Foundation pile low-strain detection force hammer

Abstract

The utility model relates to the technical field of foundation pile detection, in particular to a foundation pile low-strain detection force hammer which comprises a hammer rod, one end of the hammer rod is provided with a hammer body with the axis collinear, one end, away from the hammer rod, of the hammer body is in threaded connection with a nylon head, and the hammer body extends to form a lantern ring wrapping the outer wall of the nylon head. At least two round holes are evenly distributed in the circumferential wall of the hammer body, a through hole penetrates through the circumferential wall of the hammer rod, the axis of the through hole is intersected and perpendicular to the axis of the hammer rod, and the axis extension line of the round holes is intersected and perpendicular to the axis of the hammer body. The round hole of the hammer body and the through hole of the hammer rod can amplify sound waves generated by excitation reflection, the condition of the pile body can be more obviously listened, and detection misjudgment is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of pile foundation detection, in particular to a low-strain detection hammer for pile foundations. Background Art

[0002] The pile foundation is the foundation of the entire building. Its bearing capacity affects the safety of the entire superstructure. Shallow defects in the pile body pose the greatest threat to project quality, making detection of pile defects particularly important. Low-strain detection devices are typically used. The basic principle of low-strain dynamic testing is to treat the pile as a one-dimensional elastic rod. When the pile top is subjected to a vertical excitation force from a force rod, the resulting elastic wave propagates downward along the pile body. Reflected waves are generated at interfaces with significant impedance differences (such as the pile bottom, broken piles, and severe segregation) or at locations where the pile cross-sectional area changes (such as shrinkage or expansion). Through data processing such as reception, amplification, and filtering, the reflected information from different parts of the pile body can be identified and used to determine pile integrity.

[0003] Patent CN205189020U discloses a low-strain dynamic detection excitation force rod, which includes a force rod rod, a force rod hammer body and a nylon head fixed in sequence from top to bottom. A protective steel ring is provided around the upper part of the nylon head, and the upper end of the protective steel ring is connected to the lower end of the force rod hammer body through an internal thread. This solution effectively solves the problem of short service life of the force rod.

[0004] However, in the process of low-strain dynamic testing, the more intuitive and easier to judge reflected wave is the sound wave generated by the excitation. The sound wave is used to judge whether the shallow part of the pile body is broken or the pile head is empty. The force rod in the existing technology does not have a structure to help the sound wave transmission, which makes it difficult to judge. Utility Model Content

[0005] The purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art and to provide a low-strain detection hammer for pile foundations. The present invention has a structure for amplifying sound waves, that is, the circular hole in the hammer body and the through hole in the hammer rod can amplify the sound waves generated by the excitation reflection, so that the condition of the pile body can be heard more clearly and misjudgment of detection can be reduced.

[0006] The technical solution adopted by the present invention is as follows: A low-strain detection hammer for pile foundation, including a hammer rod, a hammer body with a colinear axis provided at one end of the hammer rod, a nylon head being threadedly connected to the end of the hammer body away from the hammer rod, a ring extending from the hammer body and covering the outer wall of the nylon head, at least two circular holes evenly distributed on the circumferential wall of the hammer body, a through hole passing through the circumferential wall of the hammer rod, the axis of the through hole intersecting and being perpendicular to the axis of the hammer rod, and the extended line of the axis of the circular hole intersecting and being perpendicular to the axis of the hammer body.

[0007] Preferably, a knurled section is provided on the circumferential wall of one end of the hammer rod away from the hammer body.

[0008] Preferably, the inner diameter of the circular hole is larger than the inner diameter of the through hole.

[0009] Preferably, the nylon head is provided with a threaded column, the hammer body is provided with a threaded hole adapted to the threaded column, and the axial end surface of the hammer body close to the hammer rod is provided with an oil filling hole connected to the threaded hole, and the oil filling hole includes an inlet section, a transition section and an outlet section connected in sequence, the outlet section is located at one end close to the threaded hole, and the inlet section is located on the side close to the outer edge of the hammer body.

