关键词: 西部地区, 白垩系地层, 富水基岩, 冻结法, 冻结压力

Abstract: To solve the technological problems of mine construction by freezing of cretaceous water-rich bedrock in western region, by using the vibrating wire sensors to measure and analyze bedrock’s freezing pressure and interface temperature of air shaft in a Gansu mine, the change rules, causes and inhomogeneity on freezing pressure of cretaceous bedrock during shaft sinking have been studied. The results show that the freezing pressure contains four stages: rapid growth, dramatic increase, slow rise and gradual steadiness. It has obvious inhomogeneity at the same level and is caused by many factors. Its final stable value reaches 1.708-2.047 MPa, less than the maximal theoretical and empirical value of western bedrock at the same depth, and the upper limit of freezing pressure pω in eastern shock layer. The interface temperature of frozen wall and shaft lining rises sharply and then reduces quickly, with the maximum of each point reaching 42.4-59.4 ℃ within 30 h and the difference values 51.86-71.3 ℃after the temperature decrease, which is extremely unfavorable to the security and stability of the two wall. Following the eastern design methods and experiences tends to cause the wall to become much thicker and produce ringed temperature cracks because of temperature stress, so there still exists an optimized space on structural design and construction of the western mine shaft.

Key words: western region, cretaceous strata, water-rich bedrock, freezing method, freezing pressure