A method for ultrasonic testing of concrete structure permeability

Abstract

The present invention relates to the field of civil engineering technology, and discloses a method for ultrasonic detection of the permeability of a concrete structure. The concrete structure to be measured is selected from a sample of the concrete to be measured on site, and the length L between the two ends of the concrete structure is measured. The time difference Δt required for the ultrasonic wave to pass through the concrete structure is obtained by a measuring device, and the propagation speed v of the ultrasonic wave passing through the concrete structure is obtained according to the ratio of the length L between the two ends of the concrete structure, and the speed is transmitted to a data processing device for corresponding processing to obtain the concrete permeability K of the concrete structure. The present invention uses ultrasonic waves to detect the permeability of concrete. Compared with the traditional method of calculating the permeability by adding water pressure or air pressure, the measuring device required by the design method is simple, and the permeability of concrete can be quickly measured. The device has good portability and can be quickly operated and used in a limited construction site. Since the required device is small in size and light in weight, it has a wider range of applications.

Description

Technical Field

[0001] The invention relates to the technical field of civil engineering, and in particular to a method for ultrasonically detecting the permeability of a concrete structure. Background Art

[0002] Since the 1980s, the carbonization of concrete and the corrosion of steel bars have gradually attracted people's attention. There are more and more water-related concrete structures, such as dams, canals, culverts, lake bottoms, and submarine tunnels. The impermeability of concrete is a crucial link to ensure the safe and stable operation of water-related projects. Permeability is an important parameter for evaluating the impermeability of concrete. It is relatively easy to measure the permeability of concrete blocks in the laboratory, but it is more difficult to conduct on-site tests on concrete structures in projects that have been built or are under construction. Currently, the commonly used concrete permeability evaluation methods are mainly water permeability method, gas permeability method and electrical measurement method. Both the water permeability method and the gas permeability method require the permeability to be calculated back through the permeation flow rate. The test cycle is relatively long, and the test samples are generally concrete blocks that match the size of the test equipment. It is difficult to measure the concrete structure on site. The electrical measurement method usually has errors caused by electrode reactions, which has a certain impact on the test results. Summary of the invention

[0003] The present invention aims to provide a method for ultrasonically detecting the permeability of concrete structures. The method can measure the permeability of concrete structures under limited construction sites and conditions, is easy to operate and use, and can quickly obtain data. It is of great significance for predicting the durability of new projects, improving the design level of projects, and increasing the service life of buildings.

[0004] The present invention is implemented by the following technical solution: A method for ultrasonically detecting the permeability of a concrete structure, characterized in that it comprises the following steps:

[0005] Step S1: Select the concrete structure to be measured from the concrete on-site sampling, and measure the length L between the two ends of the concrete structure;

[0006] Step S2: obtaining the time difference Δt required for the ultrasonic wave to propagate through the concrete structure by a measuring device, and obtaining the propagation velocity v of the ultrasonic wave through the concrete structure according to the ratio of the length L between the two ends of the concrete structure and the time difference Δt required for the ultrasonic wave to propagate through the concrete structure;

[0007] Step S3: The time difference Δt required for the ultrasonic wave to propagate through the concrete structure, the length L between the two ends of the concrete structure, and the propagation speed v of the ultrasonic wave through the concrete structure are transmitted to a data processing device for corresponding processing to obtain the concrete permeability K of the concrete structure.

[0008] As a further improvement of the above solution, in step S1, a concrete structure that is easy to measure and has been cast is selected by surveying the site.

[0009] As a further improvement of the above solution, in step S1, a tape measure, a vernier caliper or a mobile phone distance measurement software is used to measure the length L between the two ends of the concrete structure.

[0010] As a further improvement of the above scheme, the measuring device in step S2 includes an oscilloscope and an ultrasonic transmitting probe and an ultrasonic receiving probe respectively connected to the oscilloscope, and the ultrasonic transmitting probe and the ultrasonic receiving probe are respectively attached to the two ends of the concrete structure; the ultrasonic transmitting probe is used to transmit an ultrasonic signal to one end of the concrete structure; the ultrasonic receiving probe is used to receive the ultrasonic signal transmitted through the other end of the concrete structure and convert it into an electrical signal; the oscilloscope is used to convert the electrical signal into a waveform curve that is easy to observe;

[0011] The corresponding waveform starting point moment is obtained according to the waveform curve to obtain the time difference Δt required for the ultrasonic wave to propagate through the concrete structure.

