A gas blasting pile foundation mechanical properties testing device

Abstract

The present invention relates to a gas-blasting pile foundation mechanical property testing device, comprising a gas-blasting tube and a device tube for placement on top of a pile foundation during use. The device tube comprises a tube bottom and a tube body disposed around the tube bottom. The device tube also comprises a tube cover movably disposed at the upper end of the tube body. The gas outlet of the gas-blasting tube is connected to the inner cavity of the device tube. The device tube is provided with a pressure-limiting valve and a pressure sensor. The tube cover, relying on its own weight and / or a counterweight structure provided on the tube cover, limits upward movement of the tube cover when the gas outlet is exhausted. The present invention provides a lightweight gas-blasting pile foundation mechanical property testing device that can apply a vertical load to the pile foundation head.

Description

Technical Field

[0001] The invention relates to a gas explosion type pile foundation mechanical property detection device in the field of pile foundation mechanical property detection. Background Art

[0002] Pile foundation static load test is a technology used in engineering to detect the bearing capacity of pile foundations. It is currently the most accurate and reliable inspection method for determining the ultimate bearing capacity of a single pile. Therefore, each foundation design and treatment specification lists the single pile static load test as the first priority.

[0003] In static load tests, the load acting on the pile is generally provided by a reaction device. The ease of use of the reaction device directly affects the process and results of the test. Commonly used devices include pile load reaction devices and anchor pile reaction devices.

[0004] The loading reaction device is to use a steel beam to set up a weighing platform on the top of the pile, pile heavy objects on it, and rely on the jack placed on the pile head to gradually lift the platform, thereby applying force to the pile body. The main beam of the reaction device can be made of steel or a self-made box beam. The shape of the platform can be set to square or rectangular as needed. The heavy objects used for loading can be sandbags, precast concrete blocks, etc. In specific experience, the anchor pile reaction device can be divided into two types according to the different reaction anchors. The reaction frame is connected to the anchor piles to provide reaction force, which is commonly known as the anchor pile reaction device. The anchor pile reaction device is to connect several anchor piles symmetrically around the measured pile with anchor bars and the reaction frame. The reaction frame is lifted by the jack on the pile top, and the reaction force is provided by the connected anchor piles. The amount of reaction force provided is determined by the number of anchor piles, the strength of the reaction frame and the pull-out resistance of the connected anchor piles.

[0005] As can be seen from the above, during a static load test of a pile foundation, a vertical load is applied to the pile head, and the pile settlement under this load is measured to determine the ultimate bearing capacity of the pile foundation. In the prior art, applying a vertical load to the pile head, whether by applying a weight or using a jack, is cumbersome and inconvenient. For example, applying a weight requires a weight bracket and numerous weights, while a jack requires a high-power hydraulic circuit. This not only results in high energy consumption and a complex circuit, but also low loading efficiency. Summary of the Invention

[0006] The object of the present invention is to provide a lightweight gas explosion type pile foundation mechanical property testing device which can apply a vertical load to the pile foundation head.

[0007] In order to solve the above technical problems, the technical solutions of the present invention are as follows:

[0008] A gas blasting pile foundation mechanical property testing device comprises a gas blasting tube and a device tube for being placed on top of the pile foundation when in use, the device tube comprising a tube bottom and a tube body arranged on the periphery of the tube bottom, the device tube further comprising a tube cover movably arranged on the upper end of the tube body, the gas outlet of the gas blasting tube is connected to the inner cavity of the device tube, a pressure limiting valve and a pressure sensor are arranged on the device tube, and the tube cover relies on its own weight and / or a counterweight structure provided on the tube cover to limit the upward movement of the tube cover when the gas outlet is exhausted.

[0009] The gas blasting tube is vertically arranged on the tube cover, and the gas outlet of the gas blasting tube is located at the lower end of the gas blasting tube.

[0010] The pressure limiting valve and the pressure sensor are both arranged on the cylinder cover.

[0011] The cylinder bottom is sealed with the cylinder body, and a liquid filling space for filling liquid is formed between the cylinder bottom and the cylinder body.

[0012] The pressure-limiting valve includes a valve seat with a valve port, the valve port is connected to the inner cavity of the device cylinder, a valve core for sealing the valve port is provided on the valve seat through the top of a pressure relief spring, a threaded adjustment mechanism for adjusting the compression amount of the pressure relief spring is provided between the valve seat and the pressure relief spring, and a force sensor is provided between the threaded adjustment mechanism and the pressure relief spring.

