Mechanical and seepage characteristics of mining unloading sandstone under action of confined water

Abstract:With the continuous deepening of coal mining to the deep, the threat of high confined water to coal mining face increases significantly, which is easy to induce water inrush disaster. Based on this, Rock Top multi-field coupling tester is used to simulate the mining stress under confined wa...

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Main Authors: Peisen ZHANG, Hongwei WANG, Shouzhen YANG, Daqiang XU, Yeqiang LIU, Chao LIU, Jiaxin FANG, Zhaoqiang JU
Format: Article
Language:Chinese
Published: Editorial Department of Coal Science and Technology 2025-07-01
Series:Meitan kexue jishu
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Online Access:http://www.mtkxjs.com.cn/article/doi/10.12438/cst.2025-0548
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author Peisen ZHANG
Hongwei WANG
Shouzhen YANG
Daqiang XU
Yeqiang LIU
Chao LIU
Jiaxin FANG
Zhaoqiang JU
author_facet Peisen ZHANG
Hongwei WANG
Shouzhen YANG
Daqiang XU
Yeqiang LIU
Chao LIU
Jiaxin FANG
Zhaoqiang JU
author_sort Peisen ZHANG
collection DOAJ
description Abstract:With the continuous deepening of coal mining to the deep, the threat of high confined water to coal mining face increases significantly, which is easy to induce water inrush disaster. Based on this, Rock Top multi-field coupling tester is used to simulate the mining stress under confined water environment, and sandstone unloading test is carried out. The stress path of axial pressure (stress concentration) and confining pressure reduction (excavation unloading) is adopted to explore the mechanical and seepage characteristics of sandstone under different initial unloading levels and different osmotic pressure differences. The mechanical and seepage characteristics of mining unloading sandstone under the action of confined water are obtained. The results show that: The stress-strain curve of sandstone appears “shunt” phenomenon due to different initial unloading levels, and unloading will accelerate the development process of internal cracks in rock samples. The peak average effective stress of rock sample increases with the increase of osmotic pressure difference and unloading level. The peak radial strain increases with the increase of unloading level. With the increase of the initial unloading level, the peak circumferential strain shows a downward trend as a whole. The effective unloading modulus of the internal structure of rock mass is defined. The higher the initial unloading level is, the smaller the osmotic pressure difference is, the lower the effective unloading modulus of the internal structure of rock mass is, and the worse the deformation resistance of the internal structure of rock sample. The typical permeability curve of sandstone shows the law of “decrease−increase−decrease−stability.” The permeability curve of sandstone in low permeability environment shows obvious “peak” stage after rock failure, and the “peak” stage in high permeability environment is relatively not obvious. The total volume curve of the seepage channel has a good correspondence with the permeability curve; the flow velocity curve of the seepage field conforms to the change rule of “drop−increase−flat”. The flow velocity is large under high osmotic pressure difference, and the flow velocity is small and reverse seepage occurs under low osmotic pressure difference.
