Application and Research of Stress-strain Monitoring of Central Division Wall in Double-arch Tunnel

Abstract

According to the structure characteristics of double-arch tunnel and monitoring-measurement principles of NATM, steel-chord pressure box and DKY-51-2 vibrating-wire sensor recording devices were used to measure the pressure between top rock mass and supporting layer of central division walls of three double-arch tunnels. Photoelastic strain gauges were also used for the measurement of stress and strain of concrete surface. It is indicated from the results that (1) the pressure value of top central division walls increases with the time and reaches 7 MPa at maximum, and it could get a larger mutation after blasting; (2) the stress value of concrete sections of central division walls is smaller than 3 MPa, and it is somewhat different with the directions and depths. The structural stress state was also numerical simulated by