Mechanical behaviors of surrounding rock and supporting structure of shallow-buried unsymmetrical pressure tunnel crossing soil–rock interface

Shallow bias tunnels are sensitive at the entrance section, where existence of soil–rock interface (SRI) results in more complex deformation surrounding rock and supporting structure. This study investigates mechanical properties structure a shallow-buried tunnel crossing by combination model tests numerical simulations. A biased with significant cracking its section is selected southwest China. The plastic zone distribution, deformation, pressure rock, as well stress structure, analyzed under different conditions vault, arch haunch, spring, wall foot interface. test show that internal force lining largest left haunch right cracks occurring project. most prominently influenced spring among positions tunnel. subjected to three modes: there mainly shearing when vault passes through interface, extrusion co-exist pass dominant Inserting grouting steel pipes perpendicular on deep-buried side can effectively control