Rapid roadbed compactness detection method based on dynamic sounding penetration

Abstract

The invention discloses a rapid roadbed compactness detection method based on dynamic sounding penetration, which adopts a light dynamic sounding device, and the light dynamic sounding device structurally comprises a probe rod device and an orifice stool. Before field testing, the light dynamic sounding device is adopted for indoor testing, and the penetration PL of each N times of hammering under the drop distance H corresponding to the compactness DF required by the roadbed is obtained and serves as a field testing standard; according to the determined on-site detection standard, the light dynamic sounding device is adopted for engineering on-site detection, the light dynamic sounding device is adopted for detection of a single detection point, and the penetration degree of each N times of hammering at the drop distance H is obtained and recorded as PF; and when the PF is not greater than the PL, determining that the compactness of the detection point is qualified, otherwise, determining that the compactness is not qualified. The method is easy to operate, high in detection speed and small in damage to the compacted roadbed, indoor tests are not needed after field tests are started, and the roadbed compactness can be obtained on site.

Description

Technical Field

[0001] The invention belongs to the technical field of rapid detection of roadbed compaction, and in particular relates to a rapid detection method of roadbed compaction based on dynamic penetration. Background Art

[0002] Compaction is an important indicator for controlling the quality of roadbed construction. In actual projects, the common methods for testing compaction are sand filling method, water filling method and ring knife method. These methods are recommended by the specification and can accurately and truly obtain compaction indicators. Their test results can be used as the basis for acceptance. However, these methods also have disadvantages: first, these detection methods are destructive and cause great damage to the roadbed. For example, the sand filling method and the water filling method both require excavating test pits on the compacted roadbed to achieve; second, the detection speed of these methods is slow. Taking the sand filling method as an example, for a measuring point, it is necessary to conduct on-site pit digging, sand filling and weighing tests, as well as indoor moisture content tests. The efficiency is very low and sometimes affects the progress of the project. In fact, for some situations, such as the compaction self-inspection of the construction party, it is not necessary to use such cumbersome detection methods. Therefore, it is necessary to develop a faster compaction detection method.

[0003] Dynamic penetration is a field testing method that can reflect indicators such as the bearing capacity or strength of the roadbed. The bearing capacity or strength is often closely related to the compaction degree. Therefore, it is technically feasible to use dynamic penetration to detect the compaction degree of the roadbed. Dynamic penetration can be divided into three types: super heavy, heavy and light. Among them, the light dynamic penetration is the lightest and can be completed by manpower without the help of large-scale mechanical equipment. Conventional light dynamic penetration uses a 10kg drop hammer, and the number of hammer strikes with a penetration of 30cm is used as the test value. There have been attempts to use light dynamic penetration to detect the compaction degree of the roadbed, but these attempts still have some defects, mainly reflected in the detection accuracy and applicability. For the roadbed, its rolling construction process is layered, and the compaction degree detection is also carried out in layers. The thickness of each layer of the roadbed after rolling is mostly less than the penetration target value of 30cm for light dynamic penetration. When the penetration depth does not reach 30cm, it must be converted, and this conversion will bring corresponding errors. Secondly, the impact energy of a 10kg drop hammer is relatively large, and the penetration depth of each drop hammer is relatively large, so it is difficult to accurately make the total penetration depth reach the predetermined value, which will also cause errors, because the farther away from the predetermined value, the greater the error caused by conversion. Thirdly, conventional dynamic probing takes penetration as the target. For example, 30cm penetration is often counted as one hammer blow. In fact, the number of hammer blows required for 30cm penetration is basically impossible to be an integer, because the penetration depth of the probe rod is difficult to be exactly 30cm. In addition, the penetration depth is generally based on the roadbed hole as a reference. During the penetration process, the hole will deform or collapse due to extrusion and vibration, which also makes it difficult to accurately measure the penetration depth. Some attempts are to use the cumulative number of hammer blows and cumulative penetration of multiple 30cm penetrations to obtain indicators similar to or closely related to compaction, such as relative density or maximum dry density. This method is not suitable for the needs of roadbed layered rolling and layered detection. Roadbed layers generally do not exceed 30cm. Therefore, it is necessary to improve the light dynamic probing device and detection method to make it better adapt to the detection of compaction. Summary of the invention

[0004] In order to overcome the deficiencies of the prior art, the present invention provides a method for quickly detecting the compactness of a roadbed based on the penetration rate of dynamic penetration.

