Advanced Grouting Model and Influencing Factors Analysis of Tunnels with High Stress and Broken Surrounding Rock

Abstract

Grouting can effectively seal and reinforce broken rock masses in deep geotechnical engineering, which have an important impact on groundwater-related disaster prevention and control. Based on multi-field coupling mechanics and rotational viscosity experiments, an advance grouting migration model of cement slurry in tunnels with high-stress broken surrounding rock is built against the background of the Xianglushan Tunnel for water diversion in central Yunnan Province. The influence characteristics of water–cement ratio, grouting pressure, and initial permeability on the process of grouting material migration are analyzed by combining classical column theory and spherical theory. The results show the following: Overall, the growth rate of grouting radius is fast during the earlier 5 min and slows down later. At the fifth minute, the normal grouting ranges are 22 cm, 51 cm, and 58 cm, at water–cement ratios 0.6, 0.8, and 1.0, respectively, while the normal grouting ranges are 58 cm, 51 cm, and 36 cm at grouting pressures 2 MPa, 1 MPa, and 0.5 MPa, respectively; the normal grouting ranges are 58 cm, 24 cm, and 11 cm at initial permeabilities 5D, 0.5D, and 0.05D, respectively. At the 60th minute, the normal grouting ranges are 47 cm, 133 cm, and 155 cm at water–cement ratios 0.6, 0.8, and 1.0, respectively; the normal grouting ranges are 155 cm, 131 cm, and 96 cm at grouting pressures 2 MPa, 1 MPa, and 0.5 MPa, respectively; meanwhile, the normal grouting ranges are 155 cm, 63 cm, and 29 cm at initial permeabilities 5D, 0.5D, and 0.05D, respectively. This study can provide theoretical guidance for on-site grouting design in unfavorable geological treatment projects.

Comparative Study on the Application of Different Slug Test Models for Determining the Permeability Coefficients of Rock Mass in Long-Distance Deep Buried Tunnel Projects

“…It is the longest deep-buried tunnel of the project, with a total length of about 63 km and a maximum buried depth of 1512 m. Meanwhile, it is a large-slope inclined shaft tunnel with the most difficult construction and complex hydrogeological conditions along the whole line. The tunnel construction has problems such as water inrush and mud inrush, a high external water pressure, crossing active faults, a large buried depth, a difficult construction and groundwater treatment [27,28]. After the completion of the project, water can be diverted from the main stream of Jinsha River, with relatively abundant water, to central Yunnan, which will solve severe water shortages in the central Yunnan region, improve the ecological and environmental conditions of rivers and lakes in the region and effectively promote the sustainable economic and social development of Yunnan [29,30].…”

Grouting anchor cable active advanced support technology for mining roadways

“…In the theory of fracture grout migration and diffusion, the main theories adopted are porous medium theory, equivalent continuous medium theory, discrete fracture network medium theory, and fracture-pore double-medium theory 10 . Jiang 11 established the advanced grouting migration theoretical model of cement slurry in high-stress fractured surrounding rock, Zheng 12 proposed the theoretical model and empirical formula of grouting strength based on the discrete element model, and Qin et al derived the formula of different fluid grout diffusion radius based on fractal theory. In the numerical simulation of grouting technology, Yuan 13 used FLAC3D to simulate and study the mechanism of surrounding rock stress release and grouting, Liang 14 used the finite level set method to reveal the time-varying law of the pressure at the grout diffusion interface, Zheng 15 simulated and studied the spatiotemporal distribution of permeability during grouting, and Pan 16 established a flow-solidification coupling model based on COMSOL and analyzed the influence law of grouting pressure and initial permeability on grouting diffusion.…”