CN114199955A - Cylindrical honeycomb ceramic soft soil water content test probe device - Google Patents
Cylindrical honeycomb ceramic soft soil water content test probe device Download PDFInfo
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 78
- 239000000523 sample Substances 0.000 title claims abstract description 76
- 239000002689 soil Substances 0.000 title claims abstract description 55
- 239000000919 ceramic Substances 0.000 title claims abstract description 48
- 238000012360 testing method Methods 0.000 title claims abstract description 44
- 239000004575 stone Substances 0.000 claims abstract description 14
- 238000004364 calculation method Methods 0.000 claims abstract description 9
- 238000001035 drying Methods 0.000 claims abstract description 3
- 239000000463 material Substances 0.000 claims description 18
- 238000000034 method Methods 0.000 claims description 16
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 12
- 229920001971 elastomer Polymers 0.000 claims description 9
- 239000004927 clay Substances 0.000 claims description 8
- 229910001220 stainless steel Inorganic materials 0.000 claims description 8
- 239000010935 stainless steel Substances 0.000 claims description 8
- 238000005245 sintering Methods 0.000 claims description 7
- 239000005995 Aluminium silicate Substances 0.000 claims description 6
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 6
- 235000012211 aluminium silicate Nutrition 0.000 claims description 4
- 230000008859 change Effects 0.000 claims description 4
- NLYAJNPCOHFWQQ-UHFFFAOYSA-N kaolin Chemical compound O.O.O=[Al]O[Si](=O)O[Si](=O)O[Al]=O NLYAJNPCOHFWQQ-UHFFFAOYSA-N 0.000 claims description 4
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 claims description 4
- 229910052814 silicon oxide Inorganic materials 0.000 claims description 4
- 229910001928 zirconium oxide Inorganic materials 0.000 claims description 4
- 238000005553 drilling Methods 0.000 claims description 3
- 239000003990 capacitor Substances 0.000 claims description 2
- 238000001816 cooling Methods 0.000 claims description 2
- 239000003755 preservative agent Substances 0.000 claims description 2
- 230000002335 preservative effect Effects 0.000 claims description 2
- 229920006395 saturated elastomer Polymers 0.000 claims description 2
- 238000007789 sealing Methods 0.000 claims description 2
- 238000007873 sieving Methods 0.000 claims description 2
- 238000002791 soaking Methods 0.000 claims description 2
- 239000011435 rock Substances 0.000 abstract description 3
- 230000007547 defect Effects 0.000 abstract description 2
- 238000004519 manufacturing process Methods 0.000 abstract description 2
- 238000005527 soil sampling Methods 0.000 abstract 1
- 239000010410 layer Substances 0.000 description 21
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 239000004576 sand Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 238000013142 basic testing Methods 0.000 description 1
- 230000001066 destructive effect Effects 0.000 description 1
- 239000003822 epoxy resin Substances 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/22—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance
- G01N27/223—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance for determining moisture content, e.g. humidity
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Abstract
The invention discloses a cylindrical honeycomb ceramic soft soil water content test probe device which comprises a permeable stone, an outer electrode ring, honeycomb ceramic, an inner electrode ring, a central bearing, a base, a top cover, an electrode lead, a top cover outer electrode plate and a top cover inner electrode plate. When water in the soil layer enters the water content probe buried at the same depth position, the electrode wire is connected with a power supply, the capacitance resistance value between the outer electrode ring and the outer electrode ring has a numerical relation with the water content in the honeycomb ceramic in the probe, a fitting calculation formula of the capacitance resistance value and the water content is obtained through calibration, and the water content of the tested soil body can be calculated through the capacitance resistance value obtained through testing and the formula of the capacitance resistance value and the water content. The invention can accurately measure the water content of the soil layer under the deep condition of the rock soil, avoids the defects of long time consumption, deep soil sampling and the like of the traditional drying method, and has the advantages of high compressive strength, simple structure, easy manufacture, low cost, repeated use after being disassembled and cleaned, convenient operation and wide application prospect.
