An efficient algorithm for simulating grout propagation in 2D discrete fracture networks

This study is aimed at developing a computationally efficient algorithm to simulate the grout fluid propagation by generalizing the recently developed Explicit Grout Forehead Pressure algorithm to two-dimensional discrete fracture networks. A computer program is developed by using an innovative recursive scheme to track the paths of grout propagation within the fractures, and the results can be visualized using a graphic interface. The efficiency and accuracy of the algorithm is successfully validated using two series of laboratory tests. Finally, sensitivity analyses are conducted to study the influence of key parameters, including initial pressure, grout fluid density, grout viscosity and operation time, on the grout propagation for both dry and saturated in-situ conditions. The study demonstrates that the existence of pore fluid inside the fractured medium can significantly decrease the propagation area. Some other less studied factors are also investigated, such as time-dependent hardening of the grout viscosity, initial yield stress of the grout fluid and rheology properties of the in-situ pore fluid. These factors are also found to be important for improving efficiency of the grout operation.