深立井软岩让压支护技术研究

Research on de-stressing technique applied in soft rock supportin deep shaft

为解决深立井软岩支护技术难题,提出"预留让压空间,适度让压"的技术方案,并通过设立试验段,于不同试验段设立监测断面,实时监测井壁内缘受力情况,预测研判不同让压空间条件下井壁工作状态的方法,确定合理的让压空间,为深部软岩立井顺利开拓和人员安全提供理论保障。研究结果表明:壁后让压空间合理的井壁,短时间内受力稳定,且数值较小,安全储备较大,若壁后预留让压空间过小,井壁受力随时间增减呈对数增长趋势,会导致井壁破裂;基于不同强度准则的预测结果说明,基于Von Mises强度准则的预测结果与实际情况更加符合,可靠性更强;设立试验段,以实测结果确定让压空间的技术方案,较其他手段更为直观可靠。

In order to solve the technological difficulties of soft rock support in deep shaft, a technical plan is proposed under the guideline ＂reserve space for pressure, moderately de-stress＂. The reasonable de-stressing space is determined by predicting the working state of shaft wall based on the real-time monitoring of stress distribution around its inner edge in different test sections under differ- ent spaces reserved for pressure at the monitoring section, and theoretical guarantee for soft rock support in deep shaft and technical support for personnel safety are provided. The results show that the stress of shaft wall with reasonable de-stressing space is steady in a short time, and the value of the stress is reduced. The stress of shaft wall with undersized de-stressing space increases logarithmi- cally with time, which leads to fracture of shaft lining. The predicted results based on different strength criterion show that the prediction according to Von Mises strength criterion is more in line with the actual situation and more reliable than others. A technical proposal that determines the space reserved for pressure on the basis of measured results of test sections is more intuitive and reli- able than other means.