关键词: 深井建设, 冻结法, 温度应力, 温度场, 热弹性力学, 大体积混凝土

Abstract: In order to study the early temperature stress variation law of deep frozen shaft wall at different time nodes,an analytical solution of early temperature stress of frozen shaft wall was derived based on the heat conduction principle and thermoelastic mechanics theory,considering the temperature history of frozen shaft wall and the change of concrete elastic modulus. Taking the 1. 7 m thick wall seat of No. 1 air shaft in Hongqinghe Coal Mine as the study example,the distribution law of early temperature stress in the inner wall of frozen shaft was obtained,and the main reason of early temperature stress leading to high risk area of shaft fracture was determined. The study results show that:① In the early stage,the radial stress σr is compressive stress as a whole,and the maximum σr can reach -2. 2 MPa,and decreases gradually along the frozen wall to the inner edge of the shaft wall. At any position of the borehole wall, σr decreases first and then increases with the development of age. ② In the early stage,the annular stress σθ is compressive stress as a whole,and the maximum σθ can reach -8. 98 MPa. When it tends to the frozen wall, σθ decreases rapidly first. When tending to the inner wall edge, σθ increases first and then decreases. ③ In the early stage,the vertical stress σz is compressive stress,which can reach the maximum of -19. 64 MPa,and increases rapidly at first and then decreases slowly with the development of age. ④ It is suggested that the temperature history formula of the same kind of shaft wall should be fitted according to the engineering analogy method for the theoretical calculation of temperature stress of frozen shaft wall in the future. On this basis,the measures to reduce the risk of rupture of frozen borehole wall are put forward,including two ideas:① Reduce the temperature difference between the outer edge of borehole wall and the center and the inner edge. ② Prepare crack resistant concrete suitable for freezing wellbore.