Design Of Dam Leakage Detector Based On Flowing Field Method

With the rapid development of China’s water conservancy and hydropower industry,the construction of dams has also developed rapidly.However,due to some dams have been built for a long time,they have been damaged by river immersion,rain erosion,natural weathering and other special hydrological environments,which will cause dam leakage or dam break events in every flood season.It has caused great harm to the lives and property of people.Therefore,it is particularly important to do a leak inspection of the dam.At present,many dam leakage detection equipments are affected by factors such as terrain measurement,resulting in inaccurate measurement results.In view of the above problems,this paper designed a dam leakage detector based on the flow field method.The flow field method is a method of detecting the water flow direction according to the distribution of the current field potential.The emitter electrode is placed on both sides of the dam,and a 1 Hz square wave signal is emitted.Because of the leakage,the resistivity of the leakage position is lower than that of the non-leakage,and the leakage position will becomes the main channel through which the current flows.The potential value of each point of the dam body is measured by the receiver,and the potential distribution state of each point can be obtained,thereby determining the specific location of the dam leakage.This method is not affected by the terrain and the environment.It does not need to arrange a large number of measuring points,and the detection signal has no strong attenuation.It is suitable for the leakage detection of dams under complicated conditions.The dam leakage detector based on the flow field method mainly consists of three parts,namely transmitter,receiver and upper computer.For the transmitter,a bipolar launch bridge based on the power field effect transistor IRF3205 was designed firstly.Then,the sequential generation and driving circuit were designed according to the characteristics of the transmit waveform and the switching device.Finally,the power supply was designed according to the actual detection requirement in the field.The receiver first processed the analog signals at both ends of the receiving electrode,and the processed data was sampled with high precision by the ADS1256,and the collected data was sent to the upper computer through the serial port module.The upper computer mainly implemented fast Fourier transform processing and storage of the collected data.In order to verify whether the leakage detector designed in this paper meets the design requirements,the performance of each part of the leakage detector was tested.The indoor test platform was built to test the performance of the equipment,and the test results show that the leak detector has reached the design index and the effect is good.Finally,the dam leakage detector was used for field measurement in the Qianyaozi Reservoir.And compared with the results of other measurement methods on site,the position of the measuring points is consistent and the accuracy is obviously improved,which proved the effectiveness and practicability of the detector in the field.