連続加圧タンク内一軸試験機による南極

氷床深部氷の静水圧下における力学試験

抄録

Department of Applied Physics, Faculty of Engineering, Hokkaido University
Effects of hydrostatic pressure on the mechanical properties of Antarctic deep core ice were investigated by the use of a special uniaxial testing machine nstalled in a high pressure cell. The design and construction of the pressure cell as well as of, the testing machine are here described. Hydrostatic pressure up to 100 MPa could be attained and kept for several days' duration in the cell using a hydraulic pump with silicone oil. The testing machine was driven from the outside of the pressure cell by a rod penetrated through its thick wall. Volume change of the inner space of the cell caused by the movement of the driving rod was compensated by the movement of another rod from the opposite direction at the opposite end of the cell. The frictional force exerted on the driving rod at the bore hole in the cell wall was well separated from the real stress generated in a specimen due to its uniaxial deformation. Preliminary compressive tests carried out at 30 MPa revealed that the strength of the deep core ice increased under hydrostatic pressure. This hardening effect is attributed to the shrinkage or closure of air-bubbles and cleavage cracks formed in the relaxation process of the deep core ice.