Research On Low-disturbing Sampling Theory And Truth-preserving Technique Of Deep-sea Surface Layer Sediment

While sampling the gas hydrate and the upper sediment with the traditional deep-sea sediment sample equipment, the firedamp and other gas phase dissolved components will be dissipated due to the variation of the ambient conditions, because the pressure and the temperature cannot be hold during the process. This will lead to the result that it's difficult to draw a correct conclusion of the original components and phases of the sediments. Also it will form a false judgement of the analysis of the pattern of metallogeny, the character sign for finding the gas hydrate mineral resources, lining out the distributing range of the sources and the estimation of the source perspective. Besides, the problem will also exist in the sampling process of the sediments including plenty of live microorganism addicted to the high-pressure and gas effusion round the hydrothermal-fluid vents. So, all above mentioned makes it necessary to study the truth-preserving sampling technique for the deep-sea surface layer sediments.In this paper, through the study of the truth-preserving sampling technique (disturbing-low and pressure-tight) of seabed sediments, a complete design guide rules for seabed sediment truth-preserving sampling corer is achieved to afford the academic basement for similar equipment development.The thesis includes eight chapters.Chapter 1 introduces the development actuality of the low-disturbing sampling technique, equipments and the truth-preserving sampling equipments. In this chapter, the main research content of this thesis is also put forward.In chapter 2, first part is the deduction of the spheric cavity expansion theory adapt to the seabed sediments sampling. On this base, a low-disturbing sampling module for the gravity sampler and the piston corer, in which the infection of the dust harass due to the contact corer can be quantified based on the known data. At the end of this chapter, on the foundation of the above study, the design rules for the corer-head of the corer is come to a conclusion.In the third part, the design rules for the pressure hull, the retaining ring, the connect screw thread of the truth-preserving canister are analyzed.In chapter 4, the design rules for the pressure tight and compensation of the truth-preserving structure: the rule of the transfer of the sampler, the rule of the auto-tight seal and the rule of the half-auto pressure tight are studied.On the theory analysis basis of the chapter2, 3 and 4, three types of the deep-sea sedimentstruth-preserving corer are designed and will be introduced separately in the next parts.In chapter 5, an original equipment for seabed sediment truth-preserving sampling, which is named as manipulator holding sediment truth-preserving corer, is introduced and also the test research on it.In chapter 6, the spring principles of two types deep-sea sediments truth-preserving sampling systems are compared and the structures are analyzed. Through the ocean test, the system based on the support force controlled truth-preserving spring theory is more adapted for the deep-sea sampling.In chapter 7, the structure and the working principle of the gas hydrate temperature-hold and pressure-tight sampling corer are discussed.In the last chapter, there is a conclusion of the research fruits of this thesis and also the further study direction is brought forward.