复合井壁中泡沫塑料板缓压作用实测分析

Actual Measurement and Analysis on Delay Action of Pressure Insulation of Polyethylene Foam Board in Composite Shaft Lining

冻结法施工的井筒,通常在外壁与冻结壁之间铺设一层聚乙烯泡沫塑料板,以减缓冻结压力对井壁结构的影响.为深入研究冻结复合井壁中聚乙烯泡沫塑料板的缓压作用,在山东某煤矿副井特厚冲积层冻结法凿井施工中开展了竖井井壁冻结压力的现场实测研究.实测结果表明：泡沫塑料板具有明显的缓压作用,对冻结井壁外壁混凝土早期强度的提高十分有利,但是泡沫塑料板只能延缓冻结压力的增长,而不能减小最终冻结压力值.

Commonly,it lays a layer of polyethylene foam board to reduce the influence of the freezing pressure acting on the structure of the shaft. In order to thoroughly investigate the effect of polyethylene foam board outside of the freezing shaft ,in-situ measurements on freezing pressure of vertical shaft lining are carried out in the shaft sinking with the freezing method in deep alluvium in a coal mine in Shandong Province. The in-situ measurement result reveals that polyethylene foam board has obvious affect to delay the freezing pressure insulation, this is very advantageous to improve the early strength of concrete of the mine freezing shaft lining, but the polyethylene foam board can only delay the freezing pressure, it can not reduce the final value.