A neutron transmission imaging system for assembled wall detection and its application

Abstract

The present invention discloses a neutron transmission imaging system for prefabricated wall detection and its application, which relates to the technical field of nondestructive detection, and comprises a neutron transmitter assembly for emitting fast neutrons and a neutron receiver assembly for receiving thermal neutrons, which are arranged on both sides of the prefabricated wall to be detected. The neutron transmitter assembly and the neutron receiver assembly are respectively fixedly mounted on a first driving device and a second driving device which can drive them to move in a two-dimensional plane on a vertical plane parallel to the vertical plane where the prefabricated wall to be detected is located. The neutron transmitter assembly is connected to the first driving device, the neutron receiver assembly is connected to the second driving device, and the first driving device and the second driving device are respectively connected to a main control device. At the same time, the present invention also provides a detection method using the above technology; the present invention can effectively detect the connection quality in the building wall, and has high credibility.

Description

Technical Field

[0001] The present invention relates to the field of nondestructive testing, and in particular to a neutron transmission imaging system for detecting prefabricated building walls. Background Art

[0002] The quality of the connection between the prefabricated concrete wall structure and its walls, such as sleeve connection and grout anchor connection, and its grout saturation directly affect the safety of the structure. At present, there is a lack of effective detection methods for the quality of the connection nodes of prefabricated concrete structures. In recent years, the detection method of the grouting fullness of the sleeve connection nodes of prefabricated concrete structures has received more and more attention. Various methods and patents have emerged one after another, but there is still no reliable and effective detection method. There are also problems such as missing reinforcement, voids, and substandard concrete grades inside the wall structure itself.

[0003] The mainstream detection methods that can be found in the literature are: ultrasonic flaw detection, electromagnetic wave method (radar method), impact echo method and X-ray method. When ultrasonic flaw detection is used to detect the internal structure of concrete, the detection results are greatly affected by the coupling of the transducer, and the diffraction and scattering of ultrasonic waves in the internal structure of concrete lead to a large number of solutions. When the electromagnetic wave method (radar method) is used to detect the saturation of the sleeve grouting in the concrete, it is shielded by the metal material of the sleeve and cannot detect the internal situation. The mechanism of the impact echo method is to use a pulsed mechanical wave to impact the detection point and measure its echo. Similar to the ultrasonic method, the echo of the impact echo method has a great deal of multi-solutions and cannot reliably draw conclusions about the quality of the sleeve grouting. The X-ray method is a new method used in construction engineering detection in recent years. Its characteristic is to perform imaging by transmitting the object to be inspected. However, the X-ray method has the problem of limited penetration depth of metal objects, and the imaging effect of the details inside the metal pipe is general, and the specific element components cannot be distinguished. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a neutron transmission imaging system for prefabricated wall detection and its application to solve the technical problem that the equipment for detecting the connection quality of prefabricated buildings in the prior art is insufficient.

[0005] The present invention is achieved through the following technical solutions:

[0006] The present invention provides a neutron transmission imaging system for prefabricated wall detection, comprising a neutron transmitter assembly for emitting fast neutrons and a neutron receiver assembly for receiving thermal neutrons, which are arranged on both sides of the prefabricated wall to be detected. The neutron transmitter assembly and the neutron receiver assembly are respectively fixedly mounted on a first driving device and a second driving device that can drive them to move in a two-dimensional plane on a vertical plane parallel to the vertical plane where the prefabricated wall to be detected is located. The neutron transmitter assembly is connected to the first driving device, the neutron receiver assembly is connected to the second driving device, and the first driving device and the second driving device are respectively connected to a main control device.

[0007] Further, the first driving device is specifically composed of a first guide rail, a first support frame horizontally slidably mounted on the first guide rail, a first horizontal driving assembly for driving the first support frame to reciprocate horizontally on the first guide rail, a first vertical driving assembly for driving the neutron transmitter assembly vertically slidably mounted on the first support frame to reciprocate vertically, and a transmitting host installed in the first support frame and connected to the neutron transmitter assembly, the first horizontal driving assembly and the first vertical driving assembly respectively, and the transmitting host is connected to the main control device.

[0008] Furthermore, the second driving device is specifically composed of a second guide rail, a second support frame horizontally slidably installed on the second guide rail, a second horizontal driving assembly for driving the second support frame to reciprocate horizontally on the second guide rail, a second vertical driving assembly for driving the neutron receiver assembly vertically slidably installed on the second support frame to reciprocate vertically, and a receiving host installed in the second support frame and connected to the neutron receiver assembly, the second horizontal driving assembly and the second vertical driving assembly respectively, and the receiving host is connected to the main control device.

