A displacement type crack meter and a judgment measurement method thereof

Abstract

The present application relates to the technical fields of concrete crack monitoring, and particularly relates to a displacement type crack meter and a judging and measuring method thereof. The displacement type crack meter comprises a shell, and further comprises two detection units arranged in the shell. The two detection units are arranged in the shell in an axial symmetry mode. The detection unit comprises a three-axis connector, two lateral elastic columns, a longitudinal elastic column, a pressure rod receiving member, three pull ropes arranged in the lateral elastic columns and the longitudinal elastic column respectively, three elastic members arranged at one end of the three pull ropes respectively, three variable resistance sensors arranged on the longitudinal elastic column and the two lateral elastic columns respectively, the variable resistance sensors being connected with the pull ropes exposed at the end of the longitudinal elastic column or the lateral elastic column, and two force transmission rods, one end of each of the two force transmission rods being fixed on the shell and the other end of each of the two force transmission rods being arranged on the two lateral elastic columns respectively.

Description

Technical Field

[0001] This invention relates to the field of concrete crack monitoring technology, and in particular to a displacement crack meter and its judgment and measurement method. Background Technology

[0002] In both civil engineering and hydraulic engineering, there are many reasons why concrete cracks occur, and the location and type of cracks vary depending on the cause. Almost all concrete components operate with cracks, although some cracks are very fine, even invisible to the naked eye (crack width less than 0.05mm), posing little threat to the structure's use and are permissible. However, some cracks continuously develop and expand under load or external environmental influences, causing concrete cracking and spalling, and steel reinforcement corrosion. This weakens the overall strength and stiffness of the component, affecting its normal use and reducing its durability. These types of cracks are the focus of our analysis and routine inspections. Different types of cracks convey different information, and different treatment methods apply to different types of cracks. Obtaining information such as the type and location of cracks helps in determining the form of structural damage and design solutions when treating cracks, thereby more effectively repairing internal cracks in the dam body, improving the dam's impermeability, and reducing uneven settlement of the dam foundation.

[0003] Chinese patent literature discloses a fiber optic crack gauge (application number: CN113758433) that measures the opening degree of cracks by measuring the displacement of different optical fibers. This instrument calculates the opening degree of the crack by measuring and calculating the displacement of the optical fibers, but it cannot determine the specific type and location of the crack. Currently, existing fiber optic crack gauges can only be embedded in existing cracks in concrete for measurement, and cannot measure cracks near the instrument. Furthermore, they cannot transmit the specific location and type information of the crack during measurement, thus hindering effective crack management. Summary of the Invention

[0004] In view of this, the purpose of this invention is to propose a displacement crack gauge and its judgment and measurement method to solve the problem that the existing technology is unable to simultaneously obtain crack type and location information.

[0005] To achieve the above objectives, the present invention provides a displacement crack gauge, comprising a housing and two detection units disposed within the housing; the two detection units are arranged axially symmetrically within the housing; each detection unit includes a triaxial connector; two transverse elastic columns respectively disposed on the two horizontal interfaces of the triaxial connector; a longitudinal elastic column disposed on the vertical direct interface of the triaxial connector; a pressure rod receiving element disposed on the longitudinal elastic column; three pull ropes respectively disposed within the transverse and longitudinal elastic columns; three elastic elements respectively disposed at one end of the three pull ropes; each of the transverse and longitudinal elastic columns is provided with two countersunk holes, the opening ends of which are disposed at the end furthest from the triaxial connector; The end of the pull rope away from the elastic element and the end of the elastic element away from the pull rope are respectively fixedly connected to the bottom of the two countersunk holes; three variable resistance sensors are respectively installed on the longitudinal elastic column and the two transverse elastic columns, and the variable resistance sensors are connected to the pull rope exposed at the end of the longitudinal elastic column or the transverse elastic column; two force transmission rods are fixed at one end to the housing and the other end is respectively installed on the two transverse elastic columns; each of the upper and lower ends of the housing is provided with a through hole, and the end of the longitudinal elastic column away from the triaxial connector extends out of the housing through the through hole, and the pressure rod receiving member is fixedly installed on the free end of the longitudinal elastic column located on the outside; the pressure rod receiving member and the housing are fixedly installed on the concrete.

[0006] As a further improvement to this application, the pull rope is in a taut state.

[0007] As a further improvement of this application, mounting plates are provided at the four corners of the outer shell, one end of the force transmission rod is fixedly connected to the mounting plate, four waist-shaped holes are provided on the surface of the shell, and the other end of the force transmission rod is fixedly installed on the transverse elastic column.

[0008] As a further improvement of this application, one end of the force transmission rod is provided with a force transmission clamp, which is fixedly clamped to the transverse elastic column.

[0009] As a further improvement of this application, the transverse elastic column is divided into two different structures: the part located between the force transmission rod and the triaxial connector is an elastic section made of elastic material, and the part located from the force transmission rod to the free end is a rigid section made of rigid material.

[0010] As a further improvement of this application, the two said transverse elastic columns are on the same straight line, the longitudinal elastic column is perpendicular to the transverse elastic column, and the transverse elastic columns on the two detection units are parallel to each other.

[0011] As a further improvement of this application, each of the free ends of the transverse elastic column and the free end of the longitudinal elastic column of the two detection units is provided with a deformable sensitive element, and the six sensitive elements are respectively connected and driven by the six variable resistance sensors.

[0012] As a further improvement of this application, the housing is provided with a movable block that is fixedly connected to the force transmission rod, and the movable block can move freely.

[0013] As a further improvement of this application, the end of the force-transmitting clamp connected to the force-transmitting rod is provided with a sleeve, the force-transmitting rod is inserted into the sleeve, and the force-transmitting rod can move along the axial direction of the sleeve within the sleeve.

