# Research on Grouting Dynamic Monitoring Based on Borehole-Tunnel Joint Resistivity Method  
[PERSON]  
1 School of Geophysics & Petroleum Resources, Yangtze University, Wuhan 430100, China; [EMAIL_ADDRESS](C.  
In China's North China-type coalfields, karst water disasters in coal seam floor strata pose particularly severe challenges [1]. Grouting treatment has emerged as the predominant technical solution for preventing and controlling pressurized karst water hazards in these geological formations. The fundamental principle involves transforming water-conducting and water-bearing strata through targeted grouting reinforcement, effectively converting them into impermeable barriers. This engineered modification achieves three critical objectives: (1) enhancing the structural integrity and thickness of the aquiclude stratum, (2) improving the composite water-resistance capacity of the rock layers, and (3) mitigating the risk of sudden water inrushes from underlying karst aquifers. Advanced regional grouting technology has now become extensively implemented in hydraulic hazard prevention systems for coalfield foundations [2; 3]. As a sophisticated technical approach combining strata consolidation and seepage control, this methodology utilizes controlled injection of cementitious grouts to achieve three-dimensional fracture filling [4], mechanical strengthening of rock masses [5], and permeability reduction. Its implementation represents a paradigm shift in disaster prevention strategies for underground mining engineering, standing as one of the cornerstone technologies in modern geotechnical hazard management. Despite its widespread application, grouting effectiveness evaluation and process monitoring remain significant challenges [6]. Conventional detection methods, such as core drilling, water pressure testing, and acoustic wave detection, suffer from inherent limitations:  
Destructiveness: Core drilling damages 12-25% of grouted structures [7], potentially compromising reinforcement efficacy. Time lag: Assessments are restricted to post-grouting stages [8], lacking real-time feedback on grout diffusion dynamics [9; 10]. Localized data: Single-point measurements fail to characterize the spatial distribution of grouted bodies [11]. High costs: Repeated drilling and testing escalate project expenses and timelines. In recent years, geophysical prospecting technologies have emerged as a research frontier in grouting monitoring due to their non-destructive nature, operational efficiency, and large-scale coverage. Notably, cement-based grouts exhibit a 3-5 increase in resistivity after solidification compared to host rocks [7], while flowing grouts--rich in free water--show 40-60% lower resistivity [12]. This stark electrical contrast provides a robust physical foundation for dynamic monitoring. Internationally, resistivity-based methods have achieved maturity in grouting monitoring, with pioneering research institutions and scholars developing cutting-edge technologies and data processing methodologies to explore their potential across diverse grouting scenarios. [PERSON] et al. [13] experimentally demonstrated a three-stage evolution of apparent resistivity (\"gradual decline \(\rightarrow\) sharp drop \(\rightarrow\) stabilization\") during chemical grouting in porous rocks, revealing significant variations in resistivity amplitude that effectively map grout migration paths. [PERSON] et al. [14] innovated a smoothness-constrained 3D inversion algorithm, systematically investigating how horizontal/vertical grid partitioning impacts inversion accuracy. Their numerical and field validations confirmed the reliability of inter-borehole resistivity systems in grout detection. [PERSON] et al. [15] identified that sodium silicate additives reduce grout resistivity more effectively than fly ash, with resistivity decreasing proportionally to fracture dip angles. [PERSON] et al.