CN202548085U - Detection device for burial depth of dam cut-off wall - Google Patents

Abstract

The utility model provides a detection device for the burial depth of a dam cut-off wall, which is used for detecting slip casting states such as burial depth and the like of an ultrathin high polymer cut-off wall in dam cut-off reinforcing engineering. Alternative direct current is transmitted to the underground through a pair of current electrodes A and B buried into the ground surface, and a potential difference between another pair of potential electrodes M and N in a drill hole formed by power supply of the current electrodes is measured; and the potential difference is decided by the position relation among the electrodes, the weakness of power supply current and the electric resistivity of a dam and a natural stratum, and the burial depth of the high polymer cut-off wall is supposed according to the space distribution of the potential difference. The detection device provided by the utility model is low in cost, rapid and convenient, a detection method is simple and reliable, and the defects in the conventional dam cut-off reinforcing engineering are overcome.

Description

The pick-up unit of permeated-proof walls of dam buried depth

Technical field

The utility model relates to a kind of Geotechnical Engineering and detect, particularly the buried depth of superpolymer cut-pff wall (low electric conductivity material) detects, and belongs to the Geotechnical Engineering field.

Background technology

With two components foaming polyurethanes is the non-aqueous reaction class high polymer grouting material of representative, has Environmental Safety, characteristics such as reaction velocity is controlled, expansivity is high, water proof anti-seepage, good endurance, has become a kind of high polymer grouting material of high comprehensive performance.High polymer grouting so that this material is the basis is technological; Through injection double component high polymer material in ground; Utilize the characteristic that volume expands and solidifies rapidly behind the high polymer material generation chemical reaction, reach consolidated subsoil, fill the purpose of coming to nothing, promote floor or leakage blocking and seepage-proofing.In recent years, the high polymer grouting Study on Technology be applied in China and receive increasingly extensive attention, demonstrating vast potential for future development aspect the infrastructure maintenance and reinforcements such as highway, tunnel, bridge, dyke, dam.

Very limited about the experimental study achievement of high polymer grouting characteristic of material mechanics, electrology characteristic, magnetism characteristic both at home and abroad, do not see as yet at present about detecting the achievement in research report of superpolymer cut-pff wall slip casting effect.

The utility model content

The utility model is to the technical matters that exists in the above-mentioned prior art; A kind of pick-up unit of permeated-proof walls of dam buried depth is provided; Be used for detecting the ultrathin superpolymer cut-pff wall of dyke seepage control reinforcing engineering buried depth; The pick-up unit cost that the utility model provided is low, quick and easy, and detection method is simple and reliable, has solved the deficiency in the existing dyke seepage control reinforcing engineering.

For realizing above-mentioned utility model purpose, the technical scheme that the utility model adopted is following:

A kind of pick-up unit of permeated-proof walls of dam buried depth; Comprise: a pair of electric current electrode A and the B that are embedded in the face of land; Be positioned in the other boring that is provided with of cut-pff wall another to potential electrode M and N; Said galvanic electrode replaces DC current to underground emission, forms potential difference (PD) thereby make between the said potential electrode; Said potential electrode can change its degree of depth in boring through an electrode lifting gear.

Said galvanic electrode is to replace DC current and ability while precision measurement strength of current and potential difference (PD) through the resistivity exploration instrument to underground transmission.

The nothing that said galvanic electrode A is embedded in cut-pff wall the hole dam slope or the dam crest position of a side, said galvanic electrode B is embedded on the face of land of distance greater than 10 times of drilling depths of leaving galvanic electrode A.

Said drilling depth is greater than estimating that the cut-pff wall buried depth is more than 1 meter.

When the degree of depth of said boring was dark, the screen casing of configuration non-conducting material do not cave in protection boring, and boring muddy water was full of.

On said potential electrode M and N, there is the outer field lead of insulation protection to be connected on two electrodes and with two and draws outside the boring with rope with promoting.

