In-situ Strength of Seafloor Soil Determined from Tests on Partially Disturbed Cores.
Technical note, Jan 71-May 72,
NAVAL CIVIL ENGINEERING LAB PORT HUENEME CALIF
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The major obstacle to rational design of seafloor foundations and anchors has been a lack of good quality information on the bottom sediment engineering properties. Considerable engineering property data have been obtained through laboratory testing of core samples, but most of these data are of questionable validity because of sample disturbance factor. To improve the usability and credibility of laboratory test data, an experimental investigation was undertaken to determine the extent of disturbance involved in seafloor soil sampling and handling. In-situ tests were performed and related to comparable laboratory tests. The soils tested were from the Santa Barbara Channel with a terrigenous land derived origin. A technique based on earlier work was developed for predicting in-situ shear strength on the basis of laboratory test results. Various disturbance mechanisms including sampling, vibration, long-term nonrefrigerated storage, and water and air expansion were investigated and analyzed quantitatively. Strength reductions varying between 15 and 50 percent were observed to result from these disturbances. The in-situ strength prediction procedure appears to be capable of compensating for all forms of disturbance except for those developing as a result of gas expansion. Author
- Physical and Dynamic Oceanography
- Soil Mechanics