A high-strain testing device for the horizontal bearing capacity of pile foundations

Abstract

This invention discloses a high-strain testing device for the horizontal bearing capacity of pile foundations, comprising a carbon dioxide phase change pulse device, a pulse transmission device, a reaction device, a pile foundation testing component, and a base. The reaction device and the pulse transmission device are respectively located at opposite ends of the carbon dioxide phase change pulse device. The pulse transmission device is installed on the test pile, and the carbon dioxide phase change pulse device releases horizontal pulses to the test pile through the pulse transmission device. The pile foundation testing component is mounted on the test pile and the pulse transmission device. The base is placed on the ground for fixing the reaction device. This device utilizes the energy released from the phase change of carbon dioxide to generate an impact force that acts on the test pile. It eliminates the need for numerous anchor piles and reaction devices to conduct horizontal bearing capacity testing on large-diameter pile foundations, significantly shortening the construction period, saving costs, and improving efficiency.

Description

Technical Field

[0001] This invention relates to the field of high strain testing of pile foundations, and in particular to a high strain testing device for the horizontal bearing capacity of pile foundations. Background Technology

[0002] As a traditional, high-performance compression-resistant component, pile foundations fully utilize vertical bearing capacity, meeting the needs of most engineering projects and are widely used in both land and marine engineering. In the construction of islands, reefs, and nearshore areas, pile foundations are one of the most common supporting structures for superstructures, with single-pile foundations accounting for as much as 87% in shallow waters along the European coastline. Besides bearing the vertical loads applied by the superstructure, pile foundations are also subjected to horizontal loads such as wind loads, wave loads, current loads, and ship impact loads, making them prone to significant skew angles and horizontal deformations. However, the damage and destruction caused by horizontal loads to pile foundations are often underestimated in pile foundation design, leading to frequent accidents in marine engineering facilities. To ensure the safe use of marine engineering facilities, on-site horizontal bearing capacity testing is necessary to provide a basis for the design of pile foundation horizontal bearing capacity.

[0003] Currently, the static sustained loading method is mainly used for testing the horizontal bearing capacity of pile foundations. This method requires driving multiple reaction anchor piles around the pile being tested, and then applying a horizontal load to the test pile using a reaction device, maintaining the load for a relatively long period to observe the horizontal displacement. While this traditional method is stable and reliable, it also has significant limitations. For offshore engineering projects with short testing windows, the static sustained loading method has a long testing cycle, resulting in very high transportation and time costs. Furthermore, with the development of marine engineering construction, pile diameters are constantly increasing, requiring a corresponding increase in the reaction force needed for bearing capacity testing, necessitating larger anchor piles. For different test piles, it is also necessary to rebuild the reaction device, significantly increasing the cost of fabricating and installing the reaction anchor piles and reaction device. In addition, the location where the horizontal load is applied in the traditional static sustained loading method usually depends on the height of the reaction anchor piles and reaction device, while the application points of horizontal loads such as wind and wave currents are not singular, making it difficult for the test results to reflect the actual situation. Compared to the entire pile surface area, the contact surface where the load is applied can be considered a point load rather than a surface load, which can easily cause excessive local pressure, leading to damage or even breakage of the free end of the pile foundation. Summary of the Invention

[0004] Purpose of the invention: In order to overcome the shortcomings of the prior art, the present invention discloses a high strain detection device for the horizontal bearing capacity of pile foundations. The device is based on carbon dioxide phase change pulse technology, which generates horizontal air pressure shock waves through an electric excitation device, collects the dynamic response of the pile body under impact load, and determines the horizontal bearing capacity of the pile foundation.

[0005] Technical Solution: The high-strain testing device for the horizontal bearing capacity of pile foundations disclosed in this invention includes a carbon dioxide phase change pulse device, a pulse transmission device, a reaction device, a pile foundation testing component, and a base. The reaction device and the pulse transmission device are respectively located at both ends of the carbon dioxide phase change pulse device. The pulse transmission device is installed on the test pile. The carbon dioxide phase change pulse device applies horizontal pulses to the test pile through the pulse transmission device. The pile foundation testing component is located on the test pile and the pulse transmission device. The base is placed on the ground for fixing the reaction device.

[0006] Furthermore, the carbon dioxide phase change pulse device includes a reaction vessel, one end of which is provided with a venting head. The venting head includes a constant pressure venting plate and a detonation nozzle. The detonation nozzle is fastened to the reaction thread, and the constant pressure venting plate is fixed to the venting end of the reaction vessel. The venting end is connected to the pulse transmission device. The other end of the reaction vessel is provided with a fastener, forming an inner chamber inside the reaction vessel. The inner chamber is filled with supercritical carbon dioxide and a carbon dioxide energy-concentrating agent. The end of the fastener in the reaction vessel is connected to the end of the reaction device.

