Subgrade compactness detection device

Abstract

The application discloses a kind of roadbed compactness detection devices, including steel ball and free falling ball device, the free falling ball device includes: base, the base includes multiple hollow straight cylinders perpendicular to ground;Column, the first end of the column is inserted into the hollow straight cylinder;Steel ball support frame, the steel ball support frame includes hinge bracket fixed in two columns, transverse support plate fixed on the opposite two columns, and steel ball support part;The steel ball support part includes arc cup mouth and operating handle, the arc cup mouth is formed by two outward protruding support bodies and is opposite to each other, one end of two support bodies is hinged to the hinge bracket;The other end of two support bodies is connected operating handle, the operating handle extends to the outside through the transverse support plate, and can move laterally in the transverse support plate.The roadbed compactness detection device has the advantages of simple disassembly and assembly, simple operation, high detection efficiency, indoor and outdoor detection can be applied.

Description

Technical Field

[0001] This invention relates to the field of roadbed compaction testing technology, and in particular, to a roadbed compaction testing device. Background Technology

[0002] Compaction degree is one of the key indicators for quality inspection of roadbed filling construction. It represents the density after on-site compaction. The higher the compaction degree, the greater the density, and the better the overall performance of the material.

[0003] Currently, the existing compaction testing methods in my country typically include the ring cutter method, sand filling method, water filling method, and nuclear humidity density meter method. The ring cutter method and sand filling method are slow in single-point compaction testing, time-consuming, and have long testing cycles, making compaction testing labor-intensive and inefficient. Furthermore, the sand filling method is highly susceptible to weather and human factors. The water filling method has even more stringent requirements for the environment and equipment, and the testing process is significantly affected by the plastic film bag, resulting in large errors. The nuclear humidity density meter method uses expensive equipment, has extremely high environmental requirements, and its radioactive materials can cause irreversible damage to the human body, severely limiting its large-scale use.

[0004] The existing testing methods described above are insufficient to meet the needs of large-scale, continuous filling construction of roadbeds. Therefore, there is an urgent need for a testing device that can achieve fast compaction testing speed, short testing cycle, large number of tests per unit time, and high testing efficiency. Summary of the Invention

[0005] This invention provides a roadbed compaction testing device to solve the technical problems that existing testing devices cannot achieve fast compaction testing speed, short testing cycle, large number of tests per unit time, and high testing efficiency.

[0006] This invention provides a roadbed compaction testing device, characterized in that it includes a steel ball and a free-falling ball device, wherein the free-falling ball device includes: The base includes multiple hollow cylindrical tubes perpendicular to the ground. Adjacent hollow cylindrical tubes are fixedly connected by bottom fixing brackets. The hollow cylindrical tubes are provided with multiple communicating first circular holes along the height direction. The number of uprights matches the number of hollow cylindrical tubes. The first end of each upright is inserted into the hollow cylindrical tube. The first end has multiple second circular holes along the height direction. The insertion depth of the upright is controlled by varying the matching and fixing of the first and second circular holes at multiple different positions. The second ends of adjacent uprights are fixedly connected by a top-mounted fixing bracket. A steel ball support frame includes a hinge bracket fixed on two of its columns, a transverse support plate fixed on two opposing columns, and a steel ball support part. The steel ball support frame (8) is horizontal to the ground. The steel ball support part includes an arc-shaped cup mouth and an operating handle. The arc-shaped cup mouth is formed by two outwardly protruding support bodies facing each other. One end of the two support bodies is hinged to the hinge bracket. The other end of the two support bodies is connected to the operating handle. The operating handle extends outward through the transverse support plate and can move laterally within the transverse support plate.

[0007] Furthermore, a baffle is connected between adjacent hollow cylindrical tubes, and the baffle is located at the upper end of the bottom fixed bracket.

[0008] Furthermore, the baffle includes a base baffle located at the upper end of the bottom fixed bracket, and a heightening baffle located at the upper end of the base baffle, wherein the vertical dimension of the heightening baffle is greater than the vertical dimension of the base baffle.

[0009] Furthermore, the hinge bracket is an "I"-shaped bracket, with the two ends of the two horizontal fixed shafts of the hinge bracket respectively fixedly connected to the column; two support bodies are hinged on the vertical fixed shaft of the hinge bracket.

[0010] Furthermore, the upper surface of the support is a slope, so that the vertical dimension of the support gradually decreases as it transitions from one end to the other.

[0011] Furthermore, the diameter of the arc-shaped cup opening is 10-20 mm smaller than the diameter of the steel ball.

[0012] Furthermore, the transverse support plate is provided with a through hole, and the operating handle can move laterally within the through hole.

[0013] Furthermore, the first end of the column is a smooth round rod, and the second end of the column is a threaded screw.

[0014] Furthermore, the first and second circular holes can be fixed by using bolts and nuts.

[0015] Furthermore, a pad is fixedly connected to the bottom end of the hollow cylindrical tube, and the lateral dimension of the pad is larger than the lateral dimension of the hollow cylindrical tube.

[0016] The present invention has the following beneficial effects: The roadbed compaction testing device of this invention, by adjusting the vertical distance between the steel ball and the top surface of the soil sample or the top surface of the roadbed, detects the horizontal condition of the top surface of the steel ball support frame. The steel ball falls freely from the free-fall ball device, impacting the top surface of the soil sample or the top surface of the roadbed and leaving a hemispherical impact mark. The depth of the hemispherical impact mark is measured, and combined with the fitting relationship between the dry density of the soil sample and the depth of the hemispherical impact mark on the top surface of the soil sample, the roadbed compaction degree is obtained. The roadbed compaction testing device of this invention has the advantages of simple processing, installation and disassembly, easy operation, low price, simple testing process, fast testing speed, short testing cycle, large number of tests per unit time, high testing efficiency, convenient outdoor portability, and applicability to both indoor and outdoor testing.

