1. Evaluation of failure modes and undrained shear strength by cone penetrometer for Natural Gas hydrate-bearing pressure-core sediment samples recovered from the Krishna–Godavari Basin, offshore India.
- Author
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Kato, Akira, Konno, Yoshihiro, Yoneda, Jun, Kida, Masato, Oshima, Motoi, Jin, Yusuke, Nagao, Jiro, and Tenma, Norio
- Subjects
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SHEAR strength , *FAILURE mode & effects analysis , *CONE penetration tests , *SEDIMENT sampling , *LONGITUDINAL waves , *NATURAL gas , *PROPER orthogonal decomposition - Abstract
Compressional wave velocity measurements and cone penetration tests were carried out for pressure cores recovered from the Krishna–Godavari Basin off the eastern coast of India, using an instrumented pressure testing chamber constructed by the Japanese National Institute of Advanced Industrial Science and Technology. For pressure cores with high gas hydrate saturations (S h) and exhibited high compressional wave velocities also display a high loading force that resulted in tensile failure. A pressure core sample with low compressional wave velocities and low gas hydrate saturations led to a low loading force, which resulted in radial shear. The cone factor connecting the cone resistance and the undrained shear strength, N k , was estimated using cone penetration testing and the uniaxial compressional results. We estimated its value as N k = 45 by using a uniaxial compression loading speed of 0.01%/min and a cone insertion loading speed of 0.25 mm/s. Undrained shear strengths, estimated from cone penetration results using N k = 45, were assumed to be equal to the tensile strengths between hydrate-hydrate and hydrate-particle interface when S h is less than 50% and increases when S h is more than 50% assuming that gas hydrate morphology was matrix supporting. • Compressional wave velocity measurements and cone penetration tests were applied to pressure cores. • Failure modes of pressure cores were assessed after cone penetration testing. • The cone factor for pressure cores was estimated to be 45. • Undrained shear strengths were estimated at 0.1–0.2 MPa under a 2400 m/s compressional wave velocity. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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