The measuring method of the pick-up unit of above-mentioned permeated-proof walls of dam buried depth, step is following:

Step 1, boring is set in that cut-pff wall is other, drilling depth is greater than estimating that the cut-pff wall buried depth is more than 1 meter;

Step 2, boring base fabric are established two potential electrode M and N;

Step 3, bury a pair of electric current electrode A and B underground on the face of land, the nothing that the A electrode is embedded in cut-pff wall the hole dam slope or the dam crest position of a side, the B electrode is embedded at a distance, and the distance of leaving the A electrode is greater than the position of drilling depth more than 10 times;

Step 4, with surveying instrument through A, the B two electrodes positive and negative alternately DC current more than underground emission 100mA, measure simultaneously and record current intensity and M, N electrode between potential difference (PD);

After step 5, measurement finish, M, N electrode are required to promote according to accuracy of detection, carry out the measurement of next depth point, so repeat until needed minimum detection depth location through the electrode lifting gear; Distance in whole measuring process between M, the N keeps immobilizing, and the position of A, B keeps immobilizing;

Step 6, measurement result is put in order, obtain apparent resistivity and change in resistance, be drawn as curve, draw the buried depth of superpolymer cut-pff wall along the degree of depth.

In the above-mentioned steps six,, make the distance between electrode A, M and A, N be respectively L if regard electrode B at infinity as approx _AM, L _AN, then the potential difference (PD) between potential electrode N, the M can be expressed with following formula:

$\mathrm{\ΔU}=\frac{I}{2\mathrm{\π}}(\frac{{\mathrm{\ρ}}_{\mathrm{AM}}}{L_{\mathrm{AM}}}-\frac{{\mathrm{\ρ}}_{\mathrm{AN}}}{L_{\mathrm{AN}}})$

$R=\frac{\mathrm{\ΔU}}{I}=\frac{I}{2\mathrm{\π}}(\frac{{\mathrm{\ρ}}_{\mathrm{AM}}}{L_{\mathrm{AM}}}-\frac{{\mathrm{\ρ}}_{\mathrm{AN}}}{L_{\mathrm{AN}}})\≅\frac{I}{2\mathrm{\πL}}({\mathrm{\ρ}}_{\mathrm{AM}}-{\mathrm{\ρ}}_{\mathrm{AN}})$

Wherein, Δ U is a potential difference (PD), ρ _AMAnd ρ _ANRepresenting apparent resistivity, R=Δ U/I between AM, the AN respectively is with the potential difference (PD) after the electrical current standardization, that is apparent resistance is anti-poor; The potential difference (PD) that measures with the electrical current standardization after, be drawn as curve along drilling depth, the corresponding degree of depth of the maximal value of curve is exactly the buried depth of cut-pff wall.

Owing to see from the material property parameter of cut-pff wall; The high polymer grouting elasticity modulus of materials is close with dykes and dams material (sand/clay); And the difference of electric conductivity parameter and dykes and dams material (sand/clay) is maximum, is a kind of feasible detection method so adopt the electric parameters testing method that cut-pff wall is detected.The utility model is the difference according to the electric conductivity of all kinds of rock soil mass in the dykes and dams and superpolymer cut-pff wall, through Measurement and analysis being contained the changes in distribution of resistivity in the superpolymer cut-pff wall dykes and dams, finds out superpolymer cut-pff wall space distribution (the slip casting degree of depth).This method replaces DC current through a pair of electric current electrode A and the B that is embedded in the face of land to underground emission, measures then and is positioned over another potential difference (PD) to being formed by the power supply of galvanic electrode between potential electrode M and the N in the boring.This potential difference (PD) is by each interelectrode position relation (being called electrode spread or combination of electrodes), and supply current resistivity strong and weak and dykes and dams and natural stratum determines, infers the buried depth of superpolymer cut-pff wall from the space distribution of potential difference (PD) according to the utility model method.Stablize when constant at supply current, also can directly infer the buried depth of superpolymer cut-pff wall from the space distribution of this potential difference (PD).

