Distribution characteristics of floor pore water pressure based on similarity simulation experiments
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ORIGINAL PAPER
Distribution characteristics of floor pore water pressure based on similarity simulation experiments Jinhai Zhao 1,2,3 & Juntao Chen 1,2,3 & Xinguo Zhang 1,2,3 & Jiang Ning 1,2 & Yunzhao Zhang 1,4 Received: 13 August 2019 / Accepted: 30 April 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract To analyse the impact of underground pressure on the variation in floor porosity and pore water pressure distribution during the coal seam mining process, this paper uses closed and open water pressure sensors to analyse rock pressure, water pressure zoning and layer distribution characteristics of the coal seam floor under mining effects based on a simulation analysis method using similar rock materials; the results determine that the separation characteristics of the pore water pressure distribution are affected by the rock pressure ‘barrier’ function, which is caused by changes in rock permeability under the coupling effect. To quantitatively analyse the rock pressure barrier’s impact on the floor mechanical structure, this paper proposes the ‘virtual separation layer’ concept and defines the virtual separation layer index to determine the scope of the floor tension fracture zone. Through monitored data of pore water pressure at different depths of the floor during field mining, the variation between the water pressure, porosity, mining distance and floor depth is obtained; similar material simulation results are verified, and a zonal distribution model of pore water pressure in the floor is established, providing a reference to investigate the distribution of pore water pressure in the floor under mining disturbances. The results show that the influence of changes in mining stress will also lead to a differential distribution of the floor mechanical properties and ultimately damage the floor and affect the inrush of the confined water. The research results play an important role in risk classification and prevention of water pressure distribution in coal seam floors. Keywords Distribution . Fluid-structure interaction . Pore pressure . Virtual separation . Porosity
Introduction
* Jinhai Zhao [email protected] * Juntao Chen [email protected] * Xinguo Zhang [email protected] 1
State Key Laboratory Breeding Base for Mining Disaster Prevention and Control, Shandong University of Science and Technology, Qingdao, 266590 China
2
College of Energy and Mining Engineering, Shandong University of Science and Technology, Qingdao, 266590 China
3
National Demonstration Center for Experimental Mining Engineering Education, Shandong University of Science and Technology, Qingdao, China
4
Shandong ding ’an testing technology co. LTD, Jinan, 250032 China
At present, research on the floor water in rush mechanism in the working face is limited to only water pressure, aquiclude thickness and rock pressure damage to the floor (Xu et al. 2019). If we suppose that water pressure acts uniformly on the bottom of an aquiclude and is a constant value, then water pressure is considered as a uni
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