Terrain flatness measuring device for civil construction

Abstract

The invention relates to the technical field of flatness measurement, and discloses a terrain flatness measuring device for civil construction, which comprises a base, the top of the base is provided with a clamping groove, the inner wall of the clamping groove is provided with a gas recovery assembly, the bottom of the gas recovery assembly is provided with a measuring wheel, and the top of the base is provided with a support frame. When the ground fluctuates to drive the movable rod to move up and down in the sleeve, the contact position of the resistance rod and the annular iron sheet changes, so that the resistance value of an access circuit changes synchronously, corresponding current changes are generated under constant voltage, and when the constant voltage is applied to the two ends of the resistance rod, the resistance value of the access circuit changes synchronously. The annular iron sheet serves as a sliding contact to divide the resistance rod into two resistors connected in series, according to the voltage dividing principle, the voltage at the two ends of the contact is in direct proportion to the position of the contact, the displacement of the movable rod can be accurately calculated by measuring the voltage change, and then the fluctuation degree of the terrain is obtained. The device has the advantages of good linearity, high response speed and simple structure.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of flatness measurement, in particular to a terrain flatness measurement device for civil construction. BACKGROUND

[0002] As a key indicator of civil construction engineering quality control, terrain flatness directly affects road driving comfort, building foundation stability and site construction quality.

[0003] Traditional terrain flatness measurement methods mainly include: contact measurement with a ruler and a wedge-shaped plug gauge, and non-contact measurement technologies such as laser profilometers and three-dimensional laser scanners; however, these technologies have many limitations in practical application: 1. Traditional ruler measurement is low in efficiency and poor in accuracy, and can only be used for single-point measurement; 2. Laser measurement equipment is expensive, and the annual operation and maintenance cost is high, of which the cost of sensor calibration and inertial platform maintenance accounts for the majority; 3. In complex terrain conditions, such as steep slopes, cliffs, rivers, lakes and other water areas in mountainous areas, and dense forests and other environments, the applicability of existing technologies is severely limited; Therefore, the above problems need to be improved. SUMMARY

[0004] The present application provides a terrain flatness measurement device for civil construction, which solves the problems raised in the background art.

[0005] The present application provides the following technical solution: a terrain flatness measurement device for civil construction, comprising a base, a clamping groove is formed in the top of the base, a gas recovery assembly is provided on the inner wall of the clamping groove, a measuring wheel is installed at the bottom of the gas recovery assembly, a support frame is installed on the top of the base, a gas storage cavity is assembled on the outer wall of the support frame, a measuring assembly is provided on the top of the gas recovery assembly, a car hook is fixedly assembled on the outer wall of one side of the base, and a push rod is fixedly installed on the outer wall of the other side of the base, a control panel is fixedly assembled on the outer wall of the push rod, a suspension structure is installed at the bottom of the base, and a moving wheel is assembled at both ends of the suspension structure.

[0006] As a preferred technical solution of the present application: the number of clamping grooves is three, and the three clamping grooves are uniformly distributed on the top of the base, the diameter of the clamping groove is matched with the diameter of the gas recovery assembly, the outer wall of the moving wheel is inlaid with anti-skid lines, the number of measuring wheels is three, and the three measuring wheels are uniformly distributed between the two groups of suspension structures.

[0007] As a preferred technical scheme of the present application: the gas recovery assembly comprises a sleeve, an airtight fixed sleeve cavity is fixedly installed on the inner wall of the sleeve, a movable rod is slidably connected to the inner wall of the sleeve, a compression plate is fixedly sleeved on the outer wall of the movable rod, a bottom plate is fixedly sleeved on the outer wall of the movable rod, one end of the compression spring is fixedly connected to the top of the bottom plate, and the other end of the compression spring is fixedly connected to a limiting sleeve ring, a gas conveying pipe is clamped on one end of the airtight fixed sleeve cavity close to the gas storage cavity, and a bidirectional check valve is arranged on the outer wall of the gas conveying pipe.

[0008] As a preferred technical scheme of the present application: the gas recovery assembly comprises a sleeve, an airtight fixed sleeve cavity is fixedly installed on the inner wall of the sleeve, a movable rod is slidably connected to the inner wall of the sleeve, a compression plate is fixedly sleeved on the outer wall of the movable rod, a bottom plate is fixedly sleeved on the outer wall of the movable rod, one end of the compression spring is fixedly connected to the top of the bottom plate, and the other end of the compression spring is fixedly connected to a limiting sleeve ring, a gas conveying pipe is clamped on one end of the airtight fixed sleeve cavity close to the gas storage cavity, and a bidirectional check valve is arranged on the outer wall of the gas conveying pipe.

[0009] As a preferred technical scheme of the present application: the diameter of the compression plate is matched with the inner diameter of the airtight fixed sleeve cavity, and the compression plate is slidably driven by the movable rod on the inner wall of the airtight fixed sleeve cavity, the number of bidirectional check valves is two, and the two bidirectional check valves are respectively installed on the outer wall of the gas conveying pipe on the outer wall of the sleeve close to the gas storage cavity, the bidirectional check valve is made of small brass, the outer edge position of the compression plate in contact with the airtight fixed sleeve cavity is embedded with a double-layer O-shaped sealing ring, and the double-layer O-shaped sealing ring is made of wear-resistant rubber.