[0013] A counterweight structure is provided on the cylinder cover to limit the cylinder cover from moving upward when the air outlet is exhausted. The counterweight structure includes a counterweight block provided on the cylinder cover.

[0014] A counterweight structure is provided on the cylinder cover to limit the upward movement of the cylinder cover when the air outlet is exhausted. The counterweight structure includes a pull rope connected to the cylinder cover through a connecting head. There are at least two pull ropes, and each pull rope is arranged at intervals along the circumference of the cylinder cover. The connecting head includes an upper connecting rod and a lower connecting sleeve. The lower end of the upper connecting rod extends into the lower connecting sleeve. A connecting rod compression spring is provided between the lower end of the upper connecting rod and the upper connecting sleeve. An adjusting nut is threadedly connected to the upper side of the lower connecting sleeve on the upper connecting rod.

[0015] The gas blasting tube is a carbon dioxide liquid-gas phase conversion blasting tube.

[0016] The cylinder cover comprises a cylinder cover edge seated on the upper end of the cylinder body and a guide section arranged on the lower side of the cylinder cover edge and matched with the upper end of the inner hole of the cylinder body.

[0017] The cylinder cover is a circular structure, and there are four gas blasting cylinders. The gas outlets of the four gas blasting cylinders are evenly spaced along the circumference of the cylinder cover, and each gas outlet is equidistant from the center position of the cylinder cover. The pressure limiting valve and pressure sensor are arranged at the edge of the cylinder cover, and the distance between the pressure limiting valve and the pressure sensor and the two adjacent gas outlets is equal.

[0018] The beneficial effects of the present invention are as follows: when in use, the gas in the gas blasting tube is released into the inner cavity of the device tube through the air outlet, and the tube cover relies on its own weight or a counterweight structure is provided on the tube cover to limit the upward movement of the tube cover when the air outlet is exhausted, so that the gas pressure will be transmitted to the pile foundation through the bottom of the tube, and the pile foundation will be subjected to a vertical load. By setting the pressure relief pressure of the pressure limiting valve, the inner cavity pressure of the device tube can be controlled, thereby controlling the vertical load on the pile foundation. In the present invention, the vertical load is generated by the impact gas generated by the gas blasting tube. Compared with the existing technology of applying load through a load or a hydraulic cylinder, the entire detection device is much lighter. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic structural diagram of embodiment 1 of the present invention;

[0020] Figure 2 yes Figure 1 Distribution diagram of the middle air outlet on the cylinder cover;

[0021] Figure 3 yes Figure 1 Schematic diagram of the coordination between the middle pressure limiting valve and the cylinder cover;

[0022] Figure 4 yes Figure 1 Schematic diagram of the structure of the middle connector;

[0023] Figure 5 is a schematic structural diagram of embodiment 2 of the present invention;

[0024] Figure 6 is a schematic structural diagram of embodiment 3 of the present invention;

[0025] Figure 7 It is a structural diagram of embodiment 4 of the present invention. DETAILED DESCRIPTION

[0026] The embodiment 1 of the gas blasting pile foundation mechanical performance detection device of the present invention is as follows Figures 1 to 4 As shown, it includes four gas blasting tubes 6 and a device tube for being placed on top of a pile foundation when in use. The device tube includes a tube bottom 10 and a tube body 20 arranged on the outer periphery of the tube bottom. The bottom of the tube body 20 has a sleeve section 21 for being sleeved on the top of the pile foundation. The device tube also includes a tube cover 17 arranged on the upper end of the tube body. The tube cover includes a tube cover edge 18 seated on the upper end of the tube body and a guide section 19 arranged on the lower side of the tube cover edge and sealingly guiding the upper end of the inner hole of the tube body. The tube cover 17, the tube body 20 and the tube bottom 10 are all circular structures.

[0027] The gas blasting tube 6 is a carbon dioxide liquid-gas phase conversion blasting tube. The carbon dioxide liquid-gas phase conversion blasting tube belongs to the existing technology. Its blasting principle is that before the blasting, liquid carbon dioxide is stored in the blasting tube. When blasting is required, the liquid carbon dioxide is heated. When the liquid-gas phase conversion temperature is reached, the liquid carbon dioxide is converted into gaseous carbon dioxide, the volume expands rapidly, the pressure is increased, and the blasting is achieved.

