Novel hole bottom standard penetration experiment device

Abstract

The invention discloses a novel hole bottom standard penetration experiment device which is characterized in that a penetration device of a standard specification is hit by 15 cm from the elevation of the hole bottom of a drill hole in advance, a worm gear lifting module is used for driving a fishing claw connected with a worm gear to move downwards, and when the fishing claw makes contact with the upper portion of a center penetrating hammer, the fishing claw is opened to grasp the center penetrating hammer; after acquiring a signal through the pressure sensor, the ground controller sends an instruction to command the worm gear lifting mechanism to drive the worm to ascend, and when the worm is lifted by 76cm, the upper part of the fishing claw is in contact with the upper part of the shell, and the fishing claw is opened to release the piercing hammer; the standard piercing hammer which is lifted by 63.5 kg is lifted in a reciprocating manner to hammer the hammer pad, the hammer pad is continuously hammered by 30 cm, the ground controller records the corresponding hammering number, and the soil property is judged according to the corresponding hammering number; standardized and automatic hammering can be achieved at the hole bottom, and the problem of standard penetration energy loss is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of engineering drilling testing, and in particular relates to a novel bottom hole standard penetration test device. Background Art

[0002] The standard penetration test is to use a 63.5kg core hammer to fall freely along the drill pipe at a drop distance of 76cm, and then drive a standard specification penetrometer 15cm from the bottom elevation of the borehole, and then drive it 30cm, and record the corresponding number of hits to judge the properties of the soil. It is one of the common in-situ testing methods in geotechnical engineering investigation. The existing standard penetration test relies on manual pulling of a heavy hammer on the ground to hammer, and manual reading of the standard penetration number and penetration thickness.

[0003] At present, in the field of engineering geological survey, the stratum buried depth for standard penetration test of boreholes is generally less than 20m, and the maximum depth of the standard penetration rod length correction specified in the relevant domestic specifications is 21m. In addition, the standard penetrator uses a drill rod to go down to the bottom of the hole, and the impact energy of the standard penetration hammer above the ground is transmitted to the standard penetrator at the bottom of the hole through the drill rod. The longer the rod is, the greater the impact energy loss is. The test data obtained cannot represent the true characteristics of the deep strata and cannot be applied.

[0004] Conducting a standard penetration test at the bottom of the hole can fundamentally solve the problem of energy transfer loss in standard penetration. Controlling the drop distance of the hammer at 76cm is one of the key technologies for implementing the standard penetration test. As the test device is penetrated and sunk, the absolute position of the hammer released each time is different. The manual distance control method is not applicable to the bottom hole test. In order to achieve deep standard penetration, it is urgent to develop a standard penetration test device suitable for the bottom of the hole. The most critical issue is how to achieve standardized and automated hammering at the bottom of the hole. Summary of the invention

[0005] The invention provides a novel bottom hole standard penetration test device to solve the problems existing in the prior art.

[0006] To solve the above problems, the technical solution provided by the present invention is as follows:

[0007] The embodiment of the present invention provides a novel bottom hole standard penetration test device, comprising a penetration head (1), a penetrator (2), a connector (3), a hammer pad (4), a core hammer (5), a housing (6), a claw seat (7), a cable (8), a ground controller (9), a worm gear lifting mechanism (10), a worm (11), a claw (12), a spring support rod (13), a spring (14) and a central hollow rod (15);

[0008] The upper and lower ends of the penetrator (2) are connected to the penetration head (1) and the connector (3) respectively by threads, and the upper end of the connector (3) is connected to the lower end of the hammer pad (4) by threads; the upper end of the hammer pad (4) is externally connected to the housing (6) by threads, and the upper end of the hammer pad (4) is internally connected to the central hollow rod (15) by threads; a distance sensor is provided inside the hammer pad (4), and the distance sensor is connected to the worm gear lifting mechanism (10) through an electric wire passing through the hollow cavity inside the central hollow rod (15);

[0009] The upper end of the central hollow rod (15) passes through the hollow cavity inside the worm gear (11) to provide a passage for the line; the core hammer (5) and the central hollow rod (15) are arranged with clearance fit; the upper part of the claw seat (7) is connected to the worm gear (11) by threading, and the central hollow rod (15) enters the central cavity inside the worm gear (11) through the central radial cavity of the claw seat (7); two claws (12) are symmetrically arranged on the claw seat (7), and the spring support rod (13) is connected between the two claws (12), and the spring support rod (13) is wound with a spring (14), and the two claws (12) are closed to grasp the core hammer (5), and the two claws (12) are opened to release the core hammer (5); the upper end of the cable (8) is connected to the ground controller (9), and the lower end of the cable (8) is connected to the worm gear lifting mechanism (10) to provide lifting force for the entire experimental device.