[0010] As a preferred technical scheme of the present application: the measuring assembly comprises a fixed frame, a fixed clamping block is fixedly installed on the outer wall of the fixed frame, an annular iron sheet is fixedly assembled on the inner wall of the fixed clamping block, an electric resistance rod is slidably sleeved on the inner wall of the annular iron sheet, a metal positioning sheet is fixedly embedded on the top of the electric resistance rod, a wire connector one is installed on the outer wall of the electric resistance rod, a wire connector two is installed on the bottom of the annular iron sheet, an insulating support is fixedly assembled on the top of the fixed frame, and an electromagnetic adsorber is installed on the bottom of the insulating support.

[0011] As a preferred technical scheme of the present application: the resistance rod is prepared by high-stability alloy copper wire, and the bottom of the resistance rod is fixedly connected with the top of the movable rod, the two ends of the connecting head one are connected with the positive and negative poles of the power supply through the connecting head one, the annular iron sheet is connected with the lead wire through the connecting head two and the oscilloscope, the inner cavity of the electromagnetic adsorber is installed with a small DC electromagnet, and the adsorption force of the electromagnetic adsorber is 5-8 N, the inner diameter of the electromagnetic adsorber is slightly larger than the outer diameter of the metal positioning sheet, the metal positioning sheet is coaxially welded and fixed with the resistance rod, and the metal positioning sheet is prepared by a thin brass sheet, and the diameter of the metal positioning sheet is smaller than the diameter of the resistance rod.

[0012] As a preferred technical scheme of the present application: the resistance value of the resistance rod is 100-500Ω, the bottom of the resistance rod is integrally fixed with the top of the movable rod, and the virtual center line of the resistance rod coincides with the virtual center line of the movable rod, the annular iron sheet is prepared by brass, and the inner wall of the annular iron sheet is silver-plated, the inner side of the annular iron sheet is coated with conductive paste, the electromagnetic adsorber is electrically connected with the control panel, the electromagnetic adsorber shares the same constant power supply with the resistance rod, and the electromagnetic adsorber is controlled by the independent switch on the control panel.

[0013] As a preferred technical scheme of the present application: the shape of the gas storage cavity is cylindrical, and the gas storage cavity is prepared by aluminum alloy, the pressure resistance of the gas storage cavity is 0.3-0.5 MPa, and the gas storage cavity is connected with the two-way one-way valve through the gas conveying pipe, the inner wall of the gas storage cavity is additionally provided with a pressure buffer pad, the volume ratio of the gas storage cavity to the inner wall of the sealed fixed sleeve gas cavity is two to one, and the bottom of the gas storage cavity is installed with a pressure relief valve.

[0014] As a preferred technical scheme of the present application: the top of the measuring assembly is installed with an instrument box which contains the oscilloscope and the power supply, and the outer wall of the instrument box is installed with a transparent observation window, and the bottom of the instrument box is provided with a heat dissipation hole.

[0015] The present application has the following advantages: 1、The terrain flatness measuring device for civil construction measures the terrain flatness through the resistance strain effect principle, and when the ground undulates to drive the movable rod to move up and down in the inside of the sleeve, the contact position of the resistance rod and the annular iron sheet changes, causing the resistance value of the connected circuit to change synchronously, and under the constant voltage, the corresponding current change is generated, and when the constant voltage is applied to the two ends of the resistance rod, the annular iron sheet divides the resistance rod into two series resistances as a sliding contact, according to the voltage division principle, the voltage at both ends of the contact is proportional to the contact position, and by measuring the voltage change, the displacement of the movable rod can be accurately calculated, and then the undulation degree of the terrain is obtained, which has the advantages of good linearity, fast response speed and simple structure.

[0016] 2、The terrain flatness measuring device for civil construction, by controlling the opening and closing state of the electromagnetic adsorber, can switch between continuous dynamic measurement and single-point static calibration double modes; In the power-off state, the device is in the "continuous dynamic measurement" mode, so that the embedded electromagnet in the electromagnetic adsorber does not affect the sliding of the resistance rod; And after the electromagnetic adsorber is powered on through the control panel, the "single-point static precision" mode can be realized, so that the electromagnet will be adsorbed with the metal positioning sheet, and after adsorption and locking, the position of the resistance rod is fixed, so that the oscilloscope can read stable static current value, avoiding the error caused by "instantaneous current fluctuation" in dynamic measurement, and making the review of key points such as the bottom of foundation pit, roadbed compaction area, beam column foundation drop point; And after calibration, the electromagnet inside the electromagnetic adsorber is powered off and released by sending a signal through the control panel, the resistance rod returns to free sliding, and the continuous measurement mode is restored, so that the device not only meets the requirements of large-area rapid scanning and captures the high-frequency fluctuations of the ground by using the advantages of electrical signal response, but also can fix the position of the resistance rod through electromagnetic adsorption and mechanical positioning, eliminate the error of "vibration interference and current drift" in dynamic measurement, and realize high-precision review of key points without the need for additional calibration tools. Even in harsh environments, the measurement can be quickly completed, and the efficiency of on-site operation is improved.