[0009] Furthermore, the transmitting host includes a first lithium battery power supply, a first mainboard, a first motor drive module and a first wireless transceiver module. The neutron transmitter assembly, the first motor drive module, the first wireless transceiver module and the first lithium battery power supply are respectively connected to the first mainboard, and the first mainboard is connected to the main control device through the first wireless transceiver module.

[0010] Furthermore, the receiving host includes a second lithium battery power supply, a second mainboard, a second motor drive module and a second wireless transceiver module. The neutron receiver assembly, the second motor drive module, the second wireless transceiver module and the second lithium battery power supply are respectively connected to the second mainboard, and the second mainboard is connected to the main control device through the second wireless transceiver module.

[0011] Furthermore, the neutron transmitter assembly includes a transmitter mainboard and a neutron source module, and the first mainboard and the neutron source module are respectively connected to the transmitter mainboard.

[0012] Furthermore, the neutron receiver assembly includes a receiver mainboard and a thermal neutron detection module, and the second mainboard and the thermal neutron detection module are respectively connected to the receiver mainboard.

[0013] Furthermore, the main control device includes a third mainboard, a display, a third wireless transceiver module and a third lithium battery power supply.

[0014] The present invention also provides a method for detecting the saturation of sleeve grouting in the wall of an assembled building using the above system. The method comprises installing a first drive device and a second drive device on both sides of the assembled building wall to be detected, and the neutron transmitter assembly and the neutron receiver assembly are symmetrically arranged about the center of the assembled building wall to be detected, and the two move synchronously under the control of the main control device through the first drive device and the second drive device, and then performing the following steps:

[0015] S1, determine the following parameters and input them into the main control device (5): delineate the detection area S, the thickness of the prefabricated building wall to be detected d, the buried depth of the sleeve in the detection area h, the outer diameter of the sleeve R, the inner diameter of the sleeve r1, and the radius of the steel bar r2;

[0016] S2. Establish a coordinate system: the lower left corner of the detection area S is the origin, the horizontal direction is the x-axis, the vertical direction is the y-axis, the horizontal length is L, L is an integer multiple of the bottom length V of the receiving cross-sectional rectangle of the neutron receiver assembly (2), the vertical length is H, H is an integer multiple of the side length U of the receiving cross-sectional rectangle of the neutron receiver assembly (2), and the detection area S is (LXH);

[0017] S3. According to the established coordinate system, the neutron transmitter assembly (1) and the neutron receiver assembly (2) move synchronously to the two sides of the lower left point of the S region, and then the probe of the neutron transmitter assembly (1) is irradiated with neutrons once and the neutron receiver assembly (2) performs thermal neutron scattering acquisition to obtain a cross-sectional thermal neutron single transmission image p of the probe of the neutron receiver assembly (2). 11 ;

[0018] S4, the neutron transmitter assembly (1) and the neutron receiver assembly (2) are synchronously moved upward by a distance of dH, and neutron irradiation and scattering collection are performed again to obtain a single transmission imaging p 12 , dH=U;

[0019] S5, move upwards again by a distance of dH, and repeat S4 until the y-axis H height scan is completed, forming a series of continuous thermal neutron transmission pattern sequences p 1m , m = 1 ~ M, M = H / dH;

[0020] S6, move rightward by dL, dL=V, repeat steps S4 and S5, and form the second column of continuous neutron scattering image sequence p 2m ;

[0021] S7, scanning from left to right, forming N columns of thermal neutron scattering image array {p NM};

[0022] S8. Perform two-dimensional filtering on all transmission images, and sequentially stitch them together to form a series of transmission images P that can be used for identification. According to the images P, the saturation of the sleeve grouting in the detection area is determined.