[0017] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the free-falling ball device structure of the roadbed compaction testing device according to a preferred embodiment of the present invention; Figure 2 This is a partial schematic diagram of the base of the roadbed compaction testing device according to a preferred embodiment of the present invention; Figure 3 This is a partial schematic diagram of the hinge bracket of the roadbed compaction detection device according to a preferred embodiment of the present invention; Figure 4 This is a schematic diagram of the test of the depth of the hemispherical pit on the top surface of the soil sample or the top surface of the roadbed according to a preferred embodiment of the present invention.

[0019] Legend: 1-Steel ball; 2-Hemispherical recess; 100-Free-fall ball device; 3-Base; 301-Hollow cylindrical tube; 301a-Hollow cylindrical tube with an outer diameter of 28mm; 301b-Hollow cylindrical tube with an outer diameter of 38mm; 302-Bolt and nut; 303-Pad (circular pad); 4-Column; 5-Bottom fixed bracket; 6-Baffle; 601-Base baffle; 602-Heightening baffle; 7-Top fixed bracket; 8-Steel ball support frame; 801-Hinge bracket; 801a-Vertical fixed shaft; 801b-Cylindrical roller bearing; 801c-Horizontal fixed shaft; 802-Arc cup mouth; 803-Operating handle; 9-Horizontal support plate; 901-Through hole (elliptical hole); 10-Circular ring washer; 10a-Circular ring washer with an inner diameter of 30mm; 10b-Circular ring washer with an inner diameter of 22mm; 11-Nut. Detailed Implementation

[0020] To make the inventive objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the embodiments described in this specification are merely illustrative of the invention and are not intended to limit the invention.

[0021] For simplicity, this paper only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form an undefined range; and any lower limit can be combined with other lower limits to form an undefined range, just as any upper limit can be combined with any other upper limit to form an undefined range. Furthermore, although not explicitly stated, every point or individual value between the endpoints of a range is included within that range. Therefore, each point or individual value can serve as its own lower or upper limit and be combined with any other point or individual value, or with other lower or upper limits, to form an undefined range.

[0022] In this description, it should be noted that, unless otherwise stated, "above" and "below" include the stated number, "multiple" in "one or more" means two or more, and "more than" in "one or more" means two or more.

[0023] This invention provides a roadbed compaction testing device, characterized in that it includes a steel ball 1 and a free-falling ball device 100, wherein the free-falling ball device 100 includes: The base 3 includes multiple hollow cylindrical tubes 301 perpendicular to the ground. Adjacent hollow cylindrical tubes 301 are fixedly connected by a bottom fixing bracket 5. The hollow cylindrical tubes 301 are provided with multiple connected first circular holes along the height direction. The number of uprights 4 matches the number of hollow cylindrical tubes 301. The first end of each upright is inserted into the hollow cylindrical tube 301. The first end is provided with multiple second circular holes along the height direction. The insertion depth of the upright is controlled by varying the matching and fixing of the first and second circular holes at multiple different positions. The second ends of adjacent uprights 4 are fixedly connected by a top fixing bracket 7. A steel ball support frame 8 includes a hinge bracket 801 fixed to two of the uprights 4, a transverse support plate 9 fixed to two opposing uprights 4, and a steel ball support part. The steel ball support frame 8 is horizontal to the ground. The steel ball support part includes an arc-shaped cup 802 and an operating handle 803. The arc-shaped cup 802 is formed by two outwardly protruding support bodies facing each other. One end of the two support bodies is hinged to the hinge bracket 801. The other end of the two support bodies is connected to the operating handle 803. The operating handle 803 extends outward through the transverse support plate 9 and can move laterally within the transverse support plate 9.

[0024] In embodiments of this application, the free-fall ball device 100 includes: (1) Base 3: It consists of a hollow cylindrical tube 301a, bolts and nuts 302, circular washer 10a, and circular pad 303.

[0025] (2) Column 4: It is composed of 4 HPB300φ20mm hot-rolled round steel bars with a length of 830mm. One end of each steel bar is a 300mm long round bar with a flat end face and perpendicular to the central axis of the steel bar of column 4; the other end is a 530mm long threaded rod with a round arc convex end face. On one side of the outer peripheral wall at a distance of 50mm, 100mm, 150mm and 200mm from the flat end face of the bottom of the steel bar of column 4, φ12mm round holes are drilled perpendicular to the central axis of the steel bar of column 4 until they penetrate the other side of the outer peripheral wall of the steel bar of column 4, forming the first-level round hole, the second-level round hole, the third-level round hole and the fourth-level round hole.

[0026] (3) Fixed brackets: including bottom fixed bracket 5 and top fixed bracket 7. Bottom fixed bracket 5 is made of HPB300φ20mm hot-rolled plain round steel bar with a length of 350mm, which is welded to the outer peripheral wall of hollow round straight cylinder 301a on two adjacent bases 3; Top fixed bracket 7 is made of HPB300φ20mm hot-rolled plain round steel bar with a length of 350mm, which is welded to the outer peripheral wall of hollow round straight cylinder 301a with a length of 30mm on two adjacent bases 3.

[0027] (4) Baffle 6: including base baffle 601 and height baffle 602. A “rectangular” base baffle 601 is formed by welding the outer walls of the hollow cylindrical straight cylinders 301a on the two adjacent bases 3 with steel plates of 350mm in length, 50mm in height and 8mm in thickness; a “rectangular” height baffle 602 is formed by welding the outer walls of the hollow cylindrical straight cylinders 301b on the two adjacent bases 3 with steel plates of 350mm in length, 60mm in height and 8mm in thickness.