[0010] Preferably, one end of the transition section close to the outlet section tilts toward the other end to form an angle of 1° to 5° with the horizontal plane.

[0011] Preferably, the end of the hammer rod close to the hammer body is provided with an end cover with the same diameter as the hammer body, the end cover is protruded with a buckle, the hammer body is provided with a slide groove for the buckle to slide and fit, and the end cover has a first position for covering the inlet section and a second position for opening the inlet section.

[0012] Preferably, a slot for the clip to engage is provided at one end of the slide groove and a stop block is provided at the other end. The stop block is connected to the hammer body through a fastener. When the end cover is in the first position, the top of the clip is against the inner wall of the slot. When the end cover is in the second position, the end of the clip is against the stop block and the top of the clip is still in the slot.

[0013] Preferably, the end cover is provided with a disassembly hole for the fastener to pass through, and when the end cover is in the second position, the disassembly hole is collinear with the axis of the fastener.

[0014] The beneficial effects of the present invention are as follows: the present invention has a structure for amplifying sound waves, that is, the circular hole of the hammer body and the through hole of the hammer rod can generate echoes, amplifying the sound waves generated by the excitation reflection, and can more clearly hear the condition of the pile body, reduce detection misjudgments, and enable on-site detection to sample a low-strain curve that meets the detection requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, without paying creative labor, other drawings obtained based on these drawings still fall within the scope of the present invention.

[0016] Figure 1 This is a structural diagram of a low-strain testing hammer for pile foundations in the utility model;

[0017] Figure 2 It is a partial cross-sectional schematic diagram of the oil filling hole of the utility model;

[0018] Figure 3 It is a partial cross-sectional schematic diagram of the buckle of the utility model;

[0019] Figure 4 This is a schematic structural diagram of the utility model when the end cover is in the second position;

[0020] Figure 5 It is a partial cross-sectional schematic diagram of the buckle portion when the end cover of the utility model is in the second position;

[0021] In the figure, 1-hammer rod, 2-hammer body, 3-nylon head, 4-ring, 5-round hole, 6-through hole, 7-knurled section, 8-threaded column, 9-threaded hole, 10-oil filling hole, 11-inlet section, 12-transition section, 13-outlet section, 14-end cover, 15-clip, 16-slide groove, 17-clip groove, 18-stopper, 19-fastener, 20-disassembly hole. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in further detail below with reference to the accompanying drawings.

[0023] It should be noted that all expressions using "first" and "second" in the embodiments of the present invention are for the purpose of distinguishing two non-identical entities or non-identical parameters with the same name. It can be seen that "first" and "second" are only for the convenience of expression and should not be understood as limitations on the embodiments of the present invention. Subsequent embodiments will not explain this one by one.

[0024] The directional and positional terms used in this invention, such as "upper," "lower," "front," "back," "left," "right," "inner," "outer," "top," "bottom," and "side," are used solely to refer to the directions or positions in the accompanying drawings. Therefore, the directional and positional terms used are intended to illustrate and facilitate understanding of this invention and are not intended to limit the scope of protection of this invention.

[0025] like Figures 1 to 5As shown in the figure, an embodiment of the present invention is a low-strain detection hammer for pile foundation, comprising a hammer rod 1, a hammer body 2 with a colinear axis provided at one end of the hammer rod, a nylon head 3 being threadedly connected to the end of the hammer body 2 away from the hammer rod 1, a collar 4 extending from the hammer body 2 and covering the outer wall of the nylon head 3, at least two circular holes 5 being evenly distributed on the circumferential wall of the hammer body 2, a through hole 6 passing through the circumferential wall of the hammer rod 1, the axis of the through hole 6 intersecting and being perpendicular to the axis of the hammer rod 1, and an extension line of the axis of the circular hole 5 intersecting and being perpendicular to the axis of the hammer body 2. The utility model has a structure for amplifying sound waves, that is, the circular hole of the hammer body and the through hole of the hammer rod can both generate echoes, amplifying the sound waves generated by the excitation reflection, and can more clearly hear the condition of the pile body, reduce detection misjudgment, and enable on-site detection to sample a low-strain curve that meets the detection requirements. The collar is used to protect the nylon head to prevent the nylon head from bending due to long-term excitation of the hammer. In this embodiment, the circular hole does not penetrate the hammer body, the hammer rod and the hammer body are both made of ordinary steel, and the nylon head is made of nylon. Such a structure can ensure the strength of the hammer and can be suitable for detecting 10-40 meter cast-in-place piles or prefabricated piles.