Description of drawings:

Fig. 1 is the single hole resistivity method synoptic diagram that the utility model provides;

Fig. 2 is the screen casing synoptic diagram of configuration in the boring;

Fig. 3 (a) is that electrode is laid synoptic diagram in the boring;

Fig. 3 (b) is the electrode laying synoptic diagram that Fig. 3 (a) peels off insulating outer layer;

Fig. 4 adopts the utility model measuring method to detect the measured result of test.

Embodiment:

Below in conjunction with accompanying drawing the technical scheme that the utility model provided is done a detailed description:

Fig. 1 is the measuring method synoptic diagram of the utility model.This method is at cut-pff wall 1 other boring 2, two potential electrode M of laying and the N in the boring 2 of being provided with.Two other electric current A and B are laid in outside the hole.During detection, galvanic electrode A and B replace the potential difference (PD) on direct current alternative current (square wave) and while precision measurement strength of current and potential electrode M and the N through surveying instrument 3 to underground transmission.Note the magnitude of current of emission and the numerical value of the potential difference (PD) that records.Then through electrode lifting gear 4 move up electrode M and N in the hole.So repeat, near ground.Then measurement result is put in order, obtain apparent resistivity and change in resistance, be drawn as curve along the degree of depth.Because cut-pff wall is to be bordering on insulator, and the place of cut-pff wall is arranged, apparent resistivity is very big, and the place that does not have can be very little, so the degree of depth of cut-pff wall comes into plain view from result curve.

The position of boring is arranged on be away from cut-pff wall to be located by about 0.5 meter.Drilling depth is greater than estimating that the cut-pff wall buried depth is more than 1 meter.The screen casing 5 of configuration non-conducting material when boring is dark is like pvc pipe.As shown in Figure 2, about 0.05 meter of sieve aperture 6 spacing are not caved in protection boring, and boring muddy water is full of.

Potential electrode M and N are placed in the hole position at a distance of about 0.3 meter.Shown in Fig. 3 (a) and Fig. 3 (b); With four (two subsequent use) the outer field lead (six conductor cable of insulation protection is arranged; Technical specification: more than the allowable voltage 220V; More than the allowable current 1A) be connected to four electrodes (two are subsequent use, with copper or aluminium matter or other antirust conduction bare wires twine a few or with the aglet of wide 10～20mm) go up (peel off the insulation sheath of cable, fix cable with electrode) and draw outside the boring with rope (about 20 meters of length) with lifting with screw or welding method.For increasing the weight of electrode weight, bottom cement injection, crust are used has the moderate non-conducting material of certain intensity thickness to make (plastic water pipe etc.).

Galvanic electrode A is embedded in the appropriate locations such as dam slope or dam crest of the opposite side (do not have boring one side) of cut-pff wall, and another galvanic electrode B is embedded at a distance, and the distance of leaving the A electrode is equivalent to the position of drilling depth more than 10 times.

During measurement, earlier potential electrode M, N are put at the bottom of the hole, by surveying instrument 4 through galvanic electrode A, B to about 100mA of underground emission or the stronger positive and negative DC current that replaces, with instrument measure simultaneously and record current intensity and M, N electrode between potential difference (PD).After measurement finishes, M, N electrode are promoted 0.2 meter (look accuracy of detection and require to decide, be generally 0.1～0.5 meter), carry out the measurement of next depth point, so repeat until needed minimum detection depth location through lifting gear.Distance in whole measuring process between M, the N keeps immobilizing, and the position of A, B keeps immobilizing.

