Search

Accurately grasping the evolution characteristics of the water-conducting fracture zone in the mining overburden is an important basis for preventing the occurrence of water inrush disasters in the working face, especially for the high strength mining conditions in the western mines. Taking the 201 west wing area of Yushuwan Coal Mine as the background, taking the uniaxial compressive strength of each sandstone layer, RQD, and thickness of sandstone layer as the system cluster analysis indexes, this paper proposes a geological generalization method for thick bedrock, systematically studies the influence of different bedrock layer thickness on the development height, fracture angle, frequency, and joint strain energy evolution law of the water-conducting fracture zone, and determines the quantitative relationship between the height of the water-conducting fracture zone and the total joint strain energy. The research results show that: the development height of the hydraulic fracture zone simulated based on the geological generalization method presents a log-positive correlation increasing trend with the increase of the bedrock thickness, and the increasing rate gradually decreases. This law is verified by comparing with the measured results of the adjacent mines; with the increase of the thickness of bedrock, the development frequency of vertical cracks in the water-conducting fracture zone increases significantly, while the horizontal cracks in the water-conducting fracture zone increase, which indicates that the increase of the thickness of bedrock has a certain inhibition effect on the initiation and expansion of horizontal cracks in the water-conducting fracture zone; the development height of the water-conducting fracture zone is closely related to the energy release degree of the overlying rock. It increases exponentially with the increase of the maximum strain energy and the total strain energy of the joint, and the increasing rate gradually increases.

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Surface subsidence caused by underground mining is a complicated spatiotemporal process. This study establishes a novel mining subsidence superposition model using variable mining thickness of coal seam by combining two models based on rock rheology theory and the Weibull subsidence method. This model better characterises the surface subsidence mechanism under geological conditions of thick bedrock and thin loose layer, and the prediction results are close to actual measurements. The bedrock and loose layer are considered viscoelastic beam and homogeneous body, respectively. The bedrock and loose layer are analysed using the theories of mechanical movement and mathematical models, respectively. Based on actual geological conditions of a mine in East China, the mechanical parameters were substituted into the Weibull composite subsidence prediction model (WCSPM) and the probability integral composite subsidence prediction model (PICSPM), and the predictions of surface subsidence movement parameters were obtained. The prediction results of the WCSPM are closer to the measured surface subsidence values, thereby verifying the applicability of the theoretical model in engineering practice. This model enables the construction of structures in mining-induced subsidence areas with confidence. • Subsidence deformation of thick bedrock studied using rheology theory. • Weibull distribution equation was used to study deformation of thin loose layer. • The subsidence deformation curves compounded to form novel superposition model. • Model accuracy verified by comparing predicted and actual mining subsidence data. • Dual medium-based WCSPM more suitable for obtaining actual ground subsidence curve. [ABSTRACT FROM AUTHOR]