[0005] The present invention is achieved through the following technical solutions:

[0006] A method for quickly detecting the compactness of a roadbed based on the penetration of dynamic penetration, the method adopts a light dynamic penetration device, the structure of the light dynamic penetration device is as follows: comprising a probe rod device and a hole stool;

[0007] The probe rod device comprises a drop hammer, a probe rod, a probe head and an adjustable positioning ring; the probe head is installed at the bottom end of the probe rod, and an expanded diameter section is fixedly arranged in the middle of the probe rod; the drop hammer is slidably sleeved on the probe rod section above the expanded diameter section; two sections of scales are arranged on the probe rod, wherein the first section of the scale is arranged on the probe rod section below the expanded diameter section, and is used to indicate the depth of downward penetration of the probe rod; the second section of the scale is arranged on the probe rod section above the expanded diameter section, and is used to indicate the drop distance of the drop hammer; an adjustable positioning ring is arranged on the probe rod section above the expanded diameter section, the adjustable positioning ring is sleeved on the probe rod, and a tightening screw is arranged on the adjustable positioning ring, by adjusting the tightening screw, the positioning position of the adjustable positioning ring on the probe rod can be adjusted, and then the drop distance of the drop hammer during the test is determined in combination with the second section of the scale;

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

[0009] The quick detection method of roadbed compaction is as follows:

[0010] Step 1: Before the on-site test, the light dynamic penetration device is used to conduct indoor tests to obtain the compaction degree D required for the roadbed. F The penetration rate P per hammer blow N at the corresponding drop distance H L , as the engineering site inspection standard; including the following steps:

[0011] Step 1.1, take the same soil sample as the roadbed engineering site, and make a sample with a compaction degree D in the test pit. D is the same as the compaction degree D required at the engineering site. F close to or equal to;

[0012] Step 1.2, testing the soil sample in the test pit using the light dynamic penetration device to obtain the penetration P of each N hammer blows at a set drop distance H;

[0013] Step 1.3: Repeat steps 1.1 to 1.2 above and conduct at least three groups of tests. In each group of tests, the compaction degree D is greater than or less than the required compaction degree D on site. F There shall be no less than one test specimen for each of the following types of testing:

[0014] Step 1.4: Draw the compaction degree D-penetration degree P curve by group, and deduce the D F The corresponding penetration

[0015] Step 1.5, take multiple groups of test P Li The arithmetic mean of L , P L That is the compaction degree D required at the engineering site F The corresponding penetration rate per hammer blow N times at a drop distance H is used as the standard for on-site inspection of the project;

[0016] Step 2: According to the engineering site inspection standard determined in step 1, the light dynamic penetration device is used to conduct engineering site inspection, and the steps are as follows:

[0017] Step 2.1, determine the location of the inspection points at the project site and mark them according to the requirements;

[0018] Step 2.2: For a single detection point, the light dynamic penetration device is used to detect and obtain the penetration rate per N hammer strikes at a drop distance H, which is recorded as P F ;

[0019] Step 2.3, when P F Not greater than P L When the compaction degree of the test point is qualified, otherwise it is unqualified;

[0020] Step 2.4: Repeat steps 2.2 to 2.3 to complete the inspection of all inspection points.

