CN1241718A - Dike leakage test instrument and test method adopting concentric current field approach - Google Patents

Abstract

The dike leakage test instrument of the present invention includes one current field transmitter providing required current field, one receiving electrode system and one receiver measuring the potential difference to obtain current density. The present invention has current concentrated in the leaking channel, so that the test method is intuitive, reliable and precise, has low limit of measurable current density superior to 100 mA/sq m and can measure the phase of AC current. The electrodes are placed inside water without need of point-to-point installation, so that the measurement is fast and continuous. The present invention has one intuitive common type with music current and may be used widely in fighting flood.

Description

Concentric current field approach dam leakage detector and measuring method

The present invention relates to a kind of detector and measuring method that adopts concentric current field approach to survey dam leakage, particularly relate to and a kind ofly survey method and the instrument accordingly that dykes and dams have the position that leaks of water one side with the specific current field distribution.

Dykes and dams comprise dike and the dam that all stop river, river, lake water cross flow, and a side of dykes and dams has water (or high water stage), is called the water side, and opposite side anhydrous (or low-water level) is called dried side.Usually be to find have water to spill in actual engineering, but do not know this leaks from what position of water side in the dried side of dykes and dams.Administer in order to implement leak stopping, need to survey the definite position of leakage point in the water side.Detection method in the past has the natural electric field method, resistivity method and induced polarization method three classes, and they all are the method application in the art in the exploration geophysics.The principle that the natural electric field method is surveyed the position institute foundation of leaking is: when water flows through the microporosity of rock or soil, rock is the negative ion in the planar water selectively, thereby be formed on current the place ahead for just, the rear is negative natural electric field, measure the distribution of natural electric field and can understand the position that leaks.Under simple situation, this method has certain effect.But the reason that forms natural electric field is a lot of, and as the redox electric field of metal object, root system of plant forms electric field, and the natural electric field in zone forms local anomaly etc. because of influences such as dykes and dams surrounding terrains, so make the reliability reduction of natural electric field method.The detection of resistivity method is lower than the resistivity of dykes and dams according to the resistivity that is leak paths.Because passage is less, and has certain depth apart from the dykes and dams top, it is weak unusually, and earth dam, Hu Di etc. itself are just inhomogeneous, thereby resolution is low, and the credible result degree is not high.Induced polarization method can obtain the resolution higher than resistivity method sometimes, but is not that all leak paths can both measure that obviously reliably to swash the method polarization method unusual.Said method is employed all to be instrument conventional in the exploration geophysics work, as spontaneous potential instrument, resistivity meter, induced polarization instrument or this triplicity instrument together.It is exactly that Measuring Time is long, inefficiency that above-mentioned three kinds of methods also have a common shortcoming, and the leakage point bearing accuracy is poor, the incompatible especially needs in flood-fighting.

The purpose of this invention is to provide a kind of detector of surveying position, leak paths porch, improve the reliability of result of detection, improve the precision of the entry position of determining to leak, improve speed of detection, to adapt to the needs of emergency dealing.

The principle of institute of the present invention foundation is: power in dried side in the dykes and dams both sides or only, a transmitting electrode is placed directly in the outlet of leaking, because resistivity of water is lower than the resistivity of dykes and dams, thereby, the main thoroughfare that leak paths has become electric current to pass through; Another transmitting electrode is placed in the water of water side or is placed on dried side, and apart from dykes and dams certain distance is arranged, so that form than the uniform current field near dykes and dams.

Ohm law according to differential form has: $\stackrel{\→}{j}=\frac{\stackrel{\→}{E}}{\mathrm{\ρ}}----\left(1\right)$

In the formula

Be the current density vector, ρ is the resistivity of medium,

Be electric field vector; From field theory as can be known, electric field intensity equals the negative gradient of current potential, promptly $\stackrel{\→}{E}=-\mathrm{grad}\mathrm{\φ}----\left(2\right)$

Grad is the gradient symbol in the formula, and j is a current potential; (2) formula substitution (1) formula is got: $\stackrel{\→}{j}=-\frac{1}{\mathrm{\ρ}}\mathrm{grad}\mathrm{\φ}----\left(3\right)$

By measuring the gradient of current potential, just can obtain the distribution of current field by (3) formula.

