Characterisation of colloidal silica grout under saline groundwater; Penetration theory and injection tests in a fracture test system

Martikainen, J.*; Tsuji, Masakuni*; Schatz, T.*; Nakashima, Hitoshi*; Okihara, Mitsunobu*; Aoyagi, Kazuhei  ; Sato, Toshinori  

This paper shows a result of the part of the study on characterisation of penetration of the colloidal silica grout (CSG) under saline groundwater, aiming to understand the impact of salinity on grout penetration by verifying the improved penetration theory with laboratory tests. This theory was proposed to add a time factor to the existing penetration theory of Funehag, especially under the saline groundwater conditions. A series of grout injection tests by the fracture test system were performed. The CSG of one European and Japanese were injected in the system, filled with the five different groundwater simulants. All no-flow tests were successful, resulting in the formation of relatively homogeneous gelled zones. Based on the analysis of acquired , it was found that as an alternative method, designing a longer gel time by multiplying the inverse value of can be proposed to attain the required penetration. Although the results were fruitful, further investigation is necessary to develop this penetration theory.