基于均匀化理论的水合物沉积物修正Duncan-Chang本构模型  

Modified Duncan-Chang model for hydrate-bearing sediments based on homogenization theory

作　　者：王辉[1] 周世琛 陈宇琪 周博[1] 薛世峰[1] WANG Hui;ZHOU Shichen;CHEN Yuqi;ZHOU Bo;XUE Shifeng(College of Pipeline and Civil Engineering,China University of Petroleum,Qingdao 266580,China)

机构地区：[1]中国石油大学(华东)储运与建筑工程学院,山东青岛266580

出　　处：《中南大学学报（自然科学版）》2021年第9期3251-3263,共13页Journal of Central South University:Science and Technology

基　　金：国家重点研发计划项目(2017YFC0307604)资助项目。

摘　　要：为了精确地描述水合物沉积物在外荷载作用下的变形,首先,基于Mori-Tanaka均匀化理论提出一种水合物沉积物等效弹性参数的有效预测方法;其次,考虑水合物胶结对沉积物侧向应变的影响,采用岩土复合体理论建立水合物沉积物的修正Duncan-Chang本构模型;最后,探讨模型参数对材料的宏观本构响应的影响,并将模型预测结果与室内三轴试验结果进行对比。研究结果表明:基于Mori-Tanaka均匀化理论的修正Duncan-Chang本构模型不仅能够较好地模拟在低饱和度高围压条件下的应变硬化现象以及在高饱和度低围压条件下的应变软化现象,也能够较好地预测水合物沉积物的侧向变形。水合物沉积物在外荷载作用下的变形主要受到与水合物饱和度和有效围压有关的模型参数的综合影响,模型参数a,b和c分别反映了水合物沉积物的刚度、强度和脆性。而侧向应变的取值主要受到模型参数f,m和n的综合影响,模型参数g的影响并不明显。In order to accurately describe the deformation of hydrate-bearing sediments under external loading,firstly,an effective prediction method for equivalent elastic parameters was proposed based on Mori-Tanaka homogenization theory.Secondly,considering the effect of hydrate bonding on lateral strain of sediments,a modified Duncan-Chang model for hydrate-bearing sediments was established by employing complexus theory of soil.Finally,influence of model parameters on macroscopic constitutive response of materials was discussed and the prediction results of constitutive model proposed in this paper were compared with the results of laboratory triaxial tests.The results show that the modified Duncan-Chang constitutive model based on Mori-Tanaka homogenization theory can well simulate the strain hardening phenomenon at low saturation and under high confining pressure and the strain softening phenomenon at high saturation and under low confining pressure.At the same time,it can reasonably predict the lateral deformation of sediments.The deformation of hydrate-bearing sediments under external loading is mainly affected by model parameters related to hydrate saturation and effective confining pressure.Model parameters a,b and c reflect the stiffness,strength and brittleness of hydrate bearing sediments,respectively.Lateral strain is mainly affected by the comprehensive effects of model parameters f,m and n,while the influence of model parameter g is not obvious.

关 键 词：水合物沉积物 修正Duncan-Chang本构模型 均匀化理论 等效弹性参数 侧向应变 

分 类 号：TE133[石油与天然气工程—油气勘探]