摘要
为了探讨在法向应力和剪应力的共同作用下裂隙开度的变化对于耦合的温度场、渗流场和应力场的作用,引入裂隙的渗透系数与开度关系的"立方定律",建立了裂隙渗透系数演化式。应用开发的遍有节理岩体双重孔隙-裂隙介质热-水-应力耦合二维有限元程序,以一个假定的位于非饱和地层中的高放废物地质处置库为算例,分别在2组裂隙斜交和正交的条件下,针对与裂隙开度3种计算方式对应的6种工况进行了数值分析,考察了围岩中的温度、孔隙和裂隙水压力、裂隙开度、裂隙的渗透系数、地下水流速、应力的变化、分布状态。结果显示,当裂隙开度仅取决于法向应力时,裂隙开度受压应力作用产生的闭合量最大,从而裂隙水压力最高;而当裂隙开度是法向应力和剪切位移的函数时,由于"剪胀"效应,裂隙开度闭合量较前述情况为小,裂隙水压力居中;而当裂隙开度是常数时,裂隙水压力最低。
In order to probe into the effects of the changes of fracture aperture casued by combined action of normal stress and shear stress on coupled temperature field,seepage field and stress field,introducing the ＂cubic law＂ describing the relationship between hydraulic conductivity and fracture aperture,the evolution expressions for hydraulic conductivity of fracture are established,using the 2D FEM code for analysis of thermo-hydro-mechanical coupling in dual-porosity medium for ubiquitous-joint rock mass developed by the author and taking a hypothetical nuclear waste repository located in an unsaturated stratum as a calculation example,the numerical simulations are carried out for six cases in which three kinds of updated pattern of fracture aperture are applied under the conditions in which two sets of joint cross obliquely and perpendicularily respectively,and the distributions and changes of temperatures,pore and fracture pressures,fracture apertures,hydraulic conductivities,flow velocities of groundwater,and stresses in the surrounding rock mass are investigated.The results show that if the fracture aperture depends on only normal stress the closure of fracture aperture is the largest acted by a compressive stress;while the fracture pressure is the highest;if the fracture aperture is a function of normal stress and shearing displacement,the closure of fracture aperture is smaller than the former due to shear dilation effect,so the fracture pressure is a moderate value;but if the fracture aperture is a constant,the fracture pressure is the lowest.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2011年第5期1513-1522,共10页
Rock and Soil Mechanics
基金
国家重点基础研究发展计划(973)资助项目(No.2010CB732101)
国家自然科学基金项目(No.51079145)
关键词
裂隙
剪胀
双重孔隙介质
热-水-应力耦合
有限元分析
fracture
shear dilation
dual-porosity medium
thermo-hydro-mechanical coupling
finite element analysis