[0021] In the above technical solution, the light dynamic penetration device is used for testing to obtain the penetration of each N hammer strikes at a drop distance H as follows:

[0022] (1) Place the orifice stool firmly at the target position, insert the probe rod of the probe rod device into the through hole in the center of the stool surface and place it on the target to be measured, and use the elastic support wheel unit of the orifice stool to elastically roll the probe rod so that the probe rod is at the center of the through hole. Then, refer to the plumb bob and manually adjust the probe position to adjust the probe rod to a vertical state.

[0023] (2) Pre-driving: lift the drop hammer and hammer the expanded diameter section of the probe rod for 1-3 times as a pre-driving of the probe rod, so that the probe is initially placed in the target soil to be measured and stabilized therein;

[0024] (3) After the pre-punch is completed, adjust the position of the adjustable positioning ring and set the drop distance H required for the drop hammer. The reading of the second scale corresponding to the bottom surface of the adjustable positioning ring is the drop distance H required for the drop hammer. Then align the top of the reading probe with the position of the first scale of the probe rod, which is taken as the reading of the first scale, recorded as p1.

[0025] (4) Start formal dynamic probing: lift the drop hammer to the bottom of the adjustable positioning ring, and make the drop hammer hit the expanded diameter section on the probe rod N times at the required drop distance H, then stop hammering, and read the reading of the first section of the scale on the probe rod again, which is recorded as p2;

[0026] (5) According to the formula P = p2-p1, the penetration P of each N hammer blows at the set drop distance H in this test is obtained.

[0027] In the above technical solution, the diameter of the probe rod is 20-30 mm.

[0028] In the above technical solution, the probe is conical and the cone angle is 50-70 degrees.

[0029] In the above technical solution, the diameter of the expanded section is 55-60 mm.

[0030] In the above technical solution, the mass of the falling weight is 6-8kg.

[0031] In the above technical solution, the second section of the scale starts from 0mm on the top surface of the expanded diameter section and is marked upward along the rod section, and the maximum marked size is 600mm.

[0032] In the above technical solution, the diameter of the through hole is 45-50 mm.

[0033] In the above technical solution, the reading probe adopts an elastic metal sheet set at an angle, the bottom of which is fixed on 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. The pointed position is used as the reading of the first section of the scale, so as to accurately read the penetration depth of the probe rod device during the test.

[0034] In the above technical solution, the number of the elastic support wheel units is 3-4.

[0035] In the above technical scheme, the elastic support wheel unit includes a mounting groove, a support rod, a slider, a roller and a spring. The mounting groove is fixedly arranged on the stool surface and is arranged radially along the through hole on the stool surface; the slider is slidably installed in the mounting groove, and the slider can slide radially along the through hole; the tail end of the support rod is fixedly connected to the slider, and the roller is installed at the front end of the support rod; the spring is installed at the tail of the slider, and is used to provide the slider with an elastic force pointing to the center direction of the through hole, so that the roller can elastically contact the probe rod, so that the rollers of multiple elastic support wheel units evenly distributed around the circumference can elastically roll and support the probe rod passing through the through hole.

[0036] The advantages and beneficial effects of the present invention are:

[0037] (1) Compared with the conventional sand filling method, water filling method and ring knife method, the method of the present invention is simple to operate, has a fast detection speed, and causes little damage to the compacted roadbed. After the field test begins, there is no need to conduct indoor tests, and the roadbed compaction degree can be obtained on site.

[0038] (2) The light dynamic probing device used in the present invention is engraved with two millimeter-level scales (i.e., the first scale and the second scale), and a hole stool with a reading elastic metal sheet is used instead of the easily deformed roadbed hole as the measurement reference point. The penetration measurement accuracy is higher, and therefore the compaction test result is more accurate.

[0039] (3) The lightweight dynamic probing device of the present invention can conveniently and accurately adjust the drop distance required for the drop hammer during the test through the adjustable positioning ring combined with the second section scale. During the test, the drop hammer only needs to be manually lifted to the bottom surface of the adjustable positioning ring (i.e., accurately positioned), and then naturally dropped to strike the expanded diameter section of the probe rod, thereby causing the entire probe rod to generate a downward impact force. This method can ensure that the drop distance of the drop hammer is the same each time, and is very convenient to operate.