[0010] In a preferred embodiment of the present invention, the weight of the core piercing hammer (5) is 63.5 kg.

[0011] In a preferred embodiment of the present invention, the exterior of the worm gear lifting mechanism (10) is connected to the housing (6) via threads.

[0012] In a preferred embodiment of the present invention, the pre-insertion distance of the penetrator (2) from the bottom elevation of the borehole is 15 cm.

[0013] In a preferred embodiment of the present invention, the worm gear lifting mechanism (10) is used to drive the claw (12) connected to the worm gear to move downward; when the claw (12) contacts the upper part of the core hammer (5), the claw (12) opens to grab the core hammer (5), and the ground controller (9) obtains a signal through a pressure sensor and issues a command to instruct the worm gear lifting mechanism (10) to drive the worm (11) to rise; when the worm (11) rises 76 cm, the upper part of the claw (12) contacts the upper part of the housing (6), and the claw (12) opens to release the core hammer (5), and the core hammer (5) of 63.5 kg is lifted reciprocally to hit the hammer pad (4), and continues to hit 30 cm, and the ground controller (9) records the corresponding number of hits, and judges the nature of the soil based on it.

[0014] Compared with the prior art, the embodiments of the present invention provide a novel bottom hole standard penetration test device, which has the following beneficial effects: (1) The present invention transfers the loading mode of the standard penetration test from the ground to the bottom hole, avoiding the attenuation and verification of the load when it is transmitted to the bottom hole through the drill pipe, and can obtain high-precision test parameters. (2) The present invention can realize standardized and automated hammering at the bottom hole, avoiding the problem of standard penetration capacity transmission loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 A schematic diagram of the structure of a novel bottom hole standard penetration test device provided in an embodiment of the present application.

[0017] Figure 2 A partial schematic diagram of a scooping claw mechanism of a novel bottom hole standard penetration test device provided in an embodiment of the present application.

[0018] Explanation of the accompanying reference numerals: 1. penetration head; 2. penetrator; 3. connecting rod; 4. hammer pad; 5. core hammer; 6. housing; 7. claw seat; 8. cable; 9. controller; 10. worm gear lifting mechanism; 11. worm; 12. claw; 13. spring support rod; 14. spring; 15. center hollow rod. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0020] like Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a novel bottom hole standard penetration test device, including a penetration head 1, a penetrator 2, a connector 3, a hammer pad 4, a core hammer 5, a housing 6, a claw seat 7, a cable 8, a ground controller 9, a worm gear lifting mechanism 10, a worm 11, a claw 12, a spring support rod 13, a spring 14 and a center hollow rod 15.

[0021] The penetrator 2 is a symmetrical device with upper and lower ends. The upper and lower ends of the penetrator 2 are connected to the penetration head 1 and the connector 3 respectively through threads. The upper end of the connector 3 is connected to the lower end of the hammer pad 4 through threads. The upper end of the hammer pad 4 is connected to the outer shell 6 through threads, and the upper end of the hammer pad 4 is connected to the central hollow rod 15 through threads; a distance sensor is provided inside the hammer pad 4, and the distance sensor passes through the wire in the hollow cavity inside the central hollow rod 15 and is connected to the worm gear lifting mechanism 10.