Description
Technical Field
The invention relates to a cylindrical honeycomb ceramic soft soil water content test probe device and a method, in particular to an on-site measuring device and a measuring method for soil layer water content under a rock-soil deep condition.
Background
The rock-soil water content test has positive significance in multiple aspects, and the water content is one of important factors influencing the mechanical property of a soil medium and is also a basic test index in engineering practice and scientific research. The water content test of deep soil layers is more prominent in practical engineering. In the anti liquefaction engineering, the water content change of the deep sand layer is obtained in advance, which is one of important means for preventing the liquefaction of the sand, and the early warning can be performed in advance and data guidance can be provided for engineers. In the side slope protection engineering, the deep soil layer water content influences the shear strength of the soil layer to change the stability of the side slope, and the side slope stability can be effectively judged and corresponding reinforcement measures can be taken through the comparison of the deep soil layer water content and the critical water content of the side slope. The water content of the soil layer of the rock soil has a plurality of testing means, but the technology capable of monitoring in real time is less. Before the invention, Chinese patent (patent number: CN 102998160B) discloses a cylindrical sample preparation device for measuring the water content of wet type clay sand by a capacitance method and a method for measuring the water content of the wet type clay sand, and the patent requires that soil samples are filled into the cylindrical device after being sampled, can be used as a test means in a laboratory, is not suitable for deep soil layers and has errors with actual soil layers on site. Chinese patent No. CN 101975802B discloses an 'embedded soil water content sensor and its application', the method is that by means of the pipe wall of the cylinder, the outer surface layer of the pipe wall is sprayed with epoxy resin material as the base layer of the humidity sensitive element, the metal electrode plates which are parallel to each other, spaced and spirally arranged around the cylinder are adhered to the base layer, and the humidity sensitive material is filled in the gap between the two metal electrode plates and covers the surface of the metal electrode plate. But has the following disadvantages: (1) the method is essentially to test the soil moisture by a parallel capacitance method, adopts a metal electrode plate to be spiral around a cylinder, and has complex process and difficult operation; (2) in the method, the humidity sensitive element needs to be in close contact with soil in the test pit directly, and the soil has destructive power on the humidity sensitive element and needs to be protected.
Disclosure of Invention
Aiming at the defects and shortcomings of the existing testing technology for the water content of deep soil layers of rock and soil, the invention aims to provide the device and the method for directly measuring the water content of the soil layers on line in real time under the condition of the deep soil layers, which have the advantages of high structural strength, simplicity in manufacturing, convenience in operation and low cost.
In order to solve the technical problem, the invention provides a cylindrical honeycomb ceramic soft soil water content probe testing device which comprises a permeable stone, an outer electrode ring, honeycomb ceramic, an inner electrode ring, a central bearing, a base, a top cover, an electrode lead, a top cover outer electrode plate, a top cover inner electrode plate and a capacitive reactance resistance value reading instrument. The method is characterized in that: the probe is cylindrical, the outermost layer of the probe is wrapped by permeable stones, the secondary outer layer of the probe is an outer electrode ring, the inner electrode ring is attached to a central bearing and is positioned in the center of the cylindrical probe, and honeycomb ceramics are filled between the inner electrode ring and the outer electrode ring; the top end and the bottom of the probe are respectively fixed by a base and a top cover in a sealing way, and are respectively contacted with an outer electrode ring and an inner electrode ring through an outer electrode plate of the top cover and an inner electrode plate of the top cover, and an electrode lead is led out; the base, the top cover and the central bearing are made of rubber materials, the inner electrode ring and the outer electrode ring are made of stainless steel porous thin-wall annular materials, the outer electrode plate of the top cover and the inner electrode plate of the top cover are made of stainless steel materials, and the electrode lead is a common wire. When water in the soil layer enters the water content probe buried at the same depth position, the electrode lead is connected with a power supply, the capacitance resistance value between the inner electrode ring and the outer electrode ring has a numerical relation with the water content in the honeycomb ceramics flowing through the probe, a fitting calculation formula of the capacitance resistance value and the water content is obtained through calibration in advance, and the water content of the tested soil body can be calculated through the capacitance resistance value obtained through testing and the formula of the capacitance resistance value and the water content.