[0028] (5) Steel ball support frame 8: It consists of a hinge bracket 801, an arc cup mouth 802, and an operating handle 803. Among them, the hinge bracket 801 includes: a vertical fixed shaft 801a, a cylindrical roller bearing 801b, a horizontal fixed shaft 801c, and a vertical hollow cylindrical tube 301a. The arc cup mouth 802 is made by selecting a rectangular steel column and cold bending it outward along the thickness direction of the rectangular steel column at a position 175mm away from the large section end of the rectangular steel column to form an arc shape with a radius of 45mm (convex surface facing outward and concave surface facing inward); cold bending another rectangular steel column is completed at the same distance, radius, and direction; the two rectangular steel columns with arc shapes in the middle section are joined together along their thickness direction to form an arc cup mouth 802 with a diameter of 90mm. The operating handle 803 is used to set the small section end of the rectangular steel column in the horizontal support plate 9 on the opposite side of the hinge bracket 801, and extends 150mm outward from the horizontal support plate 9 to form the operating handle 803 of the steel ball support frame 8.

[0029] (6) Horizontal support plate 9: It is made of a steel plate with a length of 350mm, a height of 270mm and a thickness of 14mm. An elliptical hole 901 with a length of 300mm and a height of 150mm is made in the middle of the height direction of the steel plate along the length direction of the steel plate.

[0030] (7) Circular gasket 10: Includes two types: circular gasket 10a with an inner diameter of 30mm and circular gasket 10b with an inner diameter of 22mm. A steel plate with a diameter of 48mm and a thickness of 8mm is used. Circular holes with inner diameters of 30mm and 22mm are drilled at the center of the circular steel plate to form circular gasket 10a and circular gasket 10b, respectively.

[0031] (8) Nuts: Use φ20mm threaded nuts.

[0032] In the embodiments of this application, the installation of the compaction testing device includes: installation of the base 3 and column 4 with steel reinforcement connection, installation of the fixed bracket, installation of the baffle 6, installation of the transverse support plate 9, and installation of the steel ball support frame 8.

[0033] A preferred embodiment of the present invention provides a roadbed compaction testing device, comprising: (1) Composition of the roadbed compaction testing device: like Figures 1-4 As shown, the roadbed compaction testing device includes: a steel ball 1 and a free-falling ball device 100, wherein: the steel ball 1 is a stainless steel ball with a mass of 4.5 kg and a diameter of 104 mm; The free falling ball device 100 includes: 3. Base; 4. Column; 5. Fixed bracket; 6. Baffle; 8. Steel ball support frame; 9. Horizontal support plate; 10. Circular washer; 11. Nut. The base 3 includes: a hollow cylindrical tube 301a, a bolt and nut 302, a circular washer 10a, and a circular pad 303; The fixed bracket includes: a bottom fixed bracket 5 and a top fixed bracket 7; The baffle 6 includes: a base baffle 601 and a heightening baffle 602; The steel ball support frame 8 includes: a hinge bracket 801, an arc-shaped cup mouth 802, and an operating handle 803; The transverse support plate 9 includes: an elliptical hole 901.

[0034] (2) Fabrication of compaction testing device components: a. Base 3: like Figure 1 and Figure 2 As shown, the base 3 is composed of a hollow cylindrical tube 301a, bolts and nuts 302, annular washers 10a, and a circular pad 303.

[0035] 1) Hollow cylindrical tube 301a: Made of 300mm long, 28mm × 3.5mm outer diameter hollow seamless steel pipe. Both ends of the hollow cylindrical tube 301a are flat, and the flat end faces are perpendicular to the central axis of the hollow cylindrical tube 301a. At a position 78mm away from the top surface of the open end of the hollow cylindrical tube 301a, a circular annular gasket 10a with an inner diameter of 30mm is welded perpendicular to the central axis of the hollow cylindrical tube 301a; after welding, the top surface of the hollow cylindrical tube 301a is 70mm higher than the top surface of the circular annular gasket 10a to facilitate the external insertion and installation of the heightening baffle 602.

[0036] 2) Bolt and nut 302: Consists of an M10×60mm bolt, a butterfly nut, a flat washer, and a spring washer.

[0037] 3) Circular gasket 10a: A steel plate with a diameter of 48mm and a thickness of 8mm is used. A circular hole with an inner diameter of 30mm is drilled in the center of the circular steel plate to form a circular gasket 10a with an inner diameter of 30mm.

[0038] 4) Circular pad 303: Made of steel plate with a diameter of 48mm and a thickness of 8mm.

[0039] 5) Weld the circular pad 303 to one end of the hollow cylindrical tube 301a, ensuring that the circular pad 303 is perpendicular to the central axis of the hollow cylindrical tube 301a. This facilitates the vertical insertion of the reinforcing bar of the column 4 into the hollow cylindrical tube 301a of the base 3, and also facilitates the welding and installation of the top fixing bracket 7, the steel ball support frame 8, and the transverse support plate 9. The circular pad 303 covers one end of the hollow cylindrical tube 301a to close it, and the circular pad 303 covers the hollow cylindrical tube 301a and extends beyond it by 20mm. φ12mm circular holes are drilled perpendicularly to the central axis of the hollow cylindrical cylinder 301a on one side of its outer peripheral wall at positions 50mm, 100mm, 150mm, and 200mm from the bottom surface of the capped end, until the holes penetrate the other side of the outer peripheral wall of the hollow cylindrical cylinder 301a, forming the first circular hole. Multiple first circular holes are distributed along the height direction, such as first-level, second-level, third-level, and fourth-level circular holes. The four levels of circular holes on the same side of the outer peripheral wall of the hollow cylindrical cylinder 301a are on the same vertical line, and the circular holes on both sides are located on the cross-section of the maximum circumferential diameter of the hollow cylindrical cylinder 301a.

[0040] b. Column 4: like Figure 1 and Figure 2 As shown, the column 4 is composed of four 830mm long HPB300φ20mm hot-rolled round steel bars. One end of each steel bar is a 300mm long round rod with a flat end face perpendicular to the central axis of the column 4 steel bar, so that the column 4 steel bar is inserted vertically into the hollow cylindrical tube 301a of the base 3 and remains vertically parallel to the hollow cylindrical tube 301a, which facilitates the welding, installation and disassembly of the top fixing bracket 7, the steel ball support frame 8 and the transverse support plate 9; the other end is a 530mm long threaded rod with a rounded convex end face, which facilitates the welding and installation of the top fixing bracket 7, the steel ball support frame 8, the transverse support plate 9, the circular washer 10b and the nut 11. On one side of the outer peripheral wall at positions 50mm, 100mm, 150mm, and 200mm from the bottom flat end face of the column 4 rebar, drill φ12mm round holes perpendicular to the central axis of the column 4 rebar until drilling through the other side of the outer peripheral wall of the column 4 rebar to form a second round hole. There are multiple second round holes distributed along the height direction, such as first-level round holes, second-level round holes, third-level round holes, and fourth-level round holes.

