土工有限元计算中如何剔除先期固结变形

土体在重力作用下的固结变形历史上大多已经完成，土体内的自重应力场和重力场处于相互平衡状态。以此为初始条件的土工有限元计算，如果直接在模型上施加重力作外载，将产生一个较大固结变形，而这个变形对土体来说是先期完成了的，所以计算会产生不合理的结果。为此，先把初应力作为一种载荷进行理论推导，并据此提出一个如何剔除先期固结变形的方法，即先加重力，通过求解，导出土体自重应力场；然后重新开始分析，把自重应力场当初始应力导入土体单元中，再加重力进行求解，这样就剔除了先期固结变形；最后进行了算例对比分析，证明其是一种合理的方法。

A method to exclude preconsolidation deformation in finite element calculation of soil engineering

The gravity induced preconsolidation deformation of rock and soil has been finished before our consideration in many geotechnical problems. The stress field in soil mass is balanced with the gravity field. So in the FEM calculation that is based on the initial condition above, if the gravity is loaded directly, a rather big deformation will occur which should have been finished. So on the basis of initial stress load theory that is studied in this paper, an approach is proposed to exclude the preconsolidation deformation. The detailed procedure is provided by example at last and proved to be true.