Research Of Coil Parameters In Advanced Prediction Of Tunnel Water Gushing By MRS

Water is precious natural resources which could not be replaced in, but on thecontrary，water bring heavy economic loss and casualties for our country and peoplein the process of tunneling. Develops the research of advanced prediction of waterdisasters in tunnel could effectively reduce tunnel water gushing and ensure the safetyof property for people, which is a urgent major scientific and engineering problem tosolve. Magnetic resonance sounding detection technology (Magnetic ResonanceSounding, hereinafter referred to MRS) is currently the only geophysical techniqueswhich could directly detect and predict tunnel water disasters. This method takesadvantage of hydrogen nuclei’s paramagnetism in the water, artificially electrify to thecoil laying on the detection surface with larmor frequency，excitating field makeshydrogen nuclear in the detection space produce macro magnetic moment, whichmakes hydrogen proton put larmor frequency precessional motion, receives inducedelectromotive force signal with a receiving coil, by doing all of above，we coulddetect whether there is water disasters in the tunnel. In recent years, MRS technologyresearch is still in the stage of development in China，the research of applying it to thetunnel water disasters advanced prediction has just been started, in this paper, discussin detail to the exciting field calculation problem aim at the characteristics such asnarrow space and complex changeable toward when advanced predict tunnel waterdisasters, when exploring coil is small size, many turns, different orientation andseparate with receive coil, model the response signal of each coil model in thesimulation of tunnel, and design the coil circle number matching, make every effort toprovide the data processing basis and theoretical suggest for actual detection.This article research content is for "twelfth five-year" national important scientificinstruments developed special "Development and Application for Disaster Water (the mine/tunnel) direct Detection Equipment ", mainly complete the exciting fieldcalculate problem, model the response signal of each coil model in the simulation oftunnel, and design the coil circle number matching, the main research contents asbelow:The first chapter is the introduction part of this article, it mainly elaborates theresearch meaning and the status at home and abroad, illustrate the necessity of usingMRS technology in advanced prediction for tunnel water disasters, put forward themethods which are worthy of learning at home and abroad and the problems existingin the current detection method, clear this paper’s research objective.The second chapter introduces the basic theory of the MRS underground detectionsystem, it analyses structure composition and working principle of advanced MRSdetection instruments, and analysis the detection difficulties in tunnel water disastersprediction, clear this paper’s research emphasis.The third chapter explicitly states exciting field calculation principle andimplementation method when using MRS method to predict tunnel water gushing,including electric coil’s exciting field calculation method, the vertical componentcalculation of exciting field and the analysis of elliptic polarization effect, on thisbasis, using theoretical formulas and the matlab software to complete the numericalsimulation of exciting field.The forth chapter devises response signal expression and kernel function expressionby the foundation of exciting field calculation. Analyses the influence of coil’snumber of turns, size and horizontal or vertical detection toward and the resistivity ofsurrounding rock to the response signal, provides reference for actual detection.The fifth chapter designs detecting coil’s circle number using the theoreticalfoundation from preceding chapter. Firstly analysis the contribution differencesbetween transmit and receive coil to the response signal curve, secondly introducesthe theory and judgment principle how to determine the circle number, finallyaccording to the different detecting conditions, respectively designs number of turnsto match for transmit-receive identical coil and transmit-receive separation coil.The sixth chapter is the summarize of the full article, and put forward the prospect, provide a reference for the next step of research work, firstly go on to research theresponse characteristics of the whole space MRS which is aim at advanced predictionfor the underground project space water disasters, secondly puts electrical parametersto a factor model of designing the coil number which conforms to the requirements ofadvanced detection in tunnel, finally research exciting field calculation method andresponse signal numerical simulation method for MRS antenna rotary detectiontechnology.