[0017] 3、The terrain flatness measuring device for civil construction, by compressing the gas in the inner wall of the closed fixed sleeve gas cavity through the compression plate when the movable rod moves, and making the damping force generated by compression filter the high-frequency small bumps of the ground, the whole is more stable, the accuracy of continuous measurement of rough terrain is improved, and the stress load of the compression spring is reduced by gas-assisted reset, while the damping effect reduces the impact friction between the movable rod and the inner wall of the sleeve, prolonging the service life of the device. At the same time, the closed gas path in the sleeve can prevent dust and mud from entering the inside, avoiding the jamming of the movable rod, and improving the reliability of the device in harsh environments on the construction site; Without external power such as power supply and hydraulic oil, only the mechanical energy of the movable rod expansion is used to compress the gas, which is recycled and reused, the structure is extremely simple, the failure rate is low, and in continuous measurement, the transmission stability is improved; In single-point review, the movable rod is locked and fixed, the pressure in the gas cavity remains stable, and the accurate reading is not affected, solving the pain points of "high-frequency bumps leading to counting errors, movable rod jamming, and serious wear" in traditional mechanical measurement. The structure is simple, the cost is controllable, and it is completely suitable for the measurement needs of civil construction site. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The figure is a three-dimensional structure schematic diagram of the present application; Figure 2 The figure is another side structure schematic diagram of the present application; Figure 3It is a schematic view of the bottom structure of the application; Figure 4 It is a schematic view of the sectional structure of the application; Figure 5 It is a schematic view of the support frame structure of the application; Figure 6 It is a schematic view of the measuring wheel structure of the application; Figure 7 It is a schematic view of the gas recovery assembly structure of the application; Figure 8 It is a schematic view of the measuring assembly structure of the application; Figure 9 It is a schematic view of the measuring assembly structure of the application; Figure 5 It is a schematic view of the enlarged structure at A of the application; Figure 10 It is a schematic view of the performance comparison between the measuring method of the application and the traditional measuring method.

[0019] In the figure: 1, base; 2, gas recovery assembly; 3, measuring wheel; 4, gas storage cavity; 5, support frame; 6, measuring assembly; 7, car hook; 8, push rod; 9, control panel; 10, suspension structure; 11, moving wheel; 12, clamping groove; 201, sleeve; 202, airtight fixed sleeve gas cavity; 203, compression plate; 204, movable rod; 205, bottom plate; 206, compression spring; 207, limiting sleeve ring; 208, gas conveying pipe; 209, bidirectional one-way valve; 601, fixed frame; 602, fixed clamping block; 603, annular iron sheet; 604, resistance bar; 605, metal positioning sheet; 606, wiring head one; 607, wiring head two; 608, insulating support; 609, electromagnetic adsorber. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0021] Please refer to Figures 1-10The utility model provides a kind of topographic flatness measuring device for civil engineering, including base 1, the top of base 1 is equipped with clamping groove 12, the inner wall of clamping groove 12 is equipped with gas recovery component 2, the bottom of gas recovery component 2 is installed with measuring wheel 3, the top of base 1 is installed with support frame 5, support frame 5 is equipped with gas storage cavity 4 on outer wall, the top of gas recovery component 2 is equipped with measuring component 6, the outer wall of one side of base 1 is fixedly equipped with car hook 7, and the outer wall of another side of base 1 is fixedly installed with push rod 8, push rod 8 is fixedly equipped with control panel 9 on outer wall, the bottom of base 1 is installed with suspension structure 10, and both ends of suspension structure 10 are equipped with moving wheel 11.

[0022] In the above structure, by the setting of suspension structure 10 and the installation position characteristics of suspension structure 10, the measuring wheel 3 can absorb the impact of the road surface when measuring the topographic flatness, keeping the vehicle body as level and stable as possible, which makes the device work more accurately and provides a reliable attitude reference for the measurement process of the entire device. The problem of high-frequency vibration of the measuring wheel 3 caused by the slight undulation of the road surface when the vehicle is driving on uneven road surface, which directly and without attenuation transmits to the vehicle body and affects the accuracy of the measurement data, is solved.

[0023] In a preferred embodiment: the number of clamping grooves 12 is three, and the three clamping grooves 12 are evenly distributed on the top of the base 1, the diameter of the clamping groove 12 is matched with the diameter of the gas recovery component 2, the outer wall of the moving wheel 11 is inlaid with anti-skid lines, the number of measuring wheels 3 is three, and the three measuring wheels 3 are evenly distributed between the two groups of suspension structures 10.

[0024] In the above structure, by the setting of measuring wheel 3 and the number characteristics of measuring wheel 3, the measuring wheel 3 can detect the initial flatness of the construction site and the continuous flatness of the roadbed during movement, and by controlling the gas recovery component 2 and the measuring component 6, the measuring wheel 3 can quickly understand the overall topographic flatness during construction and accurately confirm the exceeding point or key area without carrying multiple sets of equipment, improving the measurement efficiency and data reliability. At the same time, through the setting of car hook 7 and push rod 8, the device can be connected to other vehicles through car hook 7 to drive the device to move and measure the topographic flatness, or the device can be moved by manually pushing the push rod 8 to measure the topographic flatness.

[0025] In one preferred embodiment: the gas recovery assembly 2 comprises a sleeve 201, the inner wall of the sleeve 201 is fixedly provided with a sealed fixed sleeve air chamber 202, the inner wall of the sleeve 201 is slidingly connected with a movable rod 204, the outer wall of the movable rod 204 is fixedly sleeved with a compression plate 203, the outer wall of the movable rod 204 is fixedly sleeved with a bottom plate 205, one end of the compression spring 206 is fixedly connected to the top of the bottom plate 205, and the other end of the compression spring 206 is fixedly connected with a limiting sleeve ring 207, one end of the sealed fixed sleeve air chamber 202 is clamped with a gas conveying pipe 208, and the outer wall of the gas conveying pipe 208 is provided with a bidirectional check valve 209.