[0023] Furthermore, the method also includes setting a neutron radiation dose before the formal test, using the dose uniformly during the test, and calibrating the neutron transmission of the standard samples on site before or after S1-8 of the prefabricated building wall to obtain the standard value of the transmission data of the standard samples, wherein the standard samples include: a concrete test block without any structure inside, a test block containing a standard sleeve, steel bars and slurry inside, and a test block containing a standard sleeve, steel bars but no slurry inside; step S8 is specifically:

[0024] S8.1. Observe the uniformity of the non-sleeve area of ​​the series of transmission images P, and compare the transmission data with the corresponding standard value. If there is image inhomogeneity, and the value of the transmission data in the image inhomogeneity area is less than the corresponding standard value, then the corresponding non-sleeve area has an internal cavity abnormality;

[0025] S8.2. Observe the uniformity of the sleeve area from a series of transmission images P, and compare the transmission data with the corresponding standard value. If there is image unevenness, and the value of the transmission data in the image uneven area is less than the corresponding standard value, then there is an abnormal grouting unsaturation in the non-sleeve area.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] 1) The present invention can detect the grouting density in the connection sleeve of the prefabricated building wall and can give a reference value, while the X-ray detection method is affected by the heavy metal of the sleeve steel and has a poor recognition effect on the inside of the sleeve steel;

[0028] 2) Compared with devices using ultrasonic method and impact echo method, the present invention can obtain internal images, can achieve quantitative judgment, and has high reliability;

[0029] 3) The present invention does not require other pre-buried sensors or other auxiliary processes, does not interfere with the construction process, and has good applicability;

[0030] 4) The present invention uses continuous automatic scanning imaging technology, which can effectively complete the inspection of prefabricated building walls and has high work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic diagram of the device structure in Example 1;

[0032] Figure 2 This is a schematic diagram of the connection of circuit components in the system shown in Example 1;

[0033] Figure 3 This is a schematic diagram of the structure of the connection between the bottom plate and the wall in Example 3;

[0034] Figure 4 is a calibration image of the area A1 without any structure inside in Example 3;

[0035] Figure 5 This is a calibration image of the area A2 containing a standard sleeve and steel bars but no slurry in Example 3;

[0036] Figure 6 is a calibration image of area A3 containing a standard sleeve, steel bars and slurry in Example 3;

[0037] Figure 7 is a series of transmission images P finally formed in the detection area in Example 3;

[0038] Figure 8 This is a series of transmission images P finally formed in the detection area formed for another connecting sleeve in Example 3.

[0039] In the figure: 1, neutron transmitter assembly; 2, neutron receiver assembly; 3, first drive device; 4, second drive device; 5, main control device; 6, first guide rail; 7, first support frame; 8, first horizontal drive assembly; 9, first vertical drive assembly; 10, transmitting host; 11, second guide rail; 12, second support frame; 13, second horizontal drive assembly; 14, second vertical drive assembly; 15, receiving host; 16, first lithium battery power supply; 17, first main board; 18, first motor drive module; 19, first wireless transceiver module; 20, second lithium battery power supply; 21, second main board; 22, second motor drive module; 23, second wireless transceiver module; 24, transmitter main board; 25, neutron source module; 26, receiver main board; 27, thermal neutron detection module; 28, third main board; 29, display; 30, third wireless transceiver module; 31, third lithium battery power supply DETAILED DESCRIPTION

[0040] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] The present invention uses the principle that neutrons are neutral and can easily penetrate the electron layer, so when neutrons irradiate precast concrete panels containing steel bars and steel bar sleeves (such as Figure 3 ), can easily penetrate the steel sleeve, collide with the hydrogen atoms contained in the grouting material inside the sleeve to form scattering, and finally slow down into thermal neutrons. The thermal neutrons scatter in all directions, and their distribution density is obtained by receiving the scattered thermal neutrons. Under automatic and continuous emission and reception, a neutron scattering image of the detection area can be formed (or its corresponding data can be obtained, so as to synthesize the corresponding distribution density image), so as to obtain the corresponding internal structure. By comparing with the standard parts (that is, the data obtained by detecting the grouting-saturated materials), the advantages and disadvantages of the internal structure can be obtained.

[0042] Utilizing the above principles, the present invention provides the following devices.

[0043] Example 1

[0044] Combination Figure 1 The present embodiment provides a neutron transmission imaging system for prefabricated wall inspection, comprising a neutron transmitter assembly 1 for emitting fast neutrons and a neutron receiver assembly 2 for receiving thermal neutrons, which are arranged on both sides of the prefabricated wall to be inspected. The neutron transmitter assembly 1 and the neutron receiver assembly 2 are respectively fixedly mounted on a first driving device 3 and a second driving device 4 that can drive them to move in a two-dimensional plane on a vertical plane parallel to the vertical plane where the prefabricated wall to be inspected is located. The neutron transmitter assembly 1 is connected to the first driving device 3, the neutron receiver assembly 2 is connected to the second driving device 4, and the first driving device 3 and the second driving device 4 are respectively connected to a main control device 5.

