Laboratory evaluation of shear strength properties for cement-based grouted coal mass
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Cement-based grouting has been widely used in underground coal mining to improve the overall quality of highly fractured rock masses. Due to the difficulties in obtaining characteristic specimens from highly fractured coal rocks, there are very limited laboratory studies investigating the effect of grout on the strength of coal. The purpose of this paper is to address this gap by examining the effects of grouting on fractured coal in terms of overall shear strength. Two failure modes associated with coal and grouted coal specimens have been identified. The results show the shear strength improvement of grouted coal specimens as indicated by the improvement of their peak and residual cohesion as well as friction angle when the amount of reinforcing grout increases. Linear regression models were constructed for the prediction of shear strength parameters based on grout percentages. These models can be used as a guideline for the preliminary design of pre-grouting applications.
KeywordsGrouting Overall shear strength Failure modes Coal mass quality improvement
The work was supported by the projects of “National Key Research and Development Program (2016YFC0600901),” “National Natural Science Foundation of China (Grant No.51574224).” The first author is grateful to the Chinese Scholarship Council for providing scholarships (Grant No.201706420023). The authors are grateful to the Huaibei Mining (Group) Co. Ltd. Special thanks to Dr Zuqi Wang for her encouragement and help.
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