The performance of grouting materials directly affects the reinforcement effect of fractured rock masses by grouting. This paper investigates the synergistic effect of graphene oxide and fly ash on the properties of cementitious grout materials and the cementing effect of grouting reinforcement on broken rock masses. Basic performance tests such as flowability, bleeding rate, and setting time of grout slurries were conducted, and macroscopic characterization were tested for flexural strength, compressive strength, permeability and resistivity of the hardened grout paste. Direct shear tests of slurry-rock interfaces were performed using a self-made shear box, and the microstructures and mineral compositions of the slurry-rock interfaces were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The test results show that the flowability, bleeding rate, and initial setting time of graphene oxide and fly ash (GO-FA) cement-based grout slurries with a water-cement ratio of 0.8 are 413 mm, 4.8 %, and 12.7 h, respectively, indicating high flowability and stability. The 28-day flexural strength, compressive strength, and permeability of GO-FA the hardened grout paste are 4.6 MPa, 25.7 MPa, and 1.50 × 10−9 cm/s, respectively, which are 28.5 %, 30.4 %, and 25.4 % higher than those of pure cement hardened grout paste. The electrical resistivity of the hardened grout pastes increases with the curing time of the slurry and eventually stabilizes, and a linear relationship between compressive strength and electrical resistivity is established. The reinforcement effect of GO-FA grout filling on broken rock masses is the best, with significantly increased peak shear strength and residual strength of the slurry-rock interface after grouting compared to traditional cement grout filling, indicating enhanced deformation resistance and a 19.8 % increase in cohesion. Grouting filling significantly improves the cohesion and internal friction angle of fractured rock mass interfaces, with the cohesion and internal friction angle of the slurry-rock interface after grouting filling with a thickness of 1 mm being 3.90 times and 1.28 times higher, respectively, than those of the unfilled fractured surface. The filling thickness has a significant effect on cohesion but little effect on the internal friction angle. The microstructure model of the slurry-rock interface is consistent with the Xie model, indicating the generation of hydration products such as calcium hydroxide and ettringite on the interface, as well as small amounts of potassium feldspar, kaolinite, and the new mineral component calcite.

中文翻译：

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氧化石墨烯胶凝灌浆材料性能及其注浆加固破碎岩体胶结效果研究


注浆材料的性能直接影响注浆对裂隙岩体的加固效果。本文研究了氧化石墨烯和粉煤灰对胶凝灌浆材料性能的协同作用以及注浆加固对破碎岩体的胶结作用。对灌浆料的流动性、泌水率、凝结时间等基本性能进行了测试，并对硬化灌浆体的抗折强度、抗压强度、渗透性和电阻率进行了宏观表征。利用自制剪切箱进行泥浆-岩石界面直接剪切试验，并通过扫描电子显微镜（SEM）和X射线衍射（XRD）分析泥浆-岩石界面的显微结构和矿物成分。测试结果表明，水灰比为0.8的氧化石墨烯粉煤灰（GO-FA）水泥基灌浆料的流动性、泌水率和初凝时间分别为413 mm、4.8%、12.7 h，分别表明高流动性和稳定性。 GO-FA硬化灌浆体的28天抗折强度、抗压强度和渗透率分别为4.6 MPa、25.7 MPa和1.50×10−9 cm/s，分别为28.5%、30.4%和25.4%高于纯水泥硬化灌浆体。硬化灌浆料的电阻率随着浆料的固化时间而增加并最终稳定，并且抗压强度和电阻率之间建立了线性关系。 GO-FA灌浆对破碎岩体的加固效果最好，与传统水泥灌浆相比，灌浆后的峰值抗剪强度和浆岩界面残余强度显着提高，抗变形能力增强，提高了19.8%在凝聚力中。注浆充填显着改善了裂隙岩体界面的黏聚力和内摩擦角，1 mm注浆充填厚度后浆岩界面的黏聚力和内摩擦角分别提高了3.90倍和1.28倍未填充的断裂面。填充厚度对内聚力影响显着，但对内摩擦角影响不大。浆岩界面的微观结构模型与谢模型一致，表明界面上生成了氢氧化钙、钙矾石等水化产物，以及少量的钾长石、高岭石和新矿物成分方解石。