点击次数：

论文类型：期刊论文

发表时间：2016-11-01

发表刊物：MARINE AND PETROLEUM GEOLOGY

收录刊物：SCIE、EI、Scopus

卷号：77

页面范围：507-514

ISSN号：0264-8172

关键字：Marine sediment; Methane hydrate-bearing sediments; Mechanical properties; Cohesive force

摘要：In this paper, a series of experiments was conducted on remoulded hydrate-bearing marine sediments from a gas hydrate core drilling site located in the Pearl River Estuary of the South China Sea. The composition and particle size distribution of marine sediments were analysed, and triaxial loading experiments were performed to study the mechanical properties of hydrate-bearing marine sediments. The strength properties of hydrate-bearing marine sediments were compared with those of hydrate-bearing kaolin clay, ice-marine sediment mixtures and hydrate-dissociated marine sediments under the same porosity (40%), temperature (8 degrees C), confining pressures (2, 3, and 4 MPa), and strain rate (1%/min) conditions. Several important results were obtained: The composition and particle size distribution analysis indicated the marine sediment and kaolin clay are both sandy clays, and the stress-strain behaviours and strength properties of hydrate-bearing marine sediments are similar to those of hydrate bearing kaolin clay. Under different confining pressures, the failure strengths of all ice-marine sediment mixtures were lower than those of methane hydrate-bearing sediments, confirming that hydrate particles enhance the cementation of sediment particles. Hydrate dissociation leads to strength reduction of gas hydrate-bearing marine sediments, as was demonstrated in our previous research of hydrate bearing kaolin clay. Through the analysis of Mohr circles and failure envelopes of three types of mixtures under different confining pressures, it can be inferred that the cohesive strength played an important role in the failure strength of hydrate-bearing marine sediments following hydrate dissociation. (C) 2016 Elsevier Ltd. All rights reserved.