Isothermal mechanical response of sediment in the ISHTE simulation experiment

Technical Report · Fri Mar 01 04:00:00 EST 1985

OSTI ID:5331782

McTigue, D F; Lipkin, J; Bennett, R H

A simulation of the In Situ Heat Transfer Experiment subjected a large cylindrical sample of deep marine sediment to a hydrostatic pressure of 55.2 MPa. The isothermal mechanical response of this material to pressurization and depressurization is analyzed using a linear theory for a fluid-saturated porous elastic body with compressible constituents. A sudden increase in external fluid pressure causes an undrained deformation and a small negative excess pore pressure (suction) due to the difference in the compressibilities of the fluid and solid. The resulting compressive effective stress relaxes due to Darcy flow of water into the sediment, and the sample expands to recover some of the undrained deformation. Experimental data for sediment surface displacement and excess pore pressure are consistent with the model analysis. Fitting of the model calculations to the data determines four material constants: permeability, drained bulk modulus, and two bulk moduli characterizing the solid clay particles. The first two of these parameters are in reasonable agreement with independent measurements, while the solid moduli are determined here for the first time. A discrepancy between model predictions and data for the pore pressures suggests that external fluid may have penetrated disrupted sediment near the heater. This offers a possible explanation for anomalous geochemical observations in the zone near the heater. 12 refs., 26 figs., 6 tabs.

• Research Organization: Sandia National Labs., Albuquerque, NM (USA); Sandia National Labs., Livermore, CA (USA); Naval Ocean Research and Development Activity, NSTL, MS (USA)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 5331782
• Report Number(s): SAND-83-1847; ON: DE85014161
• Country of Publication: United States
• Language: English

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12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
CLAYS
DATA
DEFORMATION
ENERGY TRANSFER
EXPERIMENTAL DATA
HEAT TRANSFER
INFORMATION
MANAGEMENT
MATERIALS
MATHEMATICAL MODELS
NUMERICAL DATA
PERMEABILITY
PORE PRESSURE
POROUS MATERIALS
PRESSURE EFFECTS
RADIOACTIVE WASTE DISPOSAL
SEA BED
SEDIMENTS
SIMULATION
WASTE DISPOSAL
WASTE MANAGEMENT