CN106403801B - A kind of measuring device and its measurement method of frost zone thickness - Google Patents
A kind of measuring device and its measurement method of frost zone thickness Download PDFInfo
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- CN106403801B CN106403801B CN201610842987.0A CN201610842987A CN106403801B CN 106403801 B CN106403801 B CN 106403801B CN 201610842987 A CN201610842987 A CN 201610842987A CN 106403801 B CN106403801 B CN 106403801B
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- 238000000691 measurement method Methods 0.000 title claims abstract description 12
- 239000002689 soil Substances 0.000 claims abstract description 45
- 238000005259 measurement Methods 0.000 claims abstract description 42
- 239000000523 sample Substances 0.000 claims description 75
- 230000001105 regulatory effect Effects 0.000 claims description 11
- 230000008014 freezing Effects 0.000 abstract description 4
- 238000007710 freezing Methods 0.000 abstract description 4
- 230000001932 seasonal effect Effects 0.000 abstract description 4
- 230000007423 decrease Effects 0.000 abstract description 2
- 230000000149 penetrating effect Effects 0.000 abstract description 2
- 238000000034 method Methods 0.000 description 6
- 238000002347 injection Methods 0.000 description 3
- 239000007924 injection Substances 0.000 description 3
- 230000005611 electricity Effects 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 235000015110 jellies Nutrition 0.000 description 1
- 239000008274 jelly Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000009897 systematic effect Effects 0.000 description 1
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/02—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring length, width or thickness
- G01B7/06—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring length, width or thickness for measuring thickness
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- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Abstract
The invention discloses a kind of measurement methods of Seasonal analysis thickness, it is based on " in frost zone region, upper layer of soil resistivity is much larger than lower soil resistivity, the profound degree of an electric current being embedded in two electrodes of ground end increases, it will lead to the decline of earth's surface two o'clock potential difference, after penetrating upper layer frozen soil due to electric current pole, ground resistance sharply declines, cause surface potential difference change rate sharply to reduce " principle, solves the problems, such as frost zone thickness measure, measurement accuracy is high, it is designed to earth mat buried depth and reference is provided, it can be used for assessing existing earth mat and whether be able to satisfy safety requirements in soil freezing season.
Description
Technical field
The present invention relates to power ground systematic survey fields, and in particular to a kind of measurement method of frost zone thickness.
Background technique
Since variation of ambient temperature is big, the region upper layer of soil is caused to there is seasonal freezeout, on upper layer after freezing
High soil resistivity layer is formed in soil, and compared with non-freezing situation, the soil resistivity of this layer is in different season phases
Difference ten to hundreds times, to cause ground network ground resistance very big in different calendar variations.The main indicator of earth mat safety
For ground resistance, step voltage, contact voltage, soil freezing will cause ground resistance to rise, and ground resistance increase will cause ground
Net current potential rises, and increases so as to cause step voltage and contact voltage, jeopardizes personnel and equipment safety.Therefore, frost zone
Area needs measuring frozen thickness degree, to instruct grounding grid design.
The measurement of frost zone thickness belongs to the scope of two layer soils structure and parameter measurement.It generallys use at present
Method be that a series of apparent resistivities are measured by winner four-electrode method, institute is then finally inversed by by algorithm or simulation software
The soil model needed.The soil model that this method determines is mathematically equivalent, and obtained solution is that the soil of system column is thick
Degree and resistivity, are not inconsistent, how the thickness of precise measurement frost zone is without uniqueness, therefore with actual soil texture
Very it is necessary to.
Summary of the invention
In order to solve the above-mentioned technical problem the present invention provides a kind of measurement method of frost zone thickness, can realize pair
The measurement of the thickness of frost zone and measurement accuracy is high.
Earthing pole is embedded in shallow surface and Injection Current, the current potential of earth's surface can therefore change.It is built in simulation software
Vertical double-layer soil model, 500 Ω m of upper layer of soil resistivity, 50 Ω m of lower soil resistivity, upper layer of soil with a thickness of
0.3m.Two electric current poles are added in soil model, at a distance of 20m.Positioned at point B1The buried depth for locating electric current pole is that 0.5m is constant, is located at
Point A outside 20 meters of horizontal space1The buried depth of the electric current pole at place successively take 0.1m, 0.2m, 0.3m ..., 0.9m, and in electric current
The electric current and the earth that 1 ampere is passed through in extremely constitute circuit.In electric current pole A1And B1Between line on squeeze into voltage probe C1And electricity
Press probe D1, voltage probe C1To electric current pole A1Distance be 0.5 meter;Voltage probe D1Away from electric current pole A1Distance be 1.5 meters, electricity
Press probe C1And D1Depth of placing into the soil is 5cm.
