Mechanical properties of gas hydrate-bearing sediments during hydrate dissociation  

作　　者：X.H.Zhang D.S.Luo X.B.Lu L.L.Liu C.L.Liu 

机构地区：[1]Institute of Mechanics,Chinese Academy of Sciences,Beijing 100190,China [2]College of Engineering,University of Chinese Academy of Sciences,Beijing 100049,China [3]Key Laboratory of Gas Hydrate,Ministry of Land and Resources,Qingdao 266071,China [4]Qingdao Institute of Marine Geology,Qingdao 266071,China

出　　处：《Acta Mechanica Sinica》2018年第2期266-274,共9页力学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grants 41376078,51639008,and 51239010);the China Geological Survey(Grant DD20160216);the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant 2017027)

摘　　要：The changes in the mechanical properties of gas hydrate-bearing sediments(GHBS) induced by gas hydrate(GH) dissociation are essential to the evaluation of GH exploration and stratum instabilities. Previous studies present substantial mechanical data and constitutive models for GHBS at a given GH saturation under the non-dissociated condition. In this paper, GHBS was formed by the gas saturated method, GH was dissociated by depressurization until the GH saturation reached different dissociation degrees. The stress–strain curves were measured using triaxial tests at a same pore gas pressure and different confining pressures. The results show that the shear strength decreases progressively by 30%–90% of the initial value with GH dissociation, and the modulus decreases by 50% –75%. Simplified relationships for the modulus, cohesion, and internal friction angle with GH dissociated saturation were presented.The changes in the mechanical properties of gas hydrate-bearing sediments(GHBS) induced by gas hydrate(GH) dissociation are essential to the evaluation of GH exploration and stratum instabilities. Previous studies present substantial mechanical data and constitutive models for GHBS at a given GH saturation under the non-dissociated condition. In this paper, GHBS was formed by the gas saturated method, GH was dissociated by depressurization until the GH saturation reached different dissociation degrees. The stress–strain curves were measured using triaxial tests at a same pore gas pressure and different confining pressures. The results show that the shear strength decreases progressively by 30%–90% of the initial value with GH dissociation, and the modulus decreases by 50% –75%. Simplified relationships for the modulus, cohesion, and internal friction angle with GH dissociated saturation were presented.

关 键 词：Gas hydrate-bearing sediments DISSOCIATION Mechanical properties Shear strength Triaxial test 

分 类 号：O3[理学—力学]