【摘要】 采用强度折减法求解边坡稳定安全系数时需指定极限状态判定准则,目前的方法仍存在一定的人为因素,计算精度往往依赖于研究者的经验。基于FLAC3D数值计算方法,研究了岩土体边坡极限状态的确定方法,认为边坡最大节点位移–时步曲线的收敛性与边坡稳定状态密切相关。在此基础上将最大节点位移–时步曲线的收敛性作为极限状态判定准则,采用指定某时步后在规定时步内最大节点位移增量是否一直减小来判断边坡安全状态。此判据克服了以前判定方法需要人为指定容许误差的任意性,计算精度可以根据工程要求来控制,从而得到更加客观、准确的边坡稳定安全系数值。最后,以高速公路强风化岩质边坡为实例进行了计算分析,并与简化Bishop法进行了对比,获得了较为理想的计算结果。更多还原

【Abstract】 The criteria of critical state need to be specified in determining the safety factors of rock and soil slopes when the elastoplastic shear strength reduction method is used,but there are some subjective factors in this kind of method and the precision of computation results always depends on the experience of researchers.In this paper,the critical state of rock slopes is studied based on FLAC3D numerical technique and a new method is presented.The convergence of curves of the maximum nodal displacement with time steps is closely related with the stability of slopes.This kind of curve can be used as criterion to determine the stability of slopes.The safe state of slopes can be estimated by whether the maximum nodal displacement-increment decreases during certain time-steps after a specified time-step.This method overcomes the randomness of some criteria in which the permissible error is artificially specified and the computation precision can be controlled according to the need of projects in order to obtain more objective and exact safety factors of slopes.Finally,an example of highway rock slope is studied by this method and more satisfied results are obtained compared with those by Bishop′s method.更多还原