In-Situ Monitoring Technology Study Of Seabed Erosion And Depositon Process Based On Resistivity Method

Thework in this thesis was based on National 863 Project"Marine SedimentRe-suspension Flux in-situ Monitoring Techniques during the Storm Process"(No.2008AA09Z109).A set of in situ system monitoring seabed erosion and depositiondynamic process,based on the resistivity measurement,was developed.It couldimplement in situ monitoring water-sediment interface location.In this thesis,the work consists of two parts,1 Monitoring system design:①Design the whole structure of monitoring system based on resistivity measurement;②Completion the three components design of the system,that is mechanical rod part,control part and analysis software part.Rod design was completed by choosing roddiameter,material and electrode distance through experiments and determining thering electrode resistivity calculating method.Control part was realized by dividinghardware and software into modules to design respectively.Processing and analysissoftware was completed through modularization design;③system error andprecision analysis;④experimentalize for testing and adjusting system parameters;⑤assemble the whole system,and finish system design.2.System verifyingexperiments:①indoor comparative experiment:The measured data fromself-designed instrument was compared with the data from commercialization E60BNhigh-density electrical instrument to verify the system testing data validity of soil andwater resistivity.②indoor testing experiment to verify system effectiveness;③field experiment to verify system in-situ monitoring validity.The research methods in this thesis:the top-down,dividing modules designmanner was used in the design of the entire system,which ensured the system a verygood overall;in the system debug and test validation process,a wide range ofexperiments were designed,and step-by-step validate manner was used,whichensured verification process conducting orderly and testing stability of the verifiedsystem.The main conclusions of this thesis could be summarized as follows:1.System design:①mechanical rod:ring electrode collocation manner,diameter 7cm and electrode spacing lcm;②data logger:sampling rate 64 times/s, the total system error--0.012Ω·m,sampling interval 8s;③host computerdata-processing software:VC ++ 6.0 was used in the interface and the calculationparts,and matcom 4.5 completed curve drawing and curve fitting.2.Systemexperiment verify:①indoor comparative expmeriment:the measured data wasoompared with the data from commercialization E60BN high-density electricalinstrument,which verified the system testing data validity of soil and water resistivity;②indoor interface testing experiment:the apparatus developed in this thesis wasused to conduct the indoor contrast experiment to test the accuracy of the results ofelectrical conductivity;and test effectiveness of sediment-water interface location,which was proved to be a less than 0.80cm error;③Field test results showed thatwhen the hydrodynamic conditions in the ocean was relatively calm,the test resultsreflected a very good water-sediment interface;When it has strong hydrodynamiceffect,the electrode used by the current equipment has polarization effects on theimpact of test results.Changing the electrode material in the next step would beexecuted to improve it.The main innovations in this thesis:1 seabed longtime monitoring system whichcoulde automaticly switch between multitrode;2 classifiyed electrode switchingstructure and corresponding control software,would greatly reduce the hardware costof multi-electrode circuit,and reduce the size of the entire system;3IntermidiateValue-StraightLine (Ⅳ-SL) water-sediment interface analysis method wasadvanced,and its validity was verified in a number of experiments.The system designed in this thesis would be further improved in future work,including:further perfecting the function of hardware and software,improvingelectrode rod material,and further adjusting the overall structure of the system.