[0007] Furthermore, the fastener includes a sealing plug and a cap disposed from the inside to the outside at the end of the reaction vessel. A heater is provided at the center of the inner side of the sealing plug. The lead wire of the heater passes through the seal and the cap and is led out, including a heater trigger wire and a carbon dioxide energy agent excitation wire.

[0008] Furthermore, the pulse transmission device includes a telescopic barrel and an impact protection cover. One end of the telescopic barrel is connected to the energy dissipation end of the carbon dioxide phase change pulse device. The impact protection cover includes an upper end face, a lower hole, and a side hole. The other end of the telescopic barrel is connected to the side hole. The upper end face is provided with a lifting ring for hoisting. The lower hole is fitted onto the top of the test pile.

[0009] Furthermore, the pile foundation testing assembly includes strain gauges symmetrically arranged at intervals on the test pile, an inclination sensor located at the center of the test pile, and displacement sensors, force sensors, and acceleration sensors symmetrically arranged at the side holes on the impact protection cover.

[0010] Furthermore, the reaction device includes an annular limiting device. A reserved hole is provided on the side wall of one end of the annular limiting device. The reaction vessel is inserted from this end, and the lead wire is led out from the reserved hole. The other end of the annular limiting device is provided with a hydraulic cylinder, a piston, and a rubber buffer layer in sequence. The hydraulic cylinder is filled with hydraulic fluid. The piston includes piston heads on both sides and a piston rod in the middle. Multiple reserved grooves are provided at intervals on the outer piston heads. Piston rings are provided in the reserved grooves. The annular limiting device has an annular protrusion at the position of the rubber buffer layer near the reserved hole to restrict its movement, thereby axially limiting the rubber buffer layer.

[0011] Furthermore, the annular limiting device is provided with a damping buffer pad and a tail pin at the outer end of the cylinder side, and the tail pin has a pin hole at the pin head.

[0012] Furthermore, the base includes a head connecting pin seat and a tail connecting pin. The head connecting pin seat includes a vertical block through which the annular limiting device passes and a first base plate with a pin hole. The first base plate is fixed to the ground by a first connecting nut and a first connecting screw. The tail connecting pin seat includes two spaced vertical plates and a second base plate with a pin hole. The vertical plates are fixed to the second base plate by lateral support. The pin head is placed between the two vertical plates, and the connection is achieved by the pin shaft passing through the vertical plates and the pin head. The second base plate is fixed to the ground by a second connecting nut and a second connecting screw.

[0013] Beneficial effects: Compared with the prior art, the advantages of the present invention are:

[0014] 1. By utilizing the energy released from the phase change of carbon dioxide to generate impact force and apply it to the test pile, horizontal bearing capacity testing of large-diameter pile foundations can be carried out without the need for a large number of anchor piles and reaction devices, greatly shortening the construction period, saving costs, and improving efficiency. The device is detachable, easy to assemble, and simple to operate, making it flexible for use in various scenarios and working conditions. It can meet the needs of applying horizontal load forces at different points and can be quickly and conveniently reused by replacing the carbon dioxide phase change pulse device.

[0015] 2. To prevent gas leakage, the lead side of the carbon dioxide phase change pulse device is double-sealed with a sealing plug and a cap, while the outlet side is secured with a pressure relief plate tightened by the thread of the explosion relief nozzle. The thermal activation device and the carbon dioxide energy-concentrating agent activation wire are pre-installed in the sealing plug, greatly improving the stability of the impact gas pressure;

[0016] 3. The reaction device uses four parts—rubber buffer pad, piston, hydraulic fluid, and damping buffer pad—for quadruple buffering, which effectively absorbs and dissipates the impact reaction force applied by the carbon dioxide phase change pulse device, thus improving the safety of the test.

[0017] 4. The piston head is embedded with piston rings, which deform and contract under stress, thereby pushing the piston rod to move and further compress the hydraulic fluid, providing hydraulic dissipation reaction force. At the same time, the piston rings can also effectively reduce the possibility of hydraulic fluid leakage, and can scrape off excess hydraulic fluid on the inner chamber wall during reciprocating motion;

[0018] 5. The use of green and environmentally friendly inert gas carbon dioxide as the impact source replaces the traditional diesel and gasoline-powered power systems, reducing environmental pollution and promoting the recycling of carbon dioxide, which helps to achieve the goals of carbon peaking and carbon neutrality. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0020] Figure 2 This is a structural diagram of the carbon dioxide phase change pulse device of the present invention.

