ABSTRACT
Unexpected high rate of groundwater inflow into a tunnel can engender serious hazards like mechanical instability, reduction in workability and environmental impacts. Therefore, investigation of location, flowrate, and hydraulic pressure of water-bearing zones ahead of the tunnel face and accurate prediction of groundwater inflows into tunnels is of crucial importance. The measurement of flowrate and hydraulic pressure in horizontal drilled boreholes, using a packer system, is one of the effective ways to assess water-bearing zones. However, the installation of such a packer system into a borehole required much effort from the tunnel worker just in front of the tunnel face which can be very hard and dangerous. Hence, the authors developed a measurement system which can be easily installed using a standard underground rock drilling machine (drill jumbo). In this paper, we report the details of the system and also the on-site demonstration test results.
