Groundwater Flow in Rock Mass at Deep Depth.

Research Project

Project/Area Number	61550468
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	資源開発工学
Research Institution	Kyushu University
Principal Investigator	ESAKI Tetsuro Associate Professor of Inst. of Advanced Material Study, Kyushu Univ., 機能物質科学研究所, 助教授 (40038609)
Co-Investigator(Kenkyū-buntansha)	KIMURA Tsuyoshi Research Associate of Faculty of Engineering, Kyushu Univ., 工学部, 助手 (30161566) KAMEDA Nobuhiro Research Associate of Inst. of Advanced Material Study, Kyushu Univ., 機能物質科学研究所, 助手 (70091402) NISHIDA Tadashi Professor of Inst. of Advanced Material Study, Kyushu Univ., 機能物質科学研究所, 教授 (30038575)
Project Period (FY)	1986 – 1987
Project Status	Completed (Fiscal Year 1987)
Budget Amount *help	¥2,000,000 (Direct Cost: ¥2,000,000) Fiscal Year 1987: ¥300,000 (Direct Cost: ¥300,000) Fiscal Year 1986: ¥1,700,000 (Direct Cost: ¥1,700,000)
Keywords	Permeability / Laboratory Test / Discontinuity / Shear / Joint / Rock Mass / Usage of Underground Space / 間隙水圧
Research Abstract	The characteristics of the groundwater flow and the pore pressure in rock masses at deep depth are studied. The obtained results are as follows: (1) The triaxial confining condition is excellent for the permeability test of intact rocks whose permiability is more than 10^<-9> cm/sec. The flow rate usually decreases with time, due to blocking the pores in the rocks with small grains. (2)The pore pressure reduces the strength of porous rocks. The strength reduction of rocks with low porosity is also caused under greatly forced pore pressure. (3) The permeability testing apparatus apecially designed for jointed rocks can control the inlet and outlet pressures independently by a back pressure valve and can measure the amount of outflow correctly by electlonic balance-micro computer system. (4) The mismatched joint which shows low stiffness and dilatancy is more permeable than the matched joint. The permeability of these joints is much influenced by the confining pressure and pore pressure. Under high pressure gradient, the flow along such joints does not follow the Darcy's law. (5) The permeability model of mismatched joint must be considered as the flow through a system of tortuous and variable channels and the channel nature in fractures.