2020 Volume 76 Issue 2 Pages I_34-I_48
It is important to attain hydraulic barrier performance in chemical grouting. A new approach to detect the end point of the channel caused in improvement body by imperfect chemical grouting was proposed. Salt water as tracer is infiltrated through the channel and the diffusion from the end is monitored by electrical resistivity tomography in this approach. The resistivity of measurement area is continuously changing, so the monitoring may be difficult using conventional inversion analysis method that assumes resistivity is stable. Therefore, the time-lapse analysis method is used. The time-lapse analysis method is particularly effective for the monitoring of tracer, because it is characterized by being able to handle a continuous change of the electrical resistivity distribution during measurement. As a result of an outdoor tank experiment for the verification of effectiveness of the proposed approach, decrease of electrical resistivity has been clearly detected around the end of the channel and the position of the end has been detected by use of the time-lapse analysis method. Furthermore, the validity of the experiment result has been confirmed from the advection-dispersion analysis performed for the reappearance of the experiment.
