地下工程应力松弛效应的初步理论解  

PRELIMINARY STUDY OF THEORETICAL SOLUTION TO STRESS RELAXATION EFFECT FOR UNDERGROUND ENGINEERING

作　　者：王者超[1] 陈卫忠[2] 乔丽苹[3] 张乐文[1] 

机构地区：[1]山东大学岩土与结构工程研究中心,山东济南250061 [2]中国科学院武汉岩土力学研究所,湖北武汉430071 [3]山东大学工程力学系,山东济南250061

出　　处：《岩石力学与工程学报》2010年第A02期4096-4101,共6页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金委重大国际合作项目(50720135906);国家自然科学基金资助项目(40772184)

摘　　要：蠕变和松弛是岩土材料常见的2种流变特性,岩土工程地下结构支护与围岩的相互作用不是一个单纯的蠕变过程,围岩的应力松弛对于衬砌的长期稳定性具有重要的影响。围绕地下工程圆形洞室松弛的等效蠕变过程,采用非线性蠕变模型,建立圆形洞室黏弹性围岩应力松弛效应的初步理论解,给出解答的量纲一的表达式。研究结果表明:岩土体的松弛特性可以通过蠕变参数进行表述;在没有考虑围岩松弛情况下,地下工程衬砌长期强度的设计偏于安全。从能量观点看,应力松弛可以看作是洞室围岩集中应力衰减的一个过程,该过程与材料本身力学性质和洞室围岩初始条件有关,同时受时间和空间因素控制,且微观结构演化趋势与蠕变过程相反。岩土介质松弛效应的研究成果不但可以应用于软岩地下工程开挖的工程实践,而且还可以提高对岩土材料流变性的认识。Creep and stress relaxation of geo-materials are the two frequently observed time-dependent phenomena in geotechnical engineering. For underground structures,the interaction between support system and surrounding rock or soil mass is influenced not only by the creep of rock or soil mass,but also by the stress relaxation. Based on a modified nonlinear creep model,a theoretical solution to an equivalent creep problem is proposed to describe the stress relaxation of circular caverns embedded in viscoelastic geo-materials. The dimensionless expression is also presented. Two types of soils are employed in case studies. The results show that the stress relaxation characteristics of geo-materials can be described by the parameters in the creep law;the design for long-term stability of lining without consideration of stress relaxation in rock or soil mass is safer than that in practice. In the view of energy conservation,stress relaxation can be considered as a decreasing process of concentrated ground stress,which is induced by excavation of caverns. The process is dependent on the initial condition and mechanical properties of material and influenced by time and space. Furthermore,the evolution of inner microstructure is reverse to that of creep. The study results can not only be applied to engineering applications directly,but also be helpful in understanding of rheological behavior of geo-materials.

关 键 词：岩石力学 圆形洞室 应力松弛 蠕变 理论解 应用 

分 类 号：TU45[建筑科学—岩土工程]