Research On Multicomponent Fidelity Sampling Techniques Of Sediment-water Interface

The process of sediment-water interface is the key to reveal the endogenous pollution of sediment to water.However,it is the basic work to study the migration and transformation of interface to obtain a complete sample of micro-disturbed sediment-water interface.At present,the interface samples of inland waters such as lakes and reservoirs are collected by sediment samplers.Due to respective application environments and conditions,they are unable to obtain ideal interface samples.In this paper,several existing samplers are used to investigate the reservoir sediment-water interface.The result shows relevant characteristics of the interface and the working condition of the existing sampler.The fidelity requirements of sediment-water interface sample collection are put forward based on the disturbance form of sampling.A multi-component fidelity sampler for sediment-water interface is designed in this paper.The main research results are as follows:(1)The samples of sediment-water interface in front of Biliuhe reservoir are disturbed by all sediment sampler.The experimental analysis of interface samples shows that the surface layer of sediment is saturated soft soil with fine grain size,high water content,low bearing capacity,large compression coefficient and easy to be disturbed.Therefore,it is necessary to ensure the integrity and micro-disturbance of the sediment-water interface sample.(2)The disturbance of sediment-water interface sample exists in the whole process of sampling,which involves the destruction and compression of sediment by contact sampling,the resuspension of sediment caused by oscillation of overlying water and the destruction of original sequence of sample post-treatment.The sampler should be able to control the sampling depth to ensure the solid-liquid phases,and reduce the various forms of disturbance in the sampling process through designong reasonable structure.(3)Accord to the characteristics of sediment-water interface and the analysis of the key problem of sample fidelity,a fidelity sampler for interface sample is designed.The principle is that that coiling mechanism and the transmission system provide and transmit power for the movement of the elastic closing element.The contact trigger mechanism realizes the automatic control of the sample depth.The comprehensive measures of compartment and independent sampling reduce the disturbance during the sampling process.The connection and sealing measures of the sediment-water interface fidelity sampler are described.The finite element analysis method is used to analyze and optimize the key components,and the rationality of structural parameter is verified.(4)In the process of prototype development,parts are optimized according to actual problems,and the selection,processing and assembly points of parts are introduced.On this basis,the operating rules of the sampler are summarized,which can provide reference for the field test of the sampler.The test results show that the sampler can achieve the expected movement function and has good sealing effect.(5)The sediments of the Biliuhe reservoir are acidic.The results of organic matter determination in stratified sediments shows that the vertical range varied greatly.In general,there is a trend to decrease with the increase of depth.In recent years,the transport of organic matter before the dam presents an increasing trend,and corresponding measures should be taken to control it.