2022 Volume 17 Issue 1 Pages 33-45
An 8-m-long core was taken from the seafloor from shallow gas hydrate province in the off San’in Region. Based on the observation of the cores, the muds were divided into three categories - carbonate nodules, laminated muds, and massive muds. The core samples were subjected to physical property, cone penetration, vane shear, and undrained triaxial compression tests. The void ratio of the massive mud decreased with an increase in depth, whereas that of the other lithofacies did not. Only muds containing carbonate nodules contained coarse fraction, and the activity was large in all lithologies. Cone penetration resistance and vane shear strength increased with depth only the massive muds. The difference in cohesion due to lithology was small, c’=3.1 kN/m2 or less, ccu=5.0 kN/m2 or less.
