CN100397030C - Method for measuring deep displacement and sensor based on mutual inductance unit and self-inductance unit buried underground - Google Patents

Abstract

A method for measuring displacement at deep underground by mutual inductance and self inductance includes inserting transducer with coils into underground, maintaining self inductance of each coil and mutual inductance between adjacent coils to be the same when transducer is not deformed, varying mutual inductance from M to be M1 and self inductance from L to be L1 when transducer is deformed by push force of sliding layer at underground, measuring L and M of each two coils for obtaining depth of sliding layer and size of displacement at underground.

Description

Underground method for measuring deep displacement based on mutual inductance and self-induction mechanism

Technical field

The present invention relates to measure the device of electromagnetism variable, especially relate to a kind of underground method for measuring deep displacement based on mutual inductance and self-induction mechanism.

Background technology

At present in the monitoring or engineerings such as building, water conservancy of geologic hazard, be to realize with deviational survey tube side formula or time domain reflection measurement (TDR, Time Domain Reflectometry) method to the monitoring of underground deep displacement.

With deviational survey pipe geodetic bottom offset dual mode is arranged, whether a kind of be to observe buried deviational survey pipe based on the tiltmeter of gravity mechanism and answer the underground thrust of the soil body to produce (displacement) by manually putting in the deviational survey pipe when measuring at every turn; Another kind is to have mounted some MEMS based on gravity mechanism (MEMS (micro electro mechanical system)) integrated device on the deviational survey tube wall, when buried pipe run-off the straight, MEMS (MEMS (micro electro mechanical system)) integrated device produces and the voltage that is inclined to direct ratio, and price is more expensive usually.The displacement in soil body deep will make the deviational survey pipe tilt, and the angular dimension of inclination becomes certain proportionate relationship with displacement.

The TDR technology is former to be a kind of technology that detects the communication cable break-make, its measuring principle is to send out a high-frequency signal in the end of cable, when arriving the other end, signal can produce reflection, when being arranged in the middle of the cable, distortion or fracture also have reflected signal, according to reflected signal and the phase differential that sends signal, can judge the distance of the middle distortion point of cable to the signal emission end.But the problem that this method exists is: 1. the little then reflected signal of torsional deformation is very weak, almost can not survey, and it is very big to the error of signal emission end distance 2. to measure the middle distortion point of cable, and 3. the physical dimension of twisting in the middle of the cable can't be surveyed standard.Therefore, the displacement that the TDR technology is surveyed soil body deep compare with the deviational survey pipe have cheap, easy for installation, but it can only detect the degree of depth (and error is bigger) of the shearing slipping plane of soil body deep layer, can not measure the size of displacement, have many researchers just studying and how to use the TDR technology to measure the deep layer displacement of sliding mass, but the result is undesirable.

Summary of the invention

The object of the present invention is to provide a kind of underground method for measuring deep displacement, can realize that underground deep displacement amount size is measured, underground displacement space position, i.e. displacement place depth survey overhead based on mutual inductance and self-induction mechanism.

The technical solution adopted for the present invention to solve the technical problems is:

One, a kind of underground method for measuring deep displacement based on mutual inductance and self-induction mechanism:

To have several equal turn numbers, the tight lean phase of arrangements of conductors etc. and the sensor that equates coil at interval to insert underground deep on insulation tube, when sensor did not deform, the self-induction of the identical coil of several numbers of turn be identical; The coil interbody spacer equates that promptly the mutual inductance between adjacent windings is identical; Underground sliding layer makes sensor distortion occur to the thrust of sensor, then makes mutual inductance M become mutual inductance M ', self-induction L ₂Become self-induction L ' ₂, successively adjacent windings is in twos carried out mutual inductance M and self-induction L from top to bottom during measurement ₂Measurement, thereby judge the ground size of bottom offset and the degree of depth of sliding layer; The degree of depth of sliding layer is when finding that mutual inductance M between certain a pair of adjacent windings changes, and can draw the sliding layer degree of depth overhead by the position of these two coils when the coiling.

Two, a kind of underground deep displacement survey sensor based on mutual inductance and self-induction mechanism:

Be wound with several equal turn numbers, the tight lean phase of arrangements of conductors etc. and the single layer coil that equates at interval outside insulation tube, coat insulating protective layer outside being wound with the insulation tube of coil, the end line of coil passes in the middle of insulation tube, all is connected on the aviation plug.

The beneficial effect that the present invention has is: sensor is inserted underground deep, successively adjacent windings is in twos carried out the measurement of mutual inductance and self-induction from top to bottom, thereby judge the size of ground bottom offset and the degree of depth of sliding layer.The present invention can or be out of shape big or small measurement in the underground deep displacement before geologic hazards such as landslide, avalanche, rubble flow take place, thereby provides data to the forecasting and warning system that prevents and reduces natural disasters; Also can be used in the similar engineerings such as building, water conservancy, ground, highway, railway underground deep displacement being monitored (measurement), so that the quality and the state of observation engineering.

Description of drawings

Fig. 1 is a sensor construction synoptic diagram of the present invention;

Fig. 2 is the A-A cutaway view Amplified image of Fig. 1;

Fig. 3 is a sensor measurement principle schematic of the present invention.