[0040] (4) A plurality of elastic support wheel units are arranged on the orifice stool of the light power probing device adopted by the present invention, and are evenly distributed around the through hole in a circle, so as to provide elastic rolling support for the probe rod. During the test, the probe and the probe rod need to pass through the through hole of the stool surface from top to bottom so as to insert the probe into the target to be detected. In the process of passing through the through hole, since the maximum diameter of the probe is larger than the diameter of the probe rod, the plurality of elastic support wheel units can be stretched open so that the probe can pass through the through hole, and during the test, the plurality of elastic support wheel units can ensure good elastic rolling support for the probe rod, so that the probe rod is in the center of the through hole; at the same time, since the front end of the elastic support wheel unit adopts 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 provided on the bottom surface of the orifice stool as a reference for the verticality of the probe rod. Under the joint action of the plumb bob and the elastic support wheel unit, the verticality of the probe rod can be adjusted (since the aperture of the through hole is larger than the aperture of the probe rod, and the multiple elastic support wheel units provide elastic rolling support to the probe rod, the verticality of the probe rod is adjustable; and since the supporting portion of the probe rod by the multiple elastic support wheel units is stably located in 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 maintained at the required verticality).

[0041] (5) The light dynamic probing device used in the present invention is lighter and reduces the labor intensity of the test personnel. The weight of the drop hammer is about 7.5 kg, and the penetration degree generated by each hammer blow is small, which also reduces the probability of the probe penetrating the test roadbed and entering the non-test roadbed.

[0042] (6) Compared with other methods using dynamic penetration as a detection means, the general method records the number of blows N required for each specific penetration such as 30 cm, but when the actual number of blows is N, the penetration degree is often greater than 30 cm, which will cause measurement errors due to excessive penetration. The method of the present invention uses the penetration degree corresponding to a specific number of hammer blows (generally 10 to 15) at a specific drop distance as a measurement indicator, avoiding errors caused by excessive penetration. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic diagram of the structure of the probe device in the present invention.

[0044] Figure 2 It is a schematic diagram of the top view of the hole stool in the present invention.

[0045] Figure 3 It is a side structural schematic diagram of the hole stool in the present invention.

[0046] Figure 4 It is a partial enlarged structural schematic diagram of the hole stool in the present invention.

[0047] Figure 5 Shown is a schematic diagram of the detection state of the light dynamic probing device in the present invention.

[0048] For ordinary technicians in this field, other relevant drawings can be obtained based on the above drawings without any creative work. DETAILED DESCRIPTION

[0049] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with specific embodiments.

[0050] A light dynamic penetration device comprises a probe rod device and a hole stool.

[0051] The probe device comprises a drop weight 1, a probe rod 2, a probe head 4 and an adjustable positioning ring 5. Figure 1 Its structure is introduced in detail.

[0052] A probe 4 is installed at the bottom end of the probe rod 2, the diameter of the probe rod 2 is 25 mm, the probe 4 is conical, the maximum diameter of the probe 4 is 40 mm, and the cone angle is 60 degrees; an expanded diameter section 21 is fixedly arranged in the middle of the probe rod 2, and the diameter of the expanded diameter section 21 is 55 mm; the drop hammer 1 is slidably mounted on the rod section of the probe rod 2 above the expanded diameter section 21, and the mass of the drop hammer 1 is preferably 7.5 kg. When the drop hammer 1 is lifted, the drop hammer 1 falls freely along the probe rod 2, and will hammer the expanded diameter section 21, thereby causing the entire probe rod 2 to generate a downward impact force.