[0014] A method for judging and measuring displacement crack gauges is as follows: First, the displacement crack gauge is vertically embedded in concrete, and the shell and pressure rod are fixed inside the foundation. When only two pressure rods of the two detection units are subjected to force, or when both pressure rods are subjected to force, it is determined that a horizontal transverse crack has occurred inside the concrete. When only the transverse elastic column on the same side of the two detection units is subjected to force, it is determined that a longitudinal crack has occurred inside the concrete. When the pressure rods and the transverse elastic column of the two detection units are subjected to force simultaneously, it is determined that a diagonal crack has occurred inside the concrete.

[0015] The beneficial effects of this invention are as follows: by using six variable resistance sensors on two detection units to detect the deformation of the transverse and longitudinal elastic columns, the deformation of the crack can be calculated and the type of crack can be determined, thus solving the problem that the existing technology is unable to simultaneously obtain the type and location information of the crack. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of a displacement crack gauge according to an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of the longitudinal elastic column of a displacement crack gauge before deformation, according to an embodiment of the present invention.

[0019] Figure 3 This is a schematic diagram of the longitudinal elastic column of a displacement crack gauge after tensile deformation according to an embodiment of the present invention.

[0020] Figure 4This is a schematic diagram of the transverse elastic column of a displacement crack gauge according to an embodiment of the present invention;

[0021] Figure 5 This is a schematic diagram of the structure of the force transmission rod and force transmission clamp of a displacement crack gauge according to an embodiment of the present invention.

[0022] Figure 6 This is a schematic diagram of the structure of a variable resistance sensor for a displacement crack gauge according to an embodiment of the present invention;

[0023] Figure 7 This is a schematic diagram of the structure of a displacement crack gauge according to an embodiment of the present invention, showing the cooperation between the longitudinal elastic column and the compression member;

[0024] Figure 8 This is a schematic diagram of the structure of the sensing element of a displacement crack gauge according to an embodiment of the present invention;

[0025] Figure 9 This is a side view of a displacement crack gauge before longitudinal deformation, according to an embodiment of the present invention.

[0026] Figure 10 This is a side view of a displacement crack gauge after longitudinal deformation, according to an embodiment of the present invention.

[0027] Figure 11 This is a schematic diagram of the structure of a displacement crack gauge according to an embodiment of the present invention, in which a horizontal crack is located above the upper pressure bar.

[0028] Figure 12 This is a schematic diagram of the structure of a displacement crack gauge according to an embodiment of the present invention, in which the horizontal crack is located below the pressure bar.

[0029] Figure 13 This is a schematic diagram of the structure of a displacement crack gauge used in an embodiment of the present invention, in which a horizontal crack is located between two pressure bar components;

[0030] Figure 14 This is a schematic diagram of a displacement crack gauge in use according to an embodiment of the present invention, showing a vertical crack located to the left of the displacement crack gauge.

[0031] Figure 15 This is a schematic diagram of a displacement crack gauge in use according to an embodiment of the present invention, showing a vertical crack located to the right of the displacement crack gauge.

[0032] Figure 16 This is a schematic diagram of the structure of a displacement crack gauge according to an embodiment of the present invention, in which the vertical crack is located in the middle position of the four force transmission rods.

[0033] Figure 17This is a schematic diagram of the structure of a displacement crack gauge used in an embodiment of the present invention, where the crack does not pass through the displacement crack gauge and is located below the displacement crack gauge at an angle greater than 90° with the horizontal line.

[0034] Figure 18 This is a schematic diagram of the structure of a displacement crack gauge used in an embodiment of the present invention, wherein the crack does not pass through the displacement crack gauge and is located below the displacement crack gauge with an angle of less than 90° to the horizontal line.

[0035] Figure 19 This is a schematic diagram of the structure of a displacement crack gauge used in an embodiment of the present invention, where the crack does not pass through the displacement crack gauge and is located above the displacement crack gauge at an angle of less than 90° to the horizontal line.

[0036] Figure 20 This is a schematic diagram of the structure of a displacement crack gauge used in an embodiment of the present invention, wherein the crack does not pass through the displacement crack gauge and is located above the displacement crack gauge at an angle greater than 90° with the horizontal line.

[0037] Figure 21 This is a schematic diagram of the structure of a displacement crack gauge according to an embodiment of the present invention, in which the crack is located to the right of the lower left force transmission rod, and to the left of the upper left force transmission rod, the upper right force transmission rod, the lower right force transmission rod, and the longitudinal elastic column below.

[0038] Figure 22 This is a schematic diagram of the structure of a displacement crack gauge according to an embodiment of the present invention, in which the crack is located to the left of the lower right force transmission rod, and to the right of the upper left force transmission rod, the upper right force transmission rod, the lower left force transmission rod, and the longitudinal elastic column below.

[0039] Figure 23 This is a schematic diagram of the structure of a displacement crack gauge according to an embodiment of the present invention, in which the crack is located on the right side of the force-bearing part of the left upper force rod, the force-bearing parts of the right upper force rod, the left lower force rod, and the right lower force rod and the left side of the upper longitudinal elastic column.

[0040] Figure 24 This is a schematic diagram of the structure of a displacement crack gauge in an embodiment of the present invention, in which the crack is located on the left side of the force-bearing part of the right upper force rod, the force-bearing parts of the left upper force rod, the left lower force rod, and the right lower force rod, and the right side of the upper longitudinal elastic column.

