水平荷载单桩计算的综合刚度和双参数法杆系有限元数值解

 为提高水平荷载单桩设计计算的准确度和效率，建立基于综合刚度和双参数法原理的杆系有限元数值解。同时，从理论和对静载试验实例的分析上，指出我国现行规范建议的水平荷载桩设计计算m法存在的缺陷，建议改进方法。本文建立的杆系有限元法不像解析法那样存在参数取值的限制，避免了烦琐的查表计算，且无需对桩端约束条件进行假定及区分长桩、短桩和中长桩。实例计算比较表明，当采用与解析法相同的综合刚度和双参数时，杆系有限元解与解析解结果吻合很好，能保证桩顶位移和转角、桩身最大弯矩和及其作用位置与实测结果基本一致；当根据桩长范围内土层变化确定各土层比例系数m，通过若干次试算调整幂指数n和综合刚度EI可获得较解析法更好的计算结果。

Numerical solution of link finite element based on composite stiffness and bi-parameter method for computation of laterally loaded single pile

To enhance the reliability and effectiveness in design of laterally loaded single pile，a link finite element method based on the principle of composite stiffness and bi-parameter was presented. Some flaws in the m-method recommended by the current technical codes for the design of laterally loaded pile were pin pointed through theoretical analyse and static loading experiments，and a modified method was proposed. Unlike the analytical approach，the is link finite element method established in this paper has no restrictions in parameter selection and avoids tedious calculations of table looking-up. In addition，it is not necessary to assume the restraint conditions of piles tips and discriminate the long，short or medium piles. Comparisons with the practical examples showed that the results between the link finite element method and analytical approach agreed well when the same composite stiffnesses and bi-parameters were employed. The calculated displacements and rotation angles at the tops of the piles and the maximum bending moments and their positions were in agreement with the measurement. Comparisons also showed that better results than those of the analytical approach was achieved through multiple trial calculating and adjusting of the exponent n and composite stiffness EI when the values of the proportional coefficient m were determined according to various layers of soil around the piles.