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Cui F.,Xi'an University of Science and Technology | Cui F.,Key Laboratory of Western Mines and Hazard Prevention of China Ministry of Education | Lai X.,Xi'an University of Science and Technology | Lai X.,Key Laboratory of Western Mines and Hazard Prevention of China Ministry of Education | And 4 more authors.
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2015

To establish the relationship between the scheme of coupled-crack and strength deterioration for the coal and rock mass as the target, the interaction of injection water measure and blasting measure are defined as coupled-crack, and the coupled-crack mechanism is analyzed, giving the crack propagation criterion for the implementation of coupled-crack technology. Strength deterioration analysis method of fluid-solid coupling model affected by explosion is put forward. By using numerical simulation method, we establish the models for injecting water and obtaining explosion load, axially load is applied after finishing explosion loading, the strength degradation degree of overall model at different coupled-crack schemes is analyzed. The results show that: the essence of coupled-crack is that detonation gas and shock wave formed by explosion spreads in softened coal and rock mass, coupled-crack effect is greater than the simple superposition of basting and injection water;Improve water pressure can increase the strength degradation rate of coal and rock mass, model strength has a significantly decreased with the increase of drill diameter (explosion). The relationship between the coupled-crack parameters and strength deterioration degree of f is obtained, the damage degree of coal body caused by injection water pressure of explosive consumption is quantitatively evaluated. In engineering practice, the strength of coal mass from steeply dipping extra-thick coal seam after coupled-crack is 5.48 MPa, which has a decreased by 40.07% compared with the implementation of injection water. The working face recovery rate meets the requirements of national standards for thick coal seam, which realizes the objective of improving the top coal recovery rate, providing experiment method and basis for the quantitative evaluation of coupled-crack effect. ©, 2015, Academia Sinica. All right reserved.


Wang N.-B.,China University of Mining and Technology | Zhang N.,China University of Mining and Technology | Cui F.,Xi'an University of Science and Technology | Cui F.,Key Laboratory of Western Mines and Hazard Prevention of China Ministry of Education | And 4 more authors.
Meitan Xuebao/Journal of the China Coal Society | Year: 2013

The occurrence environment of steeply dipping coal seams and mining by sublevel top-coal caving further aggravate the complexity of stope structure and stress evolution in fully mechanized top-coal caving face, increasing the difficulty of assessing working face stability. Therefore, the mode of multi-method comprehensive detection for coal and rock mass structure and fracture characteristics of surrounding rock in mining roadway was put forward. The conditions of force source for generating zonal disintegration in surrounding rock were analyzed through the overburden structure and stress in fully mechanized top-coal caving face at steeply dipping coal seams. based on the detection methods of stress monitoring, sound wave exploration and optical borehole camera etc, the quality of surrounding rock and separation area location, development degree of crack, fracture number and length on hole wall as well as the dynamic rupture evolution characteristics within the detection zone were obtained. Comprehensive analysis shows that the crushing of surrounding rock fracture in steeply dipping coal seams has the characteristics of partition distribution, the crack characteristics of irregular partition evolution occurs in roof and two sides of roadway for fracture, fracture zone and intact zone appear alternately, the distribution area of surrounding rock fracture in coal mass side is larger than the rock side.


Liu X.M.,Shenhua NingXia Coal Ltd. | Liu X.M.,University of Science and Technology of China | Lai X.P.,Shenhua NingXia Coal Ltd. | Lai X.P.,University of Science and Technology of China | And 5 more authors.
Transit Development in Rock Mechanics-Recognition, Thinking and Innovation - Proceedings of the 3rd ISRM Young Scholars Symposium on Rock Mechanics, 2014 | Year: 2015

The damage degree and acoustic emission characteristics of coal sample are closely related to coal-rock dynamic destabilization. According to destructive test of large size coal sample from Huating coal mine, the damage and acoustic emission test of large size coal samples with stratification structure of parallel and vertical are completed. The coal-rock failure process and damage degree are described by the using of state vector, which can forecast the catastrophic and rupture. Based on the analysis of related index of state vector, the damage degree of percentage is defined, which quantitatively reflects the local damage and rupture intensity of rock mass. This has theory and practice significance for the prediction of large scale mining out area instability and derivative disasters in strong earthquake zone. © 2015 Taylor & Francis Group, London.

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Loading Key Laboratory of Western Mines and Hazard Prevention of China Ministry of Education collaborators