It is assumed that being located at point A1Electric current in place's earthing pole is injection the earth, is located at point B1Electric current in place's earthing pole is stream
Ground greatly out.Go out point C by simulated measurement1, point D1Current potential V1, the V2 at place, and calculate V1-V2.Draw out electric current pole buried depth with
Curved line relation between the change rate of V1-V2 is shown in attached drawing 1.From attached drawing 1 as can be seen that electric current pole buried depth is located at soil boundary,
There is maximum in the change rate of V1-V2.When i.e. in the soil texture of electric current pole embedment vertically apparent bearing layering, in Injection Current
In the case where constant, change the length of embedment of electric current pole, the distribution of surface potential can change.Soil will be crossed in electric current pole
When earth boundary, there is maximum in the change rate of surface potential.
A kind of measurement method of field survey frost zone thickness is proposed using this rule the invention patent, it is specific logical
Cross following technical proposals realization:
A kind of measurement method of frost zone thickness, comprising:
Squeeze into two electric current poles, the respectively pole A and the pole B in frozen soil region, between the pole A and the pole B serial adjustable source and
Current measuring device, wherein the distance between the pole A and the pole B are greater than 10 meters;
Probe C is squeezed on line between the pole A and the pole B and probe D, the probe C and probe D are respectively positioned on the two poles of the earth A B
Central axes and the pole A between, wherein the distance between probe C and the pole A are not less than 10 times of probe C diameter and are not more than probe C
20 times of diameter, the depth that B places into the soil pole are greater than 10 times of probe diameter;The central axes at the two poles of the earth A B, that is, between the pole A and the pole B
Central axes.
By above structure repeatedly to the voltage difference U between probe C and probe DXIt measures, wherein X indicates time of measurement
Number, and when measurement for the first time, the depth of the pole A embedment is Y centimetres, and later every to survey once, the pole A buried depth increases Y centimetres;Measurement every time
When, the voltage of regulated power supply is adjusted, to keep loop current where the pole A and the pole B constant;
U is calculated since measuring for secondX-1-UX, and compare (U since the 4th measurementX-1-UX), (UX-2-UX-1) with
(UX-3-UX-2) size relation, as (UX-1-UX) < (UX-2-UX-1) and (UX-3-UX-2) < (UX-2-UX-1) when, the thickness of upper layer of soil
Spend D are as follows:
D=Y*(X -1)-Y/2;
Wherein, the unit of D is centimetre.
The distance between the pole A and the pole B are greater than 10 times of thickness of frozen earth layer, and frost zone thickness is generally at 1 meter or so,
Therefore its distance is disposed greater than to 10 meters of position.The distance between the pole A and probe C should not be too large also should not be too small, not small
It is that most preferably, 10 times of probe C diametral distances are that voltage is quick between 10 times and 20 times no more than probe C diameter in probe C diameter
The electrode of sensillary area section, the pole A can impact the electrode of probe C, and measurement error is big, influences precision;And it is being greater than 20 times of probe C
Diametral distance range, voltage change are little.The deeper the pole B length of embedment the better, and depth is deeper, and resistance is smaller, and electric current is bigger,
So that measurement accuracy is higher.Using this programme, measurement error is ± Y/2 centimetres.
In order to which the thickness of frozen earth layer to surface soil measures, the depth Y of the pole A measurement embedment for the first time is not less than 2
Centimetre and be not more than 10 centimetres.Within this range by Y setting, both convenient for being measured to the frozen soil of surface soil, and can be effective
By measurement error control be not more than ± 5 centimetres in the range of, to meet the requirement of engineering survey.Although the value of Y is related to
Measurement error, Y value is smaller, and measurement error is smaller, and still, when Y value very little, the variation of voltmeter is little when measurement every time,
Actual measurement is not made much sense.
Preferably, the depth Y of the pole A measurement embedment for the first time is 5 centimetres.
Preferably, the distance between the pole A and the pole B are 20 centimetres.
A kind of measuring device of frost zone thickness, the pole A and the pole B including being used to embedment earth's surface, the pole A and B
Regulated power supply and current measuring device are in series between pole;
Further include the probe C and probe D for being used to embedment earth's surface, is in series with voltage measurement between the probe C and probe D
Device, the probe C and probe D are located between the central axes and the pole A at the two poles of the earth A B.
Preferably, the distance between the pole A and the pole B are greater than 10 meters.
Preferably, being not less than 10 times of probe C diameter at a distance from the pole probe C and A and no more than probe C diameter
20 times.
Preferably, the depth of the pole the B embedment earth's surface is greater than 10 times of probe diameter.
Compared with prior art, the present invention at least having the following advantages and benefits:
Methods and apparatus of the present invention utilizes the change rate of surface potential when electric current pole will cross soil boundary to go out
The principle of existing maximum, realizes the measurement to frost zone thickness, and measurement accuracy is high.
