Experimental Investigations on Repair and Permeability Reduction for Single Sandstone Fracture Using a Mixed CaCO<sub>3</sub> and Fe(OH)<sub>3</sub> Precipitate
In China, groundwater loss caused by underground coal mining is becoming increasingly serious. The key to groundwater restoration is to repair mining-induced water-conducting fractures (WCFs) in the overlying strata. In this study, the adsorption–consolidation sealing characteristics of chemical pre...
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2024-11-01
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| author | Jinfeng Ju Quansheng Li Chenyu Wang Yanan Fan |
| author_facet | Jinfeng Ju Quansheng Li Chenyu Wang Yanan Fan |
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| description | In China, groundwater loss caused by underground coal mining is becoming increasingly serious. The key to groundwater restoration is to repair mining-induced water-conducting fractures (WCFs) in the overlying strata. In this study, the adsorption–consolidation sealing characteristics of chemical precipitates were used to conduct permeability reduction (PR) experiments, including adding mixed CaCO<sub>3</sub> and Fe(OH)<sub>3</sub> to a sandstone specimen with a single fracture at room temperature. An aqueous solution of Na<sub>2</sub>CO<sub>3</sub> was used as the simulated groundwater, and a solution of mixed CaCl<sub>2</sub> and FeCl<sub>2</sub> was used as the repair reagent to simulate the water seepage conditions of a fractured rock mass. The two aqueous solutions were simultaneously injected into a single-fractured rock specimen at a constant flow rate. The experimental results show that the Fe(OH)<sub>3</sub> colloid encapsulated CaCO<sub>3</sub> crystals in a mixed precipitate, reducing the overall structural stability of the mixed precipitate and restricting repair and PR efficiency. However, the Fe(OH)<sub>3</sub> precipitate had better PR efficiency in the initial stage of the experiment. Therefore, a better scheme was put forward to repair the WCF, utilizing a mixed Fe(OH)<sub>3</sub> and CaCO<sub>3</sub> precipitate with a molar ratio close to 1:4 in the early stage and a single CaCO<sub>3</sub> precipitate in the later stage. |
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| spelling | doaj-art-e43fe1d00d8e4758afe189fd905a024a2025-08-20T01:53:40ZengMDPI AGApplied Sciences2076-34172024-11-0114221061710.3390/app142210617Experimental Investigations on Repair and Permeability Reduction for Single Sandstone Fracture Using a Mixed CaCO<sub>3</sub> and Fe(OH)<sub>3</sub> PrecipitateJinfeng Ju0Quansheng Li1Chenyu Wang2Yanan Fan3The National and Local Joint Engineering Laboratory of Internet Application Technology on Mine, China University of Mining and Technology, Xuzhou 221008, ChinaState Key Laboratory of Water Resource Protection and Utilization in Coal Mining, Beijing 100011, ChinaState Key Laboratory for Fine Exploration and Intelligent Development of Coal Resources, China University of Mining and Technology, Xuzhou 221116, ChinaState Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering, China University of Mining and Technology, Xuzhou 221116, ChinaIn China, groundwater loss caused by underground coal mining is becoming increasingly serious. The key to groundwater restoration is to repair mining-induced water-conducting fractures (WCFs) in the overlying strata. In this study, the adsorption–consolidation sealing characteristics of chemical precipitates were used to conduct permeability reduction (PR) experiments, including adding mixed CaCO<sub>3</sub> and Fe(OH)<sub>3</sub> to a sandstone specimen with a single fracture at room temperature. An aqueous solution of Na<sub>2</sub>CO<sub>3</sub> was used as the simulated groundwater, and a solution of mixed CaCl<sub>2</sub> and FeCl<sub>2</sub> was used as the repair reagent to simulate the water seepage conditions of a fractured rock mass. The two aqueous solutions were simultaneously injected into a single-fractured rock specimen at a constant flow rate. The experimental results show that the Fe(OH)<sub>3</sub> colloid encapsulated CaCO<sub>3</sub> crystals in a mixed precipitate, reducing the overall structural stability of the mixed precipitate and restricting repair and PR efficiency. However, the Fe(OH)<sub>3</sub> precipitate had better PR efficiency in the initial stage of the experiment. Therefore, a better scheme was put forward to repair the WCF, utilizing a mixed Fe(OH)<sub>3</sub> and CaCO<sub>3</sub> precipitate with a molar ratio close to 1:4 in the early stage and a single CaCO<sub>3</sub> precipitate in the later stage.https://www.mdpi.com/2076-3417/14/22/10617water-conducting fracture (WCF)mixed precipitatepermeability reduction (PR)restoration of aquifer ecological functiongreen mining |
| spellingShingle | Jinfeng Ju Quansheng Li Chenyu Wang Yanan Fan Experimental Investigations on Repair and Permeability Reduction for Single Sandstone Fracture Using a Mixed CaCO<sub>3</sub> and Fe(OH)<sub>3</sub> Precipitate Applied Sciences water-conducting fracture (WCF) mixed precipitate permeability reduction (PR) restoration of aquifer ecological function green mining |
| title | Experimental Investigations on Repair and Permeability Reduction for Single Sandstone Fracture Using a Mixed CaCO<sub>3</sub> and Fe(OH)<sub>3</sub> Precipitate |
| title_full | Experimental Investigations on Repair and Permeability Reduction for Single Sandstone Fracture Using a Mixed CaCO<sub>3</sub> and Fe(OH)<sub>3</sub> Precipitate |
| title_fullStr | Experimental Investigations on Repair and Permeability Reduction for Single Sandstone Fracture Using a Mixed CaCO<sub>3</sub> and Fe(OH)<sub>3</sub> Precipitate |
| title_full_unstemmed | Experimental Investigations on Repair and Permeability Reduction for Single Sandstone Fracture Using a Mixed CaCO<sub>3</sub> and Fe(OH)<sub>3</sub> Precipitate |
| title_short | Experimental Investigations on Repair and Permeability Reduction for Single Sandstone Fracture Using a Mixed CaCO<sub>3</sub> and Fe(OH)<sub>3</sub> Precipitate |
| title_sort | experimental investigations on repair and permeability reduction for single sandstone fracture using a mixed caco sub 3 sub and fe oh sub 3 sub precipitate |
| topic | water-conducting fracture (WCF) mixed precipitate permeability reduction (PR) restoration of aquifer ecological function green mining |
| url | https://www.mdpi.com/2076-3417/14/22/10617 |
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