Pore Pressure Response to Probe Insertion and Thermal Gradient: ISIMU-II (In Situ Heat Transfer Experiment)
NAVAL OCEAN RESEARCH AND DEVELOPMENT ACTIVITY STENNIS SPACE CENTER MS
Pagination or Media Count:
The described experiment and the evaluation of its results were designed to assess the significance of the sediment cracking occurring during piezometer and heater probe insertion, and the influence of the cracking on the subsequent excess pore pressure and thermals fields to be measured in the In Situ Heat Transfer Experiment ISHTE. The ISHTE is part of the Subseabed Disposal Program SDP. Observed sediment radial cracking was estimated to penetrate to about one-half penetrator diameter. Measured penetrator insertion pore pressures and excess pore pressure dissipation indicate that sediment cracking has no identifiable influence at the penetration depth of the sensors. Proper prediction of the dissipation of insertion pore pressures was found to require incorporation of a smear factor, accounting for sediment remolding at the piezometer wall. An analytical model to concurrently describe the rise in excess pore pressure due to sediment heating and the pore pressure dissipation radially away from the heat source is described and the results of its application to the experiment data evaluated.
- Physical and Dynamic Oceanography
- Test Facilities, Equipment and Methods