Field Determination of Surrounding Rock Strength under TBM Construction in Zhongtianshan Tunnel

Rock strength is a key factor in the tunneling efficiency of TBM construction. An issue needing special attention on the work site is how to determine rapidly and accurately the strength of the surrounding rock which makes a crucial reference for the choice of TBM tunneling parameters and corresponding support measures. In the study conducted on the TBM construction site of Zhongtianshan Tunnel, point load test (PLT) of rocks is adopted to measure the rock strength and the data is compared with those of the uniaxial compressive strength (UCS). Finally, the correlation between the two is revealed through regression analysis method.