Pressurized bentonite slurry is applied on a tunnel face to form a filter cake to stabilize the tunnel face when the slurryshield excavates through the sandy soil. Failure of the tunnel face may be caused by a high pe...Pressurized bentonite slurry is applied on a tunnel face to form a filter cake to stabilize the tunnel face when the slurryshield excavates through the sandy soil. Failure of the tunnel face may be caused by a high permeable filter cake, which commonlyhas a long penetration distance of slurry in sands. A column system with a height of 680 mm and a diameter of 300 mm was de-veloped to model pressurized slurry infiltration in sands. Pressure transducers were installed to estimate the hydraulic conductivityof the filter cake during slurry infiltration. The electrical conductivity of the leachate of collected samples was measured. Resultsshow that the majority of fine particles in slurry are within the range 100-300 mm into the sand specimen. The time for forming animpermeable filter cake is about 300 s, which indicates the impermeable filter cake is hard to form during the excavation.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51225804,U1234204,and 41472244)the Doctoral Fund of the Ministry of Education of China(No.20120101110027)+1 种基金the Research Fund from the China Railway Corporation(No.2014G003-B)the Zhejiang Provincial Communication Department(No.2014H07),China
文摘Pressurized bentonite slurry is applied on a tunnel face to form a filter cake to stabilize the tunnel face when the slurryshield excavates through the sandy soil. Failure of the tunnel face may be caused by a high permeable filter cake, which commonlyhas a long penetration distance of slurry in sands. A column system with a height of 680 mm and a diameter of 300 mm was de-veloped to model pressurized slurry infiltration in sands. Pressure transducers were installed to estimate the hydraulic conductivityof the filter cake during slurry infiltration. The electrical conductivity of the leachate of collected samples was measured. Resultsshow that the majority of fine particles in slurry are within the range 100-300 mm into the sand specimen. The time for forming animpermeable filter cake is about 300 s, which indicates the impermeable filter cake is hard to form during the excavation.
