A compaction rebound device and method of measuring compaction

Abstract

The present application relates to a kind of compaction rebound device and compaction degree measuring method, compaction rebound device includes impact head and device support, the bottom of impact head has for with road surface contact cooperation impact head contact part, device base includes annular contact part for with road surface contact cooperation, annularly arranged in the periphery of impact head contact part, spring is arranged between device base and impact head for to impact head is applied to the force of direction action towards down, compaction rebound device also includes for the height of the height measuring device for detecting the rebound height of impact hammer after impact hammer collides impact head, impact hammer and the height lifting mechanism for lifting the height of impact hammer upper end is struck down.The present application provides a kind of compaction degree measuring method for measuring road surface compaction degree using road surface rebound amount and the compaction degree measuring method used in this compaction degree measuring method.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of pavement compaction degree measurement, and in particular to a compaction degree measurement method using a rebound device. BACKGROUND

[0002] The compaction degree refers to the ratio of the density of the compacted road material to the standard density, expressed in percentage, and the letter k represents.

[0003] The compaction of road material is usually achieved by using a compactor on site, and the standard density refers to the maximum density of the road material under standard laboratory conditions as the specified optimal proportion. For the on-site soil-based road material which is sensitive to water content, the standard density is the maximum dry density.

[0004] The standard density is usually obtained in a laboratory, and the specific method is as follows: the road material with the same proportion as the on-site one is placed in a compaction cylinder, and then the road material is compacted by a striking head. The judgment standard for compaction is that the volume of the road material does not change, which is called compaction, so that the volume of the compacted road material is obtained. Then, the standard density of the road material is obtained according to the mass of the road material.

[0005] The on-site density of the roadbed made of road material is obtained as follows: at the construction site, a cylindrical pit with a certain cross-sectional area is dug on the road surface, and then sand is filled in the cylindrical pit. After the sand is leveled, the sand is taken out, and the sand is used to measure the volume of the cylindrical pit. The weight of the road material dug out of the cylindrical pit is measured, so as to calculate the actual density of the on-site road material. Compared with the standard density, the compaction degree of the road material is obtained. The closer the actual density is to the standard density, the better the compaction effect of the roadbed.

[0006] At the construction site, multiple sections of the road surface need to be tested, which means that the work of on-site digging, sand filling, and sand collecting needs to be performed on each section of the road surface. The work intensity is high, the measurement efficiency is low, and the road surface digging operation is a kind of destructive detection, which is not conducive to the structural stability of the roadbed. SUMMARY

[0007] The present application provides a compaction degree measurement method using the rebound amount of the road surface to measure the compaction degree of the road surface, and the present application also provides a rebound device used in the compaction degree measurement method.

[0008] To solve the above technical problems, the technical scheme of a rebound device in the present application is as follows:

[0009] A compaction rebound device comprises a ram head and a device base, the bottom of the ram head has a ram head contact part for contact matching with the road surface, the device base comprises an annular contact part for contact matching with the road surface, which is arranged around the periphery of the ram head contact part, a spring is arranged between the device base and the ram head for applying a downward force to the ram head, the compaction rebound device further comprises a rammer for hitting the upper end of the ram head downward and a height lifting mechanism for lifting the height of the rammer, and the compaction rebound device further comprises a height measuring device for detecting the rebound height of the rammer after hitting the ram head.

[0010] Further, the weight of the ram head is the same as the weight of the rammer.

[0011] Further, the stress area generated by the ram head when impacting the road surface is located in the projection of the annular contact part in the upward and downward directions.

[0012] Further, the device base comprises a base sleeve arranged around the periphery of the ram head, the upper end of the base sleeve is provided with a sleeve upper end inward flange, the ram head is provided with a ram head flange arranged side by side with the sleeve upper end inward flange, the ram head flange is located on the lower side of the sleeve upper end inward flange, and the spring is a compression spring mounted between the sleeve upper end inward flange and the ram head flange.

[0013] Further, the lower end of the base sleeve is provided with a sleeve lower end inward flange, the bottom of the ram head is in contact with the ground after passing through the inner hole of the sleeve lower end inward flange, and the bottom surface of the sleeve lower end inward flange constitutes the annular contact part.

[0014] Further, the bottom of the rammer is a ball head structure for realizing point contact and impact with the upper end of the ram head.

[0015] Further, a vertically arranged guide rod is arranged on the device base, and the rammer is guided and moved in cooperation with the guide rod.

[0016] Further, the height measuring device comprises a laser displacement sensor arranged between the device base and the rammer.

