ABSTRACT
Xiaozhuang Coal Mine locates in Bin county, Shaanxi province, the main wellbore diameter is 7.5 m, the biggest thickness of the frozen wall is 1 m, the depth of wellbore is 418.2 m, the partial deep freezing method construction is adopted in this project, the frozen depth is 242 m, the thickness of frozen wall is 2.5 m, adopting the double layer reinforced concrete to support the topsoil and weathered bedrock of the wellbore wall, the thickness of outer wall is 400 mm, the thickness of inner wall is 600 mm, the concrete strength is C45 and C55; adopting the single-layer reinforced concrete to support the weathered bedrock of the wellbore wall, the thickness of wall is 600 mm, the concrete strength are all C45.
