Experimental Study on Mechanical Property of Highly Weathered Tuff for High-altitude Tunnel

In the context of Milashan Tunnel in predominantly tuff whose mechanical property quickly deteriorates when in contact with water, it is necessary to study through lab test the creep property of highly weathered tuff surrounding the high altitude tunnel. This paper covers reconstruction of standard specimen with measurements of tuff dry density, natural water content and particle grading curve; analysis of axial stress and strain curves based on triaxial compression test; plotting failure stress circle to obtain tuff strength parameters c and φ; obtaining tuff rheological parameters from triaxial rheological test; deriving creep process curve by multi-specimen method; simulation of its rheological characteristics using Burgers model; and lastly identifying rheological parameters using MATLAB. It provides basic data to study deformation mode and monitoring measurement in actual construction.