Experimental and numerical studies on geomechanical behavior of various gas hydrate-bearing sediments in china

� 2016 Taylor & Francis Group, London. Gas hydrates exist in pores as a solid, bonding surrounding soil grains together and also densifying the host sediments. As a result, hydrate-bearing sediments exhibit stiffer, stronger and more dilatant behavior than hydrate-free sediments. This paper presents experimental and numerical studies to capture these features of the geomechanical behavior of hydrate-bearing sediments. The experimental data includes triaxial tests on reconstituted soils of South China Sea and synthetic samples of carbon dioxide hydrate-bearing soils, while the critical state-based soil constitutive model is calibrated using an optimization-based technique. The results show that the critical state-based model is capable of predicting shearing response of the hydrate-bearing sediments under different confining stresses, drainage conditions and degrees of hydrate saturation. It is also found that the influence of gas hydrates manifests itself mainly through enlargement of the initial yield surface. The corresponding model parameters are presented for the host sediments in China, which can be adopted for the simulation of future gas exploration and gas production in China.