Calculation Method of Underground Cavern Loosening Pressure Based on Limit Analysis Using Upper-Bound Theory and Its Engineering Application

From the point of view of the failure mechanism of the disturbed zone, this paper uses the limit analysis upper-bound theory to analyze the calculation formula of the loosening pressure, distinguish the difference between the vertical pressure and the horizontal pressure in the underground cavern, combine the loosening characteristics of the disturbed zone with the open-type disturbed zone and the annular disturbed zone, and construct the multirigidity slider translation and rotation failure mode to discuss the calculation method of surrounding rock loosening pressure of underground caverns in upper soft and hard rock stratum. The relevant calculation examples are given, and the application of the upper-bound theory of limit analysis is demonstrated in detail. Based on the actual engineering background, the calculation results of the calculation method of the loosening pressure of the cavity based on the upper-bound theory of the limit analysis are analyzed and compared for the different depths and different types of caverns. The difference, rationality, and applicability of the calculation results of this method are analyzed and discussed.