Grout penetration in fractured rock mass using a new developed explicit algorithm

•A fully explicit algorithm to model grout fluid propagation into the rock joints.•This algorithm promotes accuracy of evaluations.•It is extremely compatible to program codes to estimate grout propagation in 2D&3D.•It is able to model joints in vertical section to consider the gravitational effect.•It is able to model pore fluid pressure and its effects on permeability.•It considers the effect of time-dependent hardening of grout inside the joints.•It is able to model different types of grout fluids.

A grout penetrability method based on explicit grout forehead pressure (EGFP) algorithm for joints and cracks in rock mass is developed. This algorithm is more accurate and effective, and demands less computation power and time compared to previously used methods, for almost all types of fluids, under different flow regimes. The pre-existing pore pressure in rock joints is also considered in the present developed algorithm. EGFP does not require a complex program for calculating penetration length, and any simple calculator-based program also could be utilized to implement it. This algorithm is flexible enough to develop to a network of conductors. EGFP divides the conductor to a number of elements and continues the calculations to where the grout forehead gets stopped in the conductor owing to limitation factors. In the present algorithm there is no initial experimental prediction of total penetration length or flow rate of grout fluid that causes increases the accuracy. A series of laboratory tests were conducted and were used to validate and calibrate the numerical results. The results obtained by present algorithm show good agreement with experimental results.