[0041] c. Fixed bracket: like Figure 1As shown, the device includes a bottom fixing bracket 5 and a top fixing bracket 7. The bottom fixing bracket 5 is constructed by welding 350mm long HPB300 φ20mm hot-rolled plain round steel bars to the outer peripheral walls of two adjacent hollow cylindrical tubes 301a on the base 3. The top fixing bracket 7 is constructed by welding 350mm long HPB300 φ20mm hot-rolled plain round steel bars to the outer peripheral walls of two adjacent hollow cylindrical tubes 301a with a length of 30mm. By installing the bottom fixing bracket 5 and the top fixing bracket 7 in the compaction testing device, the free-fall ball device 100 is made stable and secure as a whole.

[0042] d. Baffle 6: like Figure 1 and Figure 2 As shown, it includes a base baffle 601 and a heightening baffle 602. A rectangular base baffle 601 is formed by welding the outer walls of two adjacent hollow cylindrical tubes 301a on the base 3 using steel plates with a length of 350mm, a height of 50mm, and a thickness of 8mm. A rectangular heightening baffle 602 is formed by welding the outer walls of two adjacent hollow cylindrical tubes 301b using steel plates with a length of 350mm, a height of 60mm, and a thickness of 8mm.

[0043] The hollow cylindrical tube 301b is a 70mm long, 38mm x 4.0mm outer diameter seamless steel pipe. Both ends of the hollow cylindrical tube 301b are flat, and these flat ends are perpendicular to the central axis of the hollow cylindrical tube 301b. By installing a base baffle 601 and a heightening baffle 602 in the compaction testing device, not only can the rebound and rolling of the steel ball 1 after impacting the top surface of the soil sample or the roadbed when it falls freely be prevented from injuring operators, but the overall stability and firmness of the free-fall ball device 100 can also be ensured.

[0044] e. Steel ball support frame 8: Depend on Figure 1 and Figure 3 As shown, the steel ball support frame 8 consists of a hinge bracket 801, an arc-shaped cup mouth 802, and an operating handle 803.

[0045] 1) Hinge bracket 801. For example... Figure 1 and Figure 3 As shown. The hinge bracket 801 comprises: a vertical fixed shaft 801a, a cylindrical roller bearing 801b, a horizontal fixed shaft 801c, and a vertical hollow cylindrical tube 301a.

[0046] A 20mm φ HPB300 hot-rolled plain round steel bar with a length of 80mm is used as the concentric vertical fixed shaft of the hinge bracket 801. A ring of 6mm φ HPB300 hot-rolled plain round steel bars is welded perpendicular to the central axis of the steel bar onto the outer peripheral wall at the middle position of the vertical fixed shaft 801a to isolate the upper and lower cylindrical roller bearings 801b, maintaining a 6mm gap between them and ensuring free rotation of the bearings. NNCF5004CV steel bars with an inner diameter of 20mm, an outer diameter of 42mm, and a thickness of 30mm are respectively fitted onto the outer peripheral walls of the upper and lower ends of the vertical fixed shaft 801a. The SKF cylindrical roller bearing 801b is fixedly connected to the vertical fixed shaft 801a by welding. On the outer peripheral wall of the vertical fixed shaft 801a at the corresponding positions on the top surface of the upper cylindrical roller bearing 801b and the bottom surface of the lower cylindrical roller bearing 801b, a ring of HPB300φ6mm hot-rolled plain round steel bars is welded perpendicular to the center axis of the steel bars to fix the position of the upper and lower cylindrical roller bearings 801b and prevent the upper and lower cylindrical roller bearings 801b from moving up and down in the vertical direction.

[0047] The two ends of the vertical fixed shaft 801a are welded to two horizontal fixed shafts 801c to form an "I" shape, so that the central axis of the vertical fixed shaft 801a is perpendicular to the central axis of the two horizontal fixed shafts 801c. The horizontal fixed shafts 801c are made of HPB300 φ20mm hot-rolled plain round steel bars with a length of 350mm.

[0048] The two ends of the two horizontal fixed shafts 801c of the "I" shaped structure are welded to the outer wall of the vertical hollow cylindrical tube 301a with a length of 120mm on the steel bar of column 4 to form the hinge bracket 801.

[0049] 2) Arc-shaped cup mouth 802 and operating handle 803.

[0050] like Figure 1 As shown, it is composed of two rectangular variable cross-section steel bars, each 552mm long, 15mm thick, and 66mm high at one end (the end welded to the hinge bracket 801) (the height is the thickness of the two cylindrical roller bearings 801b plus the isolation gap), and 40mm high at the other end (the end of the operating handle 803), with an arc-shaped middle section (convex surface facing outward and concave surface facing inward), which are spliced ​​together in opposite directions along their thickness direction.

[0051] Rectangular steel column: Each steel column is made of three HPB300φ22mm hot-rolled plain round steel bars with a length of 552mm, welded together in a row, and processed into a rectangular variable cross-section steel column with a length of 552mm, a thickness of 15mm, a height of 66mm at one end (the end welded to the hinge bracket 801) and 40mm at the other end (the end of the operating handle 803).