[0026] In the above structure, the movable rod 204 is stretched upward, the compression plate 203 extrudes the sealed gas in the sealed fixed sleeve air chamber 202, so that the gas enters the inner wall of the storage cavity 4 through the bidirectional check valve 209 for recovery and storage, and the damping force generated by the compression of the gas can slow down the rapid downward movement of the movable rod 204, and the recovered gas in the storage cavity 4 is released in the opposite direction through another set of bidirectional check valves 209, which pushes the movable rod 204 to move downward and resets, assisting the compression spring 206 to reduce the jamming of the movable rod 204, and avoiding energy waste caused by direct gas discharge.

[0027] In one preferred embodiment: the number of gas recovery assemblies 2 is three, and the three gas recovery assemblies 2 are evenly distributed on the top of the base 1, the bottom of the movable rod 204 is fixedly connected with the top of the measuring wheel 3, one end of the gas conveying pipe 208 penetrates the sleeve 201 and is clamped on the inner wall of the sealed fixed sleeve air chamber 202, and the other end of the gas conveying pipe 208 is clamped on the bottom of the sleeve 201, the inner diameter of the limiting sleeve ring 207 is larger than the diameter of the movable rod 204, and the limiting sleeve ring 207 is fixedly installed on the inner wall of the sleeve 201, the gas conveying pipe 208 is made of wear-resistant nylon pipe, and the outer diameter of the gas conveying pipe 208 is φ4-6mm.

[0028] In the above structure, the outer edge position of the compression plate 203 in contact with the sealed fixed sleeve air chamber 202 is embedded with a double-layer O-shaped sealing ring, and the double-layer O-shaped sealing ring is made of wear-resistant rubber, which can effectively prevent gas leakage in the inner cavity of the sealed fixed sleeve air chamber 202, effectively reduce the friction and wear between the compression plate 203 and the sealed fixed sleeve air chamber 202, and reduce the stress load of the compression spring 206 through gas assisted reset, reduce the impact friction between the movable rod 204 and the sleeve 201, and prolong the service life of the device.

[0029] In a preferred implementation: the diameter of the compression plate 203 is matched with the inner diameter of the airtight fixed sleeve air cavity 202, and the movable rod 204 drives the compression plate 203 to slide on the inner wall of the airtight fixed sleeve air cavity 202, the number of the two-way check valve 209 is two, and the two two-way check valves 209 are respectively installed on the outer wall of the sleeve 201 near the outer wall gas pipe 208 of the one end of the gas storage cavity 4, the two-way check valve 209 is made of small brass, and the outer edge position of the compression plate 203 in contact with the airtight fixed sleeve air cavity 202 is embedded with a double-layer O-shaped sealing ring, and the double-layer O-shaped sealing ring is made of wear-resistant rubber.

[0030] In the above structure, through the installation position of the two-way check valve 209 and the characteristics of the two-way check valve 209, the two-way check valve 209 can control the one-way of the gas pipe 208 to the gas storage cavity 4, and make the gas pipe 208 and the gas storage cavity 4 in a conductive state during compression, and the other way from the gas storage cavity 4 backflow, so that the gas storage cavity 4 and the gas pipe 208 are in a conductive state through the two-way check valve 209 during reset, ensuring that the gas can only be "compressed → recovered → released" one-way circulation, so that the gas one-way flow can be effectively controlled, backflow is avoided, and the whole gas circuit is a closed loop, the gas circulates between the airtight fixed sleeve air cavity 202 and the gas storage cavity 4, there is no leakage and no emission, which is suitable for the dust and humid environment of civil construction site, without additional gas supplement, and the gas flow speed can be adjusted by replacing the diameter of the two-way check valve 209, and then the damping force size is adjusted, so that the rough terrain selects large damping, and the flat terrain selects small damping, improving the functionality of the whole device.

[0031] In a preferred implementation: the measurement assembly 6 includes a fixed frame 601, a fixed clamping block 602 is fixedly installed on the outer wall of the fixed frame 601, an annular iron sheet 603 is fixedly assembled on the inner wall of the fixed clamping block 602, an electric resistance rod 604 is slidably sleeved on the inner wall of the annular iron sheet 603, a metal positioning sheet 605 is fixedly embedded on the top of the electric resistance rod 604, a wiring head one 606 is installed on the outer wall of the electric resistance rod 604, a wiring head two 607 is installed on the bottom of the annular iron sheet 603, an insulating support 608 is fixedly assembled on the top of the fixed frame 601, and an electromagnetic attractor 609 is installed on the bottom of the insulating support 608.

