Layout design method of underground cavern group

The invention discloses a layout design method of an underground cavern group applied to a water conservancy and hydropower project and an underground storage. According to the layout method, main factors influencing the stability of surrounding rock of the underground caverns, especially, the rock strength stress ratio which is the essential factor can be fully taken into consideration. The method comprises the following steps of: firstly determining the positions of main caverns, determining the axial line directions of the main caverns, determining the thicknesses of rock pillars among the main caverns, and finally determining the shapes of the main caverns, wherein in the process of determining the thicknesses of the rock pillars among the main caverns, the thicknesses of the rock pillars are 1.0-2.5-time mean than excavation span between two adjacent main caverns and are 0.5-0.8 times that of the height of the big one in the adjacent two main caverns. Compared with the layout design with a design plan provided by a using traditional layout method, the layout design with the layout method disclosed by the invention is more scientific; and especially, in a highland stress environment and in a condition with relatively low surrounding rock strength, the phenomena of the deformation and destruction of the surrounding rock after the surrounding rock of the underground cavern group is excavation-unloaded can be greatly reduced or the deformation and destruction degrees of the surrounding rock can be reduced.