天然气水合物被公认是解决当前能源危机的潜在新型能源而备受关注。含水合物的海底土体称为深海能源土。水合物在能源土中有不同的赋存形式(如填充型水合物和胶结型水合物等),由于胶结型水合物对整体强度的贡献比其他存在形式更大,尤其是饱和度较低的情况。针对于胶结型水合物的赋存形式进行研究,水合物作为胶结物质存在于土颗粒之间,胶结厚度会在一定范围内变化。为真实地反映此现象,通过对能源土试样的电镜扫描图片整理分析,获得水合物饱和度与粒间胶结厚度的函数关系。基于前期已经完成的不同粒间胶结厚度下胶结力学特性的试验研究成果,为探究胶结厚度变化对能源土体宏观力学特性的影响,建立了考虑水合物胶结厚度的能源土粒问胶结模型,并介绍此模型中相关胶结参数及其确定方法。
Methane hydrate is recognized as one of the potential new resources to solve the current energy crisis. Soil assembly containing methane hydrate in the bottom of sea is called deep-sea methane hydrate-bearing soil (MHBS). The morphology of methane hydrate is different in MHBS, e.g. pore-filling and cementing. The cementing type has a great effect on the ensemble strength of MHBS, especially at a lower methane hydrate saturation. This constitutes the strong motivation of the paper. Methane hydrate as a cementing material forms among soil particles, and the bond thickness of methane hydrate changes in certain ranges. The relationship between methane hydrate saturation and inter-particle bond thickness is obtained through analyzing the SEM of MHBS. Based on the previous experimental findings, a novel inter-particle bonded model considering bond thickness has been proposed for investigating the effect of bond thickness of methane hydrate on the mechanical behavior of MHBS; and the calculation methods are elaborated to determine its relevant bond parameters.