[0017] The technical scheme of the compaction degree measuring method in the application is:

[0018] The compaction degree measuring method comprises the following steps: first, placing the same roadbed material as the detected road surface in n tamper barrels respectively, n is a positive integer not less than 3, using an impact hammer to impact the roadbed material in the corresponding tamper barrel, so that the density of the roadbed material in each tamper barrel is respectively ρ1, ρ2,..., ρn, wherein ρ1>ρ2>...>ρn, and ρ1 is the standard density; second, measuring the impact hammer rebound value of the roadbed material in each tamper barrel using a tamper rebound device, recording the impact hammer rebound value of the roadbed material in each tamper barrel as A1, A2,..., An, and finding out the relationship curve between the impact hammer rebound value and the density of the roadbed material; third, measuring the rebound value of the detected road surface using the tamper rebound device, recording the rebound value of the detected road surface as A, and finding out the density value ρ of the roadbed material corresponding to A, then the compaction degree of the detected road surface is ρ / ρ1*100.

[0019] Further, the diameter of the impact hammer matches the inner cavity diameter of the tamper barrel.

[0020] The present application has the following advantages: in the present application, after the impact hammer is lifted to a certain height, the impact head impacts the road surface, the density of the road surface with different compaction degrees is different, and the energy absorption capacity is also different, so that the rebound height of the impact hammer is also different for the road surface with different compaction degrees, and the rebound height of the impact hammer represents the density of the road surface, so that the rebound value of the road surface can be calculated, and the impact head contact part and the annular contact part of the impact head are always in contact with the road surface, avoiding the direct impact of the impact hammer on the road surface, which causes additional energy loss due to road surface dust and cracking. BRIEF DESCRIPTION OF DRAWINGS

[0021] The above and other objects, features and advantages of the disclosed example embodiments will become more apparent from the following detailed description, which proceeds with reference to the accompanying drawings. In the drawings, several embodiments of the disclosure are illustrated by way of example and not limitation, in which like or corresponding elements are identified with the same or corresponding reference numbers, in which:

[0022] Figure 1 is a schematic view of the cooperation between the impact hammer and the tamper barrel in the present application;

[0023] Figure 2 is a schematic view of the structure of the tamper rebound device in the present application;

[0024] Figure 3 is a schematic view of the cooperation between the tamper rebound device and the road surface in the present application;

[0025] Figure 4 is a schematic view of the cooperation between the tamper rebound device and the tamper barrel in the present application;

[0026] Reference numerals: 1, impact hammer; 2, roadbed material; 3, compaction cylinder; 4, compaction rebound device; 5, impact hammer; 6, pull rope; 7, lifting drum; 8, guide rod; 9, sleeve; 10, sleeve upper end inner turning edge; 11, spring; 12, impact head; 13, impact head turning edge; 14, laser displacement sensor; 15, impact head matching part; 16, annular contact part; 17, ball head structure; 18, stress area; 19, road surface. DETAILED DESCRIPTION

[0027] In order to facilitate the understanding of the present application, the present application will be described in more detail below in conjunction with the accompanying drawings and specific embodiments. The preferred embodiments of the present application are shown in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described in the specification. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0028] It should be noted that, unless otherwise defined, all technical and scientific terms used in the specification are the same as those commonly understood by those skilled in the art of the present application. The terms used in the specification of the present application are only for the purpose of describing the specific embodiments and are not intended to limit the present application.

[0029] An embodiment of a compaction rebound device in the present application is shown in Figures 1-4 The device includes an impact head 12 and a device base, the bottom of the impact head has an impact head contact part 15 for contact matching with the road surface, the device base includes an annular contact part 16 arranged around the outer periphery of the impact head contact part for contact matching with the road surface, a spring 11 is arranged between the device base and the impact head for applying a downward force to the impact head, the compaction rebound device further includes an impact hammer 5 for downward impact on the upper end of the impact head and a height lifting mechanism for lifting the height of the impact hammer, and the compaction rebound device further includes a height measuring device for detecting the rebound height of the impact hammer after colliding with the impact head.

[0030] In this embodiment, the weight of the impact head 12 is the same as the weight of the impact hammer 5, so that the rebound kinetic energy of the impact head on the road surface can be completely transmitted to the impact hammer. The stress area outer contour generated by the impact head when impacting the road surface is in the projection of the annular contact part in the upward and downward directions. The bottom of the impact hammer is a ball head structure for realizing point contact impact with the upper end of the impact head, the ball center of the ball head structure is on the axis of the impact hammer, and the lowermost end of the ball head structure 17 is a contact point that can transmit force with the impact head, thereby ensuring the stability of force transmission between them.