[0021] Figure 3 This is an internal cross-sectional view of the carbon dioxide phase change pulse device of the present invention;

[0022] Figure 4 This is a schematic diagram of the pulse transmission device of the present invention;

[0023] Figure 5 This is a schematic diagram of the external structure of the reaction device of the present invention;

[0024] Figure 6 This is an internal sectional view of the reaction device of the present invention;

[0025] Figure 7 This is a schematic diagram of the piston structure of the present invention;

[0026] Figure 8 This is a schematic diagram of the head connecting pin seat structure of the present invention;

[0027] Figure 9 This is a schematic diagram of the tail connecting pin seat structure of the present invention. Detailed Implementation

[0028] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0029] like Figure 1-9 The pile foundation horizontal bearing capacity high strain test device shown includes a carbon dioxide phase change pulse device 1, a pulse transmission device 2, a reaction device 3, a pile foundation test component 4, and a base 5. The reaction device 3 and the pulse transmission device 2 are respectively located at both ends of the carbon dioxide phase change pulse device 1. The pulse transmission device 2 is installed on the test pile. The carbon dioxide phase change pulse device 1 applies horizontal pulses to the test pile through the pulse transmission device 2. The pile foundation test component 4 is located on the test pile and the pulse transmission device 2. The base 5 is placed on the ground and used to fix the reaction device 3.

[0030] The carbon dioxide phase change pulse device 1 includes a reaction vessel 11. One end of the reaction vessel 11 is provided with a venting head 13. The venting head 13 includes a constant pressure venting plate 132 and a detonation nozzle 131. The detonation nozzle 131 is threadedly fastened to the reaction vessel 11, and the constant pressure venting plate 132 is fixed to the venting end of the reaction vessel 11. The venting end is connected to the pulse transmission device 2. The other end of the reaction vessel 11 is provided with a fastener 14, forming an inner chamber 12 inside the reaction vessel 11. The inner chamber 12 is filled with supercritical carbon dioxide 121 and carbon dioxide energy-concentrating agent 122. The end of the reaction vessel 11 where the fastener 14 is located is connected to the end of the reaction device 3.

[0031] The fastener 14 includes a sealing plug 142 and a cap 143 arranged from the inside to the outside at the end of the reaction vessel 11. A heater 141 is provided at the center of the inner side of the sealing plug 142. The lead wire 144 of the heater 141 passes through the sealing plug 142 and the cap 143 and is led out, including a heater trigger wire 1441 and a carbon dioxide energy agent excitation wire 1442.

[0032] The pulse transmission device 2 includes a telescopic barrel 21 and an impact protection cover 22. One end of the telescopic barrel 21 is connected to the energy dissipation end of the carbon dioxide phase change pulse device 1. The impact protection cover 22 includes an upper end face 221, a lower hole 222 and a side hole 223. The other end of the telescopic barrel 21 is connected to the side hole 223. The upper end face 221 is provided with a lifting ring 2211 for hoisting. The lower hole 222 is fitted onto the top of the test pile.

[0033] The pile foundation testing assembly 4 includes strain gauges 41 symmetrically arranged at intervals on the test pile, an inclination sensor 42 set at the center of the test pile, and displacement sensors 43, force sensors 44, and acceleration sensors 45 symmetrically arranged at the holes 223 on the upper side of the impact protection cover 22.

[0034] The reaction device 3 includes an annular limiting device 31. A reserved hole 311 is provided on the side wall of one end of the annular limiting device 31. The reaction tank 11 is inserted from this end, and the lead wire 144 is led out from the reserved hole 311. The other end of the annular limiting device 31 is provided with a hydraulic cylinder 34, a piston 33 and a rubber buffer layer 32 in sequence. The hydraulic cylinder 34 is filled with hydraulic fluid 341. The piston 33 includes piston heads 331 on both sides and a piston rod 332 in the middle. Multiple reserved grooves 3311 are provided at intervals on the piston heads 331 on the outer side. A piston ring 3312 is provided in the reserved grooves 3311. The annular limiting device 31 has an annular protrusion that restricts the movement of the rubber buffer layer 32 near the reserved hole 311, thereby axially limiting the rubber buffer layer 32.

[0035] The annular limiting device 31 is provided with a damping buffer pad 36 and a tail pin 35 at the outer end of the cylinder 34. The tail pin 35 has a pin hole at the pin head 351.