The inner electrode ring and the outer electrode ring are made of stainless steel thin-wall porous annular materials. Inner diameter D of outer electrode ring1The outer diameter of the inner electrode ring is D2The heights of the inner electrode ring and the outer electrode ring are both L, and L & gt D2-D1. The charge amount of the outer electrode ring and the charge amount of the inner electrode ring are + q and-q respectively, the charge amount of the unit length is + lambda and-lambda respectively, e is a natural constant, and epsilon0Is the dielectric constant of the medium. The size of the capacitor of the columnar honeycomb ceramic soft soil water content probe is C, the voltage is U, and the electric quantity is Q. The capacitance between the inner electrode ring and the outer electrode ring can be determined by the theorem of "U/Q" and GaussIn order to make the inner electrode ring not easy to be damaged, the capacitance value is required to be minimum to obtainI.e. the minimum value of the diameter ratio of the outer electrode ring to the inner electrode ring is e. Can calculate that L is more than or equal to 5 XD2=5×D1And (x e). When D is present1A value of 10mm, then D2Should be greater than D1e is 27.8mm, and L is greater than 5D1e=139mm。
The honeycomb ceramic is a hollow cylinder which is formed by sintering main materials such as kaolin, clay, activated alumina, silicon oxide, zirconium oxide and the like. The inner radius and the outer radius of the honeycomb ceramic are respectively oppositeIn response to external electrode ring Inner radius, outer radius of inner electrode ringNamely, the honeycomb ceramics is wholly embedded into the gap formed by the inner electrode and the outer electrode.
The central bearing is cylindrical, the diameter of the central bearing is equal to the inner diameter of the inner electrode, threads are arranged at two ends of the central bearing, one end of the central bearing is used for being connected with the base, and the other end of the central bearing is used for being connected with the top cover.
The top cover comprises a top cover outer electrode plate, a top cover inner electrode plate and an electrode lead. The outer electrode plate and the inner electrode plate are thin circular ring plates with the diameter equal to that of the outer electrode ring and the inner electrode ring respectively and are embedded on the surface of the top cover.Top cover external power The pole piece and the electrode piece in the top cover are respectively connected with an electrode lead,and is led out from the top cover. The center of the top cover is provided with a threaded hole with the diameter of the central bearing, and the threaded hole is consistent with the thread of the connecting end of the central bearing.
The base is a cone, the diameter of the bottom surface is equal to the outer diameter of the permeable stone, and the height is equal to the diameter of the bottom surface. The center of the bottom surface is provided with a threaded hole with the same diameter as the central bearing, and the threaded hole is matched with the thread of the connecting end of the central bearing.
The capacitance reactance resistance value reading instrument is connected into a voltage parallel negative feedback structure by utilizing an operational amplifier. RFBZ is the capacitance reactance resistance value of the tested moisture probe, VINIs the input terminal of an operational amplifier, VOUTFor the output end of the operational amplifier, the derived calculation formula is as follows:
the fitting calculation formula f (W, Z) of the capacitive reactance resistance value and the water content is obtained by calibrating the water content probe. Selecting a soil sample in a detected area, drying and sieving the soil sample to prepare a saturated sample; wrapping the prepared sample with a preservative film, and soaking for 12 hours to ensure that the moisture is uniformly distributed in the sample; then embedding the prepared water probes into the samples respectively, measuring the resistance value of the probes after 2 hours, and testing the water content of the samples; and finally, placing the sample embedded with the moisture probe into an oven with the set temperature of 40 ℃ for baking for 2 hours, taking out the sample, cooling the sample to room temperature, and testing the resistance value of the sensor and the water content of the test. And repeating the steps until the test reaches a dry state, namely the water content and the capacitance impedance value do not change in the data in two consecutive tests. And recording the water content W and the resistance value reading Z of the water probe, drawing a curve and fitting a calculation formula f (W, Z) of the water content W and the resistance value Z of the water probe.
