Tunnel surrounding rock crustal stress testing method based on stress equivalence principle

The invention relates to the technical field of ground stress testing, in particular to a tunnel surrounding rock ground stress testing method based on a stress equivalence principle. The method comprises the following steps: excavating a sample operation groove in a tunnel excavation surface; a prefabricated semicircular groove is formed in the middle of the rock pillar, and a strain gauge is pasted to the intersection point of the rock pillar and the central axis of the prefabricated semicircular groove; after the strain gauge is firmly pasted, measuring epsilon 0 of the initial strain of the strain gauge, and recording the temperature t0 of the test environment; s2, symmetrically cutting the rock pillar to form a rock test piece S1, cutting the rock pillar and grinding the rock pillar into a test piece S2, and packaging, storing and transporting the test piece to a laboratory for testing; and testing the strain of the rock test piece in a laboratory, and calculating the ground stress of the tunnel surround