[0053] Two sections of scales are provided on the probe rod 2, wherein the first section of the scale 31 is provided on the section of the probe rod 2 below the expanded diameter section 21, and during the test, is used to indicate the depth of the probe rod 2 penetrating downward into the roadbed (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 section of the scale 32 is provided on the section of the probe rod 2 above the expanded diameter section 21, and the second section of the scale 32 is marked upward from 0mm along the section from the top surface of the expanded diameter section 21, with a maximum marked size of 500mm. The function of the second section of the scale 32 is to indicate the drop distance of the drop weight 1 (i.e., to indicate from what height the drop weight 1 falls) during the test.

[0054] An adjustable positioning ring 5 is provided on the rod section of the probe rod 2 above the expanded diameter section 21, the adjustable positioning ring 5 is sleeved on the probe rod 2, and a tightening screw 51 is provided 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, and then the drop distance of the drop hammer 1 during the test is determined in combination with the second section scale 32, that is, during the test, the adjustable positioning ring 5 is first adjusted to the drop distance position required for the drop hammer 1 to fall with reference to the second section scale 32 (the bottom surface of the adjustable positioning ring 5 corresponds to the reading of the second section scale 32 as the drop distance position required for the drop hammer 1 to fall), and then during the test, the drop hammer 1 is manually lifted to the bottom surface of the adjustable positioning ring 5, and then falls naturally to hammer the expanded diameter section 21, thereby causing the entire probe rod 2 to generate a downward impact force.

[0055] The orifice stool 6 is used in conjunction with the probe device, as shown in the following Figure 2 -Attached Figure 4 Specifically introduce the structure and function of the aperture stool 6.

[0056] The hole stool 6 comprises a stool surface 61 and a plurality of stool legs 62 supporting the stool surface 61, and the material is a light and high-strength aluminum alloy. A through hole 63 is arranged at the center of the stool surface, and the diameter of the through hole 63 is 45-50 mm.

[0057] A reading probe 7 is arranged on the stool surface 61 of the orifice stool 6. The reading probe 7 is an elastic metal sheet set at an angle. The bottom of the reading probe 7 is fixed on the stool surface 61 by bolts 8, and the top of the reading probe 7 is used to point to the first section scale 31 on the probe rod 2. The pointed position is used as the reading of the first section scale 31, so as to accurately read the penetration depth of the probe rod device during the test.

[0058] A plurality of elastic support wheel units 9 are arranged on the stool surface 61 of the orifice stool 6. The number of the elastic support wheel units 9 is preferably 3-4 and is evenly distributed around the through hole 63. During the test, the elastic support wheel units 9 are used to provide elastic rolling support for the probe rod 2. 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 arranged on the stool surface 61 and is arranged radially along the through hole 63 on the stool surface 61; the slider 93 is slidably installed in the mounting groove 91, and the slider 93 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 roller 94 is installed at the front end of the support rod 92; the spring 95 is installed at the tail of the slider 93, and is used to provide the slider 93 with an elastic force pointing to the center direction of the through hole 63, so that the roller 94 can elastically contact the probe rod 2, so that the rollers 94 of the multiple elastic support wheel units 9 evenly distributed around the circumference can elastically roll and support the probe rod 2 passing through the through hole 63. During the test, the probe 4 and the probe rod 2 need to penetrate the through hole 63 of the bench surface from top to bottom so that the probe 4 is inserted into the roadbed to be tested. In the process of penetrating the through hole 63, since the maximum diameter of the probe 4 is larger than the diameter of the probe rod 2, the multiple elastic support wheel units 9 can be stretched out so that the probe 4 can penetrate the through hole. In addition, during the test, the multiple elastic support wheel units 9 can ensure good elastic rolling support for the probe rod 2, so that the probe rod 2 is located at the center of the through hole 63 (see attached). Figure 5 ).

