深海能源土地基承载特性离散元分析  

Bearing properties of deep-sea methane hydrate-bearing foundation by discrete element method

作　　者：蒋明镜[1,2,3] 李磊[1,2,3] 周雅萍[1,2,3] 

机构地区：[1]同济大学土木工程防灾国家重点实验室,上海200092 [2]同济大学岩土及地下工程教育部重点实验室,上海200092 [3]同济大学土木工程学院地下建筑与工程系,上海200092

出　　处：《岩土工程学报》2015年第2期343-350,共8页Chinese Journal of Geotechnical Engineering

基　　金：国家杰出青年科学基金项目(51025932);国家自然科学重点基金项目(51239010)

摘　　要：天然气水合物以胶结形式广泛赋存于深海能源土中,水合物的饱和度对能源土地基的承载特性影响巨大,水合物的开采也必将使能源土的承载特性发生重大改变。采用考虑水合物胶结厚度的微观胶结模型,分别对3种不同水合物饱和度的能源土地基进行载荷试验离散元模拟。分析水合物开采前后能源土地基的承载特性,研究水合物开采对能源土地基承载特性的影响,探讨基底压力的分布规律。结果表明:水合物开采前,能源土地基的承载力随饱和度的增加而增大。开采后,地基的承载力急剧降低,且原有水合物的饱和度越大,开采后承载力的降低量也越大;水合物饱和度越高,达到极限承载力后,p–s曲线越接近于竖直向下;胶结破坏存在临界荷载,且不同水合物饱和度地基的胶结破坏规律不相同;水合物饱和度对基底压力的分布形状影响不大,但不同沉降量下基底压力的分布形状明显不同。The bearing properties of methane hydrate-bearing foundation will be changed by massive exploitation of methane hydrate, which is originally stored in deep-sea methane hydrate-bearing soils and influences the properties of the foundation. Plate loading tests on methane hydrate-bearing foundations with three different hydrate saturations are performed using the micro-bond contact model considering hydrate cementation thickness of the deep-sea methane hydrate-bearing soils proposed by Jiang et al. The bearing properties of methane hydrate-bearing soils are analyzed, the effect of hydrate saturation on the bearing capacity of methane hydrate bearing foundation is studied, and the law of the distribution of base pressure is discussed. The results show that the bearing capacity of methane hydrate-bearing foundation increases with the increase of saturation on the original foundation. The bearing capacity of foundation sharply decreases after the methane hydrate is mined, and the higher the original hydrate saturation is, the more the bearing capacity will lose on the mined methane hydrate-bearing soils; the higher the hydrate saturation is, the closer to vertical downward the p-s curve is after reaching the ultimate bearing capacity. The destruction of the cementations has a critical load, and the foundations with different hydrate saturations follow different failure laws. The hydrate saturation just has little effect on the shape of distribution of the base pressure, but the shapes are markedly different under different settlements.

关 键 词：微观胶结厚度模型 能源土地基 承载特性 离散元 

分 类 号：TU470[建筑科学—结构工程]