Single fluid jet-grout strength and deformation properties

The use of sub-horizontal jet-grout columns in the construction of soft ground tunnels is a popular method to provide excavation support. The sequential installation of jet-grout columns in a tunneling environment will result in the jet-grout columns being loaded in a staged manner, resulting in the jet-grout material properties and installation order affecting the magnitude and distribution of surface settlements and face deformations. A laboratory program was carried out to quantify the short-term (<24 h) development of strength and stiffness of a grout with a composition similar to that found in the construction of jet-grout columns. The laboratory tests were conducted at 8 °C to simulate the ground temperatures. Also the laboratory test cylinders were insulated to simulate the boundary condition differences between 600-mm-diameter jet-grout columns in soil and the 76-mm-diameter laboratory samples.