一种高效的刀盘掘进过程数值模拟算法

An efficient numerical simulation algorithm ofcutterhead driving process

从岩土单元网格划分和接触对搜索过程两方面入手,提出一种高效的盾构刀盘掘进过程数值模拟算法。引入六结点三棱柱单元,该单元边长比接近于1,且每一个面上的内角近似相等,相比于传统六面体单元,计算效率更高,据此建立一种高效的岩土有限元模型,并通过圆柱体单轴压缩数值模拟实验验证了模型的可靠性和高效性。根据盾构刀盘的掘进行为特点,直接得到可能发生接触的岩土网格结点,相比于传统的全局搜索,更加省时,优化了接触对搜索过程,从而提出了一种新颖高效的搜索算法,并通过自编软件开展单刀破岩过程数值模拟,验证了搜索算法的可靠性和高效性。基于自编软件和上述两种策略,使用单核CPU实现了实际工程中使用的复合盾构刀盘掘进全过程的直接数值模拟,得到了掘进后的岩土掌子面形貌和刀盘刀具的法向力载荷时程曲线及分布规律,并通过与商业软件仿真结果和文献得到的刀盘刀具法向力均值对比验证了自编软件的可靠性。

Starting from the grid division of the geotechnical elements and the searching process of the contact pair,an efficient numerical simulation algorithm of the shield cutterhead driving process is proposed.Specifically,a six-node triangular prism element is introduced,whose side length ratio is close to 1,and the interior angles on each face are approximately equal.Compared with the traditional hexahedral element,the calculation efficiency is higher;therefore,an efficient geotechnical finite element model was developed,and the reliability and efficiency of the model were verified by numerical simulation experiments of cylindrical uniaxial compression.According to the characteristics of the excavation of the shield cutterhead,the geotechnical grid nodes that may be in contact can be directly obtained.Compared with the traditional global searching method,it is more time saving and optimizes the searching process of the contact pair.Therefore,a novel and efficient method is proposed.Additionally,the reliability and efficiency of the algorithm are verified through the software and the above two strategies;composite shield cutterhead which is used in the actual project is realized by a single core CPU;the rock face topography,the load time history curve as well as the load distribution law about normal force of the cutterhead cutter after the excavation are obtained through the simulation.The reliability of the software is verified by comparison with the mean normal force of the cutterhead cutter which is obtained by ABAQUS and literature.