Simple Filter Cake Formation Test Method Using a Geotextile instead of the Sand Stratum

Slurries and filter cakes are widely used to support the earth pressure and water pressure of an excavation surface to maintain stability. Most major projects of slurry shield need to carry out filter cake formation tests to study the availability of slurry parameters. Nevertheless, it takes considerable testing and lengthy preparation of sand to simulate a stratum, therefore this paper examines a filter cake formation test method in which a geotextile is used to replace the sand stratum. Using the geotextile as a known filter medium, the quantitative relationship is studied between the membrane and the simulated sand, to examine whether the same experimental results can be obtained as using the simulated sand. A series of filter cake formation tests were carried out on four different sands and five different geotextiles with four different slurries and then the filter membrane properties were measured to explore the potential of the geotextile alternative for filter cake formation. The results show that the infiltration process of slurry in sand and geotextile was similar, and slurry infiltration occurred both with and without filter cake. 0.8 times apparent opening size of geotextile could be used to replace the characteristic pore diameter of the sand stratum (0.8AOS = D0) for the filter cake formation tests. The filter cakes on sand stratum and the substituted geotextile had similar properties, such as thickness and water content.