[0012] As a further improvement of the above scheme, coupling agent is applied to the attachment points of the ultrasonic transmitting probe, the ultrasonic receiving probe and the concrete structure to increase the coupling degree between the ultrasonic transmitting probe and the ultrasonic receiving probe and the corresponding connecting end faces of the concrete structure, and reduce the reflection loss of the ultrasonic sound wave energy during the transmission process at both ends of the concrete structure.

[0013] As a further improvement of the above solution, a base for supporting the oscilloscope is provided at the bottom, a slot for inserting the base is provided on the base, and two opposite fixing plates are vertically provided on the top of the base located on both sides of the slot;

[0014] Two clamping plates are arranged opposite to each other between the two fixing plates, and a clamping space for clamping and fixing the oscilloscope is formed between the two clamping plates; an adjusting rod perpendicular to the fixing plate is threadedly inserted through each fixing plate, one end of the adjusting rod is rotatably connected to the plate surface of the adjacent clamping plate, and a telescopic rod is arranged between each clamping plate and the adjacent fixing plate;

[0015] A handle in the shape of an inverted "U" is arranged above the oscilloscope, and two bent ends of the handle are rotatably connected to the tops of the two fixing plates respectively.

[0016] As a further improvement of the above solution, a plurality of moving wheels are installed at the bottom of the base through a plurality of disassembly and assembly components; the disassembly and assembly components include a support plate, and a fixing block for connecting the moving wheels is provided at the bottom of the support plate;

[0017] A push rod is arranged on the top of the support plate, a plug groove 1 is provided at the bottom of the base for inserting the push rod, a plug groove 2 is provided at the bottom of the base located on one side of the plug groove 1 and parallel to the plug groove 1, a flow channel connecting the plug groove 1 and the plug groove 2 is provided in the base, a piston 1 and a piston 2 are provided in the plug groove 1 and the plug groove 2 respectively; the plug groove 1, the flow channel and the plug groove 2 all contain hydraulic oil;

[0018] The piston 1 is in contact with the push rod extending into the plug groove 1; the bottom of the piston 2 is provided with an insertion rod 1 parallel to the push rod, the support plate is provided with a rod hole for the insertion rod 1 to pass through, the fixed block is inserted with an insertion rod 2 perpendicular to the insertion rod 1, and the insertion rod 1 is provided with a clamping hole for the insertion rod 2 to pass through.

[0019] As a further improvement of the above scheme, a sliding groove with a notch facing downward is provided on the top of the fixed block, a slider is slidably connected in the sliding groove, a spring is provided between the top of the slider and the groove wall of the sliding groove, a support rod is fixed to the bottom of the slider, and the other end of the support rod is connected to the corresponding moving wheel.

[0020] As a further improvement of the above solution, in step S3, the data processing method of the data processing device includes the following steps:

[0021] Step a: Based on the Raymer model, a relationship model 1 is established between the propagation velocity v of ultrasonic waves passing through a concrete structure and the porosity φ of the porous medium, and expressed as: v = v m (1-φ) 2 +v f φ, where v m is the speed of ultrasound in the concrete skeleton, v f is the speed of ultrasound in the pore fluid;

[0022] Step b: The sound velocity v of the ultrasonic wave in the pore fluid f Equivalent to the known sound velocity of ultrasound in water, and based on the known mix ratio of concrete in the on-site project, two concrete block samples with the same mix ratio and known porosity φ are prepared;

[0023] According to the propagation velocity v of ultrasonic waves through concrete structures, the known porosity φ of concrete block specimens, and the sound velocity v of ultrasonic waves in pore fluids, f , and combined with the relationship model 1 in step a, calibrate the corresponding sound velocity v of the ultrasonic wave in the concrete block sample with a known mix ratio mx ; where v mx The subscript x is used to correspond to the state of concrete block specimens with different mix proportions;

[0024] Step c: According to the corresponding sound velocity v of ultrasonic wave in concrete block sample with known mix ratio mx , the propagation velocity v of ultrasonic waves through concrete structures, the sound velocity v of ultrasonic waves in porous fluids f , and combined with the relationship model 1 in step a, the corresponding porosity φ of the concrete structure is obtained;

[0025] Step d: According to the Kozeny-Carmen model, the relationship model 2 between the permeability K of the concrete structure and the porosity φ of the concrete structure is established and expressed as: Where C is the Kozeny-Carman constant and S is the specific surface area of ​​the solid phase.

