基于浆液–岩体耦合效应的微裂隙岩体注浆理论研究

在微裂隙岩体注浆工程中,浆液–岩体耦合效应对注浆扩散过程影响显著。基于宾汉流体浆液本构模型并引入两阶段裂隙变形控制方程,建立考虑浆–岩耦合效应的裂隙注浆扩散理论模型。利用质量守恒条件实现浆液扩散锋面追踪与注浆流量分配,通过试错法实现压力场与速度场的迭代求解,建立可完整描述注浆扩散过程的步进式算法。利用所创建的理论模型及步进式算法,分析浆液压力场及裂隙开度的分布规律,并从浆液扩散半径、裂隙变形所吸收的浆液量两个方面分析不同裂隙开度条件下浆–岩耦合效应对裂隙注浆扩散过程的影响程度。研究结果表明:在微裂隙岩体注浆工程中,裂隙宽度越小,浆–岩耦合效应对注浆扩散过程的影响越显著,注浆压力取代裂隙初始隙宽成为影响浆液扩散半径的主控因素。最后结合青岛地铁花岗岩微裂隙注浆工程实例验证了理论模型及步进式算法的正确性。

Grouting mechanism in fractured rock considering slurry-rock stress coupling effects

The slurry-rock stress coupling effects have a great influence on the grouting process in fractured rock. In order to describe the dynamic grouting process, a piecewise equation is used to govern the deformation process of rock fissure, and a theoretical model for fissure grouting considering slurry-rock stress coupling effects is established with the slurry being assumed as Bingham liquid. A step-wise calculation method is established, in which the tracing of grouted zone front and distribution of grouting flow rate are realized by using the mass conservation condition. The try out method is adopted to compute the pressure and velocity fields in the grouted zone. The distribution of the pressure field and fracture aperture in the grouted zone and the effect degree of slurry-rock stress coupling on the grouting process with different fracture apertures are analyzed. The results show that in the micro-fracture grouting process, the slurry-rock stress coupling has greater effect on the grouting process when the fracture aperture becomes smaller. At the same time, the grouting pressure, replacing the fracture aperture, becomes the main controlling factor for the grouting radius. By comparing the theoretical results with the measured ones in a grouting project, the validity of the theoretical model and calculation method is verified.