位移模式对重力式加筋土挡墙受力特性影响模型试验

Model test on influence of displacement mode on mechanical characteristics of gravity reinforced soil retaining wall

为研究重力式加筋土挡墙在挡墙位移至极限主动状态下的土体受力与变形形态,通过改变埋设筋材层数、筋材强度和间距、筋材与挡墙连接方式、筋材长度及挡墙位移模式,对挡墙做了6种工况的模型试验,进行了挡墙进入极限主动状态所需最大位移量、墙内竖向土压力、靠近墙面板处水平土压力、墙顶竖向位移及筋材拉伸应变等分布规律的研究.试验结果表明:加筋可以提高挡墙达到极限主动状态所需最大位移量,减小静止状态及主动状态下靠近墙面板处土压力;挡墙进入极限主动状态时,靠近墙面板处填土表面相对沉降较大;挡墙位移对筋材应变影响很小;靠近墙面板处竖向土压力衰减量与埋深正相关,平动模式衰减量最大.加载点下竖向土压力增大量与埋深负相关.在重力式加筋土挡墙上部与底部提高筋材强度及埋设筋材层数,靠近墙面板处提高埋设筋材层数或筋材强度并将筋材与挡墙连接,结构中下部适当减少筋材长度,相比普通重力式挡墙可提高挡墙抗倾覆滑移能力,增强挡墙结构稳定性.

In order to study the soil force and deformation pattern of gravity reinforced soil retaining wall when the retaining wall displacement reaches the ultimate active state,six kinds of model tests of the retaining wall are carried out by changing the number of buried reinforcement layers,the strength and space of reinforcement,the connection mode of reinforcement and retaining wall,the length of reinforcement and the displacement mode of retaining wall.The distribution laws of the maximum displacement required for the ultimate active state of retaining wall,the vertical soil pressure inside the wall,the horizontal soil pressure close to the wall panel,the vertical displacement of the wall top and the tensile strain of the reinforcement are studied.The test results show that the reinforcement can improve the maximum displacement required for the retaining wall to reach the ultimate active state,and reduce the soil pressure close to the wall panel under the static state and active state.When the retaining wall enters the ultimate active state,the relative settlement of the backfill surface close to the wall panel is large.The displacement of retaining wall has little effect on the strain of reinforcement.The attenuation of vertical soil pressure close to the wall panel is positively correlated with buried depth,and the attenuation of translational mode is the largest.The increase of vertical soil pressure under the loading point is negatively correlated with buried depth.In gravity reinforced soil retaining wall,the reinforcement strength and the number of buried reinforcement layers at the upper part and the bottom of the retaining wall are improved.Close to the wall panel,the number of buried reinforcement layers or reinforcement strength is increased and the reinforcement is connected to the retaining wall.The length of reinforcement can be appropriately reduced at the middle and lower parts of the structure.So compared with the ordinary gravity retaining wall,it can improve the anti-dumping sliding ability of the retaining wall and enhance the stability of the retaining wall structure.