[0026] As a further improvement of the above scheme, the method for ultrasonically detecting the permeability of concrete structures also includes step S4: judging the leakage situation of the measured concrete on site according to the permeability K of the concrete structure, so as to conduct on-site inspection of the waterproof ability of the measured concrete structure.

[0027] The beneficial effects of the present invention are:

[0028] Compared with the traditional detection method, the ultrasonic detection method of the present invention has a simple measuring device, good portability, and can be quickly operated and used in a limited construction site. Since the required device is small in size, light in weight, and simple in structure, it has a wider range of applications.

[0029] The present invention can be used to measure the permeability of concrete tunnels during construction, and can detect leakage problems as early as possible during construction to avoid engineering accidents such as pollution and leakage caused by unsatisfactory anti-seepage performance. It can effectively evaluate the durability and predict the remaining life of in-service reinforced concrete structures, buy time for waterproof reinforcement of buildings, and reduce the cost of leakage repair in the later stage of the project.

[0030] The present invention adopts the method of measuring permeability by ultrasonic waves, and can carry out the measurement in various difficult and complex environments during the tunnel construction period. Compared with the traditional water penetration method, it does not need to apply water pressure; and the measurement response is rapid, does not require a long period, and the efficiency is improved.

[0031] By combining the commonalities between composite materials and the conversion of the Kozeny-Carmen model equation, the relevant formulas are effectively applied to the calculation of concrete data, and the relationship between the porosity and permeability of concrete is effectively connected in series. This design method is scientific, can be carried out quickly, and can conveniently detect the permeability.

[0032] By setting a base at the bottom of the oscilloscope and installing moving wheels on the base through a disassembly assembly component, not only is it convenient to move the oscilloscope on the concrete site, but the moving wheels and the base do not need to be connected by screws, so the moving wheels can be quickly disassembled and assembled on the base, which is convenient for replacement or maintenance of the moving wheels, and is practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A flow chart of a method for ultrasonically detecting the permeability of a concrete structure provided in Example 1 of the present invention;

[0034] Figure 2 for Figure 1 Schematic diagram of the connection structure of the measuring device required in step S2;

[0035] Figure 3 A schematic diagram of the structure of an oscilloscope in a measuring device used in step S2 of the method for ultrasonically detecting the permeability of a concrete structure provided in Example 2;

[0036] Figure 4 for Figure 3 A schematic diagram of the cross-sectional structure of a part of the oscilloscope;

[0037] Figure 5 for Figure 4 Schematic diagram of the structure enlarged at point A in the middle.

[0038] Description of main symbols:

[0039] 1. Concrete structure; 2. Ultrasonic receiving probe; 3. Ultrasonic transmitting probe; 4. Data line; 5. Input channel; 6. Output channel; 7. Probe self-test calibration signal; 8. Horizontal time base knob; 9. Oscilloscope; 10. USB interface; 11. Base; 12. Slot; 13. Plug slot 1; 14. Flow channel; 15. Plug slot 2; 16. Piston 1; 17. Piston 2; 18. Push rod; 19. Support plate; 20. Insert rod 1; 21. Fixed block; 22. Slide; 23. Slider; 24. Spring; 25. Support rod; 26. Moving wheel; 27. Adjustment rod; 28. Clamp; 29. ​​Telescopic rod; 30. Fixed plate; 31. Handle; 32. Insert rod 2. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0041] Example 1

[0042] Please combine Figure 1 and Figure 2, a method for ultrasonically detecting the permeability of a concrete structure, comprising the following steps:

