【摘要】 详细分析反演强度参数的惟一性,提出其存在3个层面的多值性问题:(1)实测位移同时与弹性参数及强度参数有关;(2)塑性软化时的应力–应变关系存在多值性;(3)强度参数c,?的不同组合会使围岩某单元发生相同的塑性变形。针对这3个问题,通过假定围岩是理想弹塑性介质,利用现场实测手段将围岩位移进行弹、塑性分离,并在优化方法中考虑强度参数的内在作用机制,而且提出"塑性变形非协调性"的概念;从而探索解决强度参数反演惟一性的新途径,并利用"理想量测位移"检验新方法的可行性。最后采用数值试验方法开展强度参数反演可靠性研究,结果表明所提反演分析方法的精度与稳定性均较好,且不存在初值敏感性问题。更多还原

【Abstract】 The uniqueness of strength parameters is discussed in detail,and three aspects of this multi-value problem are discussed as following:(1) the in-situ displacement results are simultaneously concerned with elastic and strength parameters;(2) the stress-strain relationship shows multi-value under plastic softening condition;and (3) strength parameters are mutually independent,and their different combinations can make certain element of the rock with the same plastic deformation. Aiming at these problems,the new approach is presented to solve the uniqueness of strength parameters in back-analysis by assuming that the rock is an ideal elastoplastic medium;and field measurement procedures to separate elastic and plastic displacement,and the inner action mechanism in optimization method are all considered,whereas the concept of non-conformity of plastic deformation is proposed. Moreover,the feasibility of this new method is verified. Finally,the research on reliability of strength parameters in the back-analysis is developed by numerical experiments. The results show that the accuracy and stability are all favorable,and the problem of initial value sensitivity is also solved.更多还原