作用在冻结井壁上负摩擦力的计算

Calculation of Negative Frictional Force on Freezing Shaft Liner-

论述立井井壁纵向负摩擦力存在的依据,目前计算负摩擦力以桩基为基础的计算方法存在欠缺,根据一定假设、井壁自重应力、井壁破坏深度和破坏应力,反算法推算出负摩擦力,再用数理统计和考虑适当偏安全,求出淮北、大屯和徐淮矿区立井井■摩擦力的建议值。

After a completion of a freezing shaft liner construction, due to the thaw of freezing soil and subsidence of ground, a first negative frictional force was occured. A second frictional force was occured due to coal mining, mine water drainage, water table dropping in overburden, ground surface subsidence, ground compression and subsidence. Due to the seasonal exchanges and high temperature in summer, there is a temperature stress in the shaft liner and there is a negative frictional force in the shaft liner. The present calculation of the frictional force is based on a pillar foundation and has some disadvantages. It is assumed that the negative frictional force along the surface of the freezing shaft liner are evenly distributed. Except the other loads, it only calculated the net weight of the shaft liner. It is to define that the failure stress due to the failure depth of overburden and bidirectional stress of shaft liner concrete is 1. 2 higher than the unidirectional stress. The negative frictional force at the shaft failure is calculated with a reverse calculationa method. Based on 10 failure shaft liner in Huibei and Datun coal mining areas as examples. records of certain data and in consideration of a safety figure, it has defined a negative frictional force for mine shaft liner in Huibei, Datun and Xuhui coal mining areas by using math statistical method. The negative frictional force can be used for the design of mine shaft liner.