[0022] The center hollow rod 15 has a hollow structure inside, providing a channel for the line. The upper end of the center hollow rod 15 passes through the hollow cavity inside the worm 11. The core hammer 5 and the center hollow rod 15 are set with clearance fit, and the fit between the two does not affect the free fall of the core hammer 5. The upper part of the claw seat 7 is connected to the worm 11 by threads. The center hollow rod 15 enters the central cavity inside the worm 11 through the central radial cavity of the claw seat 7. Two claws 12 are symmetrically arranged on the claw seat 7, and a spring support rod 13 is connected between the two claws 12. A spring 14 is wound on the spring support rod 13. The two claws 12 are closed to grab the core hammer 5, and the two claws 12 are opened to release the core hammer 5; the upper end of the cable 8 is connected to the ground controller 9 to supply power to the ground controller 9, and the ground controller 9 is connected to the entire experimental device at the bottom through the cable 8. The lower end of the cable 8 is connected to the worm gear lifting mechanism 10 to provide lifting force for the entire experimental device.

[0023] The weight of the core hammer 5 of this embodiment is 63.5 kg. The worm gear lifting mechanism 10 is externally connected to the housing 6 by a thread. The pre-insertion distance of the penetrator 2 from the bottom elevation of the borehole is 15 cm. The worm gear lifting mechanism 10 is used to drive the claw 12 connected to the worm gear to move downward. The working principle of a new type of bottom hole standard penetration experimental device: the standard specification penetrator 2 is pre-inserted 15 cm from the bottom elevation of the borehole, and the claw connected to the worm gear is driven downward by the worm gear lifting mechanism 10. When the scoop claw 12 contacts the upper part of the core hammer 5, the scoop claw 12 opens and grabs the core hammer 5. After obtaining the signal through the pressure sensor, the ground controller 9 issues a command to instruct the worm gear lifting mechanism 10 to drive the worm 11 to rise. When the worm 11 rises 76 cm, the upper part of the scoop claw 12 contacts the upper part of the outer shell 6, and the scoop claw 12 opens to release the core hammer 5. In this way, the core hammer 5 weighing 63.5 kg is lifted back and forth to hit the hammer pad 4, and continues to hit 30 cm. The ground controller 9 records the corresponding number of hits and judges the nature of the soil accordingly.

[0024] The specific working steps of a new type of bottom hole standard penetration test device are as follows:

[0025] Drilling to the predetermined standard penetration test depth;

[0026] Before the test begins, the standard penetration test device in the hole is lowered to the bottom of the hole via cable 8;

[0027] After power is turned on, the distance sensor installed at the center of the lower end of the hammer pad 4 measures the initial distance between the standard penetration test device in the hole and the test formation, and feeds back to the ground controller 9. The ground controller 9 sends a working instruction to the worm gear lifting mechanism 10, and the worm gear lifting mechanism 10 starts to work and drives the worm 11 to rotate and fall, and the claw seat 7 fixedly connected to the worm 11 and the claw 12 on the upper part thereof fall with it. When the claw 12 contacts the core hammer 5, the spring 14 in the claw seat 7 is compressed, and the claw 12 opens to grab the core hammer 5. The pressure sensor installed in the worm gear lifting mechanism 10 transmits a signal to the ground controller 9, and the ground controller 9 sends an instruction, and the worm gear lifting mechanism 10 drives the worm 11, and the worm 11 drives the claw seat 7 and its attached parts to move upward as a whole. When the worm 11 rises 76cm, the upper part of the claw 12 contacts the upper part of the housing 6, the claw 12 opens, the spring 14 stretches, and the core hammer 5 falls freely to hit the hammer pad 4. When the distance sensor detects that the experimental device is sunk into the ground by 15 cm, the device stops the pre-experimental work and records the number of hammer blows in the ground controller 9 .

[0028] When the experiment officially begins, the ground controller 9 sends a command to the worm gear lifting mechanism 10, and the worm gear lifting mechanism 10 starts to work and drives the worm 11 to rotate and fall, and the claw seat 7 fixedly connected to the worm 11 and the claw 12 on the upper part thereof fall simultaneously with it. When the claw 12 contacts the core hammer 5, the spring 14 in the claw seat 7 is compressed, and the claw 12 opens to grab the core hammer 5. The pressure sensor installed in the worm gear lifting mechanism 10 transmits a signal to the ground controller 9, and the ground controller 9 sends a command, and the worm gear lifting mechanism 10 drives the worm 11, and the worm 11 drives the claw seat 7 and its attached parts to move upward as a whole. When the worm 11 rises 76cm, the upper part of the claw 12 contacts the upper part of the housing 6, the claw 12 opens, the spring 14 stretches, and the core hammer 5 falls freely to hit the hammer pad 4.