[0045] Working principle:

[0046] When working, the main control device 5 controls the movement of the neutron transmitter assembly 1 through the first driving device 3, and controls the movement of the neutron receiver assembly 2 through the second driving device 4. At the same time, the data generated by the neutron transmitter assembly 1, the neutron receiver assembly 2, the first driving device 3 and the second driving device 4 during the operation are all fed back to the main control author 5;

[0047] Specifically: After the equipment is installed, the main control device 5 is first used to control the neutron transmitter assembly 1 and the neutron receiver assembly 2 to move synchronously via the first drive device 3 and the second drive device 4. One emits neutrons and the other receives and obtains the thermal neutron density, which is fed back to the main control device 5. Through continuous scanning, the main control device 5 can make corresponding judgments based on the comparison of the received information with the standard data (i.e., the data obtained by detecting the saturated material of the grouting), and can also make the detected data into a neutron distribution image. When the neutron image distribution density detected in a certain part is significantly lower than the neutron density under the same conditions, it can be determined that there is an unsaturated problem in the area, and the unsaturation degree is given, thereby realizing effective detection of the quality of building connections.

[0048] In particular, in this embodiment, in conjunction with the accompanying drawings, the first driving device 3 is specifically composed of a first guide rail 6, a first support frame 7 horizontally slidably mounted on the first guide rail 6, a first horizontal driving assembly 8 for driving the first support frame 7 to reciprocate horizontally on the first guide rail 6, a first vertical driving assembly 9 for driving the neutron transmitter assembly 1 vertically slidably mounted on the first support frame 7 to reciprocate vertically, and a transmitter host 10 installed in the first support frame 7 and connected to the neutron transmitter assembly 1, the first horizontal driving assembly 8 and the first vertical driving assembly 9, respectively. The transmitter host 10 is connected to the main control device 5; the first guide rail 6 is composed of two horizontal and The first support frame 7 is composed of a plurality of rails arranged in parallel to each other (it can also be assembled from multiple rails, so that the corresponding length can be adjusted according to the needs), and a plurality of rollers mounted on the first guide rail 6 are installed at the bottom of the first support frame 7, and the first horizontal driving assembly 8 is fixedly installed in the first support frame 7, and can drive the first support frame 7 to reciprocate horizontally on the first guide rail 6 through the driving roller (the first horizontal driving assembly 8 can be a stepping motor, and its output device is connected to a roller, so that the corresponding roller can be driven to rotate, thereby driving the entire first support frame 7 to reciprocate horizontally. In particular, in order to facilitate control, the roller can also be replaced by a gear, corresponding to The first guide rail 6 is provided with uniform tooth grooves, which mesh with the gears, so that the process can be controlled by the tooth grooves. Furthermore, in order to further control the stepping accuracy, the first horizontal drive assembly 8 and the first guide rail 6 can be replaced by a linear module as a whole. Similarly, the first vertical drive assembly 8 can also be a linear module, so as to achieve the purpose of accurately controlling the position of the equipment), thereby realizing the horizontal movement of the neutron transmitter assembly 1 thereon; the first support frame 7 is provided with a first vertical drive assembly 9 in the vertical direction. In this embodiment, it can be a linear module or a hollow guide rail (the guide rail has a rectangular cross-section, and the guide rail is slidably mounted by a kit). It is composed of a neutron transmitter assembly 1) and a stepper motor, a driving groove is opened on one side wall of the guide rail facing the first vertical drive assembly 9, and internal teeth are evenly arranged on a vertical wall of the driving groove. The output shaft of the corresponding stepper motor passes through the kit and is arranged in the driving groove and is fixedly connected to the gear meshing with the internal teeth. By rotating the gear to mesh with the internal teeth, the vertical height of the neutron transmitter assembly 1 can be effectively adjusted to achieve its purpose, and the first vertical drive assembly 9 and the first support frame 7 can also be connected by other means, as long as it can drive the neutron transmitter assembly 1 to perform vertical reciprocating motion, thereby realizing the two-dimensional motion of the neutron transmitter assembly 1 on the vertical plane;