[0041] Among them, 01, pressure rod receiving component; 02, hanging component; 03, longitudinal elastic column; 04, force transmission rod; 05, mounting plate; 06, force transmission clamp; 07, pull rope; 08, long fixed rod; 09, three-axis connector; 10, transverse elastic column; 51, mounting plate; 52, connecting rod; 53, elastic component; 60, resistor; 61, input wire; 62, metal sliding block; 63, output wire; Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0043] It should be noted that, unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0044] This invention provides a displacement crack gauge, including a housing and two detection units disposed within the housing; the two detection units are arranged axially symmetrically within the housing; each detection unit includes a triaxial connector 09; two transverse elastic columns 10, respectively disposed on the two horizontal interfaces of the triaxial connector 09; a longitudinal elastic column 03, disposed on the vertical direct interface of the triaxial connector 09; a pressure rod receiving element 01, disposed on the longitudinal elastic column 03; three pull ropes 07, respectively disposed within the transverse elastic columns 10 and the longitudinal elastic columns 03; three elastic elements, respectively disposed at one end of the three pull ropes 07; each of the transverse elastic columns 10 and the longitudinal elastic column 03 has two countersunk holes, the opening ends of which are disposed at the ends away from the triaxial connector 09; the pull ropes... 07 is fixedly connected to the bottom of two countersunk holes at one end away from the elastic element and the other end of the elastic element away from the pull rope 07, respectively; three variable resistance sensors are respectively installed on the longitudinal elastic column 03 and the two transverse elastic columns 10, and the variable resistance sensors are connected to the pull rope 07 exposed at the end of the longitudinal elastic column 03 or the transverse elastic column 10; two force transmission rods 04 are fixed at one end to the housing and the other end is respectively installed on the two transverse elastic columns 10; each of the upper and lower ends of the housing is provided with a through hole, and the end of the longitudinal elastic column 03 away from the triaxial connector 09 extends out of the housing through the through hole, and the pressure rod receiving member 01 is fixedly installed on the free end of the longitudinal elastic column 03 located on the outside; the pressure rod receiving member 01 and the housing are fixedly installed on concrete.

[0045] The longitudinal elastic column 03 and the transverse elastic column 10 on the two detection units are stretched, causing the pull rope 07 to move. The displacement of the pull rope 07 is then detected by a variable resistance sensor, thereby obtaining the amount of stretching of the longitudinal elastic column 03 and the transverse elastic column 10, and thus detecting the type and opening of the crack in the concrete.

[0046] In order to ensure that the movement of the pull rope 07 is synchronized with the extension and retraction of the longitudinal elastic column 03 or the transverse elastic column 10, the pull rope 07 is kept taut to avoid inconsistencies caused by a slack state.

[0047] To allow the transverse elastic column 10 to extend and retract, mounting plates 05 are provided at the four corners of the outer shell. One end of the force transmission rod 04 is fixedly connected to the mounting plate 05. The surface of the shell has four oblong holes, and the other end of the force transmission rod 04 is fixedly installed on the transverse elastic column 10. One end of the force transmission rod 04 is provided with a force transmission clamp 06, which is fixedly clamped to the transverse elastic column 10. The deformation of the shell will cause the force transmission rod 04 to deform, thereby causing the transverse elastic column 10 to extend and retract, and moving the pull rope 07 inside the transverse elastic column 10.

[0048] To prevent the transverse elastic column 10 from contracting and deforming under the pressure of the pull rope 07, the transverse elastic column 10 is divided into two different structures: the part located between the force transmission rod 04 and the triaxial connector 09 is an elastic segment made of elastic material, and the part located from the force transmission rod 04 to the free end is a rigid segment made of rigid material. Thus, only the elastic segment will deform, while the deformation of the rigid segment is negligible. The displacement of the pull rope 07 within the transverse elastic column 10 is equal to the deformation of the transverse elastic column 10.

[0049] The two transverse elastic columns 10 are on the same straight line, the longitudinal elastic column 03 is perpendicular to the transverse elastic column 10, and the transverse elastic columns 10 on the two detection units are parallel to each other.

[0050] Each of the two detection units has a deformable sensitive element at the free end of the transverse elastic column 10 and the free end of the longitudinal elastic column 03. The six sensitive elements are connected to the six variable resistance sensors for transmission. When the pull rope 07 moves, it deforms the sensitive elements. The deformation of the sensitive elements is detected by the variable resistance sensors, which in turn allow the variable resistance sensors to indirectly measure the amount of movement of the pull rope 07.

[0051] The variable resistance sensor includes a resistor 60, an input wire 61 connected to one end of the resistor 60, a metal slider 62 connected to the side of the resistor 60, and an output wire 63 connected to the metal slider 62. The metal slider 62 is fixedly connected to a sensitive element or a pull cord 07. The resistance per unit length of the resistor 60 changes constantly. The displacement of the metal slider 62 causes a change in the contact between the metal slider 62 and the resistor 60, which in turn causes a change in the resistance of the connected section of the input wire 61, the resistor 60, the metal slider 62, and the output wire 63, resulting in a change in the current magnitude. Thus, the displacement of the metal slider 62 can be obtained.

[0052] The variable resistance sensor can measure the real-time resistance through a connected circuit. The sensitivity of the variable resistance sensor is constant, and the resistance value of the sensor and the displacement value of the pull rope 07 have a linear relationship. According to the formula, the real-time displacement of the pull rope 07 can be determined from the real-time resistance value, thus obtaining the displacement value of the pull rope 07 at a certain moment.

[0053] S = R / r

[0054] S is the displacement recorded by the variable resistance sensor, R is the measured resistance value of the variable resistance sensor, and r is the resistance value per unit length of the variable resistance sensor.

[0055] As can be seen from the above, the real-time displacement can be calculated from the resistance signal measured by the variable resistance sensor.

[0056] The sensitive element includes a mounting plate 51 fixedly mounted on a transverse elastic column 10 or a longitudinal elastic column 03, an elastic element 53 mounted on the mounting plate 51, and a connecting rod 52 mounted on the elastic element 53. The connecting rod 52 is fixedly connected to a pull rope 07 and a metal sliding block 62.

