Grouting effect on rock fracture using shear and seepage assessment

Evaluation of grouting prior to construction application is necessary. For preparing standard grouting samples, a grouting device was developed. Shear tests and confined seepage tests were conducted on single-fracture chlorite schist with and without grouting. Firstly, ungrouted fracture shear test was studied as a comparative test. The impact of water is mainly represented by cohesion decrease, while the weakening effect could be improved by increasing normal pressure. Secondly, shear test of grouted samples was conducted with indoor test and numerical modelling. The test data coincide well with simulation results. Damage initiates at the weakest position in the composite material. Increasing mechanical property of grouting material would be helpful for strengthening rock fracture. Lastly, seepage velocity decreases exponentially and evidently in confined seepage test for the grouted rock. Despite of unsatisfactory in strength, grouting works well in decreasing permeability. Although cement grouting could be applied as an effective treatment method to decrease the permeability, provide initial pre-stress and stabilize the surrounding rocks, it is suggested that performance of grouting material should be tested before industry. Selection of grouting material should be conducted with caution. (C) 2020 Elsevier Ltd. All rights reserved.