The existence of seepage, it is unusual that current field is occurred, and its amplitude increases, and direction is pointed to leakage, so can find leakage.

The present invention produces the signal of certain frequency by signal source, this signal outputs to transmitting electrode after by power amplification, and at water side generation current field, the receiving transducer that places water of receiving unit detects the distribution signal of current field, the signal that receives amplifies the back and shows current field by indicating circuit, accurately to obtain the position of leakage point.

The present invention includes transmitter 1, the receiving electrode system (probe) that is provided at needed current field when measuring in the water and measure potential difference (PD) to obtain the receiver 2 of current density.Transmitter 1 comprises the power supply 3 that is used for to the transmitting electrode power supply; can produce direct current or frequency is the signal source 4 of 0.1～3000Hz signal; power amplification circuit 8 and power output circuit 9; electrode A, B; timely rupturing duty output circuit and connection or the spike when closing high pressure disturb when guaranteeing overcurrent-overvoltage; the present invention also comprises power supply synchronizing circuit 6 and has the holding circuit 7 of overcurrent, overvoltage, no-load protection effect, makes waveform generation signal, power supply synchronizing signal, the over-current over-voltage protection signal Drive and Control Circuit 5 of control electrode output current simultaneously.Its major parameter is as follows: output voltage: 20～400 volts; Output current: 200 milliamperes～5 amperes; Output waveform: the constant amplitude sinusoid of direct current or optional frequency or constant amplitude square or comprise music or the waveform of distinctive signal.Receiving electrode system (probe) is with copper electrode or aluminium electrode or non-polarizing electrode, and electrode grounding resistance should be not more than 5 kilohms, and operating depth can reach 300 meters.Receiver 2 comprises that the waveform according to different frequency is provided with the channel mode selection circuit 10 of different metering systems, for suppressing the 50Hz trap circuit 11 that the 50Hz power frequency is disturbed, the programmable amplifying circuit 12 that enlargement factor is adjustable, the indicating circuit 13 and the 80C32 Single Chip Microcomputer (SCM) system 14 that show testing result, can survey X component, Y component, the Z component of current density, or wherein two, one of or, its frequency of operation is identical with transmitter, indicating circuit 13 both available digital is represented or the analog meter demonstration also available other audiovisual display.Can add the GPS interface in case of necessity.

The present invention also comprises the using method of described detector: in the both sides of dykes and dams or only in dried side power supply, one of them transmitting electrode is placed on the seepage outlet of doing side, electrode can be with copper rod or other metallic conductors, rod is hammered in the mud of leakage or place water, if any the many places seepage, then can be at each leakage cloth one electrode, with lead they are together in parallel then, another electrode can be with any metallic conductor of lead that is associated with (as copper rod, aluminium sheet etc.) place water side water or dried side earth, the distance of spread of electrodes dykes and dams should be greater than 10 times of seepage width, the water side is with the linear electrode of parallel dykes and dams, can make electric field more like this, can detect seepage place more easily, receiving electrode ties up to the distribution of measuring current field in the water side water, according to the characteristics that current field distributes, determine the position of seepage place, can obtain the shape of seepage place in case of necessity.

The present invention compared with prior art has the following advantages:

(1) since the present invention be with current concentration in leak paths, therefore all more direct than existent method.Result of detection reliability height, precision height can be surveyed the current density lower limit and be better than 100mA/m ²But, exchange Measurement Phase; (2) electrode be placed in the water measure, need not resemble on dykes and dams, measure pointwise peace electrode, thereby measuring speed greatly improves, even can realize with the certain speed continuous coverage; (3) comprise the popular style of music current, directly perceived, be easy to grasp, can in flood-fighting, large-scale popularization use; (4) many components, automatically record adds GPS (global position system) location type and can or vehicle-mountedly look into the danger along dike fast with boat-carrying.