[0057] To prevent loosening, a hanger 02 is provided at the connection between the pressure rod receiving member 01 and the longitudinal elastic column 03 to strengthen the structural rigidity. The hanger 02 is connected to the pressure rod receiving member 01 and the longitudinal elastic column 03 by screws.

[0058] The outer shell is made of stainless steel, which is corrosion-resistant and pressure-resistant. The shell can protect the displacement crack gauge itself from the cracking of the outer layer and maintain the internal stability of the structure during operation.

[0059] In order to drive the force transmission rod 04 to rotate, the housing is provided with a movable block that is fixedly connected to the force transmission rod 04, and the movable block can move freely. When there is displacement inside the concrete, it drives the movable block to move, pushing the force transmission rod 04 to rotate, thereby stretching the transverse elastic column 10.

[0060] To avoid interference, a sleeve is provided at the end of the force-transmitting clamp 06 connected to the force-transmitting rod 04. The force-transmitting rod 04 is inserted into the sleeve and can move along the axis of the sleeve within the sleeve. When the force-transmitting rod 04 rotates, its end moves along the sleeve.

[0061] To fix the housing, the housing is provided with mounting holes, and a long fixing rod 08 is installed in the mounting holes. Both ends of the long fixing rod 08 extend out of the mounting holes. When placed in the concrete, the long fixing rod 08 will fix the housing and prevent the housing from moving together with the pressure rod receiving member 01.

[0062] A method for judging and measuring displacement crack gauges: First, the displacement crack gauge is vertically embedded in concrete, and the shell and pressure rod 01 are fixed inside the foundation.

[0063] When only two pressure rods 01 of the two detection units are subjected to force individually or when both pressure rods 01 are subjected to force, it is determined that a horizontal transverse crack has been generated inside the concrete.

[0064] When only the transverse elastic column 10 on the same side of the two detection units is subjected to force, it is determined that a longitudinal crack has occurred inside the concrete.

[0065] When the pressure bar 01 and the transverse elastic column 10 of the two detection units are subjected to force simultaneously, it is determined that a diagonal crack has been generated inside the concrete.

[0066] The types of cracks generated inside the concrete include horizontal cracks, vertical cracks, and diagonal cracks, and the diagonal cracks include external diagonal cracks and internal diagonal cracks.

[0067] The horizontal crack is parallel to the pressure bar 01, the vertical crack is perpendicular to the pressure bar 01, and the oblique crack intersects the longitudinal elastic column 03 or its extension, and also intersects the transverse elastic column 10 or its extension.

[0068] Step 1: Determine the type and location of the cracks

[0069] The external oblique crack does not pass through the displacement crack gauge, while the internal oblique crack does pass through the displacement crack gauge.

[0070] The method used in this displacement-type crack gauge to determine crack type is as follows: Starting from the displacement detected by the variable resistance sensor, the type and location of the crack are determined by comparing the displacement values ​​of six variable resistance sensors within the time period of concrete cracking and the type of combination of variable resistance sensors with measured values. The operation and measurement process of the variable resistance sensor corresponding to different types of cracks at different locations are described in detail below, based on the distribution maps of different types of cracks at different locations:

[0071] like Figure 11 As shown, a horizontal crack is located above the upper compression member 01. When the horizontal crack expands, the upper compression member 01 is compressed and moves downward. The compression member 01 applies pressure to the concrete below it, and the concrete units below it transmit the force to the lower compression member 01. The lower compression member 01 is stretched downward by the downward crack force. Under the action of the tensile force, the longitudinal elastic column 03 connected to the lower compression member 01 is stretched, and the tension rope 07 inside the longitudinal elastic column 03 is stretched and displaced. The variable resistance sensor on the lower longitudinal elastic column 03 has a measurement value, while the variable resistance sensors on the transverse elastic column 10 and the upper longitudinal elastic column 03 have no measurement values.

[0072] Similarly, such as Figure 12 As shown, a horizontal crack is located below the lower compression member 01. When the horizontal crack expands, the lower compression member 01 is compressed and moves upward. The compression member 01 applies pressure to the concrete above it, and the concrete unit above it transmits force to the upper compression member 01. The upper compression member 01 is stretched upward by the upward crack force. Under the action of the tensile force, the longitudinal elastic column 03 connected to the upper compression member 01 is stretched, and the tension rope 07 inside the longitudinal elastic column 03 is stretched and displaced. The variable resistance sensor on the upper longitudinal elastic column 03 has a measurement value, while the variable resistance sensors on the transverse elastic column 10 and the lower longitudinal elastic column 03 have no measurement values.

[0073] Furthermore, such as Figure 13 As shown, the horizontal crack is located between two pressure members 01. When the horizontal crack expands, the upper pressure member 01 will be stretched upwards, and the lower pressure member 01 will be stretched downwards. Under the action of the tensile force of the members, both longitudinal elastic columns 03 will be stretched, and the tension ropes 07 inside the two longitudinal elastic columns 03 will be displaced. The displacement measured by the variable resistance sensors on the two longitudinal elastic columns 03 is close in magnitude, while the variable resistance sensor on the transverse elastic column 10 has no measurement value.

[0074] like Figure 14As shown, the vertical crack is located to the left of the displacement crack gauge. When the vertical crack expands, the concrete near the crack gauge will move to the right under the action of the crack force. The outer shell remains stationary under the fixation of the long fixed rod 08. The concrete moving to the right will touch the movable block, which will transmit the crack force to the two movable blocks on the right side. The two movable blocks on the right side will move to the right under the action of the force, pushing the two force transmission rods 04 on the right side to rotate, thereby stretching the two transverse elastic columns 10 on the right side. The two transverse elastic columns 10 on the right side will deform under the action of the tensile force, and the pull rope 07 inside the transverse elastic column 10 will also be displaced. The variable resistance sensors on the two transverse elastic columns 10 on the right side have measured values, while the variable resistance sensors on the two transverse elastic columns 10 on the left side and the variable resistance sensors on the two vertical elastic columns 03 on the top and bottom have no measured values.