[0032] In the above structure, the electromagnetic adsorber 609 can generate magnetic force to adsorb the metal positioning sheet 605 when powered on through the control panel 9, so as to fix the position of the resistance rod 604, and release when powered off, without affecting continuous measurement. Since the installation position of the metal positioning sheet 605 avoids the sliding contact area of the annular iron sheet 603, the metal positioning sheet 605 can effectively ensure that it does not rub with the annular iron sheet 603 when the resistance rod 604 slides, so as not to affect the current stability. Moreover, the electromagnetic force of the electromagnetic adsorber 609 is controlled at 5-8 N: it can not only stably lock the resistance rod 604 and offset the gravity of the movable rod 204 and slight ground vibration, but also will not cause the resistance rod 604 to slide and jam due to excessive suction, thereby affecting the smoothness of continuous measurement; And the electromagnetic adsorber 609 can present a dual-mode working principle through the control panel 9: Mode one: continuous dynamic measurement default mode, the electromagnet on the inner wall of the electromagnetic adsorber 609 is in a powered-off state; When the electromagnet is powered off, there is no magnetic force adsorption, and the metal positioning sheet 605 moves freely with the resistance rod 604 on the inner wall of the annular iron sheet 603; When the ground fluctuation drives the resistance rod 604 to slide up and down, the contact position of the resistance rod 604 with the annular iron sheet 603 changes, and the circuit resistance changes synchronously, and the current fluctuates in real time under constant voltage; The oscilloscope continuously collects current signals and converts them into terrain fluctuation displacement data, realizing continuous dynamic measurement without interference from the electromagnetic module; Mode two: single-point static calibration, the electromagnet on the inner wall of the electromagnetic adsorber 609 is in a powered-on state through the control panel 9; When the oscilloscope displays abnormal current changes at a certain point, such as excessive fluctuation value, or when precise rechecking is needed for key areas such as the bottom of the foundation pit and the roadbed compaction point, the control panel 9 can emit signals; The electromagnet inside the electromagnetic adsorber 609 is powered on to generate magnetic force, attract the metal positioning sheet 605 on the top of the resistance rod 604, and lock the position of the resistance rod 604 instantaneously after the two are adsorbed, which can effectively avoid reading drift caused by equipment vibration and slight current fluctuations; At this time, the current value displayed by the oscilloscope is a static stable value, and the precise fluctuation displacement of the point can be calculated by combining the conversion formula; After the measurement is completed, the electromagnet can be powered off to release, and the resistance rod 604 can restore free sliding to return to the continuous measurement mode; The structure is simple, and no redundant design is needed. Only two small components, i.e., the electromagnet on the electromagnetic adsorber 609 and the metal positioning sheet 605, are added, without the need for additional independent calibration structure, without increasing the volume and weight of the equipment, and adapting to the portability requirements of the construction site. The continuous measurement mode can meet the requirements of large-area rapid scanning, and the high-frequency fluctuations of the ground can be captured by taking advantage of the fast response of the electrical signal. The single-point calibration mode can fix the position of the resistance rod 604 through mechanical positioning by electromagnetic adsorption, eliminate the vibration interference and current drift error in dynamic measurement, and realize high-precision review of key points without the need for additional calibration tools. There is no electromagnetic interference, and the measurement is accurate. The resistance sensing circuit of the electromagnet and the resistance rod 604 is isolated by the fixed frame 601, and is only powered during static calibration, without continuously generating electromagnetic interference to affect the conductive contact between the resistance rod 604 and the annular iron sheet 603, ensuring the stability of the current signal.

[0033] In a preferred embodiment: the resistance rod 604 is made of high-stability alloy copper wire, and the bottom of the resistance rod 604 is fixedly connected to the top of the movable rod 204. The two ends of the terminal head one 606 are connected to the power supply positive and negative poles through the terminal head one 606. The annular iron sheet 603 is connected to the oscilloscope through the terminal head two 607 and the wire. The inner cavity of the electromagnetic adsorber 609 is provided with a small DC electromagnet, and the suction force of the electromagnetic adsorber 609 is slightly larger than the outer diameter of the metal positioning sheet 605. The metal positioning sheet 605 is coaxially welded and fixed with the resistance rod 604, and the metal positioning sheet 605 is made of a thin brass sheet. The diameter of the metal positioning sheet 605 is smaller than the diameter of the resistance rod 604.

[0034] In the above structure, when the measuring wheel 3 is in contact with the ground, the measuring wheel 3 will fluctuate due to the change of the terrain, thereby driving the resistance rod 604 to slide up and down on the inner wall of the annular iron sheet 603. At this time, the contact position between the inner wall of the annular iron sheet 603 and the outer wall of the resistance rod 604 changes, resulting in a change in the resistance value of the connected circuit. According to Ohm's law , the constant voltage , the current changes linearly with the resistance , the oscilloscope records the current change curve, and then converts the current signal into the extension displacement of the resistance rod 604, i.e., the terrain fluctuation, so as to complete the measurement of the terrain flatness. In a preferred embodiment: the resistance value of the resistance rod 604 is 100-500Ω, the bottom of the resistance rod 604 is integrally fixed with the top of the movable rod 204, and the virtual center line of the resistance rod 604 coincides with the virtual center line of the movable rod 204, the annular iron sheet 603 is made of brass, and the inner wall of the annular iron sheet 603 is silver-plated, the inner side of the annular iron sheet 603 is smeared with conductive paste, the electromagnetic adsorber 609 is electrically connected with the control panel 9, the electromagnetic adsorber 609 shares the same constant power supply with the resistance rod 604, and the electromagnetic adsorber 609 is controlled by the independent switch on the control panel 9.