[0049] At the same time, in order to be able to effectively control the first horizontal drive assembly 8 and the first vertical drive assembly 9 and provide power for the two, in the present embodiment, the transmitting host 10 is composed of a first lithium battery power supply 16 (all lithium battery power supplies in the present embodiment are composed of large-capacity lithium batteries, which supply power to other electrical devices, and their power supply and charging are controlled by the corresponding mainboard, which can realize simultaneous power supply while charging), a first mainboard 17 (in the present embodiment, the first mainboard 17 is composed of an STM32F103 embedded ARM chip as the core, which includes a power management circuit (CN3763 battery management unit) and a motor drive circuit (i.e., a first motor drive module 18), which is responsible for communicating with the main control device 5, driving the first vertical drive assembly 9 and the first horizontal drive assembly 8, and controlling the The neutron transmitter assembly 1), the first motor drive module 18 and the first wireless transceiver module 19 (in the present embodiment, the first wireless transceiver module 19 is composed of a 433MHz amplitude modulation AM communication module), the neutron transmitter assembly 1, the first motor drive module 18, the first wireless transceiver module 19 and the first lithium battery power supply 16 are respectively connected to the first mainboard 17, and the first mainboard 17 is connected to the main control device 5 through the first wireless transceiver module 19; the first lithium battery power supply 16 provides power for the operation of the first horizontal drive assembly 8, the first vertical drive assembly 9 and the neutron transmitter assembly 1, and the first mainboard 17 controls the first horizontal drive assembly 8 and the first vertical drive assembly 9 respectively through the first motor drive module 18; at the same time, the first mainboard 17 transmits information to the main control device 5 through the first wireless transceiver module 19.

[0050] In this embodiment, the neutron transmitter assembly 1 includes a transmitter mainboard 24 and a neutron source module 25, and the first mainboard 17 and the neutron source module 25 are respectively connected to the transmitter mainboard 24; wherein, the first mainboard 17 and the transmitter mainboard 24 are connected via a wiring harness drag chain to facilitate high-speed data transmission. At the same time, the transmitter mainboard 24 controls the working state of the neutron source module 25, and the first mainboard 17 can also control the working state of the neutron source module 25 through the first wireless transceiver module 19 via the transmitter mainboard 24 and obtain corresponding information.

[0051] In particular, in this embodiment, the second driving device 4 is specifically composed of a second guide rail 11, a second support frame 12 horizontally slidably mounted on the second guide rail 11, a second horizontal driving assembly 13 for driving the second support frame 12 to reciprocate horizontally on the second guide rail 11, a second vertical driving assembly 14 for driving the neutron receiver assembly 2 vertically slidably mounted on the second support frame 12 to reciprocate vertically, and a receiving host 15 installed in the second support frame 12 and connected to the neutron receiver assembly 2, the second horizontal driving assembly 13 and the second vertical driving assembly 14, respectively. The receiving host 15 is connected to the main The control device 5 is connected, the receiving host 15 includes a second lithium battery power supply 20, a second main board 21 (same as the first main board 17), a second motor drive module 22 and a second wireless transceiver module 23, the neutron receiver assembly 2, the second motor drive module 22, the second wireless transceiver module 23 and the second lithium battery power supply 20 are respectively connected to the second main board 21, the second main board 21 is connected to the main control device 5 through the second wireless transceiver module 23, the neutron receiver assembly 2 includes a receiver main board 26 and a thermal neutron detection module 27, and the second main board 21 and the thermal neutron detection module 27 are respectively connected to the receiver main board 26.

[0052] The structures and working principles of the first driving device 3 and the second driving device 4 are basically the same, and the only difference is that one is used to control the movement of the neutron source module 25 and the other is used to control the movement of the neutron detection module 27, that is, one side emits neutrons and the other side receives thermal neutrons, and the main control device 5 sends and receives data. Therefore, the functions of the second driving device 4, the receiving host 15 and the neutron receiver assembly 2 will not be introduced here.

[0053] In order to facilitate the overall operation of the control device, in the present embodiment, the main control device 5 includes a third mainboard 28, a display 29, a third wireless transceiver module 30 and a third lithium battery power supply 31; wherein the display 29 can be a touch display, which is convenient for the control and parameter adjustment of the device, and the third mainboard 28 controls the entire operation of the device, which controls the remote device and acquires data through the third wireless transceiver module 30, the first wireless transceiver module 19 and the second wireless transceiver module 23.