[0026] The circumferential wall of one end of the hammer rod 1 away from the hammer body 2 is provided with a knurled section 7. The knurled section increases the friction when holding the hand, preventing the hand from slipping when vibrating the pile head.

[0027] The inner diameter of the circular hole 5 is larger than that of the through hole 6. The diameter of the hammer body is larger than that of the hammer rod, so the inner diameter of the circular hole is also correspondingly larger to produce a larger echo, further amplifying the sound waves generated by the excitation reflection, ensuring that the condition of the pile body can be more clearly heard, and improving the accuracy of the detection.

[0028] The nylon head 3 is provided with a threaded column 8, and the hammer body 2 is provided with a threaded hole 9 that matches the threaded column 8. The axial end surface of the hammer body 2 near the hammer rod 1 is provided with an oil filling hole 10 that is connected to the threaded hole 9. The oil filling hole 10 includes an inlet section 11, a transition section 12, and an outlet section 13 connected in sequence. The outlet section 13 is located at one end near the threaded hole 9, and the inlet section 11 is located on the side near the outer edge of the hammer body 2. After prolonged vibration of the hammer, the threaded column of the nylon head is prone to deformation and may even break. When replacing the nylon head, the threaded column is difficult to unscrew from the threaded hole. Ventilating the other end of the threaded hole through the oil filling hole can facilitate unscrewing the threaded column.

[0029] The transition section 12 is tilted at one end, near the outlet section 13, toward the other end, forming an angle of 1° to 5° with the horizontal plane. If a threaded stud is difficult to remove even after ventilation, lubricant can be added to the oil filling hole to lubricate the stud before removal. The 1° to 5° angle between the transition section and the horizontal plane helps the lubricant flow into the threaded hole and prevents it from accumulating in the transition section. When screwing in a new nylon head, any remaining lubricant in the oil filling hole and threaded hole must be cleaned to prevent the lubricant from causing the new nylon head to slip out.

[0030] The end of the hammer rod 1 near the hammer body 2 is provided with an end cap 14 having the same diameter as the hammer body 2. A buckle 15 is protruded from the end cap 14, and the hammer body 2 is provided with a slide groove 16 for sliding engagement with the buckle 15. The end cap 14 has a first position that covers the inlet section 11 and a second position that opens the inlet section 11. The end cap can cover or open the oil filling hole, and when the nylon head does not need to be removed, the oil filling hole is covered to prevent foreign matter from falling into it and to ensure that the nylon head is firmly connected.

[0031] One end of the slide groove 16 is provided with a slot 17 for the buckle 15 to engage with, and the other end is provided with a stopper 18. The stopper 18 is connected to the hammer body 2 through a fastener 19. When the end cover 14 is in the first position, the top of the buckle 15 is against the inner wall of the slot 17. When the end cover 14 is in the second position, the end of the buckle 15 is against the stopper 18 and the top of the buckle 15 is still in the slot 17. The end cover is provided with a detachable structure, which blocks the buckle from sliding out of the slide slot through the stopper. Only when the fastener of the stopper is removed can the stopper be removed and the buckle be slid out, and then the end cover and the hammer body can be separated. The top of the buckle is located in the slot regardless of whether the end cover is in the first position or the second position, and the end cover and the hammer body remain in a snap connection. Because when the end cover is in the first position, the force hammer is in a working state for easy vibration. When it is in the second position, the end cover will not be separated from the hammer body and the oil filling hole can be opened to help remove the nylon head. It has the advantages of convenient disassembly and assembly and a sophisticated and reasonable structure. In this embodiment, the buckle and the slot form an interference fit to ensure that the hammer rod and the hammer body will not slide easily in the vibration state.

