中文摘要：

为完善圆形地连墙设计理论,探讨了现行规范方法的力学概念、环向应力计算方法、土-结构相互作用及环向刚度折减系数等关键问题,基于薄壳理论推导了地基双向弹簧条件下圆形地连墙的基本微分方程,改进非线性土体弹簧模型以考虑土压力发挥极限值所需的位移,引入连续弹簧模拟环形内衬,采用增量法计入施工过程影响,并编制了有限元程序;同时,提出采用单元体试验研究圆形地连墙环向刚度折减系数取值方法,考虑接缝刚度与宽度、地连墙半径、槽段平均长度等因素建立了折减系数计算公式,最后,以阳逻大桥圆形锚碇基坑工程为例进行了计算与对比分析。结果表明：典型条件下折减系数为0.467~0.679;该方法位移计算值与实测值基本吻合,克服了现行方法无法分析支护结构环向应力及地连墙两侧土压力发展过程的缺陷;计算参数物理意义明确、易于获取,可为工程设计提供较为全面的参考依据。

英文摘要：

To perfect the computing theory of the circular diaphragm wall, key issues of the existing specifications were discussed from the perspective of mechanical concepts, hoop stress calculation, soil-structure interactions, and the hoop stiffness reduction coefficients. Moreover, basic differential equations of the circular diaphragm wall connected to springs on its both sides were deduced by dint of the thin-shell theory, and a nonlinear soil spring model was proposed to take the ultimate displacement into account. The distributed springs were used to model inner ring beams. The incremental method was adopted to simulate excavation process, and the finite element program was drawn up. Furthermore, the hoop stiffness reduction coefficient was investigated by the testing method. A formula was then established to estimate its value based on factors such as the joint stiffness and width, the dia meter of a circular diaphragm wall, and the mean panel length. Subsequently, the program was calculated and analyzed, taken deep excavation program of Yangluo Bridge as an example. The results show that the value is in the range of 0. 467-0. 679 under the typical condition. Calculated values are basically identical with the measured ones. Compared with the traditional methods, the new method proposed in this paper can be deployed to analyze hoop stress of the supporting structure together with the development of earth pressure on both sides of the diaphragm wall. The axisymmetric finite element method （FEM） is adaptable to the calculation of parameters, and parameters can be obtained easily. The proposed method provides a comprehensive analysis on the engineering design.