[0054] In particular, in the present embodiment, the drive assembly includes a stepper motor, and the other structures only need to be able to drive the corresponding equipment to perform corresponding movements; at the same time, in order to facilitate the adjustment of the distance between the neutron transmitter assembly 1 and the neutron receiver assembly 2 and the measured wall, a vertical drive assembly that can drive it to perform horizontal reciprocating motion perpendicular to the direction of the measured wall can be added between the neutron transmitter assembly 1 or the neutron receiver assembly 2 and the corresponding vertical drive assembly. For example, the vertical drive assembly is composed of an electric telescopic rod, and the neutron transmitter assembly 1 or the neutron receiver assembly 2 is fixed to the outer end of the corresponding electric telescopic rod. The corresponding distance between the measured wall can be effectively controlled according to the telescopic distance. It can also be set to other structures as long as it can achieve the same purpose. Similarly, all drive assemblies can be synchronous belt slides and controlled by corresponding control devices, thereby facilitating the improvement of the control accuracy of the equipment.

[0055] All the main boards in this embodiment are STM32F103 embedded ARM main control units, and all the wireless transceiver modules are 433MHz wireless transceiver units.

[0056] Example 2

[0057] This embodiment provides a method for detecting the saturation of sleeve grouting in the wall of an assembled building using the above-mentioned device, specifically:

[0058] First, the first drive device 3 and the second drive device 4 are respectively installed on both sides of the prefabricated building wall to be inspected, and the neutron transmitter assembly 1 and the neutron receiver assembly 2 are symmetrically arranged about the center of the prefabricated building wall to be inspected. The two move synchronously under the control of the main control device 5 through the first drive device 3 and the second drive device 4, and then the following steps are performed:

[0059] S1. Determine the following parameters and input them into the main control device 5: delineate the detection area S, the thickness of the wall of the prefabricated building to be detected d, the buried depth of the sleeve in the detection area h, the outer diameter of the sleeve R, the inner diameter of the sleeve r1, and the radius of the steel bar r2;

[0060] S2. Establish a coordinate system: the lower left corner of the detection area S is the origin, the horizontal direction is the x-axis, the vertical direction is the y-axis, the horizontal length is L, L is an integer multiple of the bottom length V of the receiving cross-sectional rectangle of the neutron receiver assembly 2, the vertical length is H, H is an integer multiple of the side length U of the receiving cross-sectional rectangle of the neutron receiver assembly 2, and the detection area S is (LXH);

[0061] S3. According to the established coordinate system, the neutron transmitter assembly 1 and the neutron receiver assembly 2 move synchronously to the two sides of the lower left point of the S area, and then the probe of the neutron transmitter assembly 1 is irradiated with neutrons once and the neutron receiver assembly 2 performs thermal neutron scattering acquisition to obtain the cross-sectional thermal neutron single transmission imaging p of the probe of the neutron receiver assembly 2.11 ;

[0062] S4, the neutron transmitter assembly 1 and the neutron receiver assembly 2 move upward synchronously by a distance of dH, and perform neutron irradiation and scattering collection again to obtain a single transmission imaging p 12 , dH=U;

[0063] S5, move upwards again by a distance of dH, and repeat S4 until the y-axis H height scan is completed, forming a series of continuous thermal neutron transmission pattern sequences p 1m , m = 1 ~ M, M = H / dH;

[0064] S6, move rightward by dL, dL=V, repeat steps S4 and S5, and form the second column of continuous neutron scattering image sequence p 2m ;

[0065] S7, scanning from left to right, forming N columns of thermal neutron scattering image array {p NM};

[0066] S8. Perform two-dimensional filtering on all transmission images, and sequentially stitch them together to form a series of transmission images P that can be used for identification. According to the images P, the saturation of the sleeve grouting in the detection area is determined.

[0067] In particular, the method further includes setting a neutron radiation dose before the formal test, using the dose uniformly during the test, and calibrating the neutron transmission of the standard sample on site before or after S1-8 of the prefabricated building wall to obtain the standard value of the transmission data of the standard sample, wherein the standard sample includes: a concrete test block without any structure inside, a test block containing a standard sleeve, steel bars and slurry inside, and a test block containing a standard sleeve, steel bars but no slurry inside; step S1-13 is specifically:

[0068] S8.1. Observe the uniformity of the non-sleeve area of ​​the series of transmission images P, and compare the transmission data with the corresponding standard value. If there is image inhomogeneity, and the value of the transmission data in the image inhomogeneity area is less than the corresponding standard value, then the corresponding non-sleeve area has an internal cavity abnormality;

[0069] S8.2. Observe the uniformity of the sleeve area from a series of transmission images P, and compare the transmission data with the corresponding standard value. If there is image unevenness, and the value of the transmission data in the image uneven area is less than the corresponding standard value, then there is an abnormal grouting unsaturation in the non-sleeve area.

