Multi-arch tunnel surrounding rock stress release rate estimation method

The invention discloses a multi-arch tunnel surrounding rock stress release rate estimation method. The method comprises the following steps: acquiring an original crustal stress component at a multi-arch tunnel surrounding rock test section under a drilling coordinate system; excavating the pilot hole to obtain rock mass deformation parameters at the monitored section of the pilot hole; a stress release rate measuring hole is formed in the pilot hole; a three-way strain rosette is pasted in the measuring hole and is plugged; a middle guide wall is poured, a measuring connector is arranged, and strain initial values in three directions of each three-direction strain rosette are obtained; digging a front hole and a rear hole in sequence, and measuring the strain value of each three-way strain rosette; according to the positive strain change amount and the positive stress change amount of each three-way strain rosette caused by construction in the drilling coordinate system obtained through calculation, the str