[0035] In the above structure, by the resistance value of the resistance rod 604 and the length of the resistance rod 604, it can be ensured that the current change can be measured, the annular iron sheet 603 is made of brass, and the inner wall of the annular iron sheet 603 is silver-plated, which can make the annular iron sheet 603 have good conductivity, wear resistance, and can also reduce the contact resistance, and effectively reduce the wear and contact resistance, and by the uniform speed pushing device moving along the measurement route, the measurement wheel 3 drives the movable rod 204 to stretch up and down with the ground fluctuation, and synchronously drives the top resistance rod 604 to slide in the annular iron sheet 603; The up and down sliding of the resistance rod 604 changes the circuit resistance, and the current changes in real time with the terrain fluctuation under constant voltage, and the oscilloscope continuously records the current change curve, the horizontal axis is time, and the vertical axis is current; The current data is derived from the oscilloscope or the waveform peak value / valley value is directly read, and the current change amount of each sampling point is calculated ; The conversion formula is substituted , to obtain the terrain fluctuation displacement of each measurement point, the positive value is concave, the negative value is convex, and the absolute value is the fluctuation size; Statistical analysis: The maximum fluctuation value is the maximum value of all absolute values in a certain measurement section; The average flatness is the arithmetic mean or standard deviation of all absolute values in a certain measurement section, and when the oscilloscope shows that the current change amount of a certain point exceeds the standard, the moving device is stopped, and the continuous measurement of the terrain can be completed.

[0036] In a preferred embodiment: the shape of the gas storage cavity 4 is cylindrical, the gas storage cavity 4 is made of aluminum alloy, the pressure resistance of the gas storage cavity 4 is 0.3-0.5MPa, the gas storage cavity 4 is connected with the bidirectional one-way valve 209 through the gas conveying pipe 208, the inner wall of the gas storage cavity 4 is additionally provided with a pressure buffer pad, the volume ratio of the gas storage cavity 4 to the inner wall of the sealed fixed sleeve gas cavity 202 is 2:1, and the bottom of the gas storage cavity 4 is provided with a pressure relief valve.

[0037] The characteristics of the pressure buffer pad added to the inner wall of the gas storage cavity 4 can effectively avoid pressure mutation. Since the volume ratio of the gas storage cavity 4 to the inner wall of the closed fixed sleeve gas cavity 202 is 2:1, the pressure of the compressed gas can be ensured to be less than 0.5 MPa, thereby effectively avoiding the problem that the movement of the movable rod 204 is blocked due to excessive pressure. Since the site environment is humid, a small amount of water vapor may condense and be stored in the inner wall of the gas storage cavity 4. A pressure relief valve can be arranged at the bottom of the gas storage cavity 4, which is closed at ordinary times and opened during maintenance, so that the accumulated water in the gas storage cavity 4 can be periodically discharged, thereby effectively avoiding the influence on the air tightness.

[0038] In a preferred embodiment, the top of the measuring assembly 6 is provided with an instrument box which accommodates an oscilloscope and a power supply. A transparent observation window is arranged on the outer wall of the instrument box, and a heat dissipation hole is arranged at the bottom of the instrument box.

[0039] In the above structure, the transparent observation window arranged on the outer wall of the instrument box can facilitate reading of data, and the heat dissipation hole arranged at the bottom of the instrument box can effectively avoid the influence of power supply heating on the equipment. The oscilloscope can display the fluctuating waveform in real time, and the trend of terrain change such as continuous depression and local protrusion can be directly judged without manual conversion of the number of turns.

[0040] Working principle: when using the device, the device can be moved to the position where the terrain flatness measurement is needed by connecting the car hook 7 with the mobile equipment, or the measuring wheel 3 can measure the terrain flatness by moving the mobile wheel 11 on the ground by manually pushing the push rod 8. When the measuring wheel 3 contacts the ground, the measuring wheel 3 will fluctuate due to the change of the terrain, thereby driving the movable rod 204 to slide up and down on the inner wall of the sleeve 201. The compression plate 203 is pressed to compress the closed gas in the closed fixed sleeve gas cavity 202 by the upward and downward extension of the movable rod 204, so that the gas enters the inner wall of the gas storage cavity 4 through the bidirectional check valve 209 for recycling and storage. At the same time, the damping force generated by the compression of the gas can slow down the rapid downward movement of the movable rod 204, and the recycled gas in the gas storage cavity 4 is released in the opposite direction through another group of bidirectional check valves 209 to drive the movable rod 204 to move downward and reset, thereby reducing the jamming of the movable rod 204 and avoiding energy waste caused by direct discharge of the gas. The movable rod 204 drives the resistance rod 604 to slide up and down on the inner wall of the annular iron sheet 603. At this time, the contact position between the inner wall of the annular iron sheet 603 and the outer wall of the resistance rod 604 changes, resulting in a change in the resistance value of the connected circuit. According to Ohm's law , the current changes with the resistance . Linear change, oscilloscope record current change curve, and then through the conversion formula to convert the current signal to the telescopic displacement of the resistance rod 604, that is, the amount of terrain undulation, so as to complete the measurement of the terrain flatness; The measurement formula is: Since the resistance of the resistance rod 604 is linearly related to the length (uniform resistance), when the sliding rod moves , the resistance change of the access circuit is , that is:

