The invention relates to a tunnel structure for an expansible stratum. The tunnel structure comprises a steel rack sprayed concrete primary support brace, a reinforced concrete arc wall lining, an inverted arch and inverted arch filling, wherein a reinforcing steel bar grating truss is disposed in the inverted arch filling over the inverted arch; and a central seepage trench is arranged under the inverted arch. A tunnel structure is adjusted, and tunnel inverted arch curvature is enlarged; a central water trench is replaced by the reinforcing steel bar grating truss is placed in the inverted arch filling, so bearing performance of a base structure is improved; with the arrangements of the side trench and the central seepage trench, underwater in the stratum around the tunnel and the base can be discharged; and stratum expansion deformation and damages to a tunnel lining structure by the expansion and deformation can be reduced.