Among Fig. 3: 1-insulation tube, 2-insulating protective layer, 3-coil.

Embodiment

As shown in Figure 1 and Figure 2; the present invention is wound with several equal turn numbers, the tight lean phase of arrangements of conductors etc. and the single layer coil 3 that equates at interval outside insulation tube 1; coat insulating protective layer 2 outside the insulation tube 1 that is wound with coil, the end line of coil 3 passes in the middle of insulation tube, all is connected on the aviation plug.

Fig. 3 is based on the underground realization deep displacement of the insertion measured sensor measuring principle synoptic diagram of the self-induction and the mutual inductance mechanism of inductance, wherein Fig. 3 a is that sensor inserts underground virgin state when deformation does not take place, and Fig. 3 b is that sensor is subjected to the deformation state that produces after the effect of sliding layer downslide thrust.Virgin state when deformation does not take place sensor is to be wound with the identical coil of several numbers of turn (self-induction of each coil is identical) on a hollow tubular, the spacing distance between these coils identical (be between adjacent windings mutual inductance identical).Under the downslide thrust at sliding layer, the distortion shown in Fig. 3 b has appearred in sensor, then makes mutual inductance M become mutual inductance M ', self-induction L ₂Become self-induction L ' ₂Can get the relation (ignoring the coil internal resistance) of each physical quantity among Fig. 3 a according to Circuit theory:

${\stackrel{\·}{U}}_1=\mathrm{j\ω}{L}_1{\stackrel{\·}{I}}_1+\mathrm{j\ωM}{\stackrel{\·}{I}}_2---\left(1\right)$

${\stackrel{\·}{U}}_2=\mathrm{j\ω}{L}_2{\stackrel{\·}{I}}_2+\mathrm{j\ωM}{\stackrel{\·}{I}}_1---\left(2\right)$

Can get the relation of each physical quantity among Fig. 3 b according to Circuit theory:

${\stackrel{\·}{U}}_1=\mathrm{j\ω}{L}_1{\stackrel{\·}{I}}_1+\mathrm{j\ω}{M}^{\′}{\stackrel{\·}{I}}_2---\left(3\right)$

${\stackrel{\&CenterDot;}{U}}_2=\mathrm{j\&omega;}{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="C20061005281600071.png,C20061005281600073.png"\; state="\{\{state\}\}">L</figure-callout>}}_2^{\&prime;}{\stackrel{\&CenterDot;}{I}}_2+\mathrm{j\&omega;}{M}^{\&prime;}{\stackrel{\&CenterDot;}{I}}_1---\left(4\right)$

According to formula (1), (3), if order ${\stackrel{\&CenterDot;}{I}}_2=0,$ Then can get:

${\stackrel{\&CenterDot;}{U}}_1=\mathrm{j\&omega;}{L}_1{\stackrel{\&CenterDot;}{I}}_1---\left(5\right)$

According to formula (2), if order ${\stackrel{\&CenterDot;}{I}}_2=0,$ Then can get:

${\stackrel{\&CenterDot;}{U}}_2=\mathrm{j\&omega;M}{\stackrel{\&CenterDot;}{I}}_1---\left(6\right)$

According to formula (4), if order ${\stackrel{\&CenterDot;}{I}}_2=0,$ Then can get:

${\stackrel{\&CenterDot;}{U}}_2=\mathrm{j\&omega;}{M}^{\&prime;}{\stackrel{\&CenterDot;}{I}}_1---\left(7\right)$

With formula (5) substitution formula (6) and formula (7):

${\stackrel{\&CenterDot;}{U}}_2=\mathrm{j\&omega;M}\frac{{\stackrel{\&CenterDot;}{U}}_1}{\mathrm{j\&omega;}{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="C20061005281600073.png"\; state="\{\{state\}\}">L</figure-callout>}}_1}=\frac{M}{L_1}{\stackrel{\&CenterDot;}{U}}_1---\left(6^{,}\right)$

${\stackrel{\&CenterDot;}{U}}_2=\mathrm{j\&omega;}{M}^{\&prime;}\frac{{\stackrel{\&CenterDot;}{U}}_1}{\mathrm{j\&omega;}{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="C20061005281600073.png"\; state="\{\{state\}\}">L</figure-callout>}}_1}=\frac{M^{\&prime;}}{L_1}{\stackrel{\&CenterDot;}{U}}_1---\left(7^{,}\right)$

Can find from formula (6 ') and formula (7 '), when sensor deforms, can cause the variation (promptly from M → M ') of coefficient of mutual inductance M surely under the effect of sliding layer downslide thrust, then will make U ₂Value produce the variation (U be directly proportional with M ₁And L ₁Constant), the effective value expression formula of formula (6 ') and formula (7 '):

${\mathrm{<figure-callout\; id="2"\; label="U"\; filenames="C20061005281600071.png,C20061005281600073.png"\; state="\{\{state\}\}">U</figure-callout>}}_2=\frac{U_1}{L_1}M---\left(6^{,,}\right)$