[0031] The device support includes a support sleeve 9 arranged around the periphery of the impact head, the upper end of the support sleeve 9 is provided with a sleeve upper end inner turning edge 10, the impact head is provided with an impact head turning edge 13 arranged in parallel with the sleeve upper end inner turning edge, the impact head turning edge is located on the lower side of the sleeve upper end inner turning edge, and the spring is a compression spring 11 arranged between the sleeve upper end inner turning edge and the impact head turning edge. The lower end of the support sleeve is provided with a sleeve lower end inner turning edge, the bottom of the impact head passes through the inner hole of the sleeve lower end inner turning edge and contacts the ground, and the bottom surface of the sleeve lower end inner turning edge constitutes the annular contact part 16.

[0032] One side of the support sleeve is fixed with a vertical wall, the top of the vertical wall is fixed with a horizontal wall, the lifting mechanism includes a lifting drum 7 arranged on the horizontal wall, the lifting drum is driven by a speed reducer motor, a pull rope 6 is wound on the lifting drum, the pull rope is connected with the impact hammer, and the lifting drum rotates. When the speed reducer motor stops driving the lifting drum, the impact hammer can freely fall by gravity and impact the impact head.

[0033] The lower end of the horizontal wall is fixed with two spaced apart guide rods 8 arranged vertically, the impact hammer moves in guided cooperation with the guide rods, and the guide rods are located on one side of the contact point of the ball head structure. The height measuring device includes a laser displacement sensor 14 arranged between the device support and the impact hammer.

[0034] In use, the impact head contact part and the annular contact part are always in contact with the road surface, which can avoid the problem of dust generation and loss of rebound energy caused by the impact head directly impacting the road surface and causing the surrounding road surface to crack.

[0035] In use, first, the same roadbed material 2 as the detected road surface is placed in the n impact tins 3, the roadbed material refers to the mixture of sand and concrete, and the roadbed material has not been compacted by a road roller. N is a positive integer not less than 3, for example, n can be 5 in the embodiment, the impact hammer 1 is used to impact the roadbed material in the corresponding impact tin, the diameter of the impact hammer matches the inner cavity diameter of the impact tin, so that the densities of the roadbed materials in the impact tins are ρ1, ρ2, …, ρn respectively, wherein ρ1> ρ2> …> ρn, and ρ1 is the standard density. In specific operation, in order to obtain the standard density, when the impact hammer continuously impacts the roadbed material twice and the thickness of the roadbed material does not change, the roadbed material can be further compressed, and the density of the roadbed material corresponding to this time is the standard density. In order to obtain the standard density, the impact work of the impact hammer on the roadbed material is W1, since the height of the impact hammer is the same each time, the impact work corresponds to the impact times, assuming that the impact times of the impact hammer on the roadbed material to obtain the standard density is 12 times, then when the impact hammer impacts the roadbed material in other impact tins, the impact times can be gradually reduced, so as to obtain the density of the roadbed material in the corresponding impact tin.

[0036] The second step involves using a compaction rebound device to measure the impact hammer rebound value of the subgrade material in each compaction cylinder, recording the impact hammer rebound values ​​of the subgrade material in each compaction cylinder as A1, A2...An, and finding the relationship curve between the impact hammer rebound value and the density of the subgrade material; in specific operations, as follows... Figure 4 As shown, the annular contact part and the impact head contact part are placed on the surface of the subgrade material in the compaction cylinder. The impact hammer is raised to a height h and then released. The impact hammer strikes the surface of the subgrade material through the impact head, causing elastic deformation of the subgrade material and transmitting energy back to the impact hammer through the impact head. Subgrade materials of different densities absorb energy differently, resulting in different rebound heights of the impact hammer. This allows us to determine the relationship between the rebound value of the impact hammer and the density of the subgrade material. When the impact head strikes the surface of the subgrade material, it generates a pear-shaped stress region. Due to the presence of the annular contact surface, this stress region does not extend to the cylinder wall of the compaction cylinder. This means that the cylinder wall of the compaction cylinder does not restrict the impact behavior of the impact head, ensuring that the stress environment is consistent when the impact head subsequently strikes the road surface. If the cylinder wall is too close to the impact head (i.e., the stress area extends to the cylinder wall), when the impact head hits the surface of the subgrade material, the subgrade material will be squeezed by the cylinder wall. However, when measuring the subsequent road surface rebound value, there is no corresponding cylinder wall limiting environment. Therefore, the impact environment of the impact on the subgrade material surface and the road surface will change, which is not conducive to the comparison of the corresponding rebound values.

