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混凝土芯水泥土搅拌桩是在水泥土搅拌桩外壳施工完成后插入预制混凝土芯所形成的一种新型复合桩。现有研究对混凝土芯水泥土搅拌桩复合地基的承载力机理讨论很少。为完善混凝土芯水泥土搅拌桩复合地基承载力理论,依托南京绕越高速东北段软基处理工程,通过埋设传感元件,借助复合地基载荷板试验和静力触探试验,分析了其承载力机理。试验结果表明:混凝土芯水泥土搅拌桩的地基加固效果要优于同直径同桩长的水泥土搅拌桩;混凝土芯的插入,有效增大了混凝土芯水泥土搅拌桩的竖向抗压强度;混凝土芯与水泥土搅拌桩外壳之间能有效传递剪应力,且水泥土搅拌桩外壳的大表面积保证了桩土间不会发生剪切破坏;相同的上部荷载下,混凝土芯水泥土搅拌桩复合地基的桩土应力比要大于水泥土搅拌桩复合地基;混凝土芯水泥土搅拌桩施工对桩周土体有一定的挤密加固效果。
Concrete core cement-soil mixing pile is a new composite pile formed by inserting a precast concrete core after the construction of the cement-soil mixing pile shell is completed. There are few discussions on the mechanism of the bearing capacity of composite foundation with concrete core cement-soil mixed piles. In order to improve the theory of bearing capacity of composite core-concrete-soil mixing pile composite foundation, relying on Nanjing bypassing the high-speed northeastern soft section of the soft ground treatment project, the bearing capacity was analyzed by means of the composite foundation load plate test and static penetrating test. mechanism. The test results show that the foundation reinforcement effect of concrete core cement-soil mixing pile is better than the cement-soil mixing pile with the same diameter and the same length; the insertion of the concrete core effectively increases the vertical compressive strength of the concrete core cement-soil mixing pile; The shear stress can be effectively transferred between the concrete core and cement-soil mixing pile shell, and the large surface area of the cement-soil mixing pile shell ensures that no shear failure occurs between the pile and soil; under the same upper load, the concrete core cement-soil mixing pile composite The pile-soil stress ratio of the foundation is greater than that of the cement-soil mixing pile composite foundation; the cement-concrete-soil mixing pile construction of the concrete core has a certain compaction and consolidation effect on the soil around the pile.