Lubrication of Pipejacking in Soft Alluvial Deposits under Impacts of Misalignment, Geology and Lubricant Injection Mode
The impacts of the lubrication upon the pipejacking works has rarely discussed by literature. This study described a method that can be used to evaluate the lubrication performance by the reduction in the frictional coefficient μ as a function of injection type, soil and lubrication natures, and misalignment. The results of an application of the proposed method to a pipejacking project in the soft alluvial deposits of northern Taiwan were presented. The effect of misalignment increased the frictional stress τld to 12.5 kPa, reducing the reduction in the μ value to 71%. The combined effects of misalignment and varying face resistance contributed to the τ ld value of 4.0 kPa and were deemed as the main cause leading the low reduction of 84%. The misleading reduction of 60% was attributed to the inability of the occasional gravel to develop lower face resistance. The effects had greater influence on the lubrication performance than the lubricant injection mode.