Influencing Factors and Control Effects of Targeted Grouting Technology for Underground-excavated Metro Station Construction

Abstract

[Objective] In conventional grouting construction technology, the ineffective diffusion of grout is comparatively severe and leads to unsatisfactory reinforcement effects on surrounding rock and soil mass. Therefore, it is essential to investigate the application of targeted grouting technology in metro station and tunnel pre-grouting construction. [Method] The reinforcement mechanism of targeted grouting technology is expounded. Based on the rheological equation of dual-fluid grout and the theory of uniform capillary groups, the influencing factors of targeted grouting technology are analyzed, and the calculation formulas for the diffusion radius and grout pressure during the cylindrical permeation diffusion of dual-fluid grout are derived. These theoretical formulas are applied to the pre-grouting construction of a metro station to verify the effectiveness. [Result & Conclusion] Targeted grouting technology combines pressure grouting and permeation grouting, ensuring grouting effectiveness while saving material and protecting the surrounding environment. Parameter analysis indicates that the grout diffusion radius is significantly affected by groundwater pressure, grout flow speed, the viscosity parameters A and B of the dual-fluid grout. Within the assumed parameter change ranges, the variation law of the grout diffusion radius is well reflected. The field-monitored data shows that the entire pre-grouting construction process does not cause land uplift or environmental pollution, the grouting reinforcement effect meets the safety excavation requirements, and the expected results are achieved.

Keywords

• metro station
• targeted grouting technology
• pressure grouting
• permeation grouting