Abstract Aiming at the airtightness of filter cakes on the excavation face during hyperbaric chamber intervention in slurry shield tunnelling, and using the sandy cobble stratum through which the Nanjing Weisan Road river-crossing tunnel passes as anexample, airtightness tests were carried out for filter cakes formed under different slurry infiltration modes by a self-developed airtightness apparatus. The results show that when the slurry infiltrates into the stratum, some of the mud particles plug the pores of the stratum and effectively reduce the permeability; if the stratum is first infiltrated by a pure bentonite slurry with a density of 1.05~1.07g/cm3 and then the filter cake is formed by a slurry with a density above 1.15g/cm3, the period of airtightness will be several times longer than that of the filter cake only formed by the denser slurry. This study plays a significant role in slurry adjustments and filter cake schemes for slurry shields during hyperbaric interventions in highly permeable strata.
Abstract：
Aiming at the airtightness of filter cakes on the excavation face during hyperbaric chamber intervention in slurry shield tunnelling, and using the sandy cobble stratum through which the Nanjing Weisan Road river-crossing tunnel passes as anexample, airtightness tests were carried out for filter cakes formed under different slurry infiltration modes by a self-developed airtightness apparatus. The results show that when the slurry infiltrates into the stratum, some of the mud particles plug the pores of the stratum and effectively reduce the permeability; if the stratum is first infiltrated by a pure bentonite slurry with a density of 1.05~1.07g/cm3 and then the filter cake is formed by a slurry with a density above 1.15g/cm3, the period of airtightness will be several times longer than that of the filter cake only formed by the denser slurry. This study plays a significant role in slurry adjustments and filter cake schemes for slurry shields during hyperbaric interventions in highly permeable strata.
2015, Vol. 52 