截齿滚动掘进冻土过程的影响因素数值模拟研究

为了解决竖井冻土开挖难度大、人工挖掘效率低的问题，研究发明了一种新型重力式竖井掘进机，该掘进机利用截齿连续滚动向下、行走式掘进冻土，在竖井冻土掘进中具有较好的适应性，而截齿侵入深度是影响掘进冻土效率的重要因素。先采用三维软件建模，通过霍普金森压杆冲击试验，结合HJC压缩损伤模型原始参数，优化得到冻土本构模型参数；再利用有限元分析软件耦合，模拟截齿在不同侵入深度下滚动掘进冻土，得到冻土在不同凹陷破坏深度下的截齿三向力、冻土应力和应变的变化规律，便于直观研究截齿掘进冻土过程，寻求最优截齿侵入深度。仿真结果表明：随着截齿侵入深度增加，截齿三向力变大，冻土凹陷面积扩大，冻土应力向下无边界扩展递减；冻土与截齿接触区域应力、应变最大，远离截齿作用时冻土区域的应力、应变逐渐递减，其变化规律与截齿连续滚动掘进冻土特征相关；当冻土单轴抗压强度为9 MPa时，截齿滚动掘进冻土过程存在最优截齿侵入深度，为4 cm，此时冻土破坏特征明显，截齿滚动掘进冻土效率最高且能耗低。

Study on numerical simulation of influencing factors for frozen soil excavation process by cutting pick rolling

To solve the problems of difficult excavation of shaft frozen soil and low efficiency of manual excavation， a new type of gravity shaft tunnelling machine was invented. The machine has well adaptability in the excavation of shaft frozen soil. The invasion depth of cutting pick is an important factor affecting the efficiency of excavation of frozen soil. The cutting pick is used to continuously roll downward and walk to excavate frozen soil. In this study， three-dimensional software is used to establish the model， and the parameters of frozen soil constitutive model are optimized through the Hopkinson pressure bar impact test and the original parameters of HJC compression damage model. Then， the finite element analysis software is used to simulate the rolling excavation of frozen soil under different invasion depths of cutting picks， and the variation laws of three-dimensional force of cutting picks， stress and strain of frozen soil under different destruction depths of depressions are obtained. And it is convenient to visually study the process of cutting pick excavation of frozen soil and seek the optimal invasion depth of cutting picks. The simulation results show that with the increase of the invasion depth of the cutting pick， the three-dimensional force of cutting pick increases， the area of the frozen soil depression expands， and the stress and strain of the frozen soil decreases downward without boundary. The stress and strain in the contact area between the frozen soil and the cutting pick is the largest， and the stress and strain in the frozen soil area away from the cutting pick decreases gradually. The stress and strain variation laws are related to the characteristics of the frozen soil in the continuous rolling excavation of the cutting pick. When the uniaxial compressive strength of frozen soil is 9 MPa， there is an optimal intrusion depth of 4 cm in the frozen soil excavation process by cutting pick rolling. The destruction characteristics of frozen soil are obvious， and the efficiency of frozen soil excavation by cutting pick rolling is the highest and the energy consumption is low.