The geotechnical properties of two deep-sea calcareous oozes are discussed. The first ooze, a clayey silt with 56 to 75 percent calcium carbonate, was subjected to laboratory vane shear, one-dimensional compression, and triaxial shear testing. The void ratio-log pressure relationship obtained from one-dimensional compression tests, for a pressure increment ratio of 1, was found to be continuously plunging, a curve form possibly characteristic of the calcareous oozes. The failure envelope determined from triaxial shear tests defined a decreasing effective friction angle with increasing confining stress (34 deg, decreasing to 28 deg). Efforts toward establishing a connection between these phenomena and grain crushing in the sediment at engineering loads were not conclusive.

The second ooze, a fine sand-silt with 77 to 86 percent calcium carbonate, was tested both in-place (vane shear) and in the laboratory (vane shear and triaxial). In-place vane strengths are quite high, 10 to 30 kPa (1.5 to 4.5 psi), while laboratory vane strengths are near zero. The ooze exhibits high in-place vane strength sensitivities (5 to 10).