Preliminary Study on the Relationship of Strength and Electrical Resistivity for Hydrate-Bearing Sediments

[Objective]A large amount of methane hydrate exists in the South China Sea. To safely and efficiently exploit this new energy source, it is necessary to fully understand the mechanical properties of hydrate-bearing sediment. [Methods]As a geotechnical test analysis method, the electric resistivity method plays an irreplaceable role in the study of geomaterials such as unsaturated soil, expansive soil and frozen soil. Based on the grain distribution of the methane hydrate-bearing sediment in the Shenhu area of the South China Sea, the experimental soil was artificially prepared, and the tetrahydrofuran hydrate-bearing sediment sample was prepared at an appropriate temperature. The whole process of stress-strain-resistivity of hydrate-bearing sediment sample was obtained by uniaxial compression test and resistivity test.[Results]The test results show that: (1) the uniaxial compressive strength and stiffness of hydrate-bearing sediments increase with the increase of saturation, and the peak strain corresponding to the peak strength increases with the increase of hydrate saturation; (2) the stress-strain-resistivity curve of hydrate-bearing sediment mainly goes through three stages: the elastic phase (reduction in resistivity); the plastic phase (slowly increase in resistivity); the strain-softening phase (sharp increase in resistivity), and the internal structure, the