[0059] The bottom surface of the stool surface 61 of the orifice stool 6 is connected with a plumb bob 10, which is used as a reference for the verticality of the probe rod 2 during the test. During the test, after the probe 4 and the probe rod 2 are passed through the through hole 63 of the stool surface, the position of the probe 4 on the roadbed is manually adjusted with reference to the plumb bob 10, and then the verticality of the probe rod 2 is adjusted (because the aperture of the through hole 63 is larger than the aperture of the probe rod 2, and the multiple elastic support wheel units 9 provide elastic rolling support to the probe rod 2, the verticality of the probe rod 2 is adjustable; and because the support part of the multiple elastic support wheel units 9 for the probe rod 2 is stably located in the center of the through hole, it is only necessary to adjust the position of the probe 4 at the bottom end of the probe rod 2, and the verticality of the probe rod 2 can be adjusted with reference to the plumb bob 10, and the probe rod 2 can be kept at the required verticality).

[0060] 1. The basic process of using the above-mentioned light dynamic penetration device for detection is as follows:

[0061] (1) Place the orifice stool 6 firmly at the target position, and place the probe 4 and the probe 2 of the probe rod 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 ensures good elastic rolling support for the probe rod 2, so that the probe rod 2 is at the center of the through hole 63. Then, refer to the plumb bob 10 to manually adjust the position of the probe 4, and then adjust the probe rod 2 to a vertical state;

[0062] (2) Pre-driving: lift the drop hammer 1 and hammer the expanded diameter section 21 of the probe rod 1-3 times as a pre-driving of the probe rod, so that the probe 4 is initially placed in the target soil to be measured and stabilized therein;

[0063] (3) After the pre-punching is completed, the position of the adjustable positioning ring 5 is adjusted to set the drop distance H required by the drop hammer 1. The reading of the second section scale 32 corresponding to the bottom surface of the adjustable positioning ring 5 is the drop distance H required by the drop hammer 1; then the top end of the reading probe 7 is aligned with the position of the first section scale 31 of the probe rod 2, which is taken as the reading of the first section scale 31, recorded as p1;

[0064] (4) Start formal dynamic penetration: lift the drop hammer 1 to the bottom surface of the adjustable positioning ring 5, and make the drop hammer 1 hit the expanded diameter section on the probe rod 2 N times according to the required drop distance H, then stop hammering, and read the reading of the first section scale 31 on the probe rod 2 again, which is recorded as p2;

[0065] (5) According to the formula P = p2-p1, the penetration P of each N hammer blows at the set drop distance H in this test is obtained.

[0066] 2. The process of using the above-mentioned light dynamic penetration device to conduct indoor tests to determine the engineering site inspection standards is as follows (the purpose is to conduct indoor light dynamic penetration tests before the engineering site inspection to obtain the required compaction degree D of the roadbed at the engineering site. F The corresponding penetration rate P per hammer N times at the set drop distance H L , as the standard for engineering site inspection):

[0067] (1) Take the same soil sample as that at the roadbed project site and make a test sample with a compaction degree D in a test pit with a diameter of not less than 300 mm and a depth of not less than 400 mm. D is the same as the compaction degree D required at the project site. F close to or equal to;

[0068] (2) The soil samples in the test pit are tested according to the basic process of testing with the light dynamic penetration device mentioned above, and the penetration P of each N hammer strikes at the set drop distance H is obtained;

[0069] (3) Repeat steps (1) to (2) and conduct at least three sets of tests. In each set of tests, the compaction degree D is greater than or less than the required compaction degree D on site. F There shall be no less than one test specimen for each of the following types of testing:

[0070] (4) Draw the compaction degree D-penetration degree P curve by group, and deduce the D F The corresponding penetration P Li ;

[0071] (5) Take multiple groups of tests P Li The arithmetic mean of L , P L That is the compaction degree D required at the engineering site FThe penetration rate per N hammer blows at the corresponding drop distance H is used as the standard for on-site inspection of the project.