[0075] like Figure 15 As shown, the vertical crack is located to the right of the displacement crack gauge. When the vertical crack expands, the movable blocks on the two force transmission rods 04 on the left are subjected to the crack force. The outer shell remains stationary under the fixation of the long fixed rod 08. When the concrete moves to the left, it touches the movable blocks, which transmit the crack force to the movable blocks on the left force transmission rod 04. Under the action of the force, the movable blocks move to the left, pushing the two force transmission rods 04 on the left to rotate, thereby stretching the two transverse elastic columns 10 on the left. Therefore, the variable resistance sensors on the two transverse elastic columns 10 on the left have measured values, while the variable resistance sensors on the two transverse elastic columns 10 on the right and the variable resistance sensors on the two longitudinal elastic columns 03 on the top and bottom have no measured values.

[0076] like Figure 16 As shown, the vertical crack is located in the middle of the four force transmission rods 04. When the vertical crack expands, the movable blocks on the four force transmission rods 04 will be subjected to the crack force, all four transverse elastic columns 10 will deform, and the tension ropes 07 inside the four transverse elastic columns 10 will be displaced. In the early stage of concrete cracking, the expansion degree of the vertical crack at both ends along the vertical axis is approximately the same, and the force on the two force transmission rods 04 on the same side is the same. Therefore, the variable resistance sensor on the same side has a measurement value, and the measurement value is approximately equal. In the later stage of concrete cracking, the expansion degree of the vertical crack measured on the same vertical line may be different. The variable resistance sensor on the same side has a measurement value, and the measurement value may differ significantly.

[0077] like Figure 17As shown, without passing through a displacement crack gauge, for an oblique crack located below the displacement crack gauge at an angle greater than 90° to the horizontal: When the oblique crack expands, the lower pressure member 01 is compressed and moves upward. The lower pressure member 01 exerts a force on the concrete above it, and the concrete unit above it transmits the force to the upper pressure member 01. The upper pressure member 01, under the action of the upward crack force, is stretched upward. Under the action of the tensile force, the longitudinal elastic column 03 connected to the upper pressure member 01 is stretched, and the tension rope 07 inside the longitudinal elastic column 03 is also stretched, generating displacement. Therefore, a measurement value is obtained by the variable resistance sensor on the upper longitudinal elastic column 03. Simultaneously, when the oblique crack expands, the movable blocks on the two force transmission rods 04 on the right side are subjected to the crack force transmitted by the concrete moving to the right. Under the action of the force, the movable blocks move to the right, pushing the two force transmission rods 04 on the right side to rotate, thereby stretching the two transverse elastic columns 10 on the right side. The two transverse elastic columns 10 located on the right side deform under the action of tensile force, and the tension ropes 07 inside the transverse elastic columns 10 also displace. Therefore, the variable resistance sensors on the two transverse elastic columns 10 on the right side have measured values. Finally, the variable resistance sensor on the upper longitudinal elastic column 03 and the two variable resistance sensors on the two transverse elastic columns 10 on the right side have measured values, while the variable resistance sensor on the lower longitudinal elastic column 03 and the variable resistance sensors on the two transverse elastic columns 10 on the left side have no measured values.

[0078] like Figure 18As shown, without passing through a displacement crack gauge, for an oblique crack located below the displacement crack gauge at an angle less than 90° to the horizontal: When the oblique crack expands, the lower pressure member 01 is compressed and moves upward. The lower pressure member 01 exerts a force on the concrete above it, and the concrete unit above it transmits the force to the upper pressure member 01. The upper pressure member 01, under the action of the upward crack force, is stretched upward. Under the action of the tensile force, the longitudinal elastic column 03 connected to the upper pressure member 01 is stretched, and the tension rope 07 inside the longitudinal elastic column 03 is also stretched, generating displacement. Therefore, a measurement value is obtained by the variable resistance sensor on the upper longitudinal elastic column 03. Simultaneously, when the oblique crack expands, the movable blocks on the two force transmission rods 04 on the left are subjected to the crack force transmitted by the leftward movement of the concrete. Under the action of the force, the movable blocks move to the left, pushing the two force transmission rods 04 on the left to rotate, thereby stretching the two transverse elastic columns 10 on the left. The two transverse elastic columns 10 on the left deform under the tensile force, and the tension ropes 07 inside the transverse elastic columns 10 also shift. Therefore, the variable resistance sensors on the two transverse elastic columns 10 on the left take measurements. Ultimately, the variable resistance sensor on the upper longitudinal elastic column 03 and the two variable resistance sensors on the two transverse elastic columns 10 on the left take measurements, while the variable resistance sensor on the lower longitudinal elastic column 03 and the two transverse elastic columns 10 on the right take no measurements.