[0043] Step S1: Select a concrete structure 1 to be measured from the concrete sample on site, and measure the length L between the two ends of the concrete structure;

[0044] Step S2: obtaining the time difference Δt required for the ultrasonic wave to propagate through the concrete structure by a measuring device, and obtaining the propagation velocity v of the ultrasonic wave through the concrete structure according to the ratio of the length L between the two ends of the concrete structure and the time difference Δt required for the ultrasonic wave to propagate through the concrete structure;

[0045] Step S3: The time difference Δt required for the ultrasonic wave to propagate through the concrete structure, the length L between the two ends of the concrete structure, and the propagation speed v of the ultrasonic wave through the concrete structure are transmitted to a data processing device for corresponding processing to obtain the concrete permeability K of the concrete structure.

[0046] In step S1, a concrete structure 1 which is easy to measure and has been cast is selected by means of on-site survey.

[0047] In step S1, a tape measure, a vernier caliper or a mobile phone distance measurement software is used to measure the length L between the two ends of the concrete structure.

[0048] The measuring device in step S2 includes an oscilloscope 9 and an ultrasonic transmitting probe 3 and an ultrasonic receiving probe 2 respectively connected to the oscilloscope 9, and the ultrasonic transmitting probe 3 and the ultrasonic receiving probe 2 are respectively attached to the two ends of the concrete structure 1; the ultrasonic transmitting probe 3 is used to transmit an ultrasonic signal to one end of the concrete structure 1; the ultrasonic receiving probe 2 is used to receive the ultrasonic signal transmitted from the other end of the concrete structure 1 and convert it into an electrical signal; the oscilloscope 9 is used to convert the electrical signal into a waveform curve that is easy to observe;

[0049] The corresponding waveform starting point moment is obtained according to the waveform curve to obtain the time difference Δt required for the ultrasonic wave to propagate through the concrete structure.

[0050] Coupling agent is applied to the attachment points of the ultrasonic transmitting probe 3, the ultrasonic receiving probe 2 and the concrete structure 1 to increase the coupling degree between the ultrasonic transmitting probe and the ultrasonic receiving probe and the corresponding connection end faces of the concrete structure, and reduce the reflection loss of the ultrasonic sound wave energy during the transmission process at both ends of the concrete structure. The coupling agent is applied to fill the tiny gaps between the contact surfaces to prevent the trace air in these gaps from affecting the penetration of ultrasound; secondly, through the "transition" effect of the coupling agent, the acoustic impedance difference between the probe and the sample is reduced, thereby reducing the reflection loss of ultrasonic energy at this interface.

[0051] In this embodiment, the overall structures of the ultrasonic transmitting probe 3 and the ultrasonic receiving probe 2 are basically the same, and both include structures such as a plastic shell, a piezoelectric vibrator, a sound absorbing material, an insulating layer, and a protective layer. The structure of the oscilloscope 9 includes a tube amplifier, a scanning oscillator, a cathode ray tube, etc., which can be used to measure the frequency and voltage intensity. In this embodiment, the oscilloscope 9 is used to observe the waveform of the ultrasonic wave, and the time of the starting point is obtained to display the time of receiving the sound wave. In order to facilitate the observation of the waveform starting point of the waveform curve on the display screen of the oscilloscope 9, the horizontal time base knob 8 of the oscilloscope 9 can be adjusted to widen the waveform to better present the waveform time difference.

[0052] The data processing device in step S3 may be a computer, and the ultrasonic transmitting probe 3 and the ultrasonic receiving probe 2 are respectively connected to the output channel 6 and the input channel 5 of the oscilloscope 9 through the data line 4. The computer transmits and reads the image of the waveform curve on the oscilloscope 9 through its USB interface 10 and performs corresponding processing to obtain the concrete permeability K of the concrete structure.

