基于楔体滑动的结合式加筋重力墙主动土压力

Active earth pressure of combined reinforced gravity wall based on wedge-sliding

文章针对水平柔性拉筋和重力墙组合成的结合式加筋重力墙,开展基于三维楔块滑动模式的墙背主动土压力上限分析,模型建立考虑筋材拉断和筋材拔出2种不同模式,同时,公式推导体现非水平填土面、非竖直墙背、粗糙墙-土界面、土表荷载等因素的影响。研究表明:①主动土压力随着挡墙长高比的减小而减小,且加筋可以增大破坏土体的滑裂角,从而显著降低墙后主动土压力,同时,相较于分离式加筋重力墙,结合式加筋重力墙的主动土压力更小;②随着墙背倾角α、填土倾角β的增大,主动土压力均持续增大,前者对主动土压力的影响更为显著。主动土压力随着内摩擦角φ与墙土界面摩擦角δ的增大而减小。同样地,内摩擦角对于主动土压力的影响远大于界面摩擦角;③主动土压力随筋材抗拉强度T的增大而迅速减小,而与筋材间距呈正相关,同时受竖向间距S_(z)的影响比横向间距S_(x)更大。结合实际施工可行性,0.4~0.6m可作为筋材间距推荐值。

Based on the three-dimensional wedge-sliding mode,the upper limit analysis of active earth pressure on the back of the combined reinforced gravity wall composed of horizontal flexible tie bars and gravity wall was carried out.Two different modes of reinforcement breaking and reinforcement pull-out were considered in the establishment of the model.Meanwhile,the formula derivation reflected the influence of non-horizontal backfill surface,non-vertical wall back,rough wall-soil interface,surficial load and other factors.The research shows that:(1)The active earth pressure decreases with the decrease of the length-height ratio of the retaining wall,while the reinforcement leads to an enhancement of the slip angle of the failure mass and a reduction of the active earth pressure.Compared with the separated reinforced gravity wall,the combined reinforced gravity wall has moderate active earth pressure.(2)As the dip angle of the wall-backαand inclination angle of the fillerβincrease,the active earth pressure grows,and the former factor has a more significant impact.Similarly,the friction angle and the interfacial friction angel S both result in a reduction of active earth pressure,and the influence of friction angle is greater.(3)The tensile strength T of the reinforcement has a negative relationship with the active earth pressure,while the reinforcement spacings have positive relationships.Accordingly,the active earth pressure is more sensitive to vertical spacing S_(z).Considering construction applicability,0.4~0.6m can be adopted as the recommended spacing value for reinforcements.