[0079] like Figure 19As shown, for a diagonal crack located above the displacement crack gauge with an angle less than 90° to the horizontal line, without passing through a displacement crack gauge: When the diagonal crack expands, the upper pressure rod 01 is compressed and moves downwards. The upper pressure rod 01 exerts a force on the concrete below it, and the concrete unit below transmits the force to the lower pressure rod 01. The lower pressure rod 01 is stretched downwards by the downward crack force. Under the action of the tension force, the longitudinal elastic column 03 connected to the lower pressure rod 01 is stretched, and the tension rope 07 inside the longitudinal elastic column 03 is also stretched, generating displacement. Therefore, a measurement value is obtained by the variable resistance sensor on the lower longitudinal elastic column 03. Simultaneously, when the diagonal crack expands, the movable blocks on the two force transmission rods 04 on the left are subjected to the crack force transmitted by the leftward movement of the concrete. Under the action of the force, the movable blocks move to the left, pushing the two force transmission rods 04 on the left to rotate, thereby stretching the two transverse elastic columns 10 on the left. The two transverse elastic columns 10 on the left deform under the tensile force, and the tension ropes 07 inside the transverse elastic columns 10 also displace. Therefore, the variable resistance sensors on the two transverse elastic columns 10 on the left have measured values. Finally, the variable resistance sensor on the lower longitudinal elastic column 03 and the two variable resistance sensors on the two transverse elastic columns 10 on the left have measured values, while the variable resistance sensor on the upper longitudinal elastic column 03 and the two transverse elastic columns 10 on the right have no measured values.

[0080] like Figure 20As shown, without passing through a displacement crack gauge, for an oblique crack located above the displacement crack gauge at an angle greater than 90° to the horizontal: When the oblique crack expands, the upper pressure member 01 is compressed and moves downwards. The upper pressure member 01 exerts a force on the concrete below it, and the concrete unit below transmits the force to the lower pressure member 01. The lower pressure member 01 is stretched downwards by the downward crack force. Under the action of the tensile force, the longitudinal elastic column 03 connected to the lower pressure member 01 is stretched, and the tension rope 07 inside the longitudinal elastic column 03 is also stretched, generating displacement. Therefore, a measurement value is obtained by the variable resistance sensor on the lower longitudinal elastic column 03. Simultaneously, when the oblique crack expands, the movable blocks on the two force transmission rods 04 on the right side are subjected to the crack force transmitted by the rightward movement of the concrete. Under the action of the force, the movable blocks move to the right, pushing the two force transmission rods 04 on the right side to rotate, thereby stretching the two transverse elastic columns 10 on the right side. The two right-side transverse elastic columns 10 deform under tensile force, and the tension ropes 07 inside the transverse elastic columns 10 also shift. Therefore, the variable resistance sensors on the two right-side transverse elastic columns 10 register readings. Ultimately, the variable resistance sensor on the lower longitudinal elastic column 03 and the two variable resistance sensors on the two right-side transverse elastic columns 10 register readings, while the variable resistance sensor on the upper longitudinal elastic column 03 and the two left-side transverse elastic columns 10 register no readings.

[0081] like Figure 21As shown, a diagonal crack is located to the right of the lower left force transmission rod 04, and to the left of the upper left force transmission rod 04, upper right force transmission rod 04, lower right force transmission rod 04, and the lower longitudinal elastic column 03. When the diagonal crack expands, the lower compression member 01 is compressed and moves upward. The lower compression member 01 exerts a force on the concrete above it, and the concrete unit above it transmits the force to the upper compression member 01. The upper compression member 01 is stretched upward by the upward crack force. Under the action of the tensile force, the longitudinal elastic column 03 connected to the upper compression member 01 is stretched, and the tension rope 07 inside the longitudinal elastic column 03 is also stretched, resulting in displacement. Therefore, a measurement value is obtained by the variable resistance sensor on the upper longitudinal elastic column 03. Simultaneously, as the diagonal crack expands, the movable blocks on the two right-side force transmission rods 04 are subjected to the crack force transmitted by the concrete moving to the right, and the movable block on the lower left-side force transmission rod 04 is subjected to the crack force transmitted by the concrete moving to the left. Under the force, the two right-side movable blocks move to the right, pushing the two right-side force transmission rods 04 to rotate, thereby stretching the two right-side transverse elastic columns 10. The lower left-side movable block moves to the left under the force, pushing the lower left-side force transmission rod 04 to rotate, thereby stretching the lower left-side transverse elastic column 10. The two right-side transverse elastic columns 10 deform under the tensile force, and the tension rope 07 inside the right-side transverse elastic column 10 also displaces. Therefore, the variable resistance sensors on the two right-side transverse elastic columns 10 have measured values. Similarly, the lower left-side transverse elastic column 10 deforms under the tensile force, and the tension rope 07 inside the lower left-side transverse elastic column 10 also displaces. Therefore, the variable resistance sensor on the lower left-side transverse elastic column 10 has measured values. Ultimately, the variable resistance sensors on the upper vertical elastic column 03, the upper right horizontal elastic column 10, the lower left horizontal elastic column 10, and the lower right horizontal elastic column 10 will all have measured values.

[0082] like Figure 22As shown, a diagonal crack is located to the left of the lower right force transmission rod 04, and to the right of the upper left force transmission rod 04, upper right force transmission rod 04, lower left force transmission rod 04, and the lower longitudinal elastic column 03. When the diagonal crack expands, the lower pressure rod 01 is compressed and moves upward. The lower pressure rod 01 exerts a force on the concrete above it, and the concrete unit above it transmits the force to the upper pressure rod 01. The upper pressure rod 01 is stretched upward by the upward crack force. Under the action of the tensile force, the longitudinal elastic column 03 connected to the upper pressure rod 01 is stretched, and the tension rope 07 inside the longitudinal elastic column 03 is also stretched, resulting in displacement. Therefore, a measurement value is obtained by the variable resistance sensor on the upper longitudinal elastic column 03. Simultaneously, as the diagonal crack expands, the movable blocks on the two left-side force transmission rods 04 are subjected to the crack force transmitted by the concrete moving to the left, and the movable block on the lower right-side force transmission rod 04 is subjected to the crack force transmitted by the concrete moving to the right. Under the force, the two movable blocks on the left move to the left, pushing the two left-side force transmission rods 04 to rotate, thereby stretching the two left-side transverse elastic columns 10. Under the force, the movable block on the lower right moves to the right, pushing the right-side force transmission rod 04 to rotate, thereby stretching the lower right-side transverse elastic column 10. The two transverse elastic columns 10 on the left deform under the tensile force, and the tension rope 07 inside the left transverse elastic column 10 also displaces. Therefore, the variable resistance sensors on the two left transverse elastic columns 10 have measured values. Similarly, the transverse elastic column 10 on the lower right deforms under the tensile force, and the tension rope 07 inside the lower right transverse elastic column 10 also displaces. Therefore, the variable resistance sensors on the two lower right transverse elastic columns 10 have measured values. Ultimately, the variable resistance sensors on the upper vertical elastic column 03, the upper right horizontal elastic column 10, the lower left horizontal elastic column 10, and the lower left horizontal elastic column 10 will all have measured values.