[0037] The third step involves using a compaction rebound device to measure the rebound value of the inspected road surface. This rebound value is recorded as A. Based on value A, the corresponding density value ρ of the subgrade material is found. Therefore, ρ / ρ1*100 represents the compaction degree of the inspected road surface. Specifically, the annular contact part and the impact head contact part are placed on the road surface. The impact hammer is raised to a height h, and then released. The rebound height of the impact hammer is recorded using a laser displacement sensor.

[0038] The implementation of compaction measurement methods, for example Figures 1-4The first step, when in use, is to place the same roadbed material as the road surface to be detected in n tamper barrels respectively, n is a positive integer not less than 3, for example, n can be 5 in the embodiment, and a impact hammer is used to impact the roadbed material in the corresponding tamper barrel, the diameter of the impact hammer matches the inner cavity diameter of the tamper barrel, so that the density of the roadbed material in each tamper barrel is ρ1, ρ2, …, ρn respectively, wherein ρ1>ρ2>…ρn, and ρ1is the standard density. In the specific operation, in order to obtain the standard density, when the impact hammer continuously impacts the roadbed material twice, the thickness of the roadbed material no longer changes, at this time the roadbed material can be further compressed, and the density of the roadbed material corresponding to this time is the standard density. In order to obtain the standard density, the impact work of the impact hammer on the roadbed material is W1. Since the height of the impact hammer is the same each time, the impact work is correspondingly related to the number of impacts. Assuming that the number of impacts of the impact hammer on the roadbed material to obtain the standard density is 12 times, then when impacting the roadbed material in other tamper barrels, the number of impacts can be gradually reduced, so as to obtain the density of the roadbed material in the corresponding tamper barrel.

[0039] The second step is to use the tamper rebound device to measure the impact hammer rebound value of the roadbed material in each tamper barrel, and record the impact hammer rebound value of the roadbed material in each tamper barrel as A1, A2, …, An, and find the relationship curve of the impact hammer rebound value and the density of the roadbed material; in the specific operation, as shown in the figure, Figure 4 The annular contact part and the impact head contact part are placed on the surface of the roadbed material in the tamper barrel, the impact hammer is lifted to a height h, and then the impact hammer is released. The impact hammer hits the surface of the roadbed material through the impact head, the roadbed material is elastically deformed, and the energy is transmitted back to the impact hammer through the impact head. Different densities of roadbed material absorb different amounts of energy, so that the rebound height of the impact hammer is also different. In this way, the relationship curve of the impact hammer rebound value and the density of the roadbed material is found. When the impact head impacts the surface of the roadbed material, a stress area in the shape of a pear is generated. Due to the existence of the annular contact surface, the stress area does not extend to the wall of the tamper barrel. This means that the wall of the tamper barrel does not limit the impact behavior of the impact head, and can ensure that the stress environment of the impact head and the road surface is consistent in the subsequent impact. If the wall of the tamper barrel is too close to the impact head (i.e. the stress area extends to the position of the wall), when the impact head impacts the surface of the roadbed material, the roadbed material will be extruded by the wall. In the subsequent road surface rebound value measurement, there is no corresponding wall limiting environment, so the impact environment of the roadbed material surface and the road surface changes, which is not conducive to the comparison of the corresponding rebound values. The specific structure of the tamper rebound device is the same as that of the above-mentioned tamper rebound device embodiments, and will not be described in detail here.

[0040] Thirdly, the rebound value of the detected road surface is measured by using the compaction rebound device, and the rebound value of the detected road surface is recorded as A, and the density value p of the roadbed material corresponding to A is found, and then p / p1*100 is the compaction degree of the detected road surface. The specific operation is that the annular contact part and the impact head head contact part are placed on the road surface, the impact hammer is lifted to a height h, and then the rebound height of the impact hammer is recorded by the laser displacement sensor.

[0041] In the above description of the present specification, unless otherwise explicitly specified and limited, the terms "fixed", "mounted", "connected" or "linked" and the like should be understood in a broad sense. For example, as to the term "connected", it can be fixed connection, or detachable connection, or integral; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements. Therefore, unless otherwise explicitly limited in the present specification, the above terms can be understood in the specific meaning of the present application by the person skilled in the art according to the specific circumstances.

