带帽有孔管桩复合地基桩土应力比试验研究

Experimental study on pile-soil stress ratio of the composite foundation of pipe-pile with cap and holes

采用室内模型试验方法,对3种开孔方式的带帽有孔管桩复合地基和带帽无孔管桩复合地基进行试验,比较分析桩帽间土压力、桩帽下土压力、桩土荷载分担比、桩土应力比等性状规律。结果表明:带帽有孔管桩复合地基桩帽间土体表面土压力比带帽无孔管桩复合地基要大;带帽有孔管桩复合地基桩土荷载分担比、桩土应力比均小于带帽无孔管桩复合地基;带帽有孔管桩复合地基更能发挥桩周土体分担荷载的作用。研究成果验证了孔隙水能通过桩孔进入有孔管桩内腔,减少土体含水量,提高桩周土体抗剪强度,为带帽有孔管桩复合地基理论研究提供试验依据,对其应用推广具有指导价值。

By use of the indoor model test method, the tests have been carried on between the composite foundation of pipe-pile with cap and holes, which are three kinds of arrangement holes, and the composite foundation of pipe-pile with cap and without hole, the character rules of soil pressure between two pile caps, soil pressure under pile cap, pile-soil load sharing ratio and pile-soil stress ratio of the composite foundation of all piles have been analyzed comparatively. The test results show that the soil pressure between two pile cap of the pipe-pile with holes is greater than that of pipe-pile without hole, the pile-soil load sharing ratio and the pile-soil stress ratio of the composite foundation of pipe-pile with cap and holes is smaller than that of composite foundation of pipe-pile with cap and without hole, the soil around pipe-pile can play the more role of the load sharing in the composite foundation of pipe-pile with cap and holes. These results can confirm that the pore water can go into the inner cavity of the pipe-pile with holes through the pile holes, reducing soil water content, improving the shear strength of soil. These results can also provide the test basis for theoretical study of composite foundation of pipe-pile with cap and holes, and the guidance for its application.