[0070] Example 3

[0071] The following experiments were carried out using the above device and method:

[0072] 1) Use the device shown in Example 1 to Figure 3The bottom plate and the wall shown in the embodiment are tested for their connection quality using the method shown in Example 2, specifically:

[0073] 2) The wall thickness d is 200 mm. The equipment is used to calibrate and sample various parts of the 200 mm thick wall sample plate, including the area A1 without any structure inside, the area A2 with standard sleeves, steel bars but no slurry inside, and the area A3 with standard sleeves, steel bars and slurry inside. The calibration image P is formed. A1 ( Figure 4 ), P A2 ( Figure 5 ), P A3 ( Figure 6 ).

[0074] 3) As an implementation case, select Figure 3 One of the connecting sleeves defines the detection area and divides area 1 into an equally divided grid of N columns and M rows. A dedicated automated neutron scattering scanning imaging device is used to continuously and automatically scan the area according to the equally divided grid step to form a neutron scattering image array {p NM}.

[0075] 4) The neutron scattering image array {p NM}Use the data processing technology solution of the present invention to process data to form Figure 7 The series of transmission images P shown in the figure show that there is unsaturation in the sleeve at this location, and its unsaturation degree q = 14.09%, which is calculated by the following formula:

[0076]

[0077] s is the image P A1 The mean neutron density, P A1 s=1.682e5 / m 2 ;

[0078] s pi The neutron density at the unsaturated part in the image under test, Figure 7 At a sampling point in the abnormal area s pi =1.445e5 / m 2 .

[0079] 5) Similarly, select another connecting sleeve for testing. Figure 8 For the series of transmission images P, it can be found that there is an abnormal area on the left side of the middle of the series of transmission images P. The sampling point of the abnormal area in this area is s pi =1.445e5 / m 2 , unsaturation q = 29.43%

[0080] The above description is only a preferred embodiment of the present invention and is 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 detecting the saturation of sleeve grouting in the wall of an assembled building using a neutron transmission imaging system. It is characterized in that The neutron transmission imaging system comprises a neutron transmitter assembly (1) for transmitting fast neutrons and a neutron receiver assembly (2) for receiving thermal neutrons, which are arranged on both sides of the prefabricated wall to be inspected. The neutron transmitter assembly (1) and the neutron receiver assembly (2) are respectively fixedly mounted on a first drive device (3) and a second drive device (4) which can drive them to move in a two-dimensional plane on a vertical plane parallel to the vertical plane where the prefabricated wall to be inspected is located. The neutron transmitter assembly (1) is connected to the first drive device (3), the neutron receiver assembly (2) is connected to the second drive device (4), and the first drive device (3) and the second drive device (4) are respectively connected to a main control device (5); The method for detecting the saturation of sleeve grouting in the wall of an assembled building using the neutron transmission imaging system comprises: installing a first drive device (3) and a second drive device (4) on both sides of the assembled building wall to be detected, and symmetrically arranging a neutron transmitter assembly (1) and a neutron receiver assembly (2) about the center of the assembled building wall to be detected, and the two move synchronously under the control of the main control device (5) through the first drive device (3) and the second drive device (4), and then performing the following steps: S1. Determine the following parameters and input them into the main control device (5): Delimit the detection area S , the thickness of the prefabricated building wall being tested d , the buried depth of the sleeve in the detection area h , sleeve outer diameter R , sleeve inner diameter r 1 , steel bar radius r 2 ; S2. Establishing coordinate system: Detection area S The origin is at the bottom left, the horizontal direction is the x-axis, the vertical direction is the y-axis, and the horizontal length is L , L The length of the bottom side of the receiving cross section rectangle of the neutron receiver assembly (2) V The vertical length is an integer multiple of H , H The side length of the receiving cross section rectangle of the neutron receiver assembly (2) U Integer multiples of, detection area S for( L Χ H ); S3. According to the established coordinate system, the neutron transmitter assembly (1) and the neutron receiver assembly (2) move synchronously to S The probe of the neutron transmitter assembly (1) is then irradiated with neutrons once and the neutron receiver assembly (2) performs thermal neutron scattering acquisition to obtain a thermal neutron single transmission imaging of the cross section of the probe of the neutron receiver assembly (2). p 11 ; S4. The neutron transmitter assembly (1) and the neutron receiver assembly (2) move upward synchronously. dH distance, perform neutron irradiation and scattering acquisition again to obtain single transmission imaging p 12 , dH = U ; S5, move up again dH distance, repeat S4 until the y axis H The height scan is completed, forming a series of continuous thermal neutron transmission image sequences p 1m , m = 1~ M , M = H / dH ; S6, move right dL , dL = V Repeat steps S4 and S5 to form the second column of continuous neutron scattering image sequence p 2m ; S7, scanning from left to right, forming N Thermal neutron scattering image array p NM }; S8, perform two-dimensional filtering on all transmission images, and splice them in sequence to form a series of transmission images P that can be used for identification. P Determine the saturation of the sleeve grouting in the test area.

