An Alternative Method for Soil Characterisation Using Pipe-Jacking Parameters and Spoil Characteristics

As only a few boreholes are present along a tunnel design alignment, geological understanding of the worksite may not be adequate and the ability to optimise the tunnelling parameters is thus limited. Since this lack of boreholes will cause a significant potential of geo-hazards for tunnelling works. This study proposes an alternative method to determine the major and other proportions of ground. The variation of the torque of the cutter wheel and sieve residue can be utilised to determine the major ground proportion, whereas the flow rate of the supply line and pressure in the supply and discharge lines, as well as the density of bentonite slurry can be utilised to determine other proportions. The validity of the proposed method is verified by a case study. The proposed method provides an opportunity to better understand the geological structure of worksite, refining the design tunnelling parameters and minimising the potential of geo-hazards.