Technical Note: Example of the Application of Jet Grouting to the Neutralisation of Geotechnical Hazard in Shaft Structures

The article presents a geotechnical hazard neutralisation technology for shaft structures. The diagnosis of problems with uncontrolled subsidence of the ventilation duct provided by the authors enabled the development of a schedule of works required for the protection and reinforcement of foundation soil in the shaft area. The technology of protection works was selected after the analysis of the technical condition of shaft structures as well as hydrological and geomechanical conditions. Due to the closeness of the shaft lining, it was necessary to form grout columns using jet grouting and low-pressure grouting technologies. The article presents the issues related to the selected technology and its application to the neutralisation of the emergent geotechnical hazard. The method of performance of recommended works was also described together with their impact on the technical condition of structures discussed as well as their functionality and usage.