Soft rock large-deformation section lining structure for large-section tunnel through drilling and blasting method

A large-section tunnel soft rock large-deformation section lining structure adopting a drilling and blasting method is characterized by comprising a light large-deformation section lining structure unit, a medium large-deformation section lining structure unit and a heavy large-deformation section lining structure unit which are connected with one another along the center line of a tunnel; the severe large deformation section lining structure unit adopts a double-layer preliminary bracing structure, the moderate large deformation section lining structure unit and the severe large deformation section lining structure unit use small grouting guide pipes to replace system anchor rods, the reserved deformation amount is filled with a foamed aluminum buffer layer, and concrete is backfilled after convergence deformation; during construction, the grade of the large deformation section of the soft rock is judged in a grading manner, and the lining structure units are reasonably selected and matched for subsequent co