[0052] Rectangular variable cross-section steel column: Composed of two sections: a large cross-section rectangular steel column and a variable cross-section rectangular steel column. Within 300mm of the large cross-section end of the rectangular steel column, there is a large cross-section section with a thickness of 15mm and a height of 66mm, which stably supports the 4.5kg steel ball 1. Within 300mm to 552mm of the large cross-section end of the rectangular steel column, there is a variable cross-section section. Its bottom surface and two sides are the bottom surface and two sides of the large cross-section steel column extending outwards, and the top surface is a 1:9.69 slope (that is, the height of the rectangular steel column gradually changes from 66mm to 40mm). That is, the cross-section of the operating handle 803 is a small rectangular cross-section with a thickness of 15mm and a height of 40mm, which meets the comfort height requirements of the operator holding the operating handle 803. At the same time, it also overcomes the limitation of the height space of the elliptical hole 901 when the operating handle 803 is operated in the transverse support plate 9, which is not conducive to opening or closing the steel ball support frame 8.

[0053] Arc-shaped cup 802: Select any rectangular steel column and, at a position 175mm from the large-section end of the rectangular steel column, cold-bend it outward along the thickness direction to form an arc shape with a radius of 45mm (convex side facing outward, concave side facing inward); complete the cold bending of another rectangular steel column at the same distance, radius, and direction; join the two rectangular steel columns with arc-shaped sections in the middle towards each other along their thickness direction to form an arc-shaped cup 802 with a diameter of 90mm. The diameter of the arc-shaped cup 802 (90mm) is smaller than the diameter of the steel ball 1 (104mm) to support and stabilize the steel ball 1 on the top surface of the arc-shaped cup 802.

[0054] Operating handle 803: The small section end of the rectangular steel column is set in the transverse support plate 9 on the opposite side of the hinge bracket 801, and extends 150mm outward from the transverse support plate 9 to form the operating handle 803 of the steel ball support frame 8.

[0055] f. Horizontal support plate 9: like Figure 1 As shown, the steel plate is 350mm long, 270mm high, and 14mm thick. An elliptical hole 901, 300mm long and 150mm high, is made along the length of the steel plate at the midpoint of its height. An operating handle 803 extends outward through the elliptical hole 901 in the transverse support plate 9 and can move laterally within the elliptical hole 901. By controlling the operating handle 803, when the two supports are brought together, the steel ball 1 is accommodated in the arc-shaped cup opening 802; when the two supports are moved apart, the steel ball 1 is released.

[0056] (3) Installation of compaction testing device: The compaction testing device installation includes: installation of the base 3 and column 4 steel bar connection, installation of the fixed bracket, installation of the baffle 6, installation of the transverse support plate 9, and installation of the steel ball support frame 8.

[0057] a. Reinforcing steel connection and installation of base 3 and column 4: like Figure 1 and Figure 2 As shown, the flat ends of the four upright steel bars 4 are inserted into the four bases 3 respectively. The first-order circular holes on each upright steel bar 4 are aligned with the first-order circular holes on the hollow cylindrical tube 301a of each base 3, ensuring they are visible to each other. Then, the bolts and nuts 302 are passed sequentially through a flat washer, a circular hole on the hollow cylindrical tube 301a, a circular hole on the upright steel bar 4, another circular hole on the hollow cylindrical tube 301a, a flat washer, a spring washer, and a butterfly nut, and the butterfly nut is tightened. Following this method, the second, third, and fourth-order circular holes on each upright steel bar 4 are sequentially connected to the second, third, and fourth-order circular holes on the hollow cylindrical tube 301a of each base 3, thus securing the connection and installation of the four bases 3 and the four upright steel bars 4.

[0058] After installation, each column 4 steel bar is inserted vertically and parallel to each other into each base 3 hollow cylindrical tube 301a, so as to facilitate the welding, installation and disassembly of the top fixed bracket 7, steel ball support frame 8 and horizontal support plate 9.

[0059] b. Installation of fixed brackets, including: installation of the bottom fixed bracket 5 and the top fixed bracket 7. For example... Figure 1 and Figure 2 As shown.

[0060] 1) Installation of bottom fixing bracket 5: After the four bases 3 and four columns 4 are connected and fixed, use HPB300φ20mm hot-rolled round steel bars with a length of 350mm to weld the outer walls of the hollow cylindrical straight cylinder 301a on the outer periphery of the two adjacent bases 3 at a height of 50mm from the top surface of the circular pad 303, to form a "rectangular" bottom fixing bracket 5.

[0061] The weld on the bottom fixed bracket 5 must not cover the first, second, third, and fourth level circular holes on the outer peripheral wall of the hollow cylindrical tube 301a. The weld and the circular holes must be staggered to facilitate the connection and installation of the reinforcing bars of the base 3 and the column 4.

[0062] 2) Installation of the top fixed bracket: After the bottom fixed bracket 5, base baffle 601, heightening baffle 602, horizontal support plate 9, and steel ball support frame 8 are installed, screw a φ20mm nut 11 into the top of each of the four uprights 4 rebar threaded rods until it is 150mm from the top end of the upright 4 rebar threaded rod. Then place a 22mm inner diameter circular washer 10b until it contacts the top surface of the nut 11. Next, place a 30mm long, 28mm × 3.5mm outer diameter hollow cylindrical tube 301a until it contacts the top surface of the circular washer 10b. Use a spirit level to check whether the hollow cylindrical tube 301a on the four uprights 4 rebar threaded rods is on the same horizontal plane. If not, adjust the height of the hollow cylindrical tube 301a by rotating the nut 11 in the forward or reverse direction so that the four uprights 4 Hollow cylindrical tubes 301a on the threaded rod of the steel bar are on the same horizontal plane. Then, a circular washer 10b is placed until it contacts the top surface of the hollow cylindrical tube 301a. Then, a nut 11 is screwed in until it contacts the top surface of the circular washer 10b and tightened so that the hollow cylindrical tube 301a is vertical on the threaded rod of the column 4 and is vertically parallel to the steel bars of the column 4, so as to facilitate the welding, installation and disassembly of the top fixing bracket 7. Finally, HPB300 φ20mm hot-rolled plain round steel bars with a length of 350mm are used to weld the outer peripheral walls of two adjacent hollow cylindrical tubes 301a to form a "rectangular" top fixing bracket 7.