[0029] Repeat the above steps. When the distance sensor detects that the experimental device is immersed in the test stratum by 30 cm, the controller 9 stops the operation of the worm gear lifting mechanism 10, the device stops the test, and the number of hammer blows N is recorded in the ground controller 9. At the same time, when the number of hammer blows exceeds 50 and the penetration depth does not reach 30 cm, the controller also issues a command to terminate the test, and the controller records the actual penetration depth. And convert it into the standard penetration test hammer blow number N corresponding to 30 cm penetration according to the formula.

[0030]

[0031] Where: N is the standard penetration hammer number, Δs is the penetration depth at 50 blows.

[0032] Although the present invention has been disclosed as above in terms of preferred embodiments, the above preferred embodiments are not intended to limit the present invention. A person skilled in the art may make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined in the claims.

Claims

1. A new type of bottom hole standard penetration test device, characterized in that: It comprises a penetration head (1), a penetrator (2), a connector (3), a hammer pad (4), a core hammer (5), a housing (6), a claw seat (7), a cable (8), a ground controller (9), a worm gear lifting mechanism (10), a worm (11), a claw (12), a spring support rod (13), a spring (14) and a central hollow rod (15); The upper and lower ends of the penetrator (2) are connected to the penetration head (1) and the connector (3) respectively by threads, and the upper end of the connector (3) is connected to the lower end of the hammer pad (4) by threads; the upper end of the hammer pad (4) is externally connected to the housing (6) by threads, and the upper end of the hammer pad (4) is internally connected to the central hollow rod (15) by threads; a distance sensor is provided inside the hammer pad (4), and the distance sensor is connected to the worm gear lifting mechanism (10) through an electric wire passing through the hollow cavity inside the central hollow rod (15); The upper end of the central hollow rod (15) passes through the hollow cavity inside the worm gear (11) to provide a passage for the line; the core hammer (5) and the central hollow rod (15) are arranged with clearance fit; the upper part of the claw seat (7) is connected to the worm gear (11) by threading, and the central hollow rod (15) enters the central cavity inside the worm gear (11) through the central radial cavity of the claw seat (7); two claws (12) are symmetrically arranged on the claw seat (7), and the spring support rod (13) is connected between the two claws (12), and the spring support rod (13) is wound with a spring (14), and the two claws (12) are closed to grasp the core hammer (5), and the two claws (12) are opened to release the core hammer (5); the upper end of the cable (8) is connected to the ground controller (9), and the lower end of the cable (8) is connected to the worm gear lifting mechanism (10) to provide lifting force for the entire experimental device.

2. A novel bottom hole standard penetration test device according to claim 1, characterized in that: The weight of the core hammer (5) is 63.5 kg.

3. A novel bottom hole standard penetration test device according to claim 2, characterized in that: The exterior of the worm gear lifting mechanism (10) is connected to the outer shell (6) via threads.

4. A novel bottom hole standard penetration test device according to claim 3, characterized in that: The penetration distance of the penetrator (2) from the bottom elevation of the borehole is 15 cm.

5. A novel bottom hole standard penetration test device according to claim 4, characterized in that: The worm gear lifting mechanism (10) is used to drive the claw (12) connected to the worm gear to move downward; when the claw (12) contacts the upper part of the core hammer (5), the claw (12) opens to grab the core hammer (5), and the ground controller (9) obtains a signal through a pressure sensor and issues a command to instruct the worm gear lifting mechanism (10) to drive the worm (11) to rise; when the worm (11) rises 76 cm, the upper part of the claw (12) contacts the upper part of the shell (6), and the claw (12) opens to release the core hammer (5), and the core hammer (5) of 63.5 kg is lifted reciprocally to hit the hammer pad (4), and continues to hit 30 cm, and the ground controller (9) records the corresponding number of hits, and judges the nature of the soil based on the number of hits.

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