Detailed description of the invention
Attached drawing described herein is used to provide to further understand the embodiment of the present invention, constitutes one of the application
Point, do not constitute the restriction to the embodiment of the present invention.In the accompanying drawings:
Fig. 1 is earth polar buried depth and V1-V2Change rate between curved line relation.
Fig. 2 is the structural schematic diagram of apparatus of the present invention.
Specific embodiment
To make the objectives, technical solutions, and advantages of the present invention clearer, below with reference to embodiment and attached drawing, to this
Invention is described in further detail, and exemplary embodiment of the invention and its explanation for explaining only the invention, are not made
For limitation of the invention.
Embodiment
A kind of measurement method of frost zone thickness, comprising:
Squeeze into two electric current poles, the respectively pole A and the pole B in frozen soil region, between the pole A and the pole B serial adjustable source and
Current measuring device, wherein the distance between the pole A and the pole B are greater than 10 meters, and regulated power supply is using direct current or exchange;
Probe C is squeezed on line between the pole A and the pole B and probe D, the probe C and probe D are respectively positioned on the two poles of the earth A B
Central axes and the pole A between, wherein the distance between probe C and the pole A are not less than 10 times of probe C diameter and are not more than probe C
20 times of diameter, the depth that B places into the soil pole are greater than 10 times of probe diameter;
By above structure repeatedly to the voltage difference U between probe C and probe DXIt measures, wherein X indicates time of measurement
Number, and when measurement for the first time, the depth of the pole A embedment is Y centimetres, and later every to survey once, the pole A buried depth increases Y centimetres;Measurement every time
When, the voltage of regulated power supply is adjusted, to keep loop current where the pole A and the pole B constant;
U is calculated since measuring for secondX-1-UX, and compare (U since the 4th measurementX-1-UX), (UX-2-UX-1) with
(UX-3-UX-2) size relation, as (UX-1-UX) < (UX-2-UX-1) and (UX-3-UX-2) < (UX-2-UX-1) when, the thickness of upper layer of soil
Spend D are as follows:
D=Y*(X -1)-Y/2;
Wherein, the unit of D is centimetre.
The depth Y of the pole A measurement embedment for the first time not less than 2 centimetres and is not more than 10 centimetres.
The depth Y of the pole A measurement embedment for the first time is 5 centimetres.
The distance between the pole A and the pole B are 20 centimetres.
In frost zone region, upper layer of soil resistivity is much larger than lower soil resistivity, therefore lays in this area
Two electric currents extremely after, the surface potential between electric current pole is influenced by surface current density, when the profound degree of one of electric current increases
Add, will lead to the decline of earth's surface two o'clock potential difference, after penetrating upper layer frozen soil due to electric current pole, ground resistance sharply declines, and leads to ground
Table potential difference change rate is sharply reduced.According to this feature, inventor has invented above-mentioned measurement method, and this method can solve season
The problem of saving property thickness of frozen earth layer measurement, provides reference to the design of earth mat buried depth, can be used for assessing existing earth mat in soil jelly
Whether knot season is able to satisfy safety requirements.
The measurement of certain seasonal frozen soil region substation grounding web area thickness of frozen earth layer is set forth below.
Two electric current poles, the i.e. pole A and the pole B, electric current are squeezed into more flat ground at frozen ground regions to be measured selection one
Interpolar is away from 20 meters;DC current is injected to electric current pole using regulated power supply, ammeter is connected in current path, is entirely being surveyed
By adjusting the voltage of regulated power supply during amount, to keep the reading of ammeter constant;
Probe C and probe D are squeezed on line between electric current pole A and B, the distance of the pole probe C to A is 0.5 meter;Probe
Distance of the D away from the pole A is 1.5 meters, and probe C and probe D depth of placing into the soil are 5 centimetres;
Electric current pole B place into the soil depth be 25 centimetres;For the first time measure when, electric current pole A place into the soil depth be 5 centimetres;
It is later every to survey primary, 5 centimetres of electric current pole A buried depth increase.
Record the voltage U of each probe C Yu probe DX, since measuring second, calculate (UX-1-UX).
Measurement obtains U1=38.8V, U2=36.5V, U3=34.8V, U4=32.4V, U5=29.5V, U6=16.6V, U7=14.4V。
U1-U2=2.3V, U2-U3=1.7V, U3-U4=2.4V, U4-U5=2.9V, U5-U6=12.9V, U6-U7=2.2V。
By comparing the first seven measurement result, (U is found6-U7) < (U5-U6) and (U4-U5) < (U5-U6) when, using following formula meter
Calculate the thickness D of upper layer of soil:
D=5 × (7-1) -2.5=27.5cm
D is the thickness of Seasonal analysis at this time, and error is ± 2.5cm.