2. The method according to claim 1, It is characterized in that The first driving device (3) is specifically composed of a first guide rail (6), a first support frame (7) horizontally slidably mounted on the first guide rail (6), a first horizontal driving assembly (8) for driving the first support frame (7) to perform horizontal reciprocating motion on the first guide rail (6), a first vertical driving assembly (9) for driving a neutron transmitter assembly (1) vertically slidably mounted on the first support frame (7) to perform vertical reciprocating motion, and a transmitting host (10) mounted in the first support frame (7) and connected to the neutron transmitter assembly (1), the first horizontal driving assembly (8) and the first vertical driving assembly (9), respectively. The transmitting host (10) is connected to the main control device (5).

3. The method according to claim 2, It is characterized in that The second driving device (4) is specifically composed of a second guide rail (11), a second support frame (12) horizontally slidably mounted on the second guide rail (11), a second horizontal driving assembly (13) for driving the second support frame (12) to perform horizontal reciprocating motion on the second guide rail (11), a second vertical driving assembly (14) for driving a neutron receiver assembly (2) vertically slidably mounted on the second support frame (12) to perform vertical reciprocating motion, and a receiving host (15) mounted in the second support frame (12) and connected to the neutron receiver assembly (2), the second horizontal driving assembly (13) and the second vertical driving assembly (14), respectively. The receiving host (15) is connected to the main control device (5).

4. The method according to claim 3, It is characterized in that The transmitting host (10) comprises a first lithium battery power source (16), a first mainboard (17), a first motor drive module (18) and a first wireless transceiver module (19); the neutron transmitter assembly (1), the first motor drive module (18), the first wireless transceiver module (19) and the first lithium battery power source (16) are respectively connected to the first mainboard (17); and the first mainboard (17) is connected to a main control device (5) via the first wireless transceiver module (19).

5. The method according to claim 4, It is characterized in that The receiving host (15) comprises a second lithium battery power source (20), a second mainboard (21), a second motor drive module (22) and a second wireless transceiver module (23); the neutron receiver assembly (2), the second motor drive module (22), the second wireless transceiver module (23) and the second lithium battery power source (20) are respectively connected to the second mainboard (21); and the second mainboard (21) is connected to the main control device (5) via the second wireless transceiver module (23).

6. The method according to claim 5, It is characterized in that The neutron transmitter assembly (1) comprises a transmitter mainboard (24) and a neutron source module (25), and the first mainboard (17) and the neutron source module (25) are respectively connected to the transmitter mainboard (24).

7. The method according to claim 6, It is characterized in that The neutron receiver assembly (2) comprises a receiver mainboard (26) and a thermal neutron detection module (27), and the second mainboard (21) and the thermal neutron detection module (27) are respectively connected to the receiver mainboard (26).

8. The method according to claim 7, It is characterized in that The main control device (5) comprises a third mainboard (28), a display (29), a third wireless transceiver module (30) and a third lithium battery power source (31).

9. The method according to claim 1, It is characterized in that Before the formal test, the neutron radiation dose is set, and the dose is used uniformly during the test. Before or after S1-8 of the prefabricated building wall, the neutron transmission calibration of the standard sample on site is carried out to obtain the standard value of the standard sample transmission data, wherein the standard sample includes: a concrete test block without any structure inside, a test block containing a standard sleeve, steel bars and slurry inside, and a test block containing a standard sleeve, steel bars but no slurry inside; and step S8 is specifically as follows: S8.

1. Observe the uniformity of the non-sleeve area of ​​the series of transmission images P, and compare the transmission data with the corresponding standard value. If there is image inhomogeneity, and the value of the transmission data in the image inhomogeneity area is less than the corresponding standard value, then the corresponding non-sleeve area has an internal cavity abnormality; S8.

2. Observe the uniformity of the sleeve area from a series of transmission images P, and compare the transmission data with the corresponding standard value. If there is image unevenness, and the value of the transmission data in the image uneven area is less than the corresponding standard value, then there is an abnormal grouting unsaturation in the non-sleeve area.

Images