多功能水合物沉积物三轴试验系统的研制与应用

研制了新型多功能水合物沉积物三轴试验系统，系统由供-排气模块、应力加载模块、温控模块、数据采集模块和辅助模块组成。利用泵驱动高压液体施加围压和轴压，加载方式有恒压、恒流、梯度增压、跟踪气压模式，可以实现不同条件下的水合物合成、三轴剪切。围压跟踪气压的功能使水合物生成过程中净围压不变，保证了试样初始条件一致性。根据围压液体积变化测量试样体积变形，通过设置回压泵压力变化方式控制水合物气压，可以模拟不同降压速率条件下的水合物沉积物分解变形。以泥质粉细砂和二氧化碳为材料制作了三轴试样，进行了水合物合成、三轴剪切和降压分解试验，检验了仪器的可靠性。

Development and application of multi-functional triaxial test system for hydrate-bearing sediments

A new multi-functional triaxial testing system for hydrate-bearing sediments was developed. The system was consisted of a gas charge/discharge module, a stress loading module, a temperature control module, a data acquisition module, and an auxiliary module. High-pressure liquid pumps were used to generate confining pressure and axial pressure under the modes of constant pressure, constant flux, gradient pressurization, and gas pressure tracking. Therefore, the syntheses of differently conditioned hydrate-bearing sediments and triaxial shearing of samples could be achieved. The function of confining pressure tracking gas pressure kept the net confining pressure unchanged during the hydrate formation process, which ensures the consistency of initial conditions of the samples. The volumetric deformations of the samples could be measured by the volume change of the confining liquid, and the gas pressure could be controlled by adjusting the back pressure regulator. Hence, the decomposition process of hydrate-bearing sediments under different pressure reduction rates could be modelled. Triaxial specimens were made of clayey fine sand and carbon dioxide. The hydrate syntheses, triaxial shearing tests, and decomposition tests were carried out to verify the reliability of the testing system.