Plenary 2: Keynote Presentation - Roles, Responsibilities, and Paradigms: In Rock Grouting-PPT Presentation

PPT Presentation

Pdf Summary

Rock grouting has evolved from an empirical craft into a multidisciplinary engineering practice, combining hydrogeology, rock mechanics, cement chemistry, fluid flow and equipment technology. Research since the 1990s has transformed understanding of how grout moves through fractured rock and how grouting should be designed and controlled.<br /><br />A key shift is the recognition that fractures do not share water flow equally. Rock masses may contain simple, open flow paths or complex, channel-like paths, and sealing the largest water-bearing fractures can substantially reduce overall water flow. Grout penetrability depends not only on cement grain size but also on additives, mixing, time and rheological properties. Modern theories can help estimate grout spread and identify flow patterns, supporting time-based stopping criteria that account for adequate spread while limiting excessive movement.<br /><br />Grout pressure must be controlled because pressure exceeding in-situ rock stresses can cause jacking—opening fractures and increasing grout take. While jacking may improve grout penetration, it can also undermine the result. Other risks include grout erosion, backflow, changes in grout properties during prolonged pumping, and fracture movement caused by later excavation.<br /><br />Design should address both the required geometry and tightness of the sealed zone and the grouting method used to achieve them. Because conditions and predictions are uncertain, the authors advocate an observational approach: predict, observe relevant indicators, and adapt measures such as grout mix, pressure, stopping criteria or borehole spacing.<br /><br />Future practice should use modern equipment, real-time monitoring, engineering supervision, risk management and stronger field testing and quality control. The industry’s responsibility is to raise knowledge and standards, improve contracts and compensation systems, and develop grouting methods that meet sustainability and climate-efficiency goals.

Keywords

rock grouting

fractured rock

grout penetrability

grout pressure

jacking

hydrogeology

rock mechanics

real-time monitoring

quality control

observational approach