带褥垫层刚-柔性桩复合地基性状试验研究

Experimental study on behavior of composite foundation with rigid-flexible piles

为了研究带褥垫层刚-柔性桩复合地基这种新型复合地基桩土共同作用特征,在温州地区选择了一个采用刚-柔性复合地基的工程开展静荷载试验研究。在条形基础下抽取一根钻孔灌注桩(刚性桩)和四根水泥搅拌桩(柔性桩)进行刚-柔性复合地基静荷载试验,分析整个加荷过程中复合地基的承载变形规律。试验结果表明复合地基Q-s曲线呈缓变形,承压板底土反力分布呈现出中部大边部小的形态,土应力在桩端平面出现应力增大现象,复合地基中刚性桩、柔性桩桩顶均出现负摩阻力。另外,通过反分析方法确定本次试验中钻孔灌注桩、水泥搅拌桩和桩间土的承载力发挥度分别为0.97、0.73、0.99。

In order to study pile-soil interaction of composite foundation with rigid-flexible piles, static load test of composite foundation with one cast-in-place pile and four cement mixing piles under stripe foundation is carried out in Wenzhou area. On the basis of monitoring data, this paper analyses load bearing capacity and deformation under the application of load. The Q-s curve variation of composite foundation is slow. Soil pressure distribution under stripe foundation shows the shape of being large in middle part and small at the edge. The soil stress concentration occurs at the plane of pile tip. There are negative friction force at rigid pile top and flexible pile top. Furthermore, the degree of bearing capacity display on rigid pile is 0.97, while that on flexible pile is 0.73 and that on soil is 0.99.