[0053] When the ultrasonic receiving probe 2 is connected to the oscilloscope 9, it is necessary to detect whether the ultrasonic receiving probe 2 matches the input channel 5 of the oscilloscope 9. Specifically, since the measurement signal enters the oscilloscope 9 through the ultrasonic receiving probe 2, it is necessary to detect whether the ultrasonic receiving probe 2 matches the input channel 5 of the oscilloscope 9 before the test to avoid measurement errors or mistakes during the test. The probe self-test calibration signal 7 of the oscilloscope 9 can be connected to the oscilloscope 9, and then the Auto key on the oscilloscope 9 is pressed to determine whether the square wave signal on the screen is compensated or under-compensated. If the square wave signal is compensated or under-compensated, the adjustable capacitance on the probe can be adjusted by adjusting the probe's own adjustment rod, and then adjusted to a standard square wave signal based on the waveform frequency and amplitude image.

[0054] In step S3, the data processing method of the data processing device includes the following steps:

[0055] Step a: Based on the Raymer model, a relationship model 1 is established between the propagation velocity v of ultrasonic waves passing through a concrete structure and the porosity φ of the porous medium, and expressed as: v = v m (1-φ) 2 +v f φ, where v m is the speed of ultrasound in the concrete skeleton, v f is the speed of ultrasound in the pore fluid.

[0056] In step a, since the speed of sound when propagating in a medium is related to the density of the medium, Poisson's ratio, etc., the porosity of the composite material can be detected based on the change in the speed of sound. Concrete is a multi-inhomogeneous composite material containing aggregate, cement slurry, steel, and prestressed channels wrapped in corrugated pipes. In long-term application practice, it can be proved that ultrasonic measurement of strata has a good adaptability to the evaluation of porosity.

[0057] Step b: The sound velocity v of the ultrasonic wave in the pore fluid f Equivalent to the known sound velocity of ultrasound in water, and based on the known mix ratio of concrete in the on-site project, two concrete block samples with the same mix ratio and known porosity φ are prepared;

[0058] According to the propagation velocity v of ultrasonic waves through concrete structures, the known porosity φ of concrete block specimens, and the sound velocity v of ultrasonic waves in pore fluids, f , and combined with the relationship model 1 in step a, calibrate the corresponding sound velocity v of the ultrasonic wave in the concrete block sample with a known mix ratio mx ; where v mx The subscript x is used to correspond to the state of concrete block specimens with different mix proportions;

[0059] In step b, the sound velocity of ultrasound in the pore fluid is usually taken as the sound velocity of ultrasound in water, that is, v f It can be 1500m / s.

[0060] In this embodiment, the sand and gravel in the concrete act as a skeleton and are called aggregates. The concrete mix ratio refers to the ratio between the four main materials of cement, sand, gravel and water in the concrete. The conventional concrete mix ratios in construction are usually C10, C15, C20, C25, and C30. When measuring at the actual construction site, the sound velocity v of the ultrasonic wave in the corresponding concrete skeleton required for calibration at the concrete site can be directly determined by obtaining the concrete grade ratio information of the construction project in advance. m , and the sound velocity of the calibrated corresponding ultrasonic wave in the corresponding concrete skeleton can be tested through multiple sets of parallel experiments.

[0061] Step c: According to the corresponding sound velocity v of ultrasonic wave in concrete block sample with known mix ratio mx , the propagation velocity v of ultrasonic waves through concrete structures, the sound velocity v of ultrasonic waves in porous fluids f , and combined with the relationship model 1 in step a, the corresponding porosity φ of the concrete structure is obtained;

[0062] Step d: According to the Kozeny-Carmen model, the relationship model 2 between the permeability K of the concrete structure and the porosity φ of the concrete structure is established and expressed as: Where C is the Kozeny-Carman constant and S is the specific surface area of ​​the solid phase.

[0063] Example 2

[0064] Please combine Figures 3 to 5 , this embodiment 2 is an improved solution of embodiment 1, specifically, a base 11 for supporting the oscilloscope 9 is provided at the bottom, and a slot 12 for inserting the base 11 is provided on the base 11. By placing the oscilloscope 9 in the slot 12 of the base 11, the oscilloscope 9 can be placed more stably on the concrete site.

