RB模式下考虑土拱效应的非极限主动土压力

Non-limit Active Earth Pressure with Wall Movement of Rotation Considering Soil Arching Effect

针对刚性挡土墙,考虑转角位移比对非极限填土内摩擦角、墙土摩擦角的影响,假设小主应力土拱为圆弧,由摩尔应力圆得到墙背和滑裂面处的正、切应力;再根据RB模式下非极限微元滑裂土体的静力平衡条件,获得非极限主动土压力系数,进一步推导、得到非极限主动土压力计算式。参数分析结果表明:转角位移比从0增大到1过程中,非极限填土内摩擦角由静止内摩擦角逐渐增大到极限内摩擦角,非极限主动土压力及其系数逐渐减小;非极限主动土压力随着填土内摩擦角的增大而减小,其最大值随着墙土摩擦角的增大逐渐减小。与前人方法比较,文中的非极限主动土压力理论值与试验值吻合得更好。

According to the Mohr＇s stress circle of non-limit sliding backfill,the stress formulas at wall back and non-limit sliding surface are obtained based on the influences of angular displacement ratio on internal friction angle of backfill and wall-soil friction angle with the assumption that the trajectory of minor principal stress of backfill is circular arc.Then the coefficient of non-limit active earth pressure can be obtained according to the static equilibrium conditions of non-limit horizontal differential sliding backfill under RB mode.Further,a new formula of non-limit active earth pressure is put forward.In addition,effects of parametric analysis show that：during the process that the ratio of angular displacement increases from 0to 1,the non-limit internal friction angle of backfill changes from static internal friction angle to internal friction angle,non-limit active earth pressure and its coefficient decrease gradually.The non-limit active earth pressure respectively decreases with the increasing of internal friction angle of backfill,and the maximum value decreases with the increasing of non-limit wall-soil friction angle.Comparing the theoretical values calculated by proposed formula and existing methods with experimental values shows that the theoretical values of non-limit active earth pressure calculated by proposed formula is better accordant with experimental values than those calculated by other existing methods.