The device and the method for testing the water content of the cylindrical honeycomb ceramic soft soil are characterized by comprising the following steps of:
(1) the dimensions of the inner electrode ring and the outer electrode ring of the water content probe are determined. L is required to be more than or equal to 5 XD2=5×D1X e and D2>D1Requirement of e when D1A value of 10mm, then D2Should be greater than D127.8mm, L should be greater than 5D1*e=139mm。
(2) And sintering the honeycomb ceramic. Determining the length and the inner diameter of the honeycomb ceramic through the dimension determined in the step (1), wherein the wall thickness is (D)2-D1)/2. The sintered material comprises kaolin, clay, activated alumina, silica, zirconia and the like, and the sintering temperature is 800 degrees.
(3) The well sintered honeycomb ceramics, a base, a central bearing, an inner electrode ring, an outer electrode ring, permeable stones and a top cover are sequentially assembled into a water content probe, and electrode leads are led out after an outer electrode plate of the top cover and an inner electrode plate of the top cover are respectively contacted with the outer electrode ring and the inner electrode ring. The length of the electrode lead is the sum of the embedded depth and the reserved length of the field moisture probe.
(4) The calibration method according to claim 3, obtaining f (W, Z).
(5) And positioning and opening holes at preset measuring points in the working area by using a hole forming drilling machine. After the measuring hole reaches the designed depth, a moisture probe is embedded in the measuring hole, and an electrode lead is led out to be above the ground. And according to the field test requirement, calculating the capacitance impedance value obtained by the test of the reading instrument according to a formula f (W, Z), and obtaining the soil layer moisture content value of the depth at the moment.
Description of the drawings:
FIG. 1 is a schematic structural diagram of the present invention
FIG. 2 is a schematic view of the rubber base structure of the present invention
FIG. 3 is a schematic view of the rubber cap structure of the present invention
FIG. 4 is a schematic diagram of the structure of the external electrode of the present invention
FIG. 5 is a schematic circuit diagram of a capacitive reactance resistance value reading instrument of the present invention
In the figure, 1-permeable stone, 2-outer electrode ring, 3-honeycomb ceramic, 4-inner electrode ring, 5-central shaft, 6-rubber base, 7-rubber top cover, 8-electrode lead, 9-top cover outer electrode slice and 10-top cover inner electrode slice
Detailed Description
The invention is described in further detail below with reference to the following detailed description and accompanying drawings:
as shown in fig. 1, 2 and 3, the probe device for testing the water content of the cylindrical honeycomb ceramic soft soil of the present invention comprises: the electrode comprises a permeable stone 1, an outer electrode ring 2, honeycomb ceramics 3, an inner electrode ring 4, a central shaft 5, a rubber base 6, a rubber top cover 7, an electrode lead 8, a top cover outer electrode plate 9 and a top cover inner electrode plate 10.