[0072] 3. According to the above-mentioned engineering site inspection standards (i.e., the compaction degree D required at the engineering site) F The penetration rate P per hammer blow N at the corresponding drop distance H L ), the above-mentioned light dynamic penetration device is used to conduct on-site inspection of the project, and the inspection process is as follows:

[0073] (1) According to the requirements, determine the location of each inspection point on the project site and mark them;

[0074] (2) For a single test point, the basic process of testing with the light dynamic penetration device is followed to obtain the penetration rate per N hammer strikes at a drop distance H, which is recorded as P F ;

[0075] (3) When P F Not greater than P L When the compaction degree of the test point is qualified, otherwise it is unqualified;

[0076] (4) Repeat steps (2) to (3) to complete the inspection of all inspection points.

[0077] The present invention is described above by way of example. It should be noted that, without departing from the core of the present invention, any simple deformation, modification or other equivalent replacement that can be made by those skilled in the art without inventive effort falls within the protection scope of the present invention.

Claims

1. A method for rapid detection of roadbed compaction based on dynamic penetration, characterized in that: The method adopts a light dynamic penetration device, and the structure of the light dynamic penetration device is as follows: it includes a probe rod device and an orifice stool; The probe rod device comprises a drop hammer, a probe rod, a probe head and an adjustable positioning ring; the probe head is installed at the bottom end of the probe rod, and an expanded diameter section is fixedly arranged in the middle of the probe rod; the drop hammer is slidably sleeved on the probe rod section above the expanded diameter section; two sections of scales are arranged on the probe rod, wherein the first section of the scale is arranged on the probe rod section below the expanded diameter section, and is used to indicate the depth of downward penetration of the probe rod; the second section of the scale is arranged on the probe rod section above the expanded diameter section, and is used to indicate the drop distance of the drop hammer; an adjustable positioning ring is arranged on the probe rod section above the expanded diameter section, the adjustable positioning ring is sleeved on the probe rod, and a tightening screw is arranged on the adjustable positioning ring, by adjusting the tightening screw, the positioning position of the adjustable positioning ring on the probe rod can be adjusted, and then the drop distance of the drop hammer during the test is determined in combination with the second section of the scale; The orifice stool is used in conjunction with the probe rod device. The orifice stool includes a stool surface and stool legs supporting the stool surface. A through hole is provided at the center of the stool surface for the probe rod to pass through. A reading probe is provided on the stool surface of the orifice stool for assisting in reading the reading of the first section of the scale on the probe rod. A plurality of elastic support wheel units are provided on the stool surface of the orifice stool, which are evenly distributed around the through hole in a circle and are used for elastically rolling support of the probe rod. A plumb bob is connected to the bottom surface of the stool surface of the orifice stool for use as a reference for the verticality of the probe rod. The quick detection method of roadbed compaction is as follows: Step 1: Before the on-site test, the light dynamic penetration device is used to conduct indoor tests to obtain the compaction degree D required for the roadbed. F The penetration rate P per hammer blow N at the corresponding drop distance H L , as the engineering site inspection standard; including the following steps: Step 1.1, take the same soil sample as the roadbed engineering site, and make a sample with a compaction degree D in the test pit. D is the same as the compaction degree D required at the engineering site. F close to or equal to; Step 1.2, testing the soil sample in the test pit using the light dynamic penetration device to obtain the penetration P of each N hammer blows at a set drop distance H; Step 1.3: Repeat steps 1.1 to 1.2 above and conduct at least three groups of tests. In each group of tests, the compaction degree D is greater than or less than the required compaction degree D on site. F There shall be no less than one test specimen for each of the following types of testing: Step 1.4: Draw the compaction degree D-penetration degree P curve by group, and deduce the D F The corresponding penetration Step 1.5, take multiple groups of tests The arithmetic mean of L , P L That is the compaction degree D required at the engineering site F The corresponding penetration rate per hammer blow N times at a drop distance H is used as the standard for on-site inspection of the project; Step 2: According to the engineering site inspection standard determined in step 1, the light dynamic penetration device is used to conduct engineering site inspection, and the steps are as follows: Step 2.1, determine the location of the inspection points at the project site and mark them according to the requirements; Step 2.2: For a single detection point, the light dynamic penetration device is used to detect and obtain the penetration rate per N hammer strikes at a drop distance H, which is recorded as P F ; Step 2.3, when P F Not greater than P L When the compaction degree of the test point is qualified, otherwise it is unqualified; Step 2.4: Repeat steps 2.2 to 2.3 to complete the inspection of all inspection points.

