恒压群孔注浆浆液压力分布理论模型与现场试验

隧道初期支护渗漏水严重威胁隧道全寿命周期运营安全，渗漏水处治过程中隧道拱底破坏、拱顶效果差的不均一性是其根本难题。针对目前隧道渗漏水处治过程中存在的设备浪费、工艺复杂等问题，提出基于多孔注浆的新型群孔注浆工艺，设计能保证一台注浆泵多个注浆孔同时注浆，并满足所有注浆孔孔口压力一致的恒压群孔注浆装置；考虑浆液重力因素影响，分析恒压群孔注浆浆液扩散规律，推导浆液压力变化方程，建立考虑浆液重力的浆液压力分布模型，获得浆液压力分布随隧道截面角度的变化规律；设计隧道初支壁后注浆现场试验，分析实际浆液压力与隧道截面角度的关系，并与理论计算结果进行对比，从隧道初支渗漏水注浆原理、工程特点及治理效果等方面，对其注浆设计提出相关建议。研究结果发现：基于恒压群孔注浆理论设计的群孔注浆装置可极大提高工程效率，治理区域注浆整体均匀；考虑浆液重力的浆液压力分布与现场试验结果基本吻合，恒压群孔注浆浆液压力呈现明显的椭圆形分布，拱底压力为拱顶压力的2.3倍，浆液压力分布随隧道截面角度呈对称分布，未考虑浆液重力的浆液压力分布与现场试验数据差别在-43%~33%不等，因此，注浆设计应充分考虑浆液的重力，研究结果对隧道初支渗漏水注浆理论与工艺有重要的借鉴意义。

Theoretical Model and Field Test of Pressure Distribution of Constant Pressure Group-hole Grouting Slurry

The long-term operation safety of tunnel is seriously threatened by the water leakage of primary supports. The grouting inhomogeneity which could trigger destructions of arch bottom and poor effects of vault is the crucial issue for the water leakage treatment. A novel group-hole grouting theory aiming at multi-hole was put forwards in view of the existing defects such as facility waste and complicated process in the aspect of water leakage treatment. Besides, a constant pressure group-hole grouting device was developed, and accordingly several grouting holes could be performed simultaneously at the same pressure only with one grouting pump. Furthermore, the slurry diffusion law was analyzed and the pressure equation was derived in view of the slurry gravity. At the same time, the variation of grouting pressure along with tunnel section angle was obtained via the derived pressure equation. Last but not least, the field tests on the grouting behind tunnel primary supports was conducted and the relationship between the actual grouting pressure and the tunnel section angle was investigated. After comparing theoretical results and experimental results, a series of proposals for grouting design were introduced from the perspective of grouting principles, engineering characteristics and treatment effects. The results show that not only the engineering efficiency but the treatment homogeneity could be greatly improved by the group-hole grouting device. In addition, there is good consistency between the theoretical results taking slurry gravity into consideration and the field results. The pressure of group-hole grouting showing an obvious elliptical distribution is symmetrical with the tunnel section angle and the pressure at arch bottom is 2.3 times of that at vault. Nevertheless, there is a giant difference between the pressure calculated by the traditional theory without respect to slurry gravity and the field pressure, which is presented from -43% to 33%. Hence, the slurry gravity should be pay enough attention in the process of grouting design, which may provide a reference for the grouting theory and process of the water leakage of tunnel primary supports.