深部峰后破裂围岩注浆渗流扩散与加固机理研究

Grouting reinforcement technology is an effective way to maintain the stability of fractured surrounding rocks in the deep roadway, and it has both theoretical significance and engineering application value to perfect the theory of grouting reinforcement and enhance the effect of grouting reinforcement through studying the seepage and diffusion law of the slurry and grouting strengthening mechanism. The slurry permeability within fractured rocks and post-peak softening properties of rocks under different post-peak states, confining pressure and grouting pressure are systematically carried out and obtained with the developed triaxial permeability test device. The slurry permeability evolution mechanical model of the post-peak fractured rock is established based on the test results of slurry permeability evolution to reveal the seepage and diffusion mechanism of slurry within post-peak fractured surrounding rocks. Moreover, the consolidation and strength characteristics of post-peak fractured rocks in the before and after grouting are obtained by the developed triaxial compression and CT scan test. Thus, the post-peak strength degradation model and peak strength improved model of fractured rocks are established by utilizing damage-fracture mechanics to reveal the essence of the grouting reinforcement. Based on this, the slurry seepage-diffusion and reinforcement mathematical model of grouting in the fractured roadway surrounding rocks are built using seepage mechanics and quasi-continuum mechanics, and by means of FLAC3D and COMSOL software numerical simulate the coupling process between the fracture of surrounding rocks and seepage of slurry, and compared the obtained results with the experimental results. Further, the effect of the roadway surrounding rocks fractured state, stress state and grouting time on the law of slurry seepage and diffusion and fracture of roadway surrounding rocks are systematic study by using this mathematical models, and then a method to determine the optimum grouting time in the deep fractured surrounding rocks is put forward.

注浆加固是维护破裂巷道稳定的有效方式，研究浆液渗流扩散和注浆强化机理对于完善注浆加固理论和提高注浆效果具有重要的理论意义和工程应用价值。利用三轴渗透试验获得低水灰比浆液在峰后破裂状态、应力和注浆压力耦合下的渗透性及岩石峰后软化特性，并构建峰后破裂岩石浆液渗透性演化力学模型，揭示浆液在峰后破裂围岩内的渗流扩散机理。并利用三轴压缩和CT扫描试验得到不同峰后破裂岩石在注浆前后的固结及强度特征，运用损伤断裂力学建立破裂岩石峰后强度劣化模型和加固体峰值强度强化模型，以揭示注浆加固本质。基于此，运用渗流力学和拟连续介质力学建立峰后破裂围岩注浆渗流扩散与加固数学模型，借助FLAC3D和COMSOL软件数值再现围岩峰后破裂和浆液渗流耦合过程，将其结果与实验结果进行对比。并用该模型系统研究围岩破裂状态、应力和注浆时机等多因素耦合对浆液渗流扩散和围岩破坏的影响规律，进而提出确定破裂巷道最佳注浆支护时机的方法。

当前，随着矿井进入深部资源开采阶段，使得注浆加固成为控制“三高一扰动”下巷道围岩变形破裂的有效手段。但是，由于工程岩体的孔裂隙分布和地应力赋存环境复杂，且其在开挖扰动后的渐进破裂过程中的孔裂隙发育和峰后强度等有极大差异。这将显著影响浆液在破裂岩体内的渗流扩散特性和胶结围岩的强度，继而导致注浆加固理论远滞后于工程实践。因此，开展深部岩体在破裂过程中的浆液渗透性和注浆加固强化等相关机理研究，对于维护深部巷道围岩稳定和确保深部煤炭资源的安全高效开采具有重要意义。.本项目以提高注浆加固效果为研究目标，综合利用室内试验、理论分析、数值模拟和现场监测相结合的方法进行研究。首先，开展了峰后破裂岩石浆液渗透性和强度劣化与强化试验、破裂岩石固结体抗剪强度试验、不同粒径破碎岩石浆液渗透性与固结体抗压强度试验和CT扫描试验，揭示了峰后破裂岩石浆液渗透性演化机理和注浆加固强化机理。其次，基于浆液渗透性演化试验结果，构建了峰后破裂状态、围岩和注浆压力耦合下的裂隙岩石浆液渗透性演化力学模型，并结合COMSOL模拟了岩石峰后破裂与浆液渗透性演化耦合过程。再次，进一步构建了破裂围岩浆液渗流扩散数学模型，并在围岩强度劣化模型下建立了巷道围岩破裂和浆液扩散耦合数值模型，获得了峰后破裂状态、侧压系数和围岩软弱破裂程度等对浆液渗流扩散和围岩破裂的影响规律，并探讨了注浆加固时机对加固效果的影响规律。最后，以深部高地应力巷道开挖为背景，结合高地应力巷道围岩塑性破裂分布特征和浆液渗流扩散特征，提出了以“锚网喷+注浆锚索锚杆耦合全断面注浆”为主的联合支护方案，经现场监测证明其支护效果较好。.项目所取得的研究成果有助于完善注浆加固浆液渗流扩散理论和注浆加固强化理论，并对于提高深部破裂巷道围岩注浆加固支护效果具有重要的基础理论意义和工程应用价值，且能为深部高地应力复杂构造区岩土体注浆加固工程实践提供可供借鉴的方法和技术。