[0042] According to the above description of the present specification, the person skilled in the art can also understand that the terms used, such as "upper", "lower", "front", "rear", "left", "right", "length", "width", "thickness", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", "center", "longitudinal", "transverse", "clockwise" or "counterclockwise" and the like indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings of the present specification, which is only for the purpose of facilitating the description of the present application and simplifying the description, and is not explicitly or implicitly indicated that the device or element involved must have the said specific orientation, be constructed and operated in a specific orientation, therefore the above orientation or positional relationship terms cannot be understood or interpreted as a limitation on the present application.

[0043] In addition, the terms "first" or "second" and the like used in the present specification are terms used to refer to numbers or ordinal numbers only for the purpose of description, and cannot be understood as indicating relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first" or "second" can explicitly or implicitly include at least one of the features. In the description of the present specification, the meaning of "plurality" is at least two, such as two, three or more, etc., unless otherwise explicitly specified and limited.

[0044] It should be pointed out finally that the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit the same; and although the present application has been described in detail with reference to the foregoing embodiments, it should be appreciated by those skilled in the art that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features thereof can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A compaction rebound device characterized by: The rebound device comprises a percussion head and a device base, the bottom of the percussion head is provided with a percussion head contact part for contacting the road surface, the device base comprises an annular contact part for contacting the road surface and arranged around the peripheral of the percussion head contact part, a spring is arranged between the device base and the percussion head for applying a downward force to the percussion head, the rebound device further comprises a percussion hammer for percussively impacting the upper end of the percussion head and a height lifting mechanism for lifting the height of the percussion hammer, and the rebound device further comprises a height measuring device for measuring the rebound height of the percussion hammer after impacting the percussion head, the outer contour of the stress area generated by the percussion head when impacting the road surface is in the projection of the annular contact part in the upward and downward directions, in use, the percussion head contact part and the annular contact part are always in contact with the road surface, and during the percussion process, a pear-shaped stress area is generated when the percussion head impacts the surface of the roadbed material, and due to the existence of the annular contact part, the stress area does not extend to the wall of the compaction cylinder.

2. The compaction rebound device of claim 1, wherein: The weight of the percussion head is the same as the weight of the percussion hammer.

3. The compaction rebound device of claim 1, wherein: The device base comprises a base sleeve arranged around the peripheral of the percussion head, the upper end of the base sleeve is provided with a sleeve upper end inward flange, the percussion head is provided with a percussion head flange arranged side by side with the sleeve upper end inward flange, the percussion head flange is located on the lower side of the sleeve upper end inward flange, and the spring is a compression spring arranged on the sleeve upper end inward flange and the percussion head flange.

4. The compaction rebound device of claim 3, wherein: The lower end of the base sleeve is provided with a sleeve lower end inward flange, the bottom of the percussion head is in contact with the ground after passing through the inner hole of the sleeve lower end inward flange, and the bottom surface of the sleeve lower end inward flange constitutes the annular contact part.

5. The compaction rebound device of claim 1, wherein: The bottom of the percussion hammer is provided with a ball head structure for percussively impacting the upper end of the percussion head.

6. The compaction rebound device of claim 1, wherein: A vertical guide rod is arranged on the device base, and the percussion hammer is guided and moved in cooperation with the guide rod.

7. A tamper rebound apparatus according to any one of claims 1 to 6, wherein: The height measuring device comprises a laser displacement sensor arranged between the device base and the percussion hammer.

8. A method of measuring the degree of compaction using the tamper rebound apparatus according to any one of claims 1 to 7, characterized by: The method comprises the following steps: first, placing the same roadbed material as the detected road surface in n compaction cylinders, n is a positive integer not less than 3, using the percussion hammer to impact the roadbed material in the corresponding compaction cylinder, so that the densities of the roadbed materials in the compaction cylinders are ρ1, ρ2, …, ρn respectively, wherein ρ1>ρ2>…>ρn, and ρ1 is the standard density; second, measuring the rebound values of the percussion hammer of the roadbed materials in the compaction cylinders by using the rebound device, recording the rebound values of the roadbed materials in the compaction cylinders as A1, A2, …, An respectively, and finding the relationship curve between the rebound values of the percussion hammer and the densities of the roadbed materials; third, measuring the rebound value of the detected road surface by using the rebound device, recording the rebound value of the detected road surface as A, and finding the density value ρ of the roadbed material corresponding to A according to the value A, then the compaction degree of the detected road surface is ρ / ρ1*100.

9. The compactness measurement method according to claim 8, characterized in that: The diameter of the percussion hammer matches the inner cavity diameter of the compaction cylinder.

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