Shallow reinforcement effect of plant roots on construction stability of shallow tunnel

Shallow roots of plant have reinforcement function. It can improve shear strength of soil mainly by increasing cohesion of root and soil composite. Considering shallow reinforcement influence of plant roots, it can be concluded based on 3D numerical simulation and comparative study that shallow reinforcement effect of plant roots on construction stability of shallow tunnel in weak rock mass mainly includes diminishing vault subsidence and surface settlement, greatly increasing the tensile capacity of surface shallow soil, and reducing damage scope of surface shallow soil. Shallow reinforcement effect of plant roots is optimal for construction stability of shallow tunnel in weak rock mass when embedded depth of tunnel is within influencing depth of plant roots, that is, 1-2m. It is not sensitive for shallow reinforcement effect on strength of initial support in the range of reasonable parameters of initial support.