[0036] The base 5 includes a head connecting pin seat 51 and a tail connecting pin seat 52. The head connecting pin seat 51 includes a vertical block 511 through which the annular limiting device 31 passes and a first base plate 512 with a pin hole. The first base plate 512 is fixed to the ground by a first connecting nut 5121 and a first connecting screw 5122. The tail connecting pin seat 52 includes two spaced vertical plates 521 and a second base plate 523 with a pin hole. The vertical plates 521 are fixed to the second base plate 523 by a transverse support 522. The pin head 351 is placed between the two vertical plates 521 and is connected by a pin shaft 352 passing through the vertical plates 521 and the pin head 351. The second base plate 523 is fixed to the ground by a second connecting nut 5231 and a second connecting screw 5232.

[0037] The installation and use of this device include the following steps:

[0038] (1) Test pile preparation: High strain detection sensors, including displacement sensor 43, force sensor 44 and acceleration sensor 45, are installed symmetrically on the upper side of the impact protection cover 22 with holes 223. Strain gauges 41 of the pile body are pasted below it at certain intervals, and tilt sensors 42 are installed at the center line position along the horizontal loading direction.

[0039] (2) Selection and assembly of the horizontal impact device: Based on the conversion relationship between the energy released by the phase change of carbon dioxide in the critical state and the equivalent of TNT, the strength and thickness of the constant pressure energy release plate 132 are determined. The constant pressure energy release plate 132 is placed at the outlet of the inner chamber and fixed by screwing the explosion venting nozzle 131. The sealing plug 142 is inserted into the inner chamber 12 from the tail end, and then the cap 143 is installed by thread to form the fastener 14. The initial heat is provided by the carbon dioxide energy release agent excitation line 1442 to make the carbon dioxide energy release agent 122 burn rapidly. Then, the supercritical carbon dioxide 121 in the inner chamber 12 is heated by the heater trigger line 1441. Under the action of the carbon dioxide energy release agent 122, a large amount of carbon dioxide gas is produced, forming a huge pressure in the closed space, which then reaches the rated pressure value of the constant pressure energy release plate 132, and finally generates a shock wave.

[0040] (3) Selection and installation of reaction device: Determine the positions of head connecting pin seat 51 and tail connecting pin seat 52 according to the position of side hole 223, and then connect and fix them to the ground. Fill the cylinder 34 with hydraulic fluid 341, fix the piston 33 behind the annular limit device 31 and the rubber buffer layer 32, and make close contact under the balanced state of hydraulic fluid 341.

[0041] (4) Pulse transmission device assembly: Place the impact protection cover 22 on the top of the test pile, then put one side of the fastener 14 of the carbon dioxide phase change pulse device 1 into the reaction device 3, and lead out the heater trigger line 1441 and the carbon dioxide energy-concentrating agent excitation line 1442 from the reserved hole 311 on the annular limiting device 31. The energy discharge head 13 is connected to the side hole 223 through the telescopic barrel 21.

[0042] (5) High-strain testing of horizontal bearing capacity: After the assembly of all parts of the high-strain testing device for the horizontal bearing capacity of the pile foundation is completed, the heater trigger line 1441 is energized until the constant pressure energy release plate 132 breaks, generating a horizontal shock wave that acts on the top of the test pile. The pile foundation testing component 4 is connected to the dynamic data acquisition instrument through the data transmission line. After setting the channel parameters, the system is balanced and cleaned to start data acquisition. The signals detected by the sensors are then transmitted to the data processing system for processing and analysis. After the impact is completed, the reaction device needs to be disassembled, the consumed carbon dioxide phase change pulse device is removed, a new carbon dioxide phase change pulse device is loaded, and the position is readjusted for the next horizontal impact.

