An optimization approach for underground cavern layouts utilizing the surrounding rock disturbance contribution of primary and secondary caverns

Designing rational layouts for large underground cavern groups under complex geological conditions remains a major engineering challenge, requiring a balance between global stability and local safety in high-risk regions. An effective quantitative basis for decision-making is still lacking. This study proposes a layout optimization method based on Surrounding Rock Disturbance Contribution (SRDC) of primary and secondary caverns. By quantifying excavation-induced plastic failure volume and energy evolution, the method characterizes their disturbance to high-risk regions and guides layout optimization. First, a representative numerical model of Class III surrounding rock is established to analyze responses under different in-situ stress magnitudes and principal stress inclination angles, identify potential high-risk regions, and define monitoring blocks based on the extent of surrounding rock disturbance. A comprehensive evaluation indicator system integrating plastic failure volume and energy evolution then enables progressive scheme selection from global stability screening to local disturbance control. Structural plane avoidance principles are further proposed based on mechanical properties and intersections with the cavern group, enabling local checks and adjustments of the preferred layout. Engineering case analyses indicate that the method can identify optimal layouts and improve global and local safety. By translating complex stability assessments into a standardized quantitative decision-making process, this study provides a broadly applicable layout optimization method for underground engineering design.