Description of drawings:

Fig. 1: structural principle block scheme of the present invention;

Fig. 2: use principle synoptic diagram of the present invention, wherein: ■: dykes and dams, →: signal is present in the leakage current field,

Signal normal electrical flow field;

Fig. 3: measurement result synoptic diagram of the present invention.

Embodiment:

Selected coordinate system is used the xyz rectangular coordinate system, makes the parallel dykes and dams of x axle (then that X-axis is tangent in leakage and dykes and dams as the dykes and dams bending), and the vertical dykes and dams of y axle, the vertical water surface of Z axle also point to (Fig. 2) down:

1. during for DC current, measure the X component of every bit current field, Y component and Z component.Along X-axis, the X component changes direction in the leakage both sides, and the Y component is in the leakage maximum, if measurement point (as bottom leaky) between leakage and dykes and dams, then Y also changes direction, and Z component is in the leakage maximum.Both can survey X, Y, three components of Z simultaneously, and also can only survey one or its two and find leakage.

2. during for alternating current, measure three components of X, Y, Z of current field, or wherein two, or one of them.The direction of alternating-current field judges according to phase place, if with the non-undamped alternating current electricity that comprises music etc., the average amplitude of its amplitude available units time.

3. at flood control in emergency circumstances, except quick measurement, also can the point-to-point measurement electric field value, but make breakthrough apace.Use the electric current that supplies tone currents or contain music this moment, the probe that will have receiving electrode moves (or dragging) in water, and translational speed is not more than 1 meter per second, and as far as possible evenly.With the relative size of headphone monitor field value, the feature of leakage is:

X component: reach minimum, and one sound maximum is respectively arranged along the front and back of directions X; Y component and Z component: sound is the strongest.Monitoring except that available earphone or other audiovisual devices, also available simultaneously analog or digital gauge outfit video data, experience explanation, it is best that earphone adds the analog meter effect.Generally speaking, it is just much of that only to survey one-component, and advises first-selected Z component, single because of its variation, secondly is the Y component, is the X component then.

Claims (4)

1. concentric current field approach dam leakage detector; it is characterized in that: the present invention produces the signal of certain frequency by signal source; this signal outputs to transmitting electrode after by power amplification and produces current field in the water side; the receiving transducer that places water of receiving unit detects the distribution signal of current field; the signal that receives amplifies the back and shows current field by indicating circuit; accurately to obtain the position of leakage point; comprise the transmitter that is provided at needed current field when measuring in the water; receiving electrode system (i.e. probe) and measurement potential difference (PD) are to obtain the receiver of current density; wherein transmitter comprises power output circuit; power supply synchronizing circuit and have an overcurrent; overvoltage; the holding circuit of no-load protection effect; stake resistance is not more than 5 kilohms receiving electrode system (probe); receiver comprises channel mode selection circuit; trap circuit; programmable amplifying circuit, indicating circuit and Single Chip Microcomputer (SCM) system.

2. detector according to claim 1 is characterized in that: described receiving electrode is with copper electrode or aluminium electrode or non-polarizing electrode.

3. detector according to claim 1 is characterized in that: described indicating circuit both available digital is represented or the analog meter demonstration also available audiovisual display.

4. measuring method of utilizing the described detector of claim 1, it is characterized in that: the present invention is in the both sides of dykes and dams or only in dried side power supply, one of them transmitting electrode is placed on the seepage outlet of doing side, electrode is hammered in the mud of leakage or place water, another electrode places water side water or dried side earth with any metallic conductor that is associated with lead, the distance of spread of electrodes dykes and dams is greater than 10 times of seepage width, receiving electrode ties up to the distribution that the water side is measured current field, according to the characteristics that current field distributes, determine the position of seepage place.

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