2. The method for rapid detection of roadbed compaction based on dynamic penetration according to claim 1 is characterized in that: The process of using the light dynamic penetration device to test and obtain the penetration of each N hammer blows at a drop distance H is as follows: (1) Place the orifice stool firmly at the target position, insert the probe rod of the probe rod device into the through hole in the center of the stool surface and place it on the target to be measured, and use the elastic support wheel unit of the orifice stool to elastically roll the probe rod so that the probe rod is at the center of the through hole. Then, refer to the plumb bob and manually adjust the probe position to adjust the probe rod to a vertical state. (2) Pre-driving: lift the drop hammer and hammer the expanded diameter section of the probe rod for 1-3 times as a pre-driving of the probe rod, so that the probe is initially placed in the target soil to be measured and stabilized therein; (3) After the pre-punch is completed, adjust the position of the adjustable positioning ring and set the drop distance H required for the drop hammer. The reading of the second scale corresponding to the bottom surface of the adjustable positioning ring is the drop distance H required for the drop hammer. Then align the top of the reading probe with the position of the first scale of the probe rod, which is taken as the reading of the first scale, recorded as p1. (4) Start formal dynamic probing: lift the drop hammer to the bottom of the adjustable positioning ring, and make the drop hammer hit the expanded diameter section on the probe rod N times at the required drop distance H, then stop hammering, and read the reading of the first section of the scale on the probe rod again, which is recorded as p2; (5) According to the formula P = p2-p1, the penetration P of each N hammer blows at the set drop distance H in this test is obtained.

3. The method for rapid detection of roadbed compaction based on dynamic penetration according to claim 1 is characterized in that: The probe rod diameter is 20-30mm.

4. The method for rapid detection of roadbed compaction based on dynamic penetration according to claim 1 is characterized in that: The probe is conical with a cone angle of 50-70 degrees.

5. The method for rapid detection of roadbed compaction based on dynamic penetration according to claim 1 is characterized in that: The diameter of the expanded section is 55-60 mm.

6. The method for rapid detection of roadbed compaction based on dynamic penetration according to claim 1 is characterized in that: The mass of the falling weight is 6-10kg.

7. The method for rapid detection of roadbed compaction based on dynamic penetration according to claim 1 is characterized in that: The second section of the scale starts from 0mm on the top surface of the expanded diameter section and is marked upward along the rod section.

8. The method for rapid detection of roadbed compaction based on dynamic penetration according to claim 1 is characterized in that: The reading probe adopts an elastic metal sheet set at an angle, the bottom of which is fixed on 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, and the pointed position is used as the reading of the first section of the scale.

9. The method for rapid detection of roadbed compaction based on dynamic penetration according to claim 1 is characterized in that: The number of elastic support wheel units is 3-4.

10. The method for rapid detection of roadbed compaction based on dynamic penetration according to claim 1, characterized in that: The elastic support wheel unit includes a mounting groove, a support rod, a slider, a roller and a spring. The mounting groove is fixedly arranged on the stool surface and is arranged radially along the through hole on the stool surface; the slider is slidably installed in the mounting groove, and the slider can slide radially along the through hole; the tail end of the support rod is fixedly connected to the slider, and the roller is installed at the front end of the support rod; the spring is installed at the tail of the slider, and is used to provide the slider with an elastic force pointing to the center direction of the through hole, so that the roller can elastically contact the probe rod, so that the rollers of multiple elastic support wheel units evenly distributed around the circumference can elastically roll and support the probe rod passing through the through hole.

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