|
|||||
|
|
Geotechnical characterization of calcareous sediments from the Dry Tortugas Keys and Marquesas Keys CBBL SRP study sites, Lower Florida Keys |
|
| Authors: | G Veyera H Brandes A Silva |
| Institution: | Department of Civil and Environmental Engineering, University of Rhode Island, Kingston, RI 02881, USA, Department of Civil Engineering, University of Hawaii, Honolulu, HI 96822, USA, Marine Geomechanics Laboratory, College of Engineering, University of Rhode Island, Narragansett, RI 02882, USA, |
| Abstract: | Geotechnical characteristics of carbonate sediments from two test sites (Dry Tortugas Keys and Marquesas Keys) in the Lower Florida Keys were investigated as part of the Coastal Benthic Boundary Layer Special Research Program, through an extensive field coring and laboratory testing program conducted by the Marine Geomechanics Laboratory of the University of Rhode Island. Based on results from physical measurements, water content and wet bulk density values for both sites generally showed large variations in the upper 25 cm and little variation below this depth. Sediment samples exhibited low plasticity or nonplastic characteristics. Constant-rate-of-deformation consolidation test results showed strong apparent overconsolidation (stress state ratio >7.5) in the surface sediments (upper 50 cm) at the Dry Tortugas Keys, and light overconsolidation (stress state ratio <1.5) below 50-cm depth at the Marquesas Keys site. In-situ permeability values were between 10-4 and 10-7 cm/s at both sites and showed no strong depth dependence in the upper 2 m. Undrained shear strength profiles for Dry Tortugas Keys sediments indicated a marked stiffening with depth, whereas the Marquesas Keys sediments showed a gradual increase with depth. Consolidated isotropically undrained triaxial shear strength test results indicate that the undisturbed sediments had an average effective angle of internal friction of 38°, which is not fully realized until large axial strains on the order of 11% have accumulated. Evidence of cementation was not found in triaxial compression or consolidation test results. The general behavior and characteristics of these sediments are similar to those of granular materials, which is primarily due to their high calcium carbonate contents and lack of cementation. |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ | |