A light dynamic sounding penetration detection device

Abstract

This invention discloses a lightweight dynamic penetrating test (PT) penetration testing device, comprising a probe assembly and an orifice holder. The probe assembly includes a drop hammer, a probe rod, a probe head, and an adjustable positioning ring. A probe head is mounted at the bottom of the probe rod, and an enlarged diameter section is fixedly installed in the middle of the probe rod. The drop hammer is slidably mounted on the probe rod section above the enlarged diameter section. An adjustable positioning ring is installed on the probe rod section above the enlarged diameter section to determine the drop distance of the drop hammer. The orifice holder is used in conjunction with the probe assembly. A through hole is provided in the center of the orifice holder for the probe rod to pass through. A reading probe is installed on the orifice holder, and multiple elastic support wheel units are also provided for elastic rolling support of the probe rod. A plumb bob is connected to the bottom of the orifice holder to serve as a reference for the verticality of the probe rod. This invention is simple to operate and has a fast testing speed. For the target to be tested, it can measure the penetration depth P of N hammer blows at a specific drop distance H.

Description

Technical Field

[0001] This invention belongs to the field of roadbed compaction construction quality testing technology, and in particular relates to a lightweight dynamic penetration test device. Background Technology

[0002] Compaction degree is a crucial indicator for controlling the quality of roadbed construction. In practical engineering, common methods for testing compaction degree include the sand cone method, water cone method, and ring cutter method. These methods can accurately and reliably obtain compaction degree indicators, and their results can serve as a basis for acceptance. However, these methods also have drawbacks: First, they are destructive testing methods that cause significant damage to the roadbed. For example, the sand cone and water cone methods require excavating test pits on the compacted roadbed. Second, these methods are slow. Taking the sand cone method as an example, testing a single point requires both on-site excavation, sand filling, and weighing, as well as laboratory moisture content testing, which is very inefficient and can sometimes affect project progress. In reality, for certain situations, such as the construction party's self-inspection of compaction degree, it is unnecessary to use such cumbersome testing methods. Therefore, it is necessary to develop a faster compaction degree testing device.

[0003] Dynamic cone penetration testing (DCPT) is a field testing method that reflects indicators such as the bearing capacity or strength of a roadbed. Bearing capacity or strength is often closely related to compaction degree. Therefore, DCPT devices can be used to measure the penetration depth of the probe into the roadbed under specific hammer weights, drop distances, and number of blows to characterize the roadbed compaction degree. Existing DCPT devices can be divided into three types: ultra-heavy, heavy, and light. Lightweight DCPTs are the most convenient, requiring no large machinery and can be performed manually. Conventional lightweight DCPT devices still need improvement in terms of testing accuracy, ease of operation, adjustability, and ensuring probe verticality. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the present invention provides a lightweight dynamic penetration detection device.

[0005] This invention is achieved through the following technical solution:

[0006] A lightweight dynamic penetration testing device includes a probe assembly and a borehole stool.

[0007] The probe device includes a drop hammer, a probe rod, a probe, and an adjustable positioning ring. The probe is mounted at the bottom end of the probe rod, and an enlarged diameter section is fixedly installed in the middle of the probe rod. The drop hammer is slidably fitted onto the probe rod section above the enlarged diameter section. Two scales are provided on the probe rod: the first scale, located on the probe rod section below the enlarged diameter section, indicates the depth of penetration; the second scale, located on the probe rod section above the enlarged diameter section, indicates the drop distance of the drop hammer. An adjustable positioning ring is installed on the probe rod section above the enlarged diameter section, fitted onto the probe rod, and a tightening screw is provided on the adjustable positioning ring. By adjusting this tightening screw, the positioning position of the adjustable positioning ring on the probe rod can be adjusted, thereby determining the drop distance of the drop hammer during the test in conjunction with the second scale.

[0008] The orifice stool is used in conjunction with the probe device. The orifice stool includes a stool surface and stool legs supporting the stool surface. A through hole is provided in the center of the stool surface for the probe to pass through. A reading probe is provided on the stool surface to assist in reading the reading of the first section of the scale on the probe. Multiple elastic support wheel units are provided on the stool surface, evenly distributed in a circle around the through hole, for elastic rolling support of the probe. A plumb bob is connected to the bottom surface of the stool surface to serve as a reference for the verticality of the probe.

[0009] In the above technical solution, the diameter of the probe rod is 20-30mm.

[0010] In the above technical solution, the probe is conical with a cone angle of 50-70 degrees.

[0011] In the above technical solution, the diameter of the expanded section is 55-60mm.

[0012] In the above technical solution, the mass of the falling hammer is 6-8 kg.

[0013] In the above technical solution, the second scale is marked upwards from 0mm on the top surface of the expanded diameter section, with a maximum marking size of 600mm.

[0014] In the above technical solution, the diameter of the through hole is 45-50mm.

[0015] In the above technical solution, the reading probe uses an inclined elastic metal plate, the bottom of which is fixed to the bench surface by bolts, and the top of which is used to point to the first scale on the probe rod. The position it points to is used as the reading of the first scale, so as to accurately read the penetration depth of the probe rod device during the test.

[0016] In the above technical solution, the number of elastic support wheel units is 3-4.

[0017] In the above technical solution, the elastic support wheel unit includes a mounting groove, a support rod, a slider, a roller, and a spring. The mounting groove is fixedly disposed on the stool surface and is arranged radially along the through hole on the stool surface. The slider is slidably mounted in the mounting groove and can slide radially along the through hole. The tail end of the support rod is fixedly connected to the slider, and the front end of the support rod is mounted with a roller. The spring is installed at the tail end of the slider to provide elastic force to the slider in the direction of the center of the through hole, so that the roller can elastically contact the probe. In this way, the rollers of the multiple elastic support wheel units evenly distributed in a circle can provide elastic rolling support for the probe penetrating the through hole.

[0018] The lightweight dynamic penetration testing device of this invention can measure the penetration depth P of a target (typically a roadbed or roadbed soil sample from an engineering site) after N hammer blows at a set drop height H. The testing process is as follows:

[0019] (1) Place the orifice stool firmly at the target position, insert the probe of the probe device through the through hole in the center of the stool surface and stand it on the target to be measured. The elastic support wheel unit of the orifice stool provides elastic rolling support for the probe, so that the probe is in the center of the through hole. Then, with reference to the plumb bob, manually adjust the probe position and then adjust the probe to a vertical state.

[0020] (2) Pre-strike: Raise the drop hammer and strike the enlarged section of the probe rod 1-3 times as a pre-strike to allow the probe to be initially placed into the target soil and stabilized therein.

[0021] (3) After the pre-strike is completed, adjust the position of the adjustable positioning ring and set the required drop distance H of the hammer. The reading of the second scale corresponding to the bottom of the adjustable positioning ring is the required drop distance H of the hammer. Then, align the top of the reading probe with the position of the first scale of the probe rod and use it as the reading of the first scale, which is recorded as p1.

[0022] (4) Start the formal power penetration test: Raise the drop hammer to the bottom of the adjustable positioning ring, so that the drop hammer hits the enlarged section on the probe rod N times at the required drop distance H, then stop hitting, and read the reading of the first section of the scale on the probe rod at this time, and record it as p2;

[0023] (5) According to the formula P = p2 - p1, the penetration depth P of each N hammer blows under the set drop distance H in this test is obtained.

[0024] The advantages and beneficial effects of this invention are as follows:

[0025] (1) The lightweight dynamic penetration test device of the present invention is simple to operate, fast to test, and causes little damage to the compacted roadbed.

[0026] (2) The lightweight dynamic penetration test device of the present invention has two millimeter-level scales (i.e., the first scale and the second scale), and uses a hole stool with a reading elastic metal sheet instead of the easily deformable roadbed hole as the measurement reference point, so that the penetration measurement accuracy is higher.

[0027] (3) The lightweight power penetration test device of the present invention can conveniently and accurately adjust the drop distance required for the hammer during the test by means of an adjustable positioning ring combined with a second scale. During the test, the hammer can be manually raised to the bottom surface of the adjustable positioning ring (i.e., accurately positioned) and then allowed to fall naturally to strike the expanded diameter section of the probe rod, thereby generating a downward impact force on the entire probe rod. This method can ensure that the drop distance of the hammer is the same each time and is very convenient to operate.

[0028] (4) The lightweight dynamic penetration testing device of the present invention has multiple elastic support wheel units on the orifice stool, which are evenly distributed around the through hole to provide elastic rolling support for the probe rod. During the test, the probe and the probe rod need to penetrate the through hole of the stool surface from top to bottom so that the probe can be inserted into the target to be tested. During the process of penetrating the through hole, since the maximum diameter of the probe is larger than the diameter of the probe rod, the multiple elastic support wheel units can be spread open so that the probe can penetrate the through hole. In addition, during the test, the multiple elastic support wheel units can provide good elastic rolling support for the probe rod, so that the probe rod is in the center position of the through hole. At the same time, since the front end of the elastic support wheel unit uses a roller to make rolling contact with the probe rod, the friction force on the probe rod is very small and will not affect the hammering effect. In addition, a plumb bob is installed on the bottom of the orifice stool as a reference for the verticality of the probe rod. Under the combined action of the plumb bob and the aforementioned elastic support wheel unit, the verticality of the probe rod can be adjusted (since the diameter of the through hole is larger than the diameter of the probe rod, and multiple elastic support wheel units provide elastic rolling support for the probe rod, the verticality of the probe rod is adjustable; and since the support part of the probe rod by multiple elastic support wheel units is stably located at the center of the through hole, it is only necessary to adjust the position of the probe at the bottom end of the probe rod to adjust the verticality of the probe rod with reference to the plumb bob, so that the probe rod is kept at the required verticality). Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the lightweight dynamic penetration detection device of the present invention.

[0030] Figure 2 This is a top view of the perforated stool in this invention.

[0031] Figure 3 This is a side view of the perforated stool in this invention.

[0032] Figure 4This is a partially enlarged structural diagram of the orifice stool in this invention.

[0033] Figure 5 The diagram shown is a schematic representation of the detection state of the lightweight dynamic penetration detection device of the present invention.

[0034] For those skilled in the art, other related figures can be obtained from the above figures without any creative effort. Detailed Implementation

[0035] To enable those skilled in the art to better understand the present invention, the technical solution of the present invention will be further described below with reference to specific embodiments.

[0036] A lightweight dynamic penetration testing device includes a probe assembly and an orifice holder.

[0037] The probe device includes a drop hammer 1, a probe rod 2, a probe 4, and an adjustable positioning ring 5. See appendix below. Figure 1 Its structure will be described in detail.

[0038] A probe 4 is installed at the bottom of the probe rod 2. The probe rod 2 has a diameter of 25mm, and the probe 4 is conical with a maximum diameter of 40mm and a cone angle of 60 degrees. An expansion section 21 with a diameter of 55mm is fixedly installed in the middle of the probe rod 2. The drop hammer 1 is slidably mounted on the probe rod 2 above the expansion section 21. The mass of the drop hammer 1 is preferably 7.5kg. When the drop hammer 1 is lifted, it falls freely along the probe rod 2 and strikes the expansion section 21, thereby generating a downward impact force on the entire probe rod 2.

[0039] Two scales are set on the probe rod 2. The first scale 31 is set on the section of probe rod 2 below the enlarged diameter section 21. During the test, it is used to indicate the depth of the probe rod 2 penetrating into the roadbed (it needs to be used in conjunction with the reading probe 7 on the orifice stool 6, which will be described in detail later). The second scale 32 is set on the section of probe rod 2 above the enlarged diameter section 21. The second scale 32 starts from 0mm on the top surface of the enlarged diameter section 21 and marks upwards along the rod section, with a maximum marking size of 500mm. The function of the second scale 32 is to indicate the drop distance of the drop hammer 1 (i.e., to indicate the height from which the drop hammer 1 falls) during the test.

[0040] An adjustable positioning ring 5 is installed on the probe rod 2 above the expanded diameter section 21. The adjustable positioning ring 5 is fitted onto the probe rod 2, and a tightening screw 51 is installed on the adjustable positioning ring 5. By adjusting the tightening screw 51, the positioning position of the adjustable positioning ring 5 on the probe rod 2 can be adjusted. Then, in conjunction with the second scale 32, the drop distance of the hammer 1 during the test can be determined. That is, during the test, the adjustable positioning ring 5 is first adjusted to the drop distance position required for the hammer 1 to fall, referring to the second scale 32 (the reading of the second scale 32 corresponding to the bottom surface of the adjustable positioning ring 5 is the drop distance position required for the hammer 1 to fall). Then, during the test, the hammer 1 is manually raised to the bottom surface of the adjustable positioning ring 5 and then falls naturally, striking the expanded diameter section 21, thereby generating a downward impact force on the entire probe rod 2.

[0041] The orifice holder 6 is used in conjunction with the probe device; see appendix below. Figure 2 -Appendix Figure 4 The structure and function of the 6-hole stool are described in detail.

[0042] The perforated stool 6 includes a stool surface 61 and several stool legs 62 supporting the stool surface 61, and is made of lightweight, high-strength aluminum alloy. A through hole 63 is provided in the center of the stool surface, and the diameter of the through hole 63 is 45-50mm.

[0043] A reading probe 7 is installed on the seat surface 61 of the orifice stool 6. The reading probe 7 is an inclined elastic metal sheet, the bottom of which is fixedly installed on the seat surface 61 by bolts 8, and the top of which is used to point to the first section of the scale 31 on the probe rod 2. The position it points to is used as the reading of the first section of the scale 31, so as to accurately read the penetration depth of the probe device during the test.

[0044] The seat surface 61 of the orifice stool 6 is provided with multiple elastic support wheel units 9. Preferably, there are 3-4 elastic support wheel units 9, evenly distributed circumferentially around the through hole 63. During testing, they are used to provide elastic rolling support for the probe 2. For details, please refer to the appendix. Figure 4The elastic support wheel unit 9 includes a mounting groove 91, a support rod 92, a slider 93, a roller 94, and a spring 95. The mounting groove 91 is fixedly disposed on the stool surface 61 and is arranged radially along the through hole 63 on the stool surface 61. The slider 93 is slidably mounted in the mounting groove 91 and can slide radially along the through hole 63. The tail end of the support rod 92 is fixedly connected to the slider 93, and the front end of the support rod 92 is mounted with the roller 94. The spring 95 is installed at the tail of the slider 93 and is used to provide elastic force to the slider 93 in the direction of the center of the through hole 63, so that the roller 94 can elastically contact the probe 2. In this way, the rollers 94 of the multiple elastic support wheel units 9, which are evenly distributed in a circle, can provide elastic rolling support for the probe 2 that penetrates the through hole 63. During the test, probe 4 and probe rod 2 need to penetrate the through hole 63 of the bench surface from top to bottom so that probe 4 can be inserted into the roadbed to be tested. During the penetration of the through hole 63, since the maximum diameter of probe 4 is larger than the diameter of probe rod 2, multiple elastic support wheel units 9 can be spread out, allowing probe 4 to penetrate the through hole. Furthermore, during the test, the multiple elastic support wheel units 9 can provide good elastic rolling support for probe rod 2, keeping probe rod 2 at the center of the through hole 63 (see Appendix). Figure 5 ).

[0045] A plumb bob 10 is connected to the bottom surface of the seat surface 61 of the orifice bench 6. During the test, it is used as a reference for the verticality of the probe rod 2. During the test, after the probe 4 and the probe rod 2 pass through the through hole 63 of the seat surface, the position of the probe 4 on the roadbed is manually adjusted with reference to the plumb bob 10, thereby adjusting the verticality of the probe rod 2. (Since the diameter of the through hole 63 is larger than the diameter of the probe rod 2, and multiple elastic support wheel units 9 provide elastic rolling support for the probe rod 2, the verticality of the probe rod 2 is adjustable; and since the support part of the multiple elastic support wheel units 9 for the probe rod 2 is stably located at the center of the through hole, it is only necessary to adjust the position of the probe 4 at the bottom of the probe rod 2 to adjust the verticality of the probe rod 2 with reference to the plumb bob 10, and keep the probe rod 2 at the required verticality.)

[0046] The lightweight dynamic penetration testing device of this invention can measure the penetration depth P of a target (typically a roadbed or roadbed soil sample from an engineering site) after N hammer blows at a set drop height H. The testing process is as follows:

[0047] (1) Place the orifice stool 6 firmly in the target position, and place the probe 4 and probe 2 of the probe device through the through hole 63 in the center of the stool surface on the target to be measured. The elastic support wheel unit 9 on the orifice stool 6 provides good elastic rolling support for the probe 2, so that the probe 2 is in the center of the through hole 63. Then, with reference to the plumb bob 10, manually adjust the position of the probe 4, and then adjust the probe 2 to a vertical state.

[0048] (2) Pre-strike: Raise the drop hammer 1 and strike the enlarged section 21 of the probe rod 1-3 times as a pre-strike to allow the probe 4 to be initially placed into the target soil and stabilized therein.

[0049] (3) After the pre-strike is completed, adjust the position of the adjustable positioning ring 5 and set the required drop distance H of the hammer 1. The reading of the bottom surface of the adjustable positioning ring 5 corresponding to the second scale 32 is the required drop distance H of the hammer 1. Then, align the top of the reading probe 7 with the position of the first scale 31 of the probe rod 2 and use it as the reading of the first scale 31, which is recorded as p1.

[0050] (4) Start the formal power penetration test: Raise the drop hammer 1 to the bottom of the adjustable positioning ring 5, so that the drop hammer 1 hits the enlarged section on the probe rod 2 N times at the required drop distance H, then stop hitting, and read the reading of the first section of the scale 31 on the probe rod 2 again, and record it as p2.

[0051] (5) According to the formula P = p2 - p1, the penetration depth P of each N hammer blows under the set drop distance H in this test is obtained.

[0052] The present invention has been described above by way of example. It should be noted that any simple modifications, alterations or other equivalent substitutions that can be made by those skilled in the art without creative effort without departing from the core of the present invention fall within the protection scope of the present invention.

Claims

1. A method of detecting a light dynamic penetrometer penetration device, characterized by: Includes probe device and orifice holder; The probe device includes a drop hammer, a probe rod, a probe, and an adjustable positioning ring. The probe is mounted at the bottom end of the probe rod, and an enlarged diameter section is fixedly installed in the middle of the probe rod. The drop hammer is slidably fitted onto the probe rod section above the enlarged diameter section. Two scales are provided on the probe rod: the first scale, located on the probe rod section below the enlarged diameter section, indicates the depth of penetration; the second scale, located on the probe rod section above the enlarged diameter section, indicates the drop distance of the drop hammer. An adjustable positioning ring is installed on the probe rod section above the enlarged diameter section, fitted onto the probe rod, and a tightening screw is provided on the adjustable positioning ring. By adjusting this tightening screw, the positioning position of the adjustable positioning ring on the probe rod can be adjusted, thereby determining the drop distance of the drop hammer during the test in conjunction with the second scale. The orifice stool is used in conjunction with the probe device. The orifice stool includes a stool surface and stool legs supporting the stool surface. A through hole is provided in the center of the stool surface for the probe to pass through. A reading probe is provided on the stool surface to assist in reading the reading of the first section of the scale on the probe. Multiple elastic support wheel units are provided on the stool surface, evenly distributed in a circle around the through hole, for elastic rolling support of the probe. A plumb bob is connected to the bottom surface of the orifice stool surface to serve as a reference for the verticality of the probe. The elastic support wheel unit includes a mounting groove, a support rod, a slider, a roller, and a spring. The mounting groove is fixedly disposed on the bench surface and is arranged radially along the through hole on the bench surface. The slider is slidably mounted in the mounting groove and can slide radially along the through hole. The tail end of the support rod is fixedly connected to the slider, and the front end of the support rod is mounted with a roller. The spring is installed at the tail of the slider to provide elastic force to the slider in the direction of the center of the through hole. Step 1: Place the orifice stool firmly at the target position, insert the probe of the probe device through the through hole in the center of the stool surface and stand it on the target to be measured. The elastic support wheel unit of the orifice stool provides elastic rolling support for the probe, so that the probe is in the center of the through hole. Then, with reference to the plumb bob, manually adjust the probe position and then adjust the probe to a vertical state. Step 2: Pre-driving: Raise the drop hammer and hammer the enlarged section of the probe 1-3 times as a pre-driving of the probe, so that the probe is initially placed in the target soil and stabilized therein. Step 3: After pre-firing, adjust the position of the adjustable positioning ring and set the required drop distance H of the hammer. The reading on the second scale corresponding to the bottom surface of the adjustable positioning ring is the required drop distance H of the hammer. Then, align the top of the reading probe with the position of the first scale on the probe rod, and record this as the reading of the first scale. p 1; Step 4: Begin formal dynamic cone penetration testing: Raise the drop hammer to the bottom of the adjustable positioning ring, and strike the enlarged diameter section of the probe rod N times at the required drop distance H. Then stop hammering and read the reading on the first section of the scale on the probe rod at this time, and record it as . p 2; Step 5: According to the formula P = p 2- p 1. Obtain the penetration depth P of each N hammer blows under the set drop distance H in this test.

2. The lightweight dynamic penetration detection device according to claim 1, characterized in that: The probe diameter is 20-30mm.

3. The detection method of the lightweight dynamic penetration testing device according to claim 1, characterized in that: The probe is conical with a cone angle of 50-70 degrees.

4. The detection method of the lightweight dynamic penetration testing device according to claim 1, characterized in that: The diameter of the expanded section is 55-60mm.

5. The detection method of the lightweight dynamic penetration testing device according to claim 1, characterized in that: The mass of the falling hammer is 6-8 kg.

6. The detection method of the lightweight dynamic penetration testing device according to claim 1, characterized in that: The second scale is marked upwards from 0mm on the top surface of the expanded diameter section, with a maximum marking size of 600mm.

7. The detection method of the lightweight dynamic penetration testing device according to claim 1, characterized in that: The diameter of the through hole is 45-50mm.

8. The detection method of the lightweight dynamic penetration testing device according to claim 1, characterized in that: The reading probe uses an inclined elastic metal plate, the bottom of which is fixed to the bench surface by bolts, and the top of which is used to point to the first section of the scale on the probe rod.

9. The detection method of the lightweight dynamic penetration testing device according to claim 1, characterized in that: The number of elastic support wheel units is 3-4.

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