Abstract
A flow through type experimental reaction system was developed to simulate water-rock interaction in the upper crust conditions. The newly designed apparatus enables flow through experiments to be conducted under conventional triaxial compression condition at high temperature and have the ability to measure shrinkage, and permeability while the experiment is in progress. Specification is as follows : temperature to 300°C, fluid pressure up to 40 MPa, axial loads up to 25ton (250 MPa), and flow rates from 0 ml/min to 10 ml/min (flow velocities about from 0 cm/min to 1 cm/mm).
The investigation of the compaction of andesite powder (63 to 90 μm) with deionized water flow was performed using above apparatus at 300°C, fluid pressure 10 MPa, effective axial load pressure to sample 30 MPa, flow rate 1.5 ml/min for 10 days. The main elements in the reacted solution was Si, Na, and K, but Fe, Al, Ca, and Mg remained in the solid. The alteration products such as smectite was observed on grain surface. The permeability was almost the constant value during progress of the shrinkage, and the bulk density was decreased by leaching. These facts suggest that new flow pass was formed in the andesite sample under triaxial compression condition.
