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The roadway stability has been regarded as the main challenging issue for safety and productivity of deep underground coal mines, particularly where roadways are affected by coal mining activities. This study investigates the −740 m main roadway in the Jining No. 2 Coal Mine to provide a theoretical basis for the stability control of the main deep roadway affected by disturbances of adjacent working activities. Field surveys, theoretical analyses, and numerical simulations are used to reveal mechanisms of the coal mining disturbance. The field survey shows that the deformation of roadway increases when the work face advances near the roadway group. Long working face mining causes the key strata to collapse based on the key strata theory and then disturbs the adjacent roadway group. When the working face is 100 m away from the stop-mining line, the roadway group is affected by the mining face, and the width roadway protection coal pillar is determined to be about 100 m. Flac3D simulations prove the accuracy of the theoretical result. Through reinforcement and support measures for the main roadway, the overall strength of the surrounding rock is enhanced, the stability of the surrounding rock of the roadway is guaranteed, and the safe production of the mine is maintained.
Yuantian Sun; Ruiyang Bi; Qingliang Chang; Reza Taherdangkoo; Junfei Zhang; Junbo Sun; Jiandong Huang; Guichen Li. Stability Analysis of Roadway Groups under Multi-Mining Disturbances. Applied Sciences 2021, 11, 7953 .
AMA StyleYuantian Sun, Ruiyang Bi, Qingliang Chang, Reza Taherdangkoo, Junfei Zhang, Junbo Sun, Jiandong Huang, Guichen Li. Stability Analysis of Roadway Groups under Multi-Mining Disturbances. Applied Sciences. 2021; 11 (17):7953.
Chicago/Turabian StyleYuantian Sun; Ruiyang Bi; Qingliang Chang; Reza Taherdangkoo; Junfei Zhang; Junbo Sun; Jiandong Huang; Guichen Li. 2021. "Stability Analysis of Roadway Groups under Multi-Mining Disturbances." Applied Sciences 11, no. 17: 7953.
Pre-grouting as an effective means for improving the stability of roadways can reduce maintenance costs and maintain safety in complex mining conditions. In the Guobei coal mine in China, a cement pre-grouting technique was adopted to enhance the overall strength of soft coal mass and provide sufficient support for the roadway. However, there are very limited studies about the effect of grouting on the overall strength of coal in the laboratory. In this paper, based on the field observation of a coal-grout structure after grouting, a series of direct shear tests were conducted on coal and grouted coal specimens to quantitatively evaluate the quality improvement of grouted coal mass. The results showed that the peak and residual shear strength, cohesion, friction angle and the shear stiffness of grouted coal were significantly improved with the increase of the diameter of grout column. Linear regression models were established for predicting these mechanical parameters. In addition, three failure models associated with coal and grouted coal specimens were revealed. According to microstructure and macroscopic failure performance of specimens, the application of the proposed models and some methods for further improving the stability of grouted coal mass were suggested. The research can provide the basic evaluation and guideline for the parametric design of cement pre-grouting applications in soft coal mass.
Yuantian Sun; Guichen Li; Junfei Zhang; Junbo Sun; Jiandong Huang; Reza Taherdangkoo. New Insights of Grouting in Coal Mass: From Small-Scale Experiments to Microstructures. Sustainability 2021, 13, 9315 .
AMA StyleYuantian Sun, Guichen Li, Junfei Zhang, Junbo Sun, Jiandong Huang, Reza Taherdangkoo. New Insights of Grouting in Coal Mass: From Small-Scale Experiments to Microstructures. Sustainability. 2021; 13 (16):9315.
Chicago/Turabian StyleYuantian Sun; Guichen Li; Junfei Zhang; Junbo Sun; Jiandong Huang; Reza Taherdangkoo. 2021. "New Insights of Grouting in Coal Mass: From Small-Scale Experiments to Microstructures." Sustainability 13, no. 16: 9315.