门架式双排抗滑桩的弹塑性模型与计算分析

门架式双排抗滑桩的计算模型大部分将桩排间岩土体视为弹性材料，而岩土体为弹塑性材料，使得抗滑桩内力、位移计算结果与实际情况相差较大。假设桩排间岩土体为弹塑性材料，提出一种弹塑性计算模型，该模型将桩排间岩土体看作线弹性单元和塑性单元的组合，根据结构力学知识、土的本构关系和数值分析方法建立一种计算前后排抗滑桩内力的计算方法。首先，由已知的桩顶位移，并结合结构力学位移法求出桩间土总应力。根据Lade-Duncan模型导出这两个单元的基本参数，然后，结合数值分析方法计算出抗滑桩的内力，最后，结合工程实例，运用ANSYS有限元软件进行计算分析，得出门架式双排抗滑桩的内力图。对比监测数据和弹性模型计算结果表明，弹塑性模型的计算结果比弹性模型更加接近监测值。

Elastoplastic models and calculation analysis of portal double-row anti-slide piles

Now，the soil between the piles is usually considered to be elastic in many calculation models of portal double-row anti-slide piles. Because of the soil being the elastoplastic material, the results of elastic models are not consistent with the reality. A new plane link finite element model is established. The soil between the piles is considered to be the elastoplastic in this model which combined the linear elastic model and the plastic model. A calculation method for calculating internal force of the fore-pile and the rear-pile is developed, which is based on structural mechanics, soil constitutive relationship and numerical method. First, the soil total stress between the piles is acquired by calculation based on the displacement of pile top used in the displacement method. Then the internal force of portal double-row anti-slide piles is calculated by numerical method, linear elastic elements and plastic elements of this numerical method, whose basic parameters are derived according to the Lade-Duncan constitutive model. Last, combining with engineering example, the internal force of portal double-row anti-slide piles is calculated with the finite element program ANSYS. Compared with the monitoring data and the calculating results of elastic model, the calculating results of elastoplastic model are more consistent with the monitoring values.