高内压储气库围岩承载机理及承载分区方法研究OA

[Objective]To address the issue that traditional underground gas storage facilities rely excessively on lining and sealing systems to bear high internal pressure,thereby limiting the operating pressure and energy storage efficiency due to the inability to fully utilize the bearing capacity of the surrounding rock.[Methods]This study was conducted based on the elastoplastic thick-walled cylinder theory and the Mohr-Coulomb criterion.[Results]A framework of three major effects governing surrounding rock bearing capacity was proposed:spatial effect,strength effect,and confining pressure effect.The mechanical mechanism of internal pressure transmission,diffusion,and attenuation into the surrounding rock through the lining was systematically analyzed.A bearing capacity zoning criterion with the attenuation rate of additional stress as an indicator was constructed,and the zoning results were used for defect detection range delineation,detection accuracy classification,and differentiated reinforcement design.[Conclusion]The spatial effect determines the spatial range of surrounding rock involved in load bearing,the strength effect controls the upper limit of the surrounding rock bearing capacity,and the confining pressure effect affects the closure of surrounding rock fissures,shear and tensile resistance,and the risk of local instability.Based on the law of additional stress attenuation,engineering assessment can be conducted to divide the surrounding rock into a primary load-bearing zone,a secondary load-bearing zone,and an in-situ stress zone.The area where the additional stress attenuation does not exceed 50％is the primary load-bearing zone,the area where the attenuation is 50％～90％is the secondary load-bearing zone,and the area where the attenuation exceeds 90％is the in-situ stress zone.For hard,intact surrounding rock,the outer boundaries of the primary and secondary load-bearing zones are approximately 1.4 times and 3.2 times the tunnel radius,respectively.The stress nature of a high-internal-pressure gas storage cavern is not solely borne by the lining structure,but rather a collaborative load-bearing process under the combined action of internal pressure,structure,surrounding rock,and in-situ stress.The proposed three major effect mechanisms reveal the intrinsic control relationship between the load-bearing range,load-bearing level,and stability state of the surrounding rock.The zoning criteria provide a quantitative basis for determining operating pressure,evaluating surrounding rock stability,inspection layout,and optimizing support reinforcement,and provide theoretical support for the safe operation and economic design of gas storage caverns under high internal pressure.