一种三维耦合单元模型在涂抹层模拟中的应用

Application of One 3D Coupled Element Model in Simulation of Smear Layer

研究目的:排水井的材料性能与周围的土层有很大的不同,在数值计算时需要在涂抹层处设置接触单元来进行模拟,但一般的接触面单元大多仅仅考虑单元的应力-应变,不能反映涂抹层的渗透性问题。为了能同时考虑排水井沉降与周围土层沉降的差异性及普通接触面单元无法反映涂抹层渗透性的问题,本文通过研究,推导出一种新型单元来对涂抹层进行模拟。研究结论:在充分考虑涂抹层效应的基础上,构造了一种以20结点六面体等参单元耦合16结点等厚度接触面单元的耦合单元,来模拟排水井地基中的涂抹层,并编制了相应的有限元程序。通过程序计算分析了两算例,计算结果合理可靠,表明构造的耦合单元模型可以有效地应用于实际工程的数值模拟。

Research purposes： The material properties of drain well are so different than those of surrounding soil, so the contact interface elements are needed in the simulation of smear layer. But most contact interface elements only can reflect the stress - strain property and can not reflect the penetrable property. In order to consider the settlement difference between drain well and soft soil as well as the penetrability of contact interface elements, a new kind coupled contact interface element is developed to simulate smear layer. Research conclusions： Based on considering the effect of smear layer, 16 -node constant thickness contact interface elements coupled with 8 - node isometric elements are used to simulate the smear layer of drain wells. A relevant finite - element program is made to analyze two practical examples. The result is verified reasonable shows that the coupled element model is effective and can be used in numerical analysis for construction.