[0028] Each gas blasting tube 6 is vertically arranged on the tube cover 17, and the gas blasting tubes are evenly spaced along the circumferential direction. The gas outlet 23 of the gas blasting tube is located at the lower end of the gas blasting tube. In the present invention, the tube bottom 10 is sealed with the tube body 20, and a liquid filling space for filling with liquid 11 is formed between the tube bottom 10 and the tube body 20. When in use, liquid 11, such as water, is filled into the liquid filling space. Since the liquid is incompressible, when the gas blasting tube explodes, the gas force will be evenly transmitted to the tube bottom 10 through the liquid 11, thereby achieving uniformity of the load on the pile foundation.

[0029] The device cylinder is provided with a pressure limiting valve 13 and a pressure sensor 5. The distance between each gas outlet and the center position of the cylinder cover is equal. The pressure limiting valve 13 is provided at the edge position of the cylinder cover 17. The distance between the pressure limiting valve and the adjacent gas outlets is equal. Figure 2 As shown, the installation position of the pressure limiting valve 13 is defined as point A, the positions of the two adjacent air outlets are O1 and O2 respectively, and the center position of the cylinder cover is O. Then the lines connecting the four points O, O1, A and O2 form a square structure. The reason for setting the position of the pressure limiting valve in this way is that, Figure 2 In the figure, the dotted line represents the blasting shock wave generated in all directions with the outlet as the center during the blasting. The blasting shock wave spreads outward from the outlet like a ripple. It can be seen that at point A, the blasting shock waves generated by points O1 and O2 finally meet, and the superposition value of the blasting shock waves is the smallest compared to point O. Point O has four superimposed blasting shock waves, while point A has only two blasting shock waves. Therefore, point A is the last pressure uniformity position, that is, the position where uniformity is established the latest. Setting the pressure limiting valve and pressure sensor 5 here can truly reflect the gas pressure in the device cylinder. The positions of A, O1, and O2 can be obtained by the following method: draw the angle bisector OA of the right angle BOC and the perpendicular bisector O1O2 of the line segment OA. O1O2 and the line OA are compared to point D. Points O1 and O2 are the placement positions of the corresponding two blasting cylinders, and point A is the position where the pressure uniformity is established the latest.

[0030] The pressure limiting valve includes a valve seat 26 with a valve port 25, which is connected to the inner cavity of the device cylinder. A valve core 14 for sealing the valve port is provided on the valve seat through the pressure relief spring 4. The valve core 14 and the valve port 25 are matched through a conical surface. A threaded adjustment mechanism for adjusting the compression amount of the pressure relief spring is provided between the valve seat 26 and the pressure relief spring 4. The threaded adjustment mechanism includes an adjusting screw 2 and a nut 1 threadedly matched with the adjusting screw. A force sensor 3 is provided between the threaded adjustment mechanism and the pressure relief spring. Figure 1 Middle item 12 represents the ball joint connecting the force sensor 3 and the threaded adjustment mechanism. By rotating the nut 1, the compression of the pressure relief spring can be adjusted, thereby adjusting the maximum pressure required to open the valve core 14. In this embodiment, the valve port 25 is connected to the cylinder cover 17 via a curved connecting tube 15. The pressure sensor 5 is mounted on this connecting tube 15. The entire pressure relief valve is arranged vertically, which prevents the pressure relief valve from protruding beyond the outer edge of the cylinder cover, thus preventing the radial dimensions of the entire device from being excessive.

[0031] The cylinder cover is provided with a counterweight structure to limit the upward movement of the cylinder cover when exhaust is discharged from the air outlet. The counterweight structure includes a counterweight block 7 provided on the cylinder cover; the counterweight structure also includes a pull rope 9 connected to the cylinder cover 17 via a connector 8. There are at least two pull ropes 9, each of which is spaced apart along the circumference of the cylinder cover 17. The connector 8 includes an upper connecting rod 28 and a lower connecting sleeve 29. The lower end of the upper connecting rod 28 extends into the lower connecting sleeve 29. A connecting rod compression spring 30 is provided between the lower end of the upper connecting rod 28 and the upper connecting sleeve. An adjusting nut 27 is threadedly connected to the upper side of the lower connecting sleeve 29 on the upper connecting rod 28. The upper end of the upper connecting rod 28 is hingedly connected to the cylinder cover 17, and the pull rope 9 is connected to the lower end of the lower connecting sleeve 29.

