Abstract: Herein, the feasibility of using a point load for rapid evaluation of the saturated compressive strength(SCS) of tunnel muck is assessed by analyzing the effect of the loading mode and hydrous state of tunnel muck on the point load strength index(PLSI) of 20 tunnel muck samples with various lithologies. A correlation analysis is performed on the PLSI and SCS of the tunnel muck. The following results are obtained: (1) The PLSI is highly correlated with the SCS for samples with different lithologies, including metamorphic, sedimentary, and igneous rocks. (2) When the axial PLSI is >8.0 MPa, the PLSIs measured under different loading modes vary; the PLSIs measured under radial and axial loading are similar. However, the difference in the PLSIs measured under irregular and axial loading increases with the point load. The loss rate of the PLSI is positively and linearly correlated with the water content of the tunnel muck. The aforementioned results are used to propose prediction formulas for tunnel muck SCS in different hydrous states.

Key words: tunnel muck, point load, saturated compressive strength, rapid evaluation