正确选择深井冻结开挖时间,是加快井筒施工速度、改善劳动条件、提高井壁质量、降低成本的主要措施之一。深井冻结圈径大,冻结时间长,若等待上部冻土壁达到荒径时,才进行开挖,势必造成井筒深部冻土壁扩展到荒径以内,甚至会使井筒内岩层全部冻实,给井筒掘进工作带来一定困难,降低掘进速度。 Proper selection of deep-well frozen excavation time is one of the main measures to speed up the wellbore construction speed, improve the working conditions, improve the quality of wellbore and reduce the cost. Deep frozen ring diameter, frozen for a long time, if waiting for the top of the frozen soil wall to reach desolation before excavation, will inevitably cause the deep borehole wall extended to desolate diameter, or even make the rock formation completely frozen, to Borehole boring work to bring some difficulties and reduce driving speed.