${\mathrm{<figure-callout\; id="2"\; label="U"\; filenames="C20061005281600071.png,C20061005281600073.png"\; state="\{\{state\}\}">U</figure-callout>}}_2=\frac{U_1}{L_1}{M}^{\&prime;}---\left(7^{,,}\right)$

Because coefficient of mutual inductance M reflection is the magnetic coupling situation of two adjacent windings, when the distortion shown in Fig. 3 b takes place, coil L ₁With coil L ₂Between the magnetic coupling situation variation M → M ' has also taken place, and this variation is relevant with the physical dimension of being out of shape shown in Fig. 3 b.Can draw from the situation of Fig. 3 b: M＞M ', and the back coil L of distortion ₁With coil L ₂M ' is more little for the distance that central shaft staggers big more (being that underground slide displacement is big more).Can demarcate bottom offset (coil L definitely by experiment ₁With coil L ₂The distance that central shaft staggers) with the relation of the variable quantity (Δ M=M-M ') of coefficient of mutual inductance, this relation can be the form type, can be kept in advance in the storer of measuring system when measuring.Above-mentioned formula (6 ") and formula (7 "), be such in actual measuring system,

Be ac signal which,

Be measuring voltage, as long as with L ₂The input impedance of the metering circuit of end is designed to enough big, then ${\stackrel{\&CenterDot;}{I}}_2=0$ Set up, like this U ₂The size of value promptly be directly proportional with the size of M, during actual measurement as long as survey

Effective value U ₂Get final product.

From Fig. 3 b as seen, under the promotion of underground sliding layer,, make coil L because of the distortion of sensor ₂Distortion has taken place, its coefficient of self-induction L ₂Become L ' ₂Also may not occur may appear in actual measurement in this situation, and this position with the sensor distortion is relevant.And when deforming, coil also will influence coefficient of mutual inductance.If coil is indeformable, then coefficient of mutual inductance M is that two identical coils (are designed to L in practice ₁=L ₂) between coefficient of mutual inductance; But winding deformation, then coefficient of mutual inductance M ' is a positive cylindrical coil and a coefficient of mutual inductance that is out of shape between cylindrical coil.Therefore, by test coil L ₂Self-induction, can know coil L ₂Whether be out of shape,, can draw the different L ' in distortion back by calibration experiment ₂During value, the relation of variable quantity of coefficient of mutual inductance (Δ M=M-M ') and underground displacement.

Mandatory declaration, for the coil on the sensor, no matter be coefficient of mutual inductance or coefficient of self-induction, Theoretical Calculation is than complicated, after distortion will be more complicated, thereby utilize mutual inductance and self-induction mechanism geodetic bottom offset, may can only draw the relation of variable quantity (Δ M=M-M ') Yu the underground displacement of coefficient of mutual inductance under different distortion coefficient of self-induction prerequisites by demarcation by the variation of Theoretical Calculation coefficient of mutual inductance and the relation of underground shift value hardly.

When reality is used this sensor, with the coil of coiling on the sensor from top to bottom, successively coil is in twos carried out the measurement of coefficient of mutual inductance and coefficient of self-induction, thereby draw the size of ground bottom offset and the degree of depth of sliding layer; The concrete metering circuit and the design proposal of system will be finished by the research of measurement instrument part, and the design of instrument part is not within the present invention.

Based on above-mentioned measuring principle, the structure of the sensor of making, as shown in Figure 1 and Figure 2: by the insulation tube (can select the plastic tube of certain toughness) of sensor, the coil on the insulation tube, and outermost insulating protective layer is formed.The xsect signal of sensor as shown in Figure 2; The profile of sensor is a hollow oval pipe, a plurality of single layer coils of coiling between insulation tube and outermost layer insulation course, and the number of turn 90～580 of each coil, the spacing between coil are 4～5cm, the end line of coil passes from the centre of insulation tube.The length of survey sensor is generally determined by the needs of tested geo-logical terrain, common scope at 30m～70m; The actual realization generally made the long sensor of 3m by above-mentioned requirements earlier, top coil all is connected on the aviation plug with the outside end line that is connected, the long sensor of a section 3m is finished mechanical connection at the scene by pipe adapter, finishes being connected of each coil and metering circuit by aviation plug.

Claims (1)

1. underground method for measuring deep displacement based on mutual inductance and self-induction mechanism, it is characterized in that: will on insulation tube, have several equal turn numbers, the tight lean phase of arrangements of conductors etc. and the sensor that equates coil at interval to insert underground deep, when sensor did not deform, the self-induction of the identical coil of several numbers of turn was identical; The coil interbody spacer equates that promptly the mutual inductance between adjacent windings is identical; Underground sliding layer makes sensor distortion occur to the thrust of sensor, then makes mutual inductance M become mutual inductance M ', self-induction L ₂Become self-induction L ' ₂, successively adjacent windings is in twos carried out mutual inductance M and self-induction L from top to bottom during measurement ₂Measurement, thereby judge the ground size of bottom offset and the degree of depth of sliding layer; The degree of depth of sliding layer is when finding that mutual inductance M between certain a pair of adjacent windings changes, and can draw the sliding layer degree of depth overhead by the position of these two coils when the coiling.

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