With the rapid development of the construction of new wells in western of China, it's necessary to solve these technical problems that are about drilling wells through the cretaceous water-rich stratum by the technique of artificial frozen. Based on wind shaft freezing engineering in Gansu xin-zhuang mine, the physical mechanical characteristics and thermal properties of cretaceous rocks are studied in frozen conditions by laboratory physical mechanics testing, field measurement and finite element numerical simulation. The stress mechanism of frozen wall is discussed by field measurement during shaft wall sinking period, and the change rule and causes of freezing pressure with the cretaceous frozen wall are analyzed. The actual measurement results and simulated results about the radial temperature of thermometer hole and frozen wall are compared, mainly to study the influence of concrete hydration heat on the frozen wall by fitting. The results show that the influence depth is 440 mm-480 mm. The study not only plays a positive role in enriching the basic theory of rock mechanics in China, but also provides the basis for the optimization design and the security and stability study of shaft sinking by freezing method in the western region.
With the rapid development of China's coal industry, well construction encounters a lot of the Cretaceous strata which has the characteristics of weak cementation, low strength and rich in water. At present, the achievements of freezing method in China are more concentrated in the eastern alluvial area (Ma & Cheng 2007, Hu et al. 2010, Yang & Xi 2010), and there are seldom reports about the study of the Cretaceous strata (Yue & Wang 2009, Yao et al. 2010). The design and construction of the wall still follow the theory of experience in the East (Yang et al. 2010, Hua et al. 2010). Because of the difference in physical and mechanical properties between rock and soil (Yang et al. 2010, Sun et al. 2010), the frozen wall and shaft lining design are conservative. There are still problems about high temperature stress and even the rupture of the outer shaft wall (Chen 2007). The physical mechanical characteristics and thermal properties of cretaceous rocks are studied in frozen conditions by laboratory physical mechanics testing, field measurement and finite element numerical simulation, and will provides the basis for the optimization design and the security and stability study of shaft sinking by freezing method in the western regions.