[0041] According to Ohm's law, under a constant voltage ; The circuit current change is: ; Since is much smaller than , the formula can be simplified as: ; Substitute , and finally derive the terrain undulation displacement formula: ; Formula simplification and calibration (eliminate system error): In practical application, the proportional coefficient of "current change-displacement" can be determined by the reference calibration , and the calculation is simplified: ; Calibration method: fix the movable rod 204 on the reference frame with known displacement, record the corresponding , calculate the value through linear fitting (ensure the fitting degree ), turn on the constant power supply, place the movable rod 204 in the middle, and record the reference current displayed by the oscilloscope , determine the proportional coefficient through the calibration formula; and turn on the waveform recording function. At this time, by transmitting signals through the control panel 9, the electromagnetic adsorber 609 can generate magnetic force to adsorb the metal positioning sheet 605 when powered on, so that it can fix the position of the resistance rod 604, and release when powered off, without affecting continuous measurement. Since the installation position of the metal positioning sheet 605 avoids the sliding contact area of the annular iron sheet 603, the metal positioning sheet 605 can effectively ensure that the resistance rod 604 does not rub with the annular iron sheet 603 when sliding, so as not to affect the current stability. By controlling the electromagnetic force of the electromagnetic adsorber 609 to be 5-8N, the resistance rod 604 can be stably locked, and the gravity of the movable rod 204 and slight ground vibration can be offset, without causing the resistance rod 604 to slide and jam due to excessive suction, affecting the smoothness of continuous measurement. And the electromagnetic adsorber 609 controlled by the control panel 9 can present the dual-mode working principle of the device:​ Mode one: continuous dynamic measurement default mode, the electromagnet in the inner wall of the electromagnetic adsorber 609 is in a power-off state; When the electromagnet is powered off, there is no magnetic force adsorption, and the metal positioning sheet 605 will move freely with the resistance rod 604 on the inner wall of the annular iron sheet 603; When the ground undulates to drive the resistance rod 604 to slide up and down, the contact position of the resistance rod 604 with the annular iron sheet 603 changes, and the circuit resistance changes synchronously, and the current fluctuates in real time under constant voltage; The oscilloscope continuously collects current signals, converts them into terrain undulation displacement data, and realizes continuous dynamic measurement without interference from the electromagnetic module; Mode two: single-point static calibration, switch by sending signals from the control panel 9, so that the electromagnet in the inner wall of the electromagnetic adsorber 609 is in a powered-on state; When the oscilloscope shows that the current of a certain point changes abnormally, such as undulation value exceeding the standard or the need for accurate rechecking of key areas such as the bottom of the foundation pit and the roadbed compaction point, the control panel 9 can send signals; The electromagnet inside the electromagnetic adsorber 609 is powered on to generate a magnetic force, attracting the metal positioning sheet 605 on the top of the resistance rod 604, so that the two are adsorbed and the position of the resistance rod 604 is locked instantly, which can effectively avoid reading drift caused by equipment vibration and slight current fluctuations; At this time, the current value displayed by the oscilloscope is a static stable value, and the accurate undulation displacement of the point can be calculated by combining the conversion formula; After the measurement is completed, the electromagnet can be powered off to release, and the resistance rod 604 can resume free sliding to return to the continuous measurement mode, and the current change can be ensured to be measurable through the resistance value of the resistance rod 604 and the length of the resistance rod 604; The up and down sliding of the resistance rod 604 changes the circuit resistance, and the current changes in real time with the terrain undulation under constant voltage, and the oscilloscope continuously records the current change curve, with the horizontal axis as time and the vertical axis as current; The current data is derived from the oscilloscope or the waveform peak / valley is directly read, and the current change of each sampling point is calculated ; Substitute the conversion formula , and get the terrain undulation displacement of each measurement point, positive value = depression, negative value = protrusion, and absolute value = undulation size; Statistical analysis: Maximum undulation value: the maximum value of all absolute values in a certain measurement section; Average flatness: the average value of all The absolute value arithmetic average or standard deviation is calculated, and when the oscilloscope shows that the current change of a certain point exceeds the standard, the moving device is stopped, and continuous measurement of the terrain can be completed, so that the device can meet the demand of large-area rapid scanning through the continuous measurement mode, and the single-point calibration mode eliminates dynamic interference through mechanical positioning, and improves the measurement efficiency.

[0042] It should be noted that the relational terms herein such as first and second and the like are used solely to distinguish one entity or action from another, without necessarily requiring or implying any such actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0043] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, alternatives, and variations can be made in the embodiments without departing from the spirit and scope of the present application as defined by the appended claims and their equivalents.

Claims

1. A device for measuring the flatness of a terrain for civil engineering, comprising a base (1), characterized in that: The top of the base (1) is provided with a clamping groove (12), the inner wall of the clamping groove (12) is provided with a gas recovery assembly (2), the bottom of the gas recovery assembly (2) is provided with a measuring wheel (3), and the top of the gas recovery assembly (2) is provided with a measuring assembly (6). The gas recovery assembly (2) comprises a sleeve (201), the inner wall of the sleeve (201) is slidably connected with a movable rod (204), the outer wall of the movable rod (204) is fixedly sleeved with a compression plate (203), the outer wall of the movable rod (204) is fixedly sleeved with a bottom plate (205), one end of the compression spring (206) is fixedly connected with the top of the bottom plate (205), and the other end of the compression spring (206) is fixedly connected with a limiting sleeve ring (207). The bottom of the movable rod (204) is fixedly connected with the top of the measuring wheel (3), the inner diameter of the limiting sleeve ring (207) is greater than the diameter of the movable rod (204), and the limiting sleeve ring (207) is fixedly installed on the inner wall of the sleeve (201). The measuring assembly (6) comprises a fixed frame (601), the outer wall of the fixed frame (601) is fixedly installed with a fixed clamping block (602), the inner wall of the fixed clamping block (602) is fixedly assembled with an annular iron sheet (603), the inner wall of the annular iron sheet (603) is slidably sleeved with a resistance stick (604), the top of the resistance stick (604) is fixedly embedded with a metal positioning sheet (605), the top of the fixed frame (601) is fixedly assembled with an insulating support (608), the bottom of the insulating support (608) is installed with an electromagnetic adsorber (609), the bottom of the resistance stick (604) is fixedly connected with the top of the movable rod (204), and the inner cavity of the electromagnetic adsorber (609) is installed with a small DC electromagnet.