[0065] Two opposite fixing plates 30 are vertically arranged on the top of the base 11 located on both sides of the slot 12. Two clamping plates 28 are arranged opposite to each other between the two fixing plates 30, and a clamping space for clamping and fixing the oscilloscope 9 is formed between the two clamping plates 28. An adjusting rod 27 perpendicular to the fixing plate 30 is threadedly inserted, and one end of the adjusting rod 27 is rotatably connected to the plate surface of the adjacent clamping plate 28, and the adjusting rod 27 and the clamping plate 28 are rotatably connected through a bearing. A telescopic rod 29 is arranged between each clamping plate 28 and the adjacent fixing plate 30. The telescopic rod 29 can prevent the clamping plate 28 from rotating under the transmission of the adjusting rod 27, so that the movement direction of the clamping plate 28 remains in the horizontal direction.

[0066] A handle 31 in the shape of an inverted "U" is provided above the oscilloscope 9, and the two bent ends of the handle 31 are respectively rotatably connected to the tops of the two fixing plates 30. The two bent ends of the handle 31 in this embodiment are respectively rotatably connected to the tops of the two fixing plates 30 through pins, so that the handle 31 can be turned over on the tops of the fixing plates 30.

[0067] The bottom of the base 11 is equipped with a plurality of moving wheels 26 through a plurality of disassembly and assembly components, so as to conveniently move the oscilloscope 9 to a designated position on the concrete site. The disassembly and assembly components include a support plate 19, and a fixing block 21 for connecting the moving wheels 26 is provided at the bottom of the support plate 19. The disassembly and assembly components facilitate the disassembly and assembly of the moving wheels 26 at the bottom of the base 11.

[0068] A push rod 18 is arranged on the top of the support plate 19, a plug groove 13 is provided at the bottom of the base 11 for the push rod 18 to be inserted, a plug groove 2 15 is provided at the bottom of the base 11 on one side of the plug groove 13 and parallel to the plug groove 13, a flow channel 14 is provided in the base 11 to connect the plug groove 13 and the plug groove 2 15, a piston 16 and a piston 2 17 are provided in the plug groove 13 and the plug groove 2 15 respectively. Hydraulic oil (not marked) is contained in the plug groove 13, the flow channel 14 and the plug groove 2 15.

[0069] The piston 16 abuts against the push rod 18 extending into the plug groove 13. The bottom of the piston 17 is provided with an insertion rod 20 parallel to the push rod 18, and the support plate 19 is provided with a rod hole (not shown) for the insertion rod 20 to pass through. There is a clearance fit between the rod hole and the insertion rod 20, and the rod hole can allow the rod body of the insertion rod 20 to pass through.

[0070] The fixing block 21 is provided with a second insertion rod 32 perpendicular to the first insertion rod 20, and the first insertion rod 20 is provided with a clamping hole (not shown) for the second insertion rod 32 to pass through. The fixing block 21 in this embodiment is provided with a through hole (not shown) for the second insertion rod 32 to be inserted, and the moving wheel is fixedly mounted on the base 11 by inserting the second insertion rod 32 into the clamping hole of the first insertion rod 20.

[0071] The top of the fixed block 21 is provided with a slide groove 22 with a notch facing downward, a slider 23 is slidably connected in the slide groove 22, a spring 24 is provided between the top of the slider 23 and the groove wall of the slide groove 22, a support rod 25 is fixed to the bottom of the slider 23, and the other end of the support rod 25 is connected to the corresponding moving wheel 26. The support rod 25 drives the slider 23 to slide in the slide groove 22 and squeeze the spring 24, which can absorb the vibration of the moving wheel 26 from the ground, and ensure the stability of the oscilloscope 9 when moving.

[0072] The working principle of this embodiment is specifically as follows: when the oscilloscope 9 needs to be used at a concrete site, the oscilloscope 9 can be inserted into the slot 12 of the base 11, and then the two adjustment rods 27 are respectively screwed to drive the two clamping plates 28 to move, so that the two clamping plates 28 are close to each other under the limiting action of the corresponding telescopic rods 29, so as to clamp and fix the oscilloscope 9.

