关键词: 岩土工程；危岩冲击；钢棚洞；拼装式；多级减震；模型试验；数值模拟

Abstract: To explore the dangerous rock protection structures with higher construction efficiency and safety factors, numerical simulation and indoor testing methods were jointly adopted to verify the reliability of numerical calculation software from both qualitative and quantitative aspects. A new type of assembly steel shed tunnel was constructed based on the concept of multi-level shock absorption and strong roof support. The composite cushion was composed of sand, EPE and foam rubber. The roof of shed tunnel was composed of hollow steel plate and foam concrete. Matrix steel supports were arranged at the belly of the roof for strong support, and shock-absorbing rubber bearings were installed between the columns and the roof. The research results indicate that when falling rocks impact steel shed tunnels at speeds of 16 m/s, 20 m/s and 24 m/s, the peak stresses at the center of the slab belly are 28.54 MPa, 34.71 MPa and 40.92 MPa, respectively, and the peak displacements are 15.83 mm, 15.92 mm and 16.04 mm, respectively. The protective structure is within a safe range. The stress of EPE and the central unit of the foam rubber cushion layer is maintained at about 0.3 MPa and 0.5 MPa, and the composite cushion layer has superior energy dissipation and shock absorption effects. The matrix steel support is subjected to significant stress, with peak stress reaching around 60 MPa during the impact process. The non-rigidity of rubber bearings results in a triangular variation trend of their overall stress curve, with stress inside the support of approximately 5 MPa.

Key words: geotechnical engineering; dangerous rock impact; steel shed tunnel; assembly type; multi-level shock absorption; model experiment; numerical simulation