Top measurement result is carried out data analysis: in above-mentioned combination of electrodes,, make the distance between A, M and A, N be respectively L if regard the B electrode at infinity as approx _AM, L _AN, then the potential difference (PD) between potential electrode N, the M can be expressed with following formula:

$\mathrm{\ΔU}=\frac{I}{2\mathrm{\π}}(\frac{{\mathrm{\ρ}}_{\mathrm{AM}}}{L_{\mathrm{AM}}}-\frac{{\mathrm{\ρ}}_{\mathrm{AN}}}{L_{\mathrm{AN}}})$

$R=\frac{\mathrm{\ΔU}}{I}=\frac{I}{2\mathrm{\π}}(\frac{{\mathrm{\ρ}}_{\mathrm{AM}}}{L_{\mathrm{AM}}}-\frac{{\mathrm{\ρ}}_{\mathrm{AN}}}{L_{\mathrm{AN}}})\≅\frac{I}{2\mathrm{\πL}}({\mathrm{\ρ}}_{\mathrm{AM}}-{\mathrm{\ρ}}_{\mathrm{AN}})$

Wherein, Δ U is a potential difference (PD), ρ _AMAnd ρ _ANRepresenting apparent resistivity, R=Δ U/I between AM, the AN respectively is with the potential difference (PD) after the electrical current standardization, that is apparent resistance is anti-poor.Because with respect to the distance (several Mi Yuan are arranged usually) of A electrode, the distance between the MN (common about 0.3 meter) can be ignored, and can use the A electrode to replace L approx to the distance L of MN two electrode intermediate points _AMAnd L _ANMore shallow when boring, when simultaneously the distance of A electrode was big, L changed little, only depended on the poor of apparent resistivity between AM, the AN with the potential difference (PD) after the electrical current standardization.When MN two electrodes are positioned at no cut-pff wall simultaneously or the hole section of cut-pff wall is arranged, ρ _AMAnd ρ _ANApproximately equal, measured value approach zero, still, be positioned at the hole section of no cut-pff wall one of in two electrodes, and another electrode are positioned at when the hole of cut-pff wall section is arranged, and owing to the electric conductivity and the dykes and dams differences in materials of cut-pff wall are very big, measured value can be very big.Therefore, according to shown in Figure 4, the potential difference (PD) that measures with the electrical current standardization after, be drawn as curve along drilling depth, the corresponding degree of depth of the maximal value of curve is exactly the buried depth of cut-pff wall.If the A electrode leaves nearerly, perhaps boring is darker, changes greatly along drilling depth direction L, can be according to the geometric relationship of the reality between each electrode, and the size of calculating L is to proofread and correct.

Claims (6)

1. the pick-up unit of a permeated-proof walls of dam buried depth; It is characterized in that; Comprise: a pair of electric current electrode A and the B that are embedded in the face of land; Be positioned in the other boring that is provided with of cut-pff wall another to potential electrode M and N, said galvanic electrode replaces DC current to underground emission, forms potential difference (PD) thereby make between the said potential electrode; Said potential electrode can change its degree of depth in boring through an electrode lifting gear.

2. the pick-up unit of permeated-proof walls of dam buried depth according to claim 1 is characterized in that, said galvanic electrode is to replace DC current and ability while precision measurement strength of current and potential difference (PD) through the resistivity exploration instrument to underground transmission.

3. the pick-up unit of permeated-proof walls of dam buried depth according to claim 1; It is characterized in that; The nothing that said galvanic electrode A is embedded in cut-pff wall the hole dam slope or the dam crest position of a side, said galvanic electrode B is embedded in the distance of the leaving galvanic electrode A face of land greater than 10 times of drilling depths.

4. the pick-up unit of permeated-proof walls of dam buried depth according to claim 1 is characterized in that, said drilling depth is greater than estimating that the cut-pff wall buried depth is more than 1 meter.

5. the pick-up unit of permeated-proof walls of dam buried depth according to claim 4 is characterized in that, when the degree of depth of said boring is dark, and the screen casing of configuration non-conducting material, and boring muddy water is full of.

6. the pick-up unit of permeated-proof walls of dam buried depth according to claim 1 is characterized in that, on said potential electrode M and N, has the outer field lead of insulation protection to be connected on two electrodes and with promoting with two and draws outside the boring with rope.

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