[0063] 3) Installation of baffle 6, including: installation of base baffle 601 and heightening baffle 602. For example... Figure 1 and Figure 2 As shown.

[0064] Base baffle installation: After the bottom fixed bracket 5 is installed, steel plates with a length of 350mm, a height of 50mm, and a thickness of 8mm are used to weld the outer peripheral walls of the hollow cylindrical straight cylinder 301a on the bottom fixed bracket 5 at a height of 50mm above the steel bar to form a "rectangular" base baffle 601.

[0065] After welding, the top surface of the base baffle 601 should be at least 170mm away from the bottom surface of the circular pad 303. This is to prevent the steel ball 1 from bouncing and rolling after impacting the top surface of the roadbed during the depth test of the hemispherical pit 2 on the outdoor roadbed surface, thus avoiding injury to operators. The weld on the base baffle 601 must not cover the first, second, third, and fourth level circular holes on the outer peripheral wall of the hollow cylindrical tube 301a. The weld and the circular holes must be staggered to facilitate the connection and installation of the reinforcing bars of the base 3 and the column 4.

[0066] Installation of the heightened baffle 602: After the bottom fixed bracket 5 and the base baffle 601 are installed, a hollow seamless steel pipe with a length of 70mm and an outer diameter of 38mm×4.0mm is inserted into the outer wall of the hollow cylindrical straight cylinder 301a in the base 3, and contacts the top surface of the annular gasket 10a on the outer wall of the hollow cylindrical straight cylinder 301a; a steel plate with a length of 350mm, a height of 60mm, and a thickness of 8mm is used to weld the outer peripheral walls of two adjacent hollow cylindrical straight cylinders 301b to form a "rectangular" heightened baffle 602, so that when the depth test of the hemispherical pit 2 on the top surface of the indoor soil sample specimen is conducted, the heightened free-fall ball device 100 is used to prevent the steel ball 1 from bouncing and rolling after hitting the top surface of the soil sample specimen when it falls freely, thus preventing injury to the operators.

[0067] 4) Installation of horizontal support plate 9: like Figure 1 As shown, after the bottom fixing bracket 5, base baffle 601, and heightening baffle 602 are installed, screw a φ20mm nut 11 into the threaded rods of the reinforcing bars of two adjacent columns 4 on any side until it is 520mm from the top end of the threaded rod. Then, place a 22mm inner diameter circular washer 10b until it contacts the top surface of the nut 11. Next, place a 270mm long, 28mm × 3.5mm outer diameter hollow cylindrical tube 301a until it contacts the top surface of the circular washer 10b. Use a spirit level to check whether the hollow cylindrical tube 301a on the threaded rods of the two columns 4 are on the same horizontal plane. If not, adjust the height of the hollow cylindrical tube 301a by rotating the nut 11 in the forward or reverse direction so that the two columns 4 are aligned. The hollow cylindrical tubes 301a on the threaded rod of the steel bar are on the same horizontal plane. Then, a circular washer 10b is placed until it contacts the top surface of the hollow cylindrical tube 301a. Then, a nut 11 is screwed in until it contacts the top surface of the circular washer 10b and tightened. This makes the hollow cylindrical tube 301a vertical on the threaded rod of the steel bar of column 4 and parallel to the steel bar of column 4 in the vertical direction, so as to facilitate the welding, installation and disassembly of the transverse support plate 9. The two ends of the transverse support plate 9 are welded to the outer peripheral wall of the hollow cylindrical tubes 301a on the two adjacent steel bars of column 4 to form the transverse support plate 9.

[0068] The steel ball support frame 8 is installed, including the hinge bracket 801 and the rectangular steel column installation, as follows: Figure 1 and Figure 3 As shown.

[0069] Hinge bracket 801 installation: Weld both ends of the vertical fixed shaft 801a to the two horizontal fixed shafts 801c respectively to form an "I" shape, so that the central axis of the vertical fixed shaft 801a is perpendicular to the central axes of the two horizontal fixed shafts 801c. The horizontal fixed shafts 801c are made of 350mm long HPB300 φ20mm hot-rolled plain round steel bars.

[0070] like Figure 1 As shown, after the bottom fixing bracket 5, base baffle 601, heightening baffle 602, and horizontal support plate 9 are installed, screw a φ20mm nut 11 into the threaded rods of the two adjacent upright columns 4 on opposite sides of the horizontal support plate 9, until it is 517mm from the top end of the threaded rod of the upright column 4. Then, place a 22mm inner diameter circular washer 10b until it contacts the top surface of the nut 11. Then, place a 120mm long, 28mm × 3.5mm outer diameter hollow cylindrical tube 301a until it contacts the top surface of the circular washer 10b. Use a spirit level to check whether the hollow cylindrical tube 301a on the threaded rods of the two upright columns 4 are on the same horizontal plane. If not, adjust the height of the hollow cylindrical tube 301a by rotating the nut 11 in the forward or reverse direction so that the two upright columns 4 are on the same horizontal plane. The hollow cylindrical tube 301a on the threaded rod of the steel bar is on the same horizontal plane. Then, a circular washer 10b is placed until it contacts the top surface of the hollow cylindrical tube 301a. Then, a nut 11 is screwed in until it contacts the top surface of the circular washer 10b and the nut 11 is tightened so that the hollow cylindrical tube 301a is in a vertical position on the threaded rod of the steel bar of the column 4 and is kept vertically parallel to the steel bar of the column 4, so as to facilitate the welding, installation and disassembly of the hinge bracket 801.

[0071] The two ends of the two horizontal fixed shafts 801c of the "I" shaped structure are welded to the outer wall of the vertical hollow cylindrical tube 301a with a length of 120mm on the steel bar of column 4 to form the hinge bracket 801.

