Numerical analysis of the grout injection conducted in the ventilation shaft of the Horonobe Underground Research Laboratory

Nakashima, Hiroyoshi*; Koyama, Tomofumi*; Tatsuta, Keisuke*; Katayama, Tatsuo*; Aoyagi, Kazuhei

Dai-14-Kai Iwa No Rikigaku Kokunai Shimpojiumu Koen Rombunshu (Internet), 6 Pages, 2017/01

In this study, we created the three dimensional model based on equivalent continuum approach to study the penetration length and enhancement of the hydraulic conductivity of the rock mass. The developed numerical model was applied to the in situ grout injection conducted in the ventilation shaft of the Horonobe Underground Research Laboratory. We evaluated the hydraulic conductivity of the rock mass after the grout operation. As a result, hydraulic conductivity of the highly permeable fault was decreased in 4 orders of magnitude, which is almost consistent with the in situ hydraulic conductivity obtained from in situ Luegeon test after the grout injection. Thus the simulation method described in this paper can be applied to the evaluation of the efficiency of in situ grout injection.