冻结管断裂应力分析及断裂位置的确定

Fracture Stress Analysis and Fracture Position Determination of Freezing Pipe

煤矿立井冻结法施工中 ,冻结管断裂一直是一个未能得到很好解决的国际性课题 ,主要原因是冻结管的力学模型设计不合理 ,进而导致应力计算结果错误。通过冻结管在工作过程中受力因素的分析及变形特征的研究建立一个较为准确的力学模型 ,找出正确的应力分布规律 ,确定符合现场的冻结管断裂位置 ,提出切实可行的防止冻结管断裂的有效措施。首次考虑了因冻结管的冷缩及冻土的冷胀所产生的冻土对冻结管的负向摩擦力的作用 ,并依据负向摩擦力的分布规律及材料力学中的温度应力理论求解出了对确定冻结管断裂应力分布规律具有重要作用的“中性层”位置。通过国内外大量冻结管断管实例 。

Freezing pipe fracture has become a international problem, which has not been solved in shaft sinking by freezing. The main reason is that inappropriate design of mechanical model for a freezing pipe led to errors in calculated stress data. By analysing applied stress and deformation characteristics of a freezing pipes, a more accurate mechanical model is set up, the law of stress distribution and determinate the fractured position of a freezing pipe are found out, and the effective measures to prevent its practure is put forward. This is the first time to investigate the negative skin friction between frozen soil and freezing pipe, which is caused by freezing pipe's temperature shrinkage and frozen soil's frost heave. According to the law of the negative friction distribution and the theory of thermal stress of material machanics, the 'neutral level' position is solved, which playing an important role in determination of the distribution law of freezing pipe's fracture stress. The theorey of freezing pipe fracture is proved to be correct through a lot of cases at home and abroad.