Evaluation of Jet Grouting Design Parameters for TBM Launching and Arrival in Bangkok Soils

In urban areas, it is essential to employ ground stabilization and enhancement methods during the excavation of soft ground tunnels. It is necessary to improve the soil before the Tunnel Boring Machine (TBM) break-through to ensure soil stability and control groundwater. Jet grouting is a commonly used technique in underground projects to strengthen soft ground, maintain TBM tunneling stability, prevent groundwater leakage, and ensure safety. The dimensions of the jet grouting construction may deviate from the original design due to site complexities. This study aims to assess and compare the actual construction dimensions with the design dimensions. Furthermore, a parametric study was conducted using numerical analysis to investigate the impact of modifying specific jet grouting design parameters on soil stability and seepage issues when opening the diaphragm wall for TBM launching and arrival in Bangkok soils. This paper presents the findings of the comparison between the actual construction dimensions and calculated design dimensions. Suggestions on the design of jet grouting zones derived from the parametric study in the numerical analysis are also presented in the paper.