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publisher Editorial Department of Coal Science and Technology
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series Meitan kexue jishu
spelling doaj-art-ffbe29ecee0c421883c31fa1a69ed2ad2025-08-04T02:53:35ZzhoEditorial Department of Coal Science and TechnologyMeitan kexue jishu0253-23362025-07-0153718319610.12438/cst.2025-05482025-0548Mechanical and seepage characteristics of mining unloading sandstone under action of confined waterPeisen ZHANG0Hongwei WANG1Shouzhen YANG2Daqiang XU3Yeqiang LIU4Chao LIU5Jiaxin FANG6Zhaoqiang JU7College of Energy and Mining Engineering, Shandong University of Science and Technology, Qingdao 266590, ChinaCollege of Energy and Mining Engineering, Shandong University of Science and Technology, Qingdao 266590, ChinaZaozhuang Mining ( Group ) Co., Ltd., Zaozhuang 277000, ChinaState Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering, China University of Mining and Technology, Xuzhou 221116, ChinaZaozhuang Mining ( Group ) Co., Ltd., Zaozhuang 277000, ChinaZaozhuang Mining ( Group ) Co., Ltd., Zaozhuang 277000, ChinaCollege of Energy and Mining Engineering, Shandong University of Science and Technology, Qingdao 266590, ChinaCollege of Energy and Mining Engineering, Shandong University of Science and Technology, Qingdao 266590, ChinaAbstract:With the continuous deepening of coal mining to the deep, the threat of high confined water to coal mining face increases significantly, which is easy to induce water inrush disaster. Based on this, Rock Top multi-field coupling tester is used to simulate the mining stress under confined water environment, and sandstone unloading test is carried out. The stress path of axial pressure (stress concentration) and confining pressure reduction (excavation unloading) is adopted to explore the mechanical and seepage characteristics of sandstone under different initial unloading levels and different osmotic pressure differences. The mechanical and seepage characteristics of mining unloading sandstone under the action of confined water are obtained. The results show that: The stress-strain curve of sandstone appears “shunt” phenomenon due to different initial unloading levels, and unloading will accelerate the development process of internal cracks in rock samples. The peak average effective stress of rock sample increases with the increase of osmotic pressure difference and unloading level. The peak radial strain increases with the increase of unloading level. With the increase of the initial unloading level, the peak circumferential strain shows a downward trend as a whole. The effective unloading modulus of the internal structure of rock mass is defined. The higher the initial unloading level is, the smaller the osmotic pressure difference is, the lower the effective unloading modulus of the internal structure of rock mass is, and the worse the deformation resistance of the internal structure of rock sample. The typical permeability curve of sandstone shows the law of “decrease−increase−decrease−stability.” The permeability curve of sandstone in low permeability environment shows obvious “peak” stage after rock failure, and the “peak” stage in high permeability environment is relatively not obvious. The total volume curve of the seepage channel has a good correspondence with the permeability curve; the flow velocity curve of the seepage field conforms to the change rule of “drop−increase−flat”. The flow velocity is large under high osmotic pressure difference, and the flow velocity is small and reverse seepage occurs under low osmotic pressure difference.http://www.mtkxjs.com.cn/article/doi/10.12438/cst.2025-0548confined groundwatermining effectseepage characteristicsmechanical propertiesosmotic pressure difference
spellingShingle Peisen ZHANG
Hongwei WANG
Shouzhen YANG
Daqiang XU
Yeqiang LIU
Chao LIU
Jiaxin FANG
Zhaoqiang JU
Mechanical and seepage characteristics of mining unloading sandstone under action of confined water
Meitan kexue jishu
confined groundwater
mining effect
seepage characteristics
mechanical properties
osmotic pressure difference
title Mechanical and seepage characteristics of mining unloading sandstone under action of confined water
title_full Mechanical and seepage characteristics of mining unloading sandstone under action of confined water
title_fullStr Mechanical and seepage characteristics of mining unloading sandstone under action of confined water
title_full_unstemmed Mechanical and seepage characteristics of mining unloading sandstone under action of confined water
title_short Mechanical and seepage characteristics of mining unloading sandstone under action of confined water
title_sort mechanical and seepage characteristics of mining unloading sandstone under action of confined water
topic confined groundwater
mining effect
seepage characteristics
mechanical properties
osmotic pressure difference
url http://www.mtkxjs.com.cn/article/doi/10.12438/cst.2025-0548
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AT daqiangxu mechanicalandseepagecharacteristicsofminingunloadingsandstoneunderactionofconfinedwater
AT yeqiangliu mechanicalandseepagecharacteristicsofminingunloadingsandstoneunderactionofconfinedwater
AT chaoliu mechanicalandseepagecharacteristicsofminingunloadingsandstoneunderactionofconfinedwater
AT jiaxinfang mechanicalandseepagecharacteristicsofminingunloadingsandstoneunderactionofconfinedwater
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