Vertical critical pressure of a new shaft lining compressive device consisting of pipes and shells

Through numerical analysis and model test, the influence factors and calculating method of the vertical critical pressure of a new shaft lining compressive device consisting of pipes and shells were carried out. The device can be installed in shaft lining to mend or avoid shaft lining fracture based on the mechanism of the shaft lining frature - "vertical additional force" theory. According to the analysis results, thickness of the inner and outer rib and widness of the device are the main influence factors of the vertical critical pressure. In addition, the critical pressure is linear with thickness and in inverse proportation to the widness. And also, the formula for computing the critical pressure is obtained. The model tests show that the relative error between the formula and test results of the vertical critical pressure is within 15%.