Tunnel Deformation Behavior due to Ground Surface Excavation above the Tunnel
Yoshiyuki KOJIMA, Toshihiro ASAKURA, Kazuyuki YOSHIKAWA, Yoshiyuki SHIGETA, Takashi TUCHIYA and Koji NAKAGAWA
Abstract:To establish an adequate evaluative method of existing tunnel deformation behaviors due to ground surface excavation above the tunnels, case studies of 23 tunnels' field measurement data and numerical parametric analyses using two dimensional FEM have been conducted. To sum up the contents; 1) Cracking of tunnel lining are roughly found in cases of the final/initial overburden ratio h/H <0.2`0.3 (h: final overburden, H : initial overburden). 2) Tunnel deformation behaviors consist mainly of B/2(h+D) (B : excavation width, D : tunnel diameter), lining rigidity, ground rigidity, contact condition between ground and tunnel lining, and ground initial stress K0. Key Words:Ground surface excavation, Existing tunnel, Deformation behavior, Evaluation method, Case study, FEM