多因素作用下高聚物岩体裂隙动水注浆扩散机理研究

Aiming at the prevention and control of water disaster in fractured rock mass in the field of underground engineering construction, the study on polyurethane grouting in rock fracture with flowing water is conducted. This project intends to use methods of model test, numerical simulation and theoretical analysis to discuss the diffusion characteristics of polyurethane grout in rock fracture with flowing water considering various affecting factors. The diffusion behavior of polyurethane grout in rock fracture is investigated by performing the single fracture grouting test and fracture network grouting test under the coupling effect of multi-factor. Based on the chemical reaction kinetics model, the expansion and diffusion process of polyurethane grout in a single fracture is simulated numerically. The analytical solution of polyurethane grout diffusion in a single fracture is derived and a two-dimensional discrete fracture network model is established to simulate the grout diffusion behavior. The numerical simulation is compared with the experimental results to indicate the effects of various factors such as flow rate, temperature, polyurethane rheology, grouting quantity, fracture aperture and roughness on the diffusion behavior of polyurethane grout in the fracture. The key factor that affects the diffusion range is identified. The intrinsic relationship of diffusion behavior between grouting in a single fracture and grouting in the fracture network is explored to reveal the diffusion mechanism of polyurethane grout in the rock fracture under hydrodynamic condition.

本项目定位于地下工程建设领域裂隙岩体水害防治这一热点问题，针对高聚物动水注浆理论空白这一现状，拟采用模型试验、数值模拟和理论分析相结合的方法研究多因素作用下高聚物岩体裂隙动水注浆扩散特性。通过开展单裂隙和裂隙网络动水注浆模型试验，分析多因素耦合作用下高聚物浆液在裂隙中的扩散特性；基于化学反应动力学模型，对高聚物浆液在单裂隙中的膨胀扩散过程进行数值模拟；推导高聚物浆液在单裂隙中扩散的解析解，建立二维离散裂隙网络模型，模拟高聚物浆液在裂隙网络中的扩散行为；将数值模拟与试验结果进行对比，分析动水流速、温度、高聚物浆液流变性、注浆量、裂隙开度和粗糙度等多种因素对高聚物浆液在裂隙中扩散行为的影响，确定影响高聚物裂隙动水注浆扩散范围的关键因素；探讨高聚物浆液在单裂隙中的扩散行为与在裂隙网络中扩散行为的内在联系，揭示动水条件下高聚物浆液在岩体裂隙中的扩散机制。

自膨胀高聚物注浆材料已广泛应用于隧道及地下工程建设领域的岩体裂隙加固和水害防治，但对其注浆扩散机理的研究远远滞后于工程实际，这导致注浆工程设计主要依赖于操作人员经验，制约了高聚物注浆向精细化发展。本项目通过模型试验、数值模拟和理论分析相结合的方法研究多因素作用下高聚物岩体裂隙注浆扩散特性。主要结果如下：研制了三维装配式交叉裂隙可视化试验装置，开展了系列岩体裂隙高聚物注浆试验，揭示了注浆量、裂隙交叉方式、交叉角度和裂隙开度对浆液扩散模式、扩散范围和压力分布的影响规律。（2）基于化学反应动力学模型，建立了高聚物浆液在富水岩体裂隙中膨胀扩散的数值方法，与Fluent数值模拟结果对比验证了数值方法的可靠性，分析了高聚物浆液在动水和静水条件下浆液的扩散行为。（3）考虑自膨胀源和对流驱动力，建立了高聚物浆液在含水单裂隙中扩散行为的解析解。（4）揭示了多因素作用下含水岩体裂隙高聚物注浆的扩散机制，分析了水流速度、水头压力、浆液温度、浆液发泡剂含量、粘度等因素对高聚物浆液在裂隙中扩散行为的影响，开展了多因素敏感性分析。研究成果为采用高聚物注浆技术进行地下工程岩体加固和水害防治提供了理论支撑和科学依据，已在郑州经北四路隧道、北京延庆站地道、西安地铁隧道等隧道和地下工程加固和渗漏治理工程中得到应用，具有显著的经济效益。