黏土岩温度–渗流–应力耦合作用的长期力学特性研究若干进展

核废料地质处置库长期处于复杂的耦合环境之中,其安全、稳定、高效的建设与运营需要考虑温度场(T)、渗流场(H)、应力场(M)的长期耦合作用。围绕黏土岩多场耦合作用下的长期力学特性,首先总结了国内外在黏土岩温度–渗流–应力耦合条件下长期力学试验研究成果与不足,主要包括HM与THM耦合长期作用对黏土岩渗透特性的影响、黏土岩TM与THM耦合长期力学特性。其次从微观唯相的角度,论述了温度对黏土岩微观结构特征的影响机制。基于上述认识,提出黏土岩THM耦合蠕变力学模型及其适用性。同时,介绍了笔者团队围绕黏土岩THM耦合长期力学特性方面的相关研究成果,结果表明:BoomClay的长期力学特性与温度、孔压、应力和各向异性等因素相关。最后,提出黏土岩THM耦合研究未来应重点关注的方向。

Progress in long-term mechanical properties of clay rocks under thermo-hydro-mechanical coupling conditions

The geological repository of nuclear waste is in a variety of complex environments for a long time,and the safe,stable and efficient construction and operation of the geological repository usually need to consider the long-term coupling effect of thermo-hydro-mechanical(T-H-M) fields. Based on the long-term mechanical properties of clay rocks under multi-field coupling,this paper first summarizes the long-term mechanical test results and shortcomings of clay rocks under the thermo-hydro-mechanical coupling condition at home and abroad,mainly including the influence of HM and THM coupling on the permeability properties of clay rocks,and TM and THM coupling long-term mechanical properties of clay rocks. In the second place,the influence mechanism of temperature on the micro structure characteristics of clay rocks is discussed starting from the micro phenomena. Based on the above understanding,the THM coupling creep mechanical model of clay rocks and its applicability are proposed. In the meantime,the research results of the authors’ team on the long-term mechanical properties of THM coupling of clay rocks are introduced. It is pointed out that the long-term mechanical properties of Boom Clay are regulated by temperature,pore pressure,stress and anisotropy,etc. Finally,the future research directions of clay rocks THM coupling that should be focused on are discussed.