到一定程度就产生软化现象,在此引入一个初始剪应力概念体现上述特征。另一方面,由于破碎颗粒的碾压和迁移作用,使得抗剪力学行为由微凸体粗糙度控制逐渐转变为由结构面上形成的紧密夹层的力学行为所控制,抗剪强度提高,在此通过弹塑性随动强化模型来体现这一变形行为。当随动强化模型与初始剪应力相结合时,即为节理岩体切向加载作用下的剪应力–切向位移本构关系。通过对各种已有试验曲线的对比分析,验证该模型的正确性。Based on the failure mechanism of jointed rock mass under shear loading, a new constitutive model is presented; the essence of which is dilatancy softening phenomenon and strengthening phenomenon that should be considered separately when asperity surface will undergo the wearing, grinding and crushing. From many direct shear tests, it is concluded that the jointed rock mass will generate dilatancy and wear as the behavior of overriding and shearing for asperity surface under normal and shear loadings. When damage is accumulated to a certain extent, it will result in softening. A new concept of initial shear stress is introduced to reflect the above characteristics. On the other hand, as the motion of broken granules, the mechanical behavior of shear which is controlled by asperities will gradually transform to compact controlled layer; and it makes shear strength increase. This microscopic change effects are described by considering elastoplastic kinematic hardening model. The constitutive equations are derived with combining kinematic hardening model and initial shear stress. The validity of proposed constitutive model is verified through applications to several existing laboratory test results on intact and artificial jointed rocks.

关 键 词：岩石力学 剪胀 本构模型 节理岩体 随动强化 

分 类 号：TU45[建筑科学—岩土工程]