[0072] Rectangular steel column installation: such as Figure 1 As shown, after the bottom fixing bracket 5, base baffle 601, heightening baffle 602, transverse support plate 9, and hinge bracket 801 are installed, two rectangular steel columns with arc-shaped middle sections are joined together along their thickness direction to form an arc-shaped cup mouth 802 with a diameter of 90mm. The operating handles 803 of the two rectangular steel columns are inserted into the elliptical holes 901 of the transverse support plate 9, and the large-section ends of the two rectangular steel columns are brought into close contact with the cylindrical roller bearings 801b in the hinge bracket 801. The large-section ends of the rectangular steel columns are temporarily supported by the fixing bracket.

[0073] Use a spirit level to check whether the large-section end of the rectangular steel column and the end of the operating handle 803 are on the same horizontal plane. If not, adjust the height of the rectangular steel column by rotating the nut 11 at the bottom of the transverse support plate 9 in the forward or reverse direction so that the large-section end of the rectangular steel column and the end of the operating handle 803 are on the same horizontal plane.

[0074] like Figure 3As shown, the large-section end of the left rectangular steel column is welded to the outer peripheral wall of the lower cylindrical roller bearing 801b in the hinge bracket 801, forming a forward "staircase step" shape. This ensures the bottom surface of the left rectangular steel column is flush with the bottom surface of the lower cylindrical roller bearing 801b, and the top surface of the left rectangular steel column is 36mm higher than the top surface of the lower cylindrical roller bearing 801b. Similarly, the large-section end of the right rectangular steel column is welded to the outer peripheral wall of the upper cylindrical roller bearing 801b in the hinge bracket 801, forming a reverse "staircase step" shape. This ensures the top surface of the right rectangular steel column is flush with the top surface of the upper cylindrical roller bearing 801b, and the bottom surface of the right rectangular steel column is 36mm lower than the bottom surface of the upper cylindrical roller bearing 801b. After welding, the temporary support brackets for the large-section ends of the rectangular steel columns are removed.

[0075] (4) Methods for increasing the height of the free-fall ball device 100, including methods for increasing the height of 50mm and 100mm.

[0076] 1) 50mm level height increase method. Loosen the bolts on the four bases 3, and remove the bolts, nuts, flat washers, and spring washers; simultaneously lift the four uprights 4 steel bars upwards so that the first-level round holes on the four uprights 4 steel bars are aligned with the second-level round holes on the four hollow cylindrical tubes 301a of the bases 3 and are visible to each other; the second-level round holes on the four uprights 4 steel bars are aligned with the third-level round holes on the four hollow cylindrical tubes 301a of the bases 3 and are visible to each other; and the third-level round holes on the four uprights 4 steel bars are aligned with the fourth-level round holes on the four hollow cylindrical tubes 301a of the bases 3 and are visible to each other.

[0077] The method for connecting and fixing the column 4 rebar to the hollow cylindrical tube 301a of the base 3 is as follows: Pass the bolt and nut 302 through a flat washer, a round hole on the hollow cylindrical tube 301a, a round hole on the column 4 rebar, another round hole on the hollow cylindrical tube 301a, a flat washer, a spring washer, and a butterfly nut in sequence. Tighten the butterfly nut to complete the connection between the first-level round hole on the column 4 rebar and the second-level round hole on the hollow cylindrical tube 301a of the base 3. Following this method, connect the second-level round hole on the column 4 rebar to the third-level round hole on the hollow cylindrical tube 301a of the base 3, the third-level round hole on the column 4 rebar to the fourth-level round hole on the hollow cylindrical tube 301a of the base 3, and the remaining three round holes on the column 4 rebar to the three round holes on the hollow cylindrical tube 301a of the base 3.

[0078] 2) 100mm level height increase method. Following the above method, complete the bolt and nut 302 connection and fixation of the first level round hole on the 4 columns 4 steel bars to the third level round hole on the 4 base 3 hollow round cylinder 301a, and the second level round hole on the 4 columns 4 steel bars to the fourth level round hole on the 4 base 3 hollow round cylinder 301a.

[0079] 3) Scope of application of the heightening method. It is applicable when the compaction testing device is used for the hemispherical pit depth test on the top surface of the indoor soil sample specimen, and the free fall ball device 100 needs to be heightened; however, when the compaction testing device is used for the hemispherical pit depth test on the top surface of the outdoor roadbed, the heightening of the free fall ball device 100 is not required.

[0080] 4) Comparison and selection of the two heightening methods. In the test of the depth of the hemispherical pit 2 on the top surface of the indoor soil sample specimen, the 50mm level heightening method is often used; however, after heightening the free fall ball device 100, the number of connection levels between the round hole on the steel bar of the column 4 and the round hole on the hollow cylindrical tube 301a of the base 3 is less than 3, resulting in poor overall stability of the heightened free fall ball device 100. Except for special requirements, the 100mm level heightening method is rarely used.

[0081] (5) Compaction degree testing process: 1) Leveling the surface of the test point. At the selected test point location, use a scraper to level the top surface of the roadbed with an area of ​​450mm×450mm. Use a spirit level to check whether the top surface of the roadbed is level after leveling.

[0082] 2) Roughly adjust the vertical distance between steel ball 1 and the top surface of the roadbed. Install the free-fall ball device 100 directly above the detection point, and roughly adjust the vertical distance between the bottom surface of steel ball 1 on the steel ball support frame 8 and the top surface of the roadbed to 450mm.

[0083] 3) Check the level of the top surface of the steel ball support frame 8. Use a spirit level to check the level of the top surface of the steel ball support frame 8. Otherwise, rotate the nut 11 at the bottom of the transverse support plate 9 or the hinge bracket 801 in the forward or reverse direction to ensure that the vertical center line of the steel ball 1 is perpendicular to the top surface of the roadbed, and ensure that the vertical distance between the bottom surface of the steel ball 1 and the top surface of the roadbed is 450mm.

[0084] 4) Steel ball 1 falls freely and impacts the top surface of the roadbed. Open the steel ball support frame 8, and let the steel ball 1 placed on the steel ball support frame 8 fall freely from the arc cup mouth 802 and impact the top surface of the roadbed, leaving a hemispherical indentation 2 impact mark on the top surface of the roadbed.

