Pressurized clay injection method using kaolinite for controlling groundwater of a saturated sand layer

In tunnel construction in the city area, NATM method is adopted for construction by the limitation of the construction condition. When classifies roughly in supporting method of construction, there are against the spring water, face stability, ground surface subsidence, cement, water glass and urethane are usually used for grouting material against the spring water, but there is the concern, such as expensive and high load on the environment because of artificial materials. On the other hand, Kaolinite is a natural material, there is less load on the environment, and many merits in the processing of the excavated muck. Therefore, we focused a pressurized clay injection method by using the above-mentioned characteristics and applied this to the construction of the underground. In this paper, the availability of the injection a fluid with a dispersion of kaolinite was discussed to summarize the applicability for controlling groundwater of the saturated sand layer. Specifically, a one-dimensional column test was conducted under the high hydraulic gradient. As a result, it was shown the possibility of effecting of decreasing hydraulic conductivity at less than one-order. Consequently, it is concluded hydraulic conductivity of sand layer was able to be reduced by Kaoline clay suspension.