Claims

1. A high-strain detection device for horizontal bearing capacity of pile foundation, characterized in that: The utility model relates to a carbon dioxide phase change pulse device (1), pulse transmission device (2), counterforce device (3), pile foundation detection assembly (4) and base (5), the counterforce device (3) and pulse transmission device (2) are separately located at the both ends of carbon dioxide phase change pulse device (1), the pulse transmission device (2) is installed on the test pile, carbon dioxide phase change pulse device (1) is through pulse transmission device (2) and is applied to the horizontal pulse to the test pile, the pile foundation detection assembly (4) is located on the test pile and pulse transmission device (2), the base (5) is placed on the ground for fixing counterforce device (3), The utility model relates to a carbon dioxide phase change pulse device (1), pulse transmission device (2), counterforce device (3), pile foundation detection assembly (4) and base (5), the counterforce device (3) and pulse transmission device (2) are separately located at the both ends of carbon dioxide phase change pulse device (1), the pulse transmission device (2) is installed on the test pile, carbon dioxide phase change pulse device (1) is through pulse transmission device (2) and is applied to the horizontal pulse to the test pile, the pile foundation detection assembly (4) is located on the test pile and pulse transmission device (2), the base (5) is placed on the ground for fixing counterforce device (3), The utility model relates to a carbon dioxide phase change pulse device (1), pulse transmission device (2), counterforce device (3), pile foundation detection assembly (4) and base (5), the counterforce device (3) and pulse transmission device (2) are separately located at the both ends of carbon dioxide phase change pulse device (1), the pulse transmission device (2) is installed on the test pile, carbon dioxide phase change pulse device (1) is through pulse transmission device (2) and is applied to the horizontal pulse to the test pile, the pile foundation detection assembly (4) is located on the test pile and pulse transmission device (2), the base (5) is placed on the ground for fixing counterforce device (3), The utility model relates to a carbon dioxide phase change pulse device (1), pulse transmission device (2), counterforce device (3), pile foundation detection assembly (4) and base (5), the counterforce device (3) and pulse transmission device (2) are separately located at the both ends of carbon dioxide phase change pulse device (1), the pulse transmission device (2) is installed on the test pile, carbon dioxide phase change pulse device (1) is through pulse transmission device (2) and is applied to the horizontal pulse to the test pile, the pile foundation detection assembly (4) is located on the test pile and pulse transmission device (2), the base (5) is placed on the ground for fixing counterforce device (3), 2. The high strain dynamic pile testing apparatus of claim 1, wherein: The utility model relates to a carbon dioxide phase change pulse device (1), pulse transmission device (2), counterforce device (3), pile foundation detection assembly (4) and base (5), the counterforce device (3) and pulse transmission device (2) are separately located at the both ends of carbon dioxide phase change pulse device (1), the pulse transmission device (2) is installed on the test pile, carbon dioxide phase change pulse device (1) is through pulse transmission device (2) and is applied to the horizontal pulse to the test pile, the pile foundation detection assembly (4) is located on the test pile and pulse transmission device (2), the base (5) is placed on the ground for fixing counterforce device (3), 3. The high strain dynamic pile testing apparatus of claim 2, wherein: The counterforce device (3) comprises a ring-shaped limiting device (31), a side wall of one end of the ring-shaped limiting device (31) is provided with a reserved hole (311), the reaction tank (11) is inserted from the end, a lead wire (144) is led out from the reserved hole (311), the other end of the inside of the ring-shaped limiting device (31) is sequentially provided with an oil cylinder (34), a piston (33) and a rubber buffer layer (32), the oil cylinder (34) is filled with hydraulic liquid (341), the piston (33) comprises piston heads (331) on two sides and a piston rod (332) in the middle, a plurality of reserved grooves (3311) are arranged on the piston head (331) on the outer side at intervals, the reserved grooves (3311) are provided with piston rings (3312), the ring-shaped limiting device (31) is provided with a ring-shaped protrusion limiting the movement of the rubber buffer layer (32) at a position close to the reserved hole (311), and the rubber buffer layer (32) is axially limited.

4. The pile capacity high strain dynamic testing apparatus of claim 3, wherein: The ring-shaped limiting device (31) is provided with a damping buffer pad (36) and a tail plug (35) at an outer end of one side of the oil cylinder (34), and the tail plug (35) is provided with a plug hole at a pin head (351).

5. The high strain dynamic pile testing apparatus of claim 4, wherein: The base (5) comprises a head connecting pin seat (51) and a tail connecting pin seat (52), the head connecting pin seat (51) comprises a vertical block (511) for the ring-shaped limiting device (31) to pass through and a first bottom plate (512) provided with a plug round hole, the first bottom plate (512) is fixed to the ground through a first connecting nut (5121) and a first connecting screw (5122), the tail connecting pin seat (52) comprises two vertically arranged vertical plates (521) and a second bottom plate (523) provided with a plug round hole, the vertical plates (521) are fixed to the second bottom plate (523) through a transverse support (522), the pin head (351) is arranged between the two vertical plates (521), and the connection is realized by passing through the vertical plates (521) and the pin head (351) through a pin shaft (352), and the second bottom plate (523) is fixed to the ground through a second connecting nut (5231) and a second connecting screw (5232).

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