Measurement System for Systematic Hydrological Characterization of Unsaturated Fractured Welded Tuff in a Mined Underground Tunnel

摘要

The possibility that certain locations in unsaturated, fractured geological environments may serve as possible disposal sites for high-level radioactive waste has in recent years spurred much research towards understanding of flow and transport phenomena in these settings. Water flow in unsaturated fractured rock is complex because it is affected by both the matrix and fracture properties, and the coupling between them, which in turn, is dependent on the degree of saturation. The intrinsic complexity of the flow processes, and the difficulty in interpreting and correlating measurements to flow and transport parameters, call for experiments executed under well-controlled conditions that are more easily attainable in the laboratory. On the other hand, because of the significant role of spatial scaling in flow phenomena, in-situ measurements are also indispensable. In this paper, we describe an experimental system for field investigations of flow and transport in partially saturated, fractured welded volcanic tuff. The in-situ measurements were designed to specifically address the issue of spatial variability.