[0073] When it is necessary to move the oscilloscope 9 on the concrete site, the oscilloscope 9 can be directly lifted to the designated position by the handle 31, and the moving wheel 26 can be installed at the bottom of the base 11, and the oscilloscope 9 can be pushed to the designated position by the moving wheel 26. The installation process of the moving wheel 26 on the base 11 is specifically as follows: first, the push rod 18 on the support plate 19 corresponding to each moving wheel 26 is inserted into the corresponding plug slot 13, and the push rod 18 inserted into the plug slot 13 will squeeze the piston 16, so that the piston 16 is transmitted to the piston 2 17 through the hydraulic oil, so that the piston 2 17 drives the insertion rod 1 20 to gradually move downward and pass through the rod hole of the support plate 19, and then the insertion rod 2 32 is passed through the through hole on the fixing block 21, and the end of the insertion rod 2 32 is inserted into the clamping hole on the insertion rod 1 20 to achieve the locking of the insertion rod 1 20 position, which is not only convenient for the installation and fixation of the moving wheel 26 on the base 11, but also convenient for the later disassembly and maintenance of the moving wheel 26.

[0074] While the oscilloscope 9 is being pushed to the designated position by the moving wheels 26 , the moving wheels 26 can transmit the vibration of the concrete pavement on site to the slider 23 through the support rod 25 , so that the slider 23 slides in the slide groove 22 and squeezes the spring 24 , converting the vibration energy into the elastic potential energy of the spring 24 , so as to reduce the vibration received by the oscilloscope 9 during the pushing process, thereby ensuring the stability of the oscilloscope 9 when moving.

[0075] Example 3

[0076] The difference between the present embodiment 2 and the embodiment 1 is that the present embodiment 2 adds step S4 on the basis of the embodiment 1, that is, judging the leakage situation of the measured concrete on site according to the permeability K of the concrete structure 1, so as to conduct on-site inspection of the waterproof ability of the measured concrete structure 1.

[0077] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for ultrasonically detecting the permeability of a concrete structure, characterized in that: The steps include: Step S1: Select the concrete structure to be measured from the concrete on-site sampling, and measure the length L between the two ends of the concrete structure; Step S2: Obtain the time difference required for the ultrasonic wave to propagate through the concrete structure through the measuring device , and based on the length L between the two ends of the concrete structure and the time difference required for the ultrasonic wave to propagate through the concrete structure The ratio of is obtained to obtain the propagation velocity v of ultrasonic wave through concrete structure; Step S3: The time difference required for the ultrasonic wave to pass through the concrete structure , the length L between the two ends of the concrete structure, and the propagation speed v of the ultrasonic wave through the concrete structure are transmitted to the data processing device for corresponding processing to obtain the concrete permeability K of the concrete structure; In step S3, the data processing method of the data processing device includes the following steps: Step a: Establish the propagation velocity v of ultrasonic waves through concrete structures and the porosity of porous media based on the Raymer model The relationship model between them is expressed as: ,in, is the speed of ultrasound in the concrete skeleton, is the speed of ultrasound in the pore fluid; Step b: The speed of ultrasound in the pore fluid Equivalent to the known sound velocity of ultrasound in water, and based on the known mix ratio of concrete in the on-site project, to make the same grade mix ratio and porosity Two concrete block specimens are known; According to the propagation velocity v of ultrasonic wave through concrete structure and the known porosity of concrete block sample, and the speed of ultrasound in the pore fluid , and combined with the relationship model 1 in step a, calibrate the corresponding sound velocity of the ultrasonic wave in the concrete block sample with a known mix ratio ;in The subscript x is used to correspond to the state of concrete block specimens with different mix proportions; Step c: According to the corresponding sound velocity of ultrasonic wave in concrete block sample with known mix ratio , the propagation velocity v of ultrasonic waves through concrete structures, and the sound velocity of ultrasonic waves in porous fluids , and combined with the relationship model 1 in step a, the corresponding porosity of the concrete structure is obtained ; Step d: Establish the permeability of the concrete structure according to the Kozeny-Carmen model Porosity of concrete structure The relationship model 2 is expressed as: ,in, is the Kozeny-Carman constant, and S is the specific surface area of ​​the solid phase.

2. The method for ultrasonically detecting the permeability of a concrete structure according to claim 1, characterized in that: In step S1, a concrete structure that is easy to measure and has been cast is selected by surveying the site.

3. The method for ultrasonically detecting the permeability of a concrete structure according to claim 1, characterized in that: In step S1, a tape measure, a vernier caliper or a mobile phone distance measurement software is used to measure the length L between the two ends of the concrete structure.

