临近复合地基侧向土压力模型试验方案设计研究

DESIGN OF LATERAL SOIL PRESSURE MODEL TEST SCHEME FOR ADJACENT COMPOSITE FOUNDATION

为了研究刚性桩复合地基对邻近支护结构侧土压力的影响,在室内模型试验方案设计前,通过有限元软件建立了邻近天然地基与复合地基模型进行数值模拟研究,对不同地基形式下静止挡墙侧土压力分布规律进行预估。两组数值模拟结果对比表明:复合地基土压力分布规律不同于天然地基,当复合地基褥垫层下方桩间土应力与天然地基土应力相同时,天然地基对挡墙相同位置处的墙侧土压力的附加作用效果要明显大于复合地基,但在"载荷传递效应"作用下,复合地基对挡墙侧向土压力的影响随着加载量的增加,逐步向更深处土体传递;与天然地基相比,复合地基对挡墙侧向土压力的影响在浅部土层相对较弱,但在深部土层中较强,并且在桩端应力集中对挡墙底部侧向土压力影响尤为显著。

In order to study the influence of the rigid pile composite foundation on the lateral soil pressure of adjacent supporting structures,prior to the design of the indoor model test scheme,the models of the adjacent natural foundation and the composite foundation are built by the finite element software for the numerical simulation,and the soil pressure distribution on the static retaining wall side under different foundation forms is estimated.The comparison of the numerical simulation results of the two groups shows that the soil pressure distribution of the composite foundation is different from that of the natural foundation.When the soil stress between the piles under the composite foundation cushion is the same as that of the natural foundation soil,the additional effect of the natural foundation on the wall side soil pressure at the same position of the retaining wall is significantly greater than that of the composite foundation,but as the'load transfer effect',the influence of the composite foundation on the lateral earth pressure of the retaining wall is gradually transmitted to the deeper soil as the load increases.It can be clearly seen that compared with the natural foundation,the effect of the composite foundation on the lateral earth pressure of the retaining wall is relatively weaker in the shallow soil layer,but stronger in the deep soil layer,and the stress concentration at the pile end has a significant effect on the lateral soil pressure at the bottom of the retaining wall.