[0085] 5) Measure the depth of the hemispherical pit 2 at the test point. Measure the maximum depth of the hemispherical pit 2 in two perpendicular directions on the circular plane of the impact mark at the test point using a depth caliper, take the arithmetic mean, and record the data.

[0086] 6) Fitting the subgrade compaction at the test points. Substitute the measured depth of the hemispherical pit at the test point directly into the fitting formula between the dry density of the indoor soil sample and the depth of the hemispherical pit on the top surface of the soil sample to calculate the dry density of the indoor soil sample at the test point. Multiply this by the correction factor for the dry density of the subgrade soil sample. The dry density of the subgrade soil sample at the test point is obtained by fitting the data, and then divided by the maximum dry density of the indoor soil sample to obtain the subgrade compaction degree at the test point.

[0087] (6) Maintenance and upkeep of compaction testing devices: 1) Maintenance of compaction testing device. After the test is completed, wipe the dirt off the surface of the steel ball 1 and put it back into the steel ball 1 storage box. Lock and secure the operating handle 803 in the steel ball support frame 8 to prevent the steel ball support frame 8 from vibrating up and down or swaying left and right during the compaction testing device carrying process, which could damage the steel ball support frame 8.

[0088] 2) Maintenance of cylindrical roller bearings. After one month of use of the compaction testing device, a small amount of lubricating oil should be injected into the cylindrical roller bearing 801b of the hinge bracket 801 to prevent the cylindrical roller bearing 801b from rusting and being unable to rotate freely, thus affecting the opening or closing of the steel ball support frame 8.

[0089] This compaction testing device is suitable for fine-grained and coarse-grained soils with a maximum particle size of 40 mm or less.

[0090] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A roadbed compaction degree testing device, characterized in that, Includes a steel ball (1) and a free-falling ball device (100), the free-falling ball device (100) comprising: The base (3) includes multiple hollow cylindrical tubes (301) perpendicular to the ground. Adjacent hollow cylindrical tubes (301) are fixedly connected by a bottom fixing bracket (5). A baffle (6) is also connected between adjacent hollow cylindrical tubes (301). The baffle (6) is located at the upper end of the bottom fixing bracket (5). The baffle (6) includes a base baffle (601) located at the upper end of the bottom fixing bracket (5) and a heightening baffle (602) located at the upper end of the base baffle (601). The hollow cylindrical tubes (301) are provided with multiple communicating first circular holes along the height direction. The number of columns (4) matches the number of hollow cylindrical tubes (301). The first end of the column (4) is inserted into the hollow cylindrical tube (301). The first end is provided with multiple second circular holes along the height direction. The matching and fixing of the first and second circular holes at multiple different positions are varied to control the insertion depth of the column (4). By selecting the first and second circular holes at different positions for alignment and fixing, the column (4) has at least two installation heights relative to the base, and the free-fall ball device is selectively raised by 50mm or 100mm relative to the reference state. The second ends of the adjacent columns (4) are fixedly connected by the top fixing bracket (7). A steel ball support frame (8) includes a hinge bracket (801) fixed on two of the columns (4), a transverse support plate (9) fixed on two opposing columns (4), and a steel ball support part. The steel ball support frame (8) is horizontal to the ground. The steel ball support part includes an arc-shaped cup mouth (802) and an operating handle (803). The arc-shaped cup mouth (802) is formed by two outwardly protruding support bodies facing each other. One end of the two support bodies is hinged to the hinge bracket (801). The other end of the two support bodies is connected to the operating handle (803). The operating handle (803) extends outward through the transverse support plate (9) and can be used for... The transverse support plate (9) moves laterally, and the two supports can move closer to each other under the action of the operating handle (803) to form an arc cup mouth and support the steel ball; the two supports can also move away from each other to release the support of the steel ball and release the steel ball; the hinge bracket (801) and the transverse support plate (9) are respectively set on the corresponding two columns (4) through hollow cylindrical tubes (301). The upper and lower sides of the hollow cylindrical tubes (301) are respectively provided with nuts (11) that are threaded to the columns (4) and circular washers. The installation height of the hinge bracket (801) and the transverse support plate (9) can be adjusted by adjusting the axial position of the nuts (11) on the columns so that the arc cup mouth is kept horizontal.

2. The roadbed compaction testing device according to claim 1, characterized in that, The baffle (6) includes a base baffle (601) located at the upper end of the bottom fixed bracket (5) and a heightening baffle (602) located at the upper end of the base baffle (601), wherein the vertical dimension of the heightening baffle (602) is greater than the vertical dimension of the base baffle (601).

3. The roadbed compaction testing device according to claim 1, characterized in that, The hinge bracket (801) is an "I" shaped bracket. The two ends of the two horizontal fixed shafts (801c) of the hinge bracket (801) are fixedly connected to the column (4) respectively. Two support bodies are hinged on the vertical fixed shaft (801a) of the hinge bracket (801).

4. The roadbed compaction testing device according to claim 3, characterized in that, The upper surface of the support is sloping, so that the vertical dimension of the support gradually decreases as it transitions from one end to the other.

5. The roadbed compaction testing device according to claim 1, characterized in that, The diameter of the arc-shaped cup mouth (802) is 10~20mm smaller than the diameter of the steel ball (1).

6. The roadbed compaction testing device according to claim 1, characterized in that, The transverse support plate (9) is provided with a through hole (901), and the operating handle (803) can move laterally within the through hole (901).

7. The roadbed compaction testing device according to claim 1, characterized in that, The first end of the column (4) is a smooth round rod, and the second end of the column (4) is a threaded screw.

8. The roadbed compaction testing device according to claim 1, characterized in that, The first and second round holes can be fixed by using bolts and nuts.

9. The roadbed compaction testing device according to claim 1, characterized in that, A pad (303) is fixedly connected to the bottom end of the hollow cylindrical tube (301), and the lateral dimension of the pad is larger than the lateral dimension of the hollow cylindrical tube (301).

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