[0083] like Figure 23As shown, the diagonal cracks on the right side of the force-bearing portion of the left upper force rod 04, the right upper force rod 04, the left lower force rod 04, and the right lower force rod 04, and the left side of the upper longitudinal elastic column 03: When the diagonal cracks expand, the upper pressure rod 01 is compressed and moves downward. The upper pressure rod 01 exerts a force on the concrete below it, and the concrete unit above it transmits the force to the lower pressure rod 01. The lower pressure rod 01 is stretched downward by the downward crack force. Under the action of the tensile force, the longitudinal elastic column 03 connected to the lower pressure rod 01 is stretched, and the tension rope 07 inside the longitudinal elastic column 03 is stretched and displaced. Therefore, a measurement value is obtained by the variable resistance sensor on the lower longitudinal elastic column 03. Simultaneously, as the diagonal crack expands, the movable blocks on the two right-side force transmission rods 04 are subjected to the crack force transmitted by the concrete moving to the right, and the movable block on the upper left-side force transmission rod 04 is also subjected to the crack force transmitted by the concrete moving to the right. Under the action of this force, the two movable blocks on the right move to the right, pushing the two right-side force transmission rods 04 to rotate, thereby stretching the two right-side transverse elastic columns 10. The movable block on the upper left moves to the left under the action of this force, pushing the left-side force transmission rod 04 to rotate, thereby stretching the upper left-side transverse elastic column 10. The two right-side transverse elastic columns 10 deform under the tensile force, and the tension ropes 07 inside the right-side transverse elastic columns 10 also displace, thus generating measurement values ​​from the variable resistance sensors on the two right-side transverse elastic columns 10. Similarly, the upper left-side transverse elastic column 10 deforms under the tensile force, and the tension ropes 07 inside the upper left-side transverse elastic column 10 also displace, thus generating measurement values ​​from the variable resistance sensors on the two upper left-side transverse elastic columns 10. Ultimately, the variable resistance sensors on the lower vertical elastic column 03, the upper left horizontal elastic column 10, the lower right horizontal elastic column 10, and the upper right horizontal elastic column 10 will all have measured values.

[0084] like Figure 24As shown, on the left side of the force-bearing portion of the right upper force-bearing rod 04, the force-bearing portions of the left upper force-bearing rod 04, the left lower force-bearing rod 04, and the right lower force-bearing rod 04, and the diagonal crack on the right side of the upper longitudinal elastic column 03: When the diagonal crack expands, the upper pressure rod 01 is compressed and moves downward. The upper pressure rod 01 exerts a force on the concrete below it, and the concrete unit above it transmits the force to the lower pressure rod 01. The lower pressure rod 01 is stretched downward by the downward crack force. Under the action of the tensile force of the member, the longitudinal elastic column 03 connected to the lower pressure rod 01 will be stretched, and the tension rope 07 inside the longitudinal elastic column 03 will be stretched together, generating displacement. Therefore, a measurement value is obtained by the variable resistance sensor on the lower longitudinal elastic column 03. Simultaneously, as the diagonal crack expands, the movable blocks on the two left-side force transmission rods 04 are subjected to the crack force transmitted by the concrete moving to the left, and the movable block on the upper right-side force transmission rod 04 is subjected to the crack force transmitted by the concrete moving to the right. Under the force, the two movable blocks on the left move to the left, pushing the two left-side force transmission rods 04 to rotate, thereby stretching the two left-side transverse elastic columns 10. The movable block on the upper right moves to the right under the force, pushing the left and right force transmission rods 04 to rotate, thereby stretching the upper right-side transverse elastic column 10. The two transverse elastic columns 10 on the left deform under the tensile force, and the tension rope 07 inside the left transverse elastic column 10 also displaces. Therefore, the variable resistance sensors on the two left transverse elastic columns 10 have measured values. Similarly, the transverse elastic column 10 on the upper right deforms under the tensile force, and the tension rope 07 inside the upper right transverse elastic column 10 also displaces. Therefore, the variable resistance sensors on the two upper right transverse elastic columns 10 have measured values. Ultimately, the variable resistance sensors on the lower vertical elastic column 03, the upper right horizontal elastic column 10, the lower left horizontal elastic column 10, and the upper left horizontal elastic column 10 will all have measured values.

[0085] In summary, since the types of variable resistance sensors with measurement values ​​correspond to different types and locations of cracks, the type of crack and its position relative to the displacement crack gauge can be determined based on the types of variable resistance sensors with measurement values ​​corresponding to different types and locations of cracks. This information can then be used to measure the degree of crack opening and closing.

[0086] Step 2: Measure the degree of opening and closing of the cracks.

