复合地基固结解析理论研究方法与进展

Research methodologies and advances in analytical theory for consolidation of composite ground

复合地基固结理论源于砂井地基固结理论,其研究所采用的基本假设和研究方法也借鉴了砂井理论的研究成果。然而,由于复合地基具有桩体直径大和桩体应力集中的特点,砂井地基的某些假定条件在复合地基固结理论中并不适用,并导致复合地基固结度计算产生较大误差。基于此,本文从复合地基固结理论基本假定的适用性出发,对误差产生的根源进行分析,揭示基本假定背后隐含的科学问题以及对应的工程问题。具体内容包括控制方程在等应变条件下的适用性、初始条件的改进、桩周流量相等假设的适用性、一维变形假设、非圆截面桩等效半径的确定、群桩单元划分方法及理论体系建立等基本问题。

Consolidation theories for composite grounds originated from consolidation theories of sand-drained ground.The studies and the research methods about composite grounds adopted some basic assumptions in the theories of vertical drains.However,some assumptions of vertical drains theories are not applicable in composite ground theories;this is due to the large diameter of columns and stress concentration on the columns in the composite ground,which can inevitably lead to a large deviation in the calculation of the degree of consolidation.On this context,the reason for the resulting deviation is investigated from the analysis of applicability of the basic assumptions.The underlying scientific significances and the engineering problems corresponding to these investigated assumptions are revealed.The detailed contents of this paper include the analysis on the following basic problems,such as the adaptability of the governing equations with the equal strain assumption,the modification of the initial condition,the applicability of the assumption of equal flow at column-soil interface,one-dimensional deformation assumption,the determination of the equivalent radius of the columns with non-circular cross section,and the partition of the ground into elements with pile groups columns and the establishment of the associated theoretical frame.