软土地基MPC劲性复合桩现场试验研究

Field test of MPC rigid composite pile in soft soil foundation

水泥土与预制混凝土复合桩(MPC劲性复合桩)采用搅拌法先施工水泥土桩,在水泥土桩桩身达到适当强度之后压入预制混凝土桩。桩顶荷载先通过预制桩桩侧传递至桩周水泥土中,再通过水泥土搅拌桩传递至水泥土桩桩周土,形成MPC劲性复合桩的荷载传递规律。为了研究其荷载传递规律和承载特性,在昆明盆地软土分布区进行了MPC劲性复合桩现场载荷试验。通过复合单桩静载试验测定了各级荷载下预制桩身各截面轴力和相应的桩顶沉降量。根据预制桩身各截面轴力与桩顶各级荷载、桩身压缩量的关系,分析了预制桩侧摩阻力变化规律,初步得出了竖向荷载下MPC劲性复合桩的荷载传递规律,为以后该桩型的推广应用提供了一定的理论依据。

Cement soil and precast concrete composite pile(MPC rigid composite pile) is used to construct the cement soil pile first, and then it is pressed into the precast concrete pile after the cement soil pile body reaches the appropriate strength. The load on the top of the pile is transferred to the cement soil around the pile through the side of the prefabricated pile, and then transferred to the soil around the pile through the cement soil mixing pile, forming the load transfer law of MPC rigid composite pile. In order to study the load transfer law and bearing characteristics of MPC rigid composite piles, field load tests were carried out in the soft soil distribution area of Kunming Basin. Through the static load test of composite single pile, the axial force of each section of precast pile body and the corresponding settlement of pile top were measured. According to the relationship between the axial force of each section of the precast pile body and the load at all levels on the top of the pile and the compression amount of the pile body, the variation law of the side friction resistance of the precast pile was analyzed, and the load transfer law of the MPC rigid composite pile under the vertical load was preliminarily obtained, which provided a certain theoretical basis for the popularization and application of the pile type in the future.