A kind of measuring device of frost zone thickness, the pole A and the pole B including being used to embedment earth's surface, the pole A and B
Regulated power supply and current measuring device are in series between pole;Regulated power supply can be used adjustable power of direct current with exchange regulated power supply,
Power supply can be used and transformer is realized, be ordinary skill in the art means;The structures such as ammeter can be used in current measuring device
It realizes;
Further include the probe C and probe D for being used to embedment earth's surface, is in series with voltage measurement between the probe C and probe D
Device, the probe C and probe D are located between the central axes and the pole A at the two poles of the earth A B;Voltmeter etc. can be used in voltage measuring apparatus
Structure is realized.
The distance between the pole A and the pole B are greater than 10 meters, can preferably be set as 20 meters.
It is not less than 10 times of probe C diameter at a distance from the pole probe C and A and is not more than 20 times of probe C diameter.
The depth that the pole B is embedded to earth's surface is greater than 10 times of probe diameter.
Above-described specific embodiment has carried out further the purpose of the present invention, technical scheme and beneficial effects
It is described in detail, it should be understood that being not intended to limit the present invention the foregoing is merely a specific embodiment of the invention
Protection scope, all within the spirits and principles of the present invention, any modification, equivalent substitution, improvement and etc. done should all include
Within protection scope of the present invention.
Claims (5)
1. a kind of measurement method of frost zone thickness characterized by comprising
Two electric current poles, the respectively pole A and the pole B are squeezed into frozen soil region, serial adjustable source and electric current between the pole A and the pole B
Measuring device, wherein the distance between the pole A and the pole B are greater than 10 meters;
Probe C is squeezed on line between the pole A and the pole B and probe D, the probe C and probe D are respectively positioned in the two poles of the earth A B
Between axis and the pole A, wherein the distance between probe C and the pole A are not less than 10 times of probe C diameter and are not more than probe C diameter
20 times, the depth that B places into the soil pole is greater than 10 times of probe diameter;
By above structure repeatedly to the voltage difference U between probe C and probe DXIt measuring, wherein X indicates the number of measurement, and
When measuring for the first time, the depth that the pole A is embedded to is Y centimetres, later every to survey primary, Y centimetres of the pole A buried depth increase;Every time when measurement, adjust
The voltage of regulated power supply is saved, to keep loop current where the pole A and the pole B constant;
U is calculated since measuring for secondX-1-UX, and compare (U since the 4th measurementX-1-UX), (UX-2-UX-1) and (UX-3-
UX-2) size relation, as (UX-1-UX) < (UX-2-UX-1) and (UX-3-UX-2) < (UX-2-UX-1) when, the thickness D of upper layer of soil are as follows:
D=Y*(X -1)-Y/2;
Wherein, the unit of D is centimetre;
Y is not less than 2 centimetres and is not more than 10 centimetres.
2. a kind of measurement method of frost zone thickness according to claim 1, it is characterised in that: the pole A first
The depth Y of secondary measurement embedment is 5 centimetres.
3. a kind of measurement method of frost zone thickness according to claim 1, it is characterised in that: the pole A and the pole B
The distance between be 20 centimetres.
4. a kind of measuring device of frost zone thickness, it is characterised in that:
The pole A and the pole B including being used to embedment earth's surface are in series with regulated power supply and current measurement dress between the pole A and the pole B
It sets;
Further include the probe C and probe D for being used to embedment earth's surface, voltage measurement dress is in series between the probe C and probe D
It sets, the probe C and probe D are located between the central axes and the pole A at the two poles of the earth A B;
The distance between the pole A and the pole B are greater than 10 meters;
It is not less than 10 times of probe C diameter at a distance from the pole probe C and A and is not more than 20 times of probe C diameter;
In measurement, the depth of the pole A embedment is Y centimetres, and every survey is primary later, and the pole A buried depth increases Y centimetres;Y is not less than 2 centimetres
And it is not more than 10 centimetres.
5. a kind of measuring device of frost zone thickness according to claim 4, it is characterised in that: the pole the B embedment
The depth of earth's surface is greater than 10 times of probe diameter.
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CN111859583A (en) * | 2020-06-28 | 2020-10-30 | 中铁第一勘察设计院集团有限公司 | Grounding grid of railway traction substation in plateau mountain area and construction method thereof |
CN112882103B (en) * | 2021-01-22 | 2023-02-21 | 中煤建设集团有限公司 | Method for detecting thickness of frozen soil curtain of urban underground large-scale freezing project |
CN114061431B (en) * | 2021-12-02 | 2024-06-11 | 吉林大学 | Surface straw thickness detection method and detection instrument |
CN114624492B (en) * | 2022-04-22 | 2023-04-07 | 西南交通大学 | Method for measuring potential difference of two remote transformer substation ground grids caused by direct current |
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