2. The device for measuring the flatness of a terrain for civil engineering and construction according to claim 1, characterized in that: The top of the base (1) is provided with a clamping groove (12), the inner wall of the clamping groove (12) is provided with a gas recovery assembly (2), the bottom of the gas recovery assembly (2) is provided with a measuring wheel (3), and the top of the gas recovery assembly (2) is provided with a measuring assembly (6).

3. The device for measuring the flatness of a terrain for civil engineering and construction according to claim 1, characterized in that: The inner wall of the sleeve (201) is fixedly installed with a sealed fixed sleeve gas cavity (202), one end of the sealed fixed sleeve gas cavity (202) close to the gas storage cavity (4) is clamped with a gas conveying pipe (208), and the outer wall of the gas conveying pipe (208) is provided with a bidirectional check valve (209).

4. The device for measuring the flatness of a terrain for civil engineering and construction according to claim 3, characterized in that: The quantity of the gas recovery assembly (2) is three groups, and the three groups of gas recovery assembly (2) are evenly distributed on the top of the base (1), one end of the gas pipe (208) penetrates the sleeve (201) and is clamped on the inner wall of the closed fixed sleeve air cavity (202), and the other end of the gas pipe (208) is clamped on the bottom of the sleeve (201), and the gas pipe (208) is made of wear-resistant nylon pipe.

5. The device for measuring the flatness of a terrain for civil engineering according to claim 4, characterized in that: The diameter of the compression plate (203) is matched with the inner diameter of the closed fixed sleeve air cavity (202), and the movable rod (204) drives the compression plate (203) to slide on the inner wall of the closed fixed sleeve air cavity (202), the quantity of the two-way check valve (209) is two, and the two two-way check valves (209) are respectively installed on the outer wall of the gas pipe (208) on the outer wall of the sleeve (201) near the gas storage cavity (4), the two-way check valve (209) is made of small brass, and the outer edge of the compression plate (203) in contact with the closed fixed sleeve air cavity (202) is embedded with a double-layer O-shaped sealing ring, and the double-layer O-shaped sealing ring is made of wear-resistant rubber.

6. The device for measuring the flatness of a terrain for civil engineering and construction according to claim 1, characterized in that: The outer wall of the resistance rod (604) is provided with a terminal (606), and the bottom of the annular iron sheet (603) is provided with a terminal (607).

7. The device for measuring the flatness of a terrain for civil engineering according to claim 6, characterized in that: The resistance rod (604) is made of high-stability alloy constantan wire, the two ends of the terminal (606) are connected with the positive and negative electrodes of the power supply through the terminal (606) connecting lead, the annular iron sheet (603) is connected with the oscilloscope through the terminal (607) and the lead, the suction force of the electromagnetic adsorber (609) is 5-8N, the inner diameter of the electromagnetic adsorber (609) is slightly larger than the outer diameter of the metal positioning sheet (605), the metal positioning sheet (605) is coaxially welded and fixed with the resistance rod (604), and the metal positioning sheet (605) is made of thin brass sheet, and the diameter of the metal positioning sheet (605) is smaller than that of the resistance rod (604).

8. The device for measuring the flatness of a terrain for civil engineering according to claim 7, characterized in that: The resistance value of the resistance rod (604) is 100-500Ω, the bottom of the resistance rod (604) is integrally fixed with the top of the movable rod (204), and the virtual center line of the resistance rod (604) coincides with the virtual center line of the movable rod (204), the annular iron sheet (603) is made of brass, and the inner wall of the annular iron sheet (603) is plated with silver, the inner side of the annular iron sheet (603) is coated with conductive paste, the electromagnetic adsorber (609) is electrically connected with the control panel (9), the electromagnetic adsorber (609) and the resistance rod (604) share the same constant power supply, and the electromagnetic adsorber (609) is controlled by the independent switch on the control panel (9).

9. The device for measuring the flatness of a terrain for civil engineering according to claim 2, characterized in that: The shape of the gas storage cavity (4) is cylindrical, and the gas storage cavity (4) is made of aluminum alloy, the pressure resistance of the gas storage cavity (4) is 0.3-0.5MPa, and the gas storage cavity (4) is connected with the two-way one-way valve (209) through the gas conveying pipe (208), the inner wall of the gas storage cavity (4) is additionally provided with a pressure buffer pad, the volume ratio of the gas storage cavity (4) to the inner wall of the sealed fixed sleeve gas cavity (202) is two to one, and the bottom of the gas storage cavity (4) is provided with a pressure relief valve.

10. The device for measuring the flatness of a terrain for civil engineering and construction according to claim 1, characterized in that: The top of the measuring assembly (6) is provided with an instrument box, which contains an oscilloscope and a power supply, a transparent observation window is arranged on the outer wall of the instrument box, and a heat dissipation hole is arranged on the bottom of the instrument box.

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