In coal mining on a high-pressure Ordovician limestone aquifer,grouting materials should have sufficient mechanical properties,particularly strong interfacial bonding performance to address stress concentration at the...In coal mining on a high-pressure Ordovician limestone aquifer,grouting materials should have sufficient mechanical properties,particularly strong interfacial bonding performance to address stress concentration at the grout-limestone interface induced by rock stress disturbances during mining.In this study,graphene oxide(GO)was integrated into cement-polyacrylate composite grout to improve its interfacial bonding.First,four-point bending tests were conducted,and the Monte Carlo method combined with the simplex search algorithm was employed to determine the variations in shear cohesion and static friction parameters.The results reveal that GO can significantly increase both the tensile and shear cohesion of the grout-limestone interface,but minimally affects the interfacial friction coefficient.Second,nuclear magnetic resonance(NMR)and scanning electron microscopy(SEM)tests were performed.The results indicate that GO nanosheets result in a squamaceous microstructure of the grout consolidation mass,increasing the adhesion of the grout-limestone interface.Moreover,spiny Aft(ettringite)clusters can be induced in limestone fracture surfaces by GO,which could serve as anchors for limestone and grout consolidation mass.展开更多
根据目前国内地下采空区注浆施工现状分析,高掺量粉煤灰注浆材料应用较为广泛,但其配比要求没有相关的规程、规范作为参考,因此,有必要通过室内试验了解大掺量粉煤灰与水泥混合浆液材料的指标性能,确定粉煤灰的掺量、浆液的水灰比、固...根据目前国内地下采空区注浆施工现状分析,高掺量粉煤灰注浆材料应用较为广泛,但其配比要求没有相关的规程、规范作为参考,因此,有必要通过室内试验了解大掺量粉煤灰与水泥混合浆液材料的指标性能,确定粉煤灰的掺量、浆液的水灰比、固结体的抗压强度等指标。本研究设计了水泥–粉煤灰浆液配比试验,开展了水泥–粉煤灰浆液粘度、析水率、凝结时间、抗压强度等指标测试,基于指标测试结果,结合相关注浆条件分析,最终确定了采空区水泥–粉煤灰注浆浆液的最优配比方案:固体料中水泥含量占比20%~30%,粉煤灰占比为70%~80%,比重为1.30。该研究成果可为类似地质条件下采空区注浆浆液的配比选择提供重要的参考依据。According to the analysis of the current situation of grouting construction in underground goaf in China, high-volume fly ash grouting materials are widely used, but there are no relevant regulations and specifications for reference in its ratio requirements. Therefore, it is necessary to understand the index performance of cement-fly ash slurry materials with high-volume fly ash through laboratory tests. Determine the amount of fly ash, the water-cement ratio of the slurry, the compressive strength of the consolidated body and other indicators. In this study, the cement-fly ash slurry ratio test was designed, and the cement-fly ash slurry viscosity, water separation rate, setting time, compressive strength and other indicators were tested. Based on the index test results, combined with the analysis of relevant grouting conditions, the optimal ratio scheme of grouting slurry in goaf was finally determined: the cement content in the solid material accounts for 20%~30%, the fly ash accounts for 70%~80%, and the proportion is 1.30. The research results can provide an important reference for the selection of grouting slurry ratio in goaf under similar geological conditions.展开更多
基金supported by the National Key R&D Program of China(Grant Nos.U25A20810 and 2024YFF0508201)the National Natural Science Foundation of China(Grant No.12302504).
文摘In coal mining on a high-pressure Ordovician limestone aquifer,grouting materials should have sufficient mechanical properties,particularly strong interfacial bonding performance to address stress concentration at the grout-limestone interface induced by rock stress disturbances during mining.In this study,graphene oxide(GO)was integrated into cement-polyacrylate composite grout to improve its interfacial bonding.First,four-point bending tests were conducted,and the Monte Carlo method combined with the simplex search algorithm was employed to determine the variations in shear cohesion and static friction parameters.The results reveal that GO can significantly increase both the tensile and shear cohesion of the grout-limestone interface,but minimally affects the interfacial friction coefficient.Second,nuclear magnetic resonance(NMR)and scanning electron microscopy(SEM)tests were performed.The results indicate that GO nanosheets result in a squamaceous microstructure of the grout consolidation mass,increasing the adhesion of the grout-limestone interface.Moreover,spiny Aft(ettringite)clusters can be induced in limestone fracture surfaces by GO,which could serve as anchors for limestone and grout consolidation mass.
文摘根据目前国内地下采空区注浆施工现状分析,高掺量粉煤灰注浆材料应用较为广泛,但其配比要求没有相关的规程、规范作为参考,因此,有必要通过室内试验了解大掺量粉煤灰与水泥混合浆液材料的指标性能,确定粉煤灰的掺量、浆液的水灰比、固结体的抗压强度等指标。本研究设计了水泥–粉煤灰浆液配比试验,开展了水泥–粉煤灰浆液粘度、析水率、凝结时间、抗压强度等指标测试,基于指标测试结果,结合相关注浆条件分析,最终确定了采空区水泥–粉煤灰注浆浆液的最优配比方案:固体料中水泥含量占比20%~30%,粉煤灰占比为70%~80%,比重为1.30。该研究成果可为类似地质条件下采空区注浆浆液的配比选择提供重要的参考依据。According to the analysis of the current situation of grouting construction in underground goaf in China, high-volume fly ash grouting materials are widely used, but there are no relevant regulations and specifications for reference in its ratio requirements. Therefore, it is necessary to understand the index performance of cement-fly ash slurry materials with high-volume fly ash through laboratory tests. Determine the amount of fly ash, the water-cement ratio of the slurry, the compressive strength of the consolidated body and other indicators. In this study, the cement-fly ash slurry ratio test was designed, and the cement-fly ash slurry viscosity, water separation rate, setting time, compressive strength and other indicators were tested. Based on the index test results, combined with the analysis of relevant grouting conditions, the optimal ratio scheme of grouting slurry in goaf was finally determined: the cement content in the solid material accounts for 20%~30%, the fly ash accounts for 70%~80%, and the proportion is 1.30. The research results can provide an important reference for the selection of grouting slurry ratio in goaf under similar geological conditions.
