An advanced experimental set-up for studying a monodirectional grout injection process

In this paper, an advanced experimental set-up is presented for studying the monodirectional grout injection process in sand matrices. The prototype presented is based on the use of sand pluviation for the reconstitution of vertical sand columns (80 mm in diameter and 104 cm in height), which makes it possible to obtain, within the whole column, a good homogeneity of the sand at a controlled preselected state of density. Also, the pore fluid pressure is measured at five equidistant points on the columns, which provides useful information on the injection process. The procedure used to perform a test is described in detail, and the result of a typical test carried out on a medium-size silica sand with a cement-bentonite grout is presented, showing the importance of the filtration mechanism with progressive plugging of the sand matrix for the injection process and for the mechanical properties of the grouted material. Finally, some comments are made on the influence of grain size distribution curve on the i...