Despite several well-established jacking force models being available for determining the jacking loads, their ability to characterise the tunnel bore conditions is very limited. In this study, a simple approach to characterise the tunnel bore conditions is proposed and applied to a case history where four wastewater pipelines were constructed in soft alluvial deposits to verify its validity. Four jacking force models are reviewed. By the given soil properties and pipe dimensions as well as buried depth of pipeline, the normal contact pressure in each model and the measured frictional stress in each section of baseline which is constituted by the minima of total jacking load are used for back-analysis of the frictional coefficient μ_avg. The μ_avg values outside the 0.1–0.3 range suggested for lubricated drives can be linked to the increasing pipe friction resulting from excessive pipe deviation or ground closure or the gravel formation not being long enough to develop lower face resistance or total jacking load.