The probe is cylindrical, the outermost layer of the probe is wrapped by a permeable stone 1, the secondary outer layer of the probe is an outer electrode ring 2, an inner electrode ring 4 is attached to a central bearing 5 and is positioned in the center of the cylindrical probe, and honeycomb ceramics 3 are filled between the inner electrode ring 4 and the outer electrode ring 2; inner diameter D of outer electrode ring 21The outer diameter of the inner electrode ring 4 is D2The heights of the inner electrode ring 4 and the outer electrode ring 2 are both L, and L > D2-D1(ii) a The central bearing 5 is cylindrical and has a diameter equal to that of the inner electrodeThe inner diameter of the ring 4 is provided with threads at two ends, one end is used for connecting the base 6, and the other end is used for connecting the top cover 7; the honeycomb ceramic 3 is a hydrophilic metal oxide composed ofKaolin, clay, active alumina, Silicon oxide, zirconium oxideThe inner radius and the outer radius of the honeycomb ceramic 3 are the same as the outer radius of the inner electrode ring 4 and the inner radius of the outer electrode ring 2, namely the honeycomb ceramic 3 is integrally embedded into a gap formed by the inner electrode ring 3 and the outer electrode ring 2; the top end and the bottom of the probe are respectively sealed and fixed by a base 6 and a top cover 7, and an electrode lead 8 is led out after an outer electrode plate 9 of the top cover and an inner electrode plate 10 of the top cover are respectively contacted with an outer electrode 2 and an inner electrode 4; the top cover 7 comprises a top cover outer electrode plate 9, a top cover inner electrode plate 10 and an electrode lead 8, wherein the top cover outer electrode plate 9 and the top cover inner electrode plate 10 are thin circular ring plates, the diameters of the top cover outer electrode plate 9 and the top cover inner electrode plate 10 are respectively equal to those of the outer electrode ring 2 and the inner electrode ring 4, the top cover outer electrode plate and the top cover inner electrode plate are embedded in the surface of the top cover 7, the electrode lead 8 is respectively connected with the top cover outer electrode plate 9 and the top cover inner electrode plate 10 and is led out from the top cover 7, and a threaded hole with the diameter of the central bearing 5 is reserved in the center of the top cover 7 and is consistent with the thread of the connecting end of the central bearing 5; the base 6 is a cone, the diameter of the bottom surface is equal to the outer diameter of the permeable stone 1, the height is equal to the diameter of the bottom surface, a threaded hole with the same diameter as the central bearing 5 is reserved in the center of the bottom surface, and the threaded hole is matched with the thread of the connecting end of the central bearing; the capacitance-reactance resistance value reading instrument is a voltage parallel negative feedback structure formed by connecting an operational amplifier.
The base 6, the top cover 7 and the central bearing 5 are all made of rubber materials, the inner electrode ring 4 and the outer electrode ring 2 are all made of stainless steel porous thin-wall annular materials, the top cover outer electrode plate 9 and the top cover inner electrode plate 10 are all made of stainless steel materials, and the electrode lead 8 is a common wire.
The invention relates to a column-shaped honeycomb ceramic soft soil water content test probe device and a measurement method, which comprises the following steps:
(1) and determining the sizes of the inner electrode ring 4 and the outer electrode ring 2 of the water content probe. L is required to be more than or equal to 5 XD2=5×D1X e and D2>D1Requirement of e when D1A value of 10mm, then D2Should be greater than D127.8mm, LThe value should be greater than 5 x D1*e=139mm。
(2) The honeycomb ceramic 3 is sintered. Determining the length and the inner diameter of the honeycomb ceramic through the dimension determined in the step (1), wherein the wall thickness is (D)2-D1)/2. The sintered material isKaolin, clay, activated alumina, silica, zirconia and the likeThe sintering temperature is 800 degrees.
(3) The well sintered honeycomb ceramics, a base 6, a central bearing 5, an inner electrode ring 4, an outer electrode ring 2, a permeable stone 1 and a top cover 7 are sequentially assembled into a water content probe, and an electrode lead 8 is led out after an outer electrode plate 9 of the top cover and an inner electrode plate 10 of the top cover are respectively contacted with the outer electrode ring 2 and the inner electrode ring 4. The length of the electrode lead 8 is determined by the sum of the buried depth and the reserved length of the field moisture probe.
(4) The calibration method according to claim 3, obtaining f (W, Z).
(5) And positioning and opening holes at preset measuring points in the working area by using a hole forming drilling machine. After the measuring hole reaches the designed depth, a moisture probe is embedded in the measuring hole, and an electrode lead 8 is led out to be above the ground. And according to the field test requirement, calculating the capacitance impedance value obtained by the test of the reading instrument according to a formula f (W, Z), and obtaining the soil layer moisture content value of the depth at the moment.
The non-illustrated parts of the present invention are the same as or implemented by the prior art, and several modifications and improvements can be made without departing from the principle of the present invention, and the scope of the present invention should be determined by the improvements and improvements.