4. The method for ultrasonically detecting the permeability of a concrete structure according to claim 1, characterized in that: The measuring device in step S2 includes an oscilloscope and an ultrasonic transmitting probe and an ultrasonic receiving probe respectively connected to the oscilloscope, wherein the ultrasonic transmitting probe and the ultrasonic receiving probe are respectively attached to two ends of the concrete structure; the ultrasonic transmitting probe is used to transmit an ultrasonic signal to one end of the concrete structure; the ultrasonic receiving probe is used to receive the ultrasonic signal transmitted from the other end of the concrete structure and convert it into an electrical signal; the oscilloscope is used to convert the electrical signal into a waveform curve that is easy to observe; Among them, the corresponding waveform starting point time is obtained according to the waveform curve to obtain the time difference required for the ultrasonic wave to pass through the concrete structure. .

5. The method for ultrasonically detecting the permeability of a concrete structure according to claim 4, characterized in that: Coupling agent is applied to the attachment points of the ultrasonic transmitting probe, the ultrasonic receiving probe and the concrete structure to increase the coupling degree between the ultrasonic transmitting probe and the ultrasonic receiving probe and the corresponding connection end faces of the concrete structure, and to reduce the reflection loss of the ultrasonic sound wave energy during the transmission process at both ends of the concrete structure.

6. The method for ultrasonically detecting the permeability of a concrete structure according to claim 4 or 5, characterized in that: The bottom of the oscilloscope is provided with a base for supporting the oscilloscope, the base is provided with a slot for inserting the base, and two opposite fixing plates are vertically provided on the top of the base located on both sides of the slot; Two clamping plates are arranged opposite to each other between the two fixing plates, and a clamping space for clamping and fixing the oscilloscope is formed between the two clamping plates; an adjusting rod perpendicular to the fixing plate is threadedly inserted through each fixing plate, one end of the adjusting rod is rotatably connected to the plate surface of the adjacent clamping plate, and a telescopic rod is arranged between each clamping plate and the adjacent fixing plate; A handle in the shape of an inverted "U" is arranged above the oscilloscope, and two bent ends of the handle are rotatably connected to the tops of the two fixing plates respectively.

7. The method for ultrasonically detecting the permeability of a concrete structure according to claim 6, characterized in that: A plurality of moving wheels are installed at the bottom of the base through a plurality of disassembly and assembly components; the disassembly and assembly components include a support plate, and a fixing block for connecting the moving wheels is provided at the bottom of the support plate; A push rod is arranged on the top of the support plate, a plug groove 1 is provided at the bottom of the base for inserting the push rod, a plug groove 2 is provided at the bottom of the base located on one side of the plug groove 1 and parallel to the plug groove 1, a flow channel connecting the plug groove 1 and the plug groove 2 is provided in the base, a piston 1 and a piston 2 are provided in the plug groove 1 and the plug groove 2 respectively; the plug groove 1, the flow channel and the plug groove 2 all contain hydraulic oil; The piston 1 is in contact with the push rod extending into the plug groove 1; the bottom of the piston 2 is provided with an insertion rod 1 parallel to the push rod, the support plate is provided with a rod hole for the insertion rod 1 to pass through, the fixed block is inserted with an insertion rod 2 perpendicular to the insertion rod 1, and the insertion rod 1 is provided with a clamping hole for the insertion rod 2 to pass through.

8. The method for ultrasonically detecting the permeability of a concrete structure according to claim 7, characterized in that: A sliding groove with a notch facing downward is arranged on the top of the fixed block, a slider is slidably connected in the sliding groove, a spring is arranged between the top of the slider and the groove wall of the sliding groove, a support rod is fixed to the bottom of the slider, and the other end of the support rod is connected to the corresponding moving wheel.

9. The method for ultrasonically detecting the permeability of a concrete structure according to claim 1, characterized in that: The method for determining the permeability of a cast concrete structure by acoustic wave further comprises step S4: , determine the leakage situation of the measured concrete site, and conduct on-site inspection of the waterproof ability of the measured concrete structure.

Images