[0032] The end cap 14 is provided with a disassembly hole 20 for the fastener 19 to pass through. When the end cap 14 is in the second position, the disassembly hole 20 is aligned with the axis of the fastener 19. The fastener can be removed through the disassembly hole only when the end cap is in the second position. When the end cap is in the first position, the fastener is shielded from foreign matter and prevented from being unscrewed or ejected from the disassembly hole during hammer vibration, thereby maintaining a secure connection between the fastener and the hammer body.

[0033] The above disclosure is only a preferred embodiment of the present invention, and certainly cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope covered by the present invention.

Claims

1. A pile foundation low strain testing hammer, comprising a hammer rod (1), one end of the hammer rod being provided with a hammer body (2) with co-linear axes, and one end of the hammer body (2) being threadedly connected with a nylon head (3) at a distance from the hammer rod (1). Features: The hammer body (2) is extended with a collar (4) covering the outer wall of the nylon head (3); the circumferential wall of the hammer body (2) is evenly distributed with at least two circular holes (5); the circumferential wall of the hammer rod (1) is penetrated by a through hole (6); the axis of the through hole (6) intersects and is perpendicular to the axis of the hammer rod (1); and the extended axis of the circular hole (5) intersects and is perpendicular to the axis of the hammer body (2).

2. A low strain testing hammer for pile foundation according to claim 1, Features: A knurled section (7) is provided on the circumferential wall of one end of the hammer rod (1) away from the hammer body (2).

3. A pile foundation low strain testing hammer according to claim 1, Features: The inner diameter of the circular hole (5) is greater than the inner diameter of the through hole (6).

4. A pile foundation low strain testing hammer according to claim 1, Features: The nylon head (3) is provided with a threaded column (8), the hammer body (2) is provided with a threaded hole (9) matched with the threaded column (8), and an axial end surface of the hammer body (2) close to the hammer rod (1) is provided with an oil injection hole (10) connected to the threaded hole (9), the oil injection hole (10) comprising an inlet section (11), a transition section (12) and an outlet section (13) connected in sequence, the outlet section (13) being located at an end close to the threaded hole (9), and the inlet section (11) being located at a side close to the outer edge of the hammer body (2).

5. A low strain testing hammer for pile foundation according to claim 4, Features: One end of the transition section (12) close to the outlet section (13) tilts toward the other end to form an angle of 1° to 5° with the horizontal plane.

6. A low strain testing hammer for pile foundation according to claim 4, Features: An end of the hammer rod (1) close to the hammer body (2) is provided with an end cover (14) having the same diameter as the hammer body (2); a buckle (15) is protruded from the end cover (14); the hammer body (2) is provided with a slide groove (16) for sliding engagement with the buckle (15); the end cover (14) has a first position for shielding the inlet section (11) and a second position for opening the inlet section (11).

7. A low strain testing hammer for pile foundation according to claim 6, Features: A slot (17) for engaging the buckle (15) is provided at one end of the slide groove (16), and a stopper (18) is provided at the other end. The stopper (18) is connected to the hammer body (2) via a fastener (19). When the end cover (14) is in a first position, the top end of the buckle (15) abuts against the inner wall of the slot (17). When the end cover (14) is in a second position, the bottom end of the buckle (15) abuts against the stopper (18) and the top end of the buckle (15) is still located in the slot (17).

8. A pile foundation low strain testing hammer according to claim 7, Features: The end cover (14) is provided with a disassembly hole (20) for the fastener (19) to pass through, and when the end cover (14) is in the second position, the disassembly hole (20) is colinear with the axis of the fastener (19).

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