Claims (9)
1. A cylindrical honeycomb ceramic probe testing device for soft soil water content comprises a permeable stone, an outer electrode ring, honeycomb ceramic, an inner electrode ring, a central bearing, a base, a top cover, an electrode lead, a top cover outer electrode plate, a top cover inner electrode plate and a capacitive reactance resistance value reading instrument. The method is characterized in that: the probe is cylindrical, the outermost layer of the probe is wrapped by permeable stones, the secondary outer layer of the probe is an outer electrode ring, the inner electrode ring is attached to a central bearing and is positioned in the center of the cylindrical probe, and honeycomb ceramics are arranged between the inner electrode ring and the outer electrode ring; the top end and the bottom of the probe are respectively fixed by a base and a top cover in a sealing way, and an electrode lead is led out after an outer electrode plate of the top cover and an inner electrode plate of the top cover are respectively contacted with an outer electrode ring and an inner electrode ring; the base, the top cover and the central bearing are made of rubber materials, the inner electrode ring and the outer electrode ring are made of stainless steel porous thin-wall annular materials, the outer electrode plate of the top cover and the inner electrode plate of the top cover are made of stainless steel materials, and the electrode lead is a common wire. When water in the soil layer enters the water content probe buried at the same depth position, the electrode lead is connected with a power supply, the capacitance resistance value between the inner electrode ring and the outer electrode ring has a numerical relation with the water content of the honeycomb ceramics flowing through the probe, a fitting calculation formula of the capacitance resistance value and the water content is obtained through calibration in advance, and the water content of the tested soil body can be calculated through the capacitance resistance value obtained through testing and the formula of the capacitance resistance value and the water content.
2. The cylindrical honeycomb ceramic soft soil water content probe testing device of claim 1, wherein: the inner electrode ring and the outer electrode ring are made of stainless steel thin-wall porous annular materials. Inner diameter D of outer electrode ring1The outer diameter of the inner electrode ring is D2Height is L, and L > D2-D1. The charge amount of the outer electrode ring and the charge amount of the inner electrode ring are respectively + q and-q, the charge amount of the unit length is respectively + lambda and-lambda, e is a natural constant, and epsilon0Is the dielectric constant of the medium. The size of the capacitor of the columnar honeycomb ceramic soft soil water content probe is C, the voltage is U, and the electric quantity is Q. The capacitance between the inner electrode ring and the outer electrode ring can be determined by the theorem of "U/Q" and GaussIn order to prevent the inner electrode ring and the outer electrode ring from being damaged easily, the capacitance value is required to be minimum to obtainI.e. the diameter ratio of the inner electrode ring and the outer electrode ring, is at a minimum e. Can calculate that L is more than or equal to 5 XD2=5×D1And (x e). When D is present1A value of 10mm, then D2Should be greater thanD1e is 27.8mm, and L is greater than 5D1e=139mm。
3. The device for testing the water content of the honeycomb ceramic soft soil of the cylindrical shape according to claim 1, wherein: the honeycomb ceramic is a hollow cylinder which is formed by sintering main materials such as kaolin, clay, activated alumina, silicon oxide, zirconium oxide and the like. The inner radius and the outer radius of the honeycomb ceramic are respectively oppositeInner radius of outer electrode ring, inner electrode Outer radius of polar ringNamely, the honeycomb ceramics is integrally embedded into a gap formed by the inner electrode ring and the outer electrode ring.
4. The device for testing the water content of the honeycomb ceramic soft soil of the cylindrical shape according to claim 1, wherein: the central bearing is cylindrical, the diameter of the central bearing is equal to the inner diameter of the inner electrode ring, threads are arranged at two ends of the central bearing, one end of the central bearing is used for being connected with the base, and the other end of the central bearing is used for being connected with the top cover.