[0087] Different types of cracks require different formulas for calculating their opening degree. Therefore, after determining the type of crack, the opening degree can be calculated based on the formula corresponding to that type of crack and the measurement value of the variable resistance sensor. The calculation steps for each type of crack are as follows:

[0088] As described in step one, during the process of crack extension and deformation, the measured value of the variable resistance sensor inside the crack gauge is equivalent to the displacement of the internal pull rope 07. The displacement can be converted into an electrical signal through the variable resistance sensor and its subsequent circuit. The magnitude of the displacement of the pull rope 07 can be obtained by reading the change in resistance.

[0089] For horizontal cracks, the displacement of the pull rope 07 measured by the variable resistance sensor is equivalent to the crack's opening degree. Simultaneously, since the pressure bar 01 remains horizontal, the opening degree measured by the variable resistance sensor is the maximum opening degree of the horizontal crack it measures. For vertical cracks, the displacement of the pull rope 07 measured by the variable resistance sensor is proportional to the horizontal opening degree of the external crack of the displacement crack gauge, which can be calculated using the following formula:

[0090] S = R / r

[0091] S is the displacement recorded by the variable resistance sensor, R is the measured resistance value of the variable resistance sensor, and r is the resistance value per unit length of the variable resistance sensor.

[0092] The relationship between the displacement of the movable block and the deformation of the transverse elastic column 10 is as follows:

[0093] LX = Sx

[0094] S is the displacement recorded by the variable resistance sensor, X is the length of the force transmission rod 04, x is the distance between the movable block and the connection between the force transmission rod 04 and the housing, and L is the displacement of the movable block.

[0095] Measuring the opening degree of a diagonal crack is complex and requires analysis using methods for measuring both horizontal and vertical cracks. The square of the opening degree of a diagonal crack is equal to the sum of the square of the displacement of the longitudinal elastic column 03 and the square of the displacement of the transverse elastic column 10.

[0096] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in the details for the sake of brevity.

[0097] This invention is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A displacement-type crack gauge, comprising a housing, characterized in that, It also includes two detection units housed within the housing; The two detection units are arranged symmetrically within the housing; The detection unit includes a triaxial connector (09); Two transverse elastic pillars (10) are respectively disposed on the two horizontal interfaces of the three-axis connector (09); A longitudinal elastic column (03) is provided on the vertical direct opening of the triaxial connector (09); The compression member (01) is disposed on the longitudinal elastic column (03); Three pull ropes (07) are respectively installed in the horizontal elastic column (10) and the vertical elastic column (03); Three elastic elements are respectively disposed at one end of the three pull ropes (07); Both the transverse elastic column (10) and the longitudinal elastic column (03) are provided with two countersunk holes, and the opening end of each countersunk hole is located at the end away from the triaxial connector (09); the end of the pull rope (07) away from the elastic element and the end of the elastic element away from the pull rope (07) are respectively fixedly connected to the bottom of the two countersunk holes; Three variable resistance sensors are respectively installed on the longitudinal elastic column (03) and the two transverse elastic columns (10), and the variable resistance sensors are connected to the pull ropes (07) exposed at the ends of the longitudinal elastic column (03) or the transverse elastic columns (10). Two force transmission rods (04) are fixed at one end to the housing and at the other end respectively on the two transverse elastic columns (10); The housing has a through hole at each of its upper and lower ends. The end of the longitudinal elastic column (03) away from the triaxial connector (09) extends out of the housing through the through hole. The pressure rod receiving member (01) is fixedly installed on the free end of the longitudinal elastic column (03) located on the outside. The compression member (01) and the housing are fixedly installed on the concrete; The transverse elastic column (10) is divided into two different structures. The part between the force transmission rod (04) and the triaxial connector (09) is an elastic section made of elastic material, and the part from the force transmission rod (04) to the free end is a rigid section made of rigid material. The two transverse elastic columns (10) are on the same straight line, the longitudinal elastic column (03) is perpendicular to the transverse elastic column (10), and the transverse elastic columns (10) on the two detection units are parallel to each other; Each of the two detection units has a deformable sensitive element at the free end of the transverse elastic column (10) and the free end of the longitudinal elastic column (03), and the six sensitive elements are respectively connected to the six variable resistance sensors for transmission.

2. The displacement-type crack gauge according to claim 1, characterized in that, The pull rope (07) is in a taut state.

3. The displacement-type crack gauge according to claim 1, characterized in that, Mounting plates (05) are provided at the four corners of the outer shell. One end of the force transmission rod (04) is fixedly connected to the mounting plate (05). The surface of the shell is provided with four waist-shaped holes. The other end of the force transmission rod (04) is fixedly installed on the transverse elastic column (10).

4. The displacement-type crack gauge according to claim 3, characterized in that, One end of the force transmission rod (04) is provided with a force transmission clamp (06), which is fixedly clamped to the transverse elastic column (10).

5. The displacement-type crack gauge according to claim 1, characterized in that, The housing is provided with a movable block that is fixedly connected to the force transmission rod (04), and the movable block can move freely.

6. The displacement-type crack gauge according to claim 4, characterized in that, The force-transmitting clamp (06) is connected to the force-transmitting rod (04) at one end with a sleeve. The force-transmitting rod (04) is inserted into the sleeve and can move along the axial direction of the sleeve within the sleeve.

7. The displacement-type crack gauge as described in any one of claims 1-6, characterized in that, The judgment and measurement method of displacement crack gauge is as follows: First, vertically embed the displacement crack gauge into the concrete, and fix the shell and pressure rod (01) inside the foundation; When only two compression members (01) of the two detection units are subjected to force alone or both compression members (01) are subjected to force, it is determined that a horizontal transverse crack has been generated inside the concrete. When only the transverse elastic column (10) on the same side of the two detection units is subjected to force, it is determined that a longitudinal crack has been generated inside the concrete. When the pressure bar (01) and the transverse elastic column (10) of the two detection units are subjected to force at the same time, it is determined that a diagonal crack has been generated inside the concrete.

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