定圧注水時の流量‐時間曲線からの固体内亀裂特性の推定について

Abstract

Fluid injection test using a borehole for permeability of rock mass, such as Lugeon test, is to evaluate the average permeability of rock mass around the borehole, as the Lugeon value or the coefficient of permeability, although those values do not directly represent the feature or characteristic of the fracture / joint in rock mass. However, a distinctive mark of the fracture is one of the significant factors, which reflect the apparent permeability, and it may be possible to find a distinctive fracture quality by observing the trend of test data.In order to examine whether it is possible to evaluate a unique property of fracture in a solid, longitudinal percolation tests for fluid seepage in wooden samples, which contain longitudinal thin plane slit or slits were carried out. Characteristic evaluation of the fracture in the sample was tried through explanation of the flow rate-time curves under constant fluid injection pressure, which were obtained from the laboratory tests. The explanation is based on the numerical calculations of both the seepage analysis and elastic displacement analysis.Possibility of simple and economical evaluation of fracture characteristic is suggested from the results and then, one method for evaluation of fracture characteristic by using the least in-situ data and comparing it with numerical simulation result, is proposed.