冻结法凿井经验总结

Summary on Experiences of Freezing Shaft Sinking

总结主井冻结施工中合理确定开挖时间,控制冻土发展速度,挖、装、运、提和砌井壁的经验,遇到技术问题的讨论和解决的办法。

The experiences from the constructions of freezing shaft sinking in the main, auxiliary and ventilation shafts of Dongrong NO. 2 Mine are as followings: 1. The proper shaft excavation will be started after an active freezing operation of 90 to 100 days. 2. As the freezed ground circular entered into the excavation diameter, it should reduce the volume of cooling fluid in order to control the development of freezed ground. 3. It should use large equipments for excavation, loading and hoisting. 4. It should adopt a combined excavation and lining operation with a short section. 5. It should adopt metal removal form plate for the out lining. 6. It should use hydraulic sliding form plate for inner lining. 7. Additives for early strength and water reduction should be used.in the concrete. 8. Foamed plastic material should be placed between the out lining and shaft wall. 9. The operations of excavation and lining should be closely cooperated with the operation of ground freezing. The R & D and design should be closeluy cooperated with the construction management. In all three shafts, there were some failures on the out lining due to high ground pressure. There were some cracking occured on the inner lining. There were some lower strength problem occured on the freezing wall. Later all have been solved. In this paper, the freezing depth to be used in the furture operation, Chinese made freezing tube, water drainage from water well and location for mine shaft to be selected, measurements on out force and inner force effected on freezing wall have been discussed.