Control of settlement due to tunnel construction by slurry pipe jacking method

One of the most common problems due to the construction of tunnels in urban areas is settlement and its measurement. Settlement due to tunnel excavation varies in quantity and depends on several factors such as tunnel geometry, ground condition, method of excavation and so on. For construction work near existing urban facilities, underground tunnels that are excavated being by slurry pipe jacking are being increasingly employed in order to avoid problems such as subsidence. This paper will discuss and predict the raised settlement from using large diameter slurry pipe jacking methods in non-cohesive soils in Fujisawa, Japan; thus, being called the Fujisawa project. From this study, it has been found that the prediction of settlement in non-cohesive soils by traditional methods of monitoring such as surface leveling and subsurface inclination measurement is not successful and can only be controlled by using machine penetration data, particularly discharged mud density data that can give assured prediction of any hazards.