5. The device for testing the water content of the honeycomb ceramic soft soil of the cylindrical shape according to claim 1, wherein: the top cover comprises a top cover outer electrode plate, a top cover inner electrode plate and an electrode lead. The outer electrode plate and the inner electrode plate are thin circular ring plates with the diameter equal to that of the outer electrode ring and the inner electrode ring respectively and are embedded on the surface of the top cover. The top cover outer electrode plate and the top cover inner electrode plate are respectively connected with an electrode lead and are led out from the inside of the top cover. The center of the top cover is provided with a threaded hole with the diameter of the central bearing, and the threaded hole is consistent with the thread of the connecting end of the central bearing.
6. The device for testing the water content of the honeycomb ceramic soft soil of the cylindrical shape according to claim 1, wherein: the base is a cone, the diameter of the bottom surface is equal to the outer diameter of the permeable stone, and the height is equal to the diameter of the bottom surface. The center of the bottom surface is provided with a threaded hole with the same diameter as the central bearing, and the threaded hole is matched with the thread of the connecting end of the central bearing.
7. The cylindrical honeycomb ceramic soft soil water content probe testing device of claim 1, wherein: the capacitance reactance resistance value reading instrument is connected into a voltage parallel negative feedback structure by utilizing an operational amplifier. RFBZ is the capacitance reactance resistance value of the tested moisture probe, VINIs the input terminal of an operational amplifier, VOUTFor the output end of the operational amplifier, the derived calculation formula is as follows:
8. the device for testing the water content of the honeycomb ceramic soft soil in the cylindrical shape according to the claims 1 and 7, is characterized in that: the fitting calculation formula f (W, Z) of the capacitance reactance resistance value and the water content is obtained by calibrating the water content probe. Selecting a soil sample in a detected area, drying and sieving the soil sample to prepare a saturated sample; wrapping the prepared sample with a preservative film, and soaking for 12 hours to ensure that the moisture is uniformly distributed in the sample; then embedding the prepared water probes into the samples respectively, measuring the resistance value of the probes after 2 hours, and testing the water content of the samples; and finally, placing the sample embedded with the moisture probe into an oven with the set temperature of 40 ℃ for baking for 2 hours, taking out the sample, cooling the sample to room temperature, and testing the resistance value of the sensor and the water content of the test. And repeating the steps until the test reaches a dry state, namely the water content and the capacitance impedance value do not change in the data in two consecutive tests. And recording the water content W and the resistance value reading Z of the water probe, drawing a curve and fitting a calculation formula f (W, Z) of the water content W and the resistance value Z of the water probe.
9. The testing method of the cylindrical honeycomb ceramic soft soil water content testing device according to claim 1, characterized by comprising the following steps:
(1) and determining the sizes of the inner electrode ring and the outer electrode ring of the water content probe. L is required to be more than or equal to 5 XD2=5×D1X e and D2>D1E ofWhen D is required1A value of 10mm, then D2Should be greater than D127.8mm, L should be greater than 5D1*e=139mm。
(2) And sintering the honeycomb ceramic. Determining the length and the inner diameter of the honeycomb ceramic through the dimension determined in the step (1), wherein the wall thickness is (D)2-D1)/2. The sintered material mainly comprises kaolin, clay, activated alumina, silicon oxide, zirconium oxide and the like, and the sintering temperature is 800 degrees.
(3) The well sintered honeycomb ceramics, a base, a central bearing, an inner electrode ring, an outer electrode ring, permeable stones and a top cover are sequentially assembled into a water content probe, and electrode leads are led out after an inner electrode plate of the top cover and an outer electrode plate of the top cover are respectively contacted with the inner electrode ring and the outer electrode ring. The length of the electrode lead is the sum of the embedded depth and the reserved length of the field moisture probe.
(4) The calibration method according to claim 3, obtaining f (W, Z).
(5) And positioning and opening holes at preset measuring points in the working area by using a hole forming drilling machine. After the measuring hole reaches the designed depth, a moisture probe is embedded in the measuring hole, and an electrode lead is led out to be above the ground. And according to the field test requirement, calculating the capacitance impedance value obtained by the test of the reading instrument according to a formula f (W, Z), and obtaining the soil layer moisture content value of the depth at the moment.
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