Abstract:The distribution range of the tertiary strata in the tunnel of the Yellow River to Xining water diversion project in Qinghai Province is wide, and the tunnel burial depth is deep. A preliminary study on the physical mechanics and deformation characteristics of soft rock in the tertiary strata of tunnels surrounding rock was conducted using experimental and empirical analysis methods. The results showed that the rock density of the tertiary strata is low and the water absorption rate is high; Under saturated conditions, the uniaxial compressive strength of rocks decreases sharply, and the softening coefficient is extremely low; Some rock types have expansibility; A small amount of rock has poor resistance to disintegration; The mechanical properties of the rock in the tertiary strata of the Yellow River to Xining water diversion project are poor under water rich conditions, which is detrimental to the stability of the surrounding rock. When the burial depth is greater than 127m, the tertiary surrounding rock of the Y Yellow River to Xining water diversion project tunnel may undergo severe to extremely severe compression deformation. During construction, targeted engineering measures should be taken based on the deformation characteristics of the surrounding rock to reduce the harm of surrounding rock deformation.
