Coupled Thermal-Hydro-Mechanical Effect on Cement Slurry Grouting Propagation in a Single Fracture with Flowing Water

This paper presents an experimental investigation of coupled thermal-hydro-mechanical effect on the propagation of cement slurry grouting in a single fracture replica with flowing water. A visualized single fracture described as roughness plane of JRC = 2–4 for grouting test system is used for conducting the propagation by considering different temperature and water flow rate conditions. The results show that the total volume of discharged water is reduced when the temperature is lower and the water flow rate is slower. Further analyses show that due to the increased solidification speed of the cement slurry caused by higher temperature, a solidification core appears in the centre of the grouting point, which reduces the ability of the subsequent slurry to propagate to the surroundings. The perspective of a two-phase flow is introduced in the discussion part with the mechanisms of sealing efficiency. The slurry viscosity and the gel time associated with temperature not only influences the water flow rate and the slurry flow rate, but also determines the sealing efficiency. With lower temperature, the seepage pressure first greatly increases as the two-phase flow, then keeps flat since most of the slurry has been solidified and flows along the channel, due to the long initial gel time. While with higher temperature, the short initial gel time leads to a flat period and then turns to an increasing.