[0032] This embodiment tests pile foundations with high vertical load requirements. Therefore, when a gas blasting tube is blasted, a significant recoil force is generated. To prevent the tube cover from moving upward, a counterweight is placed on the tube cover, and a pull rope is used to apply tension to the tube cover. Before blasting, the adjusting nut is rotated to free the connecting rod compression spring. This prevents the connecting rod compression spring from exerting a downward force on the tube cover before blasting. If the connecting rod compression spring exerts a downward force on the tube cover, the tube cover will transmit this force to the tube body and then to the pile foundation, which will affect the vertical load on the pile foundation 22. In the present invention, before explosion, the connecting rod compression spring does not exert force on the cylinder cover. When the gas blasting cylinder explodes, the cylinder cover tends to move upward relative to the cylinder body. Although the guide section on the cylinder cover moves upward relative to the cylinder body, it will not separate from the cylinder body. Therefore, it can be ensured that the gas pressure in the device cylinder will not be lost between the cylinder cover and the cylinder body. At this time, although the pull rope generates tension on the cylinder cover, the tension will not be transmitted to the pile foundation through the cylinder body. The vertical load on the pile foundation is only related to the gas pressure in the device cylinder.

[0033] When the four gas blasting tubes explode, the generated gas pressure is evenly transferred to the bottom of the tubes through the liquid, and the entire bearing surface of the pile foundation is subjected to a uniform vertical load, which will more realistically simulate the actual use environment. By setting the pressure relief pressure of the pressure limiting valve, the vertical load on the pile foundation can be precisely controlled.

[0034] In other embodiments of the present invention: the number of blasting tubes can also be set as needed, such as one, two, three or other numbers; the blasting tubes may not be carbon dioxide liquid-gas phase conversion blasting tubes, such as conventional high-pressure blasting tubes; the blasting tubes may not be set on the tube cover, for example, the blasting tubes are set on the ground, and the blasting tubes are connected to the inner cavity of the device tube through a hose; liquid may not be set in the device tube, and in this case, during the explosion, the gas directly acts on the bottom of the tube.

[0035] Example 2 of the gas blasting pile foundation mechanical performance detection device Figure 5 As shown: Example 2 is different from Example 1 in that, when facing a smaller level of vertical load than Example 1, in order to prevent the cylinder cover 17 from separating from the cylinder body 20, the counterweight block can also be omitted, and only the pull rope 9 provides downward pulling force to the cylinder cover during blasting.

[0036] Example 3 of the gas blasting pile foundation mechanical performance detection device Figure 6 As shown: Example 3 is different from Example 2 in that, when facing a vertical load of a smaller level than that of Example 2, in order to prevent the cylinder cover 17 from separating from the cylinder body 20, only a counterweight block 7 can be set without a pull rope, and only the counterweight block is relied upon to provide pressure to the cylinder cover during blasting.

[0037] Example 4 of the gas blasting pile foundation mechanical properties detection device Figure 7 As shown: Example 4 is different from Example 3 in that, when facing a smaller level of vertical load than Example 3, in order to prevent the cylinder cover from separating from the cylinder body, a counterweight block and a pull rope may not be provided, and only the weight of the cylinder cover 17 itself can be relied upon to prevent the cylinder cover from separating from the cylinder body during blasting.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A gas blasting pile foundation mechanical properties testing device, characterized by: The utility model comprises a gas blasting tube and a device tube for being placed on the top of the pile foundation when in use, the device tube comprises a tube bottom and a tube body arranged on the periphery of the tube bottom, the device tube also comprises a tube cover movably arranged on the upper end of the tube body, the gas outlet of the gas blasting tube is connected with the inner cavity of the device tube, a pressure limiting valve and a pressure sensor are arranged on the device tube, the tube cover relies on its own weight and / or a counterweight structure is arranged on the tube cover to limit the upward movement of the tube cover when the gas outlet is exhausted, the tube cover is a circular structure, there are four gas blasting tubes, the gas outlets of the four gas blasting tubes are evenly spaced along the circumference of the tube cover, and the distance between each gas outlet and the center position of the tube cover is equal, the pressure limiting valve and the pressure sensor are arranged on the tube cover, and the gas outlet is arranged on the tube cover. It is placed at the edge of the cylinder cover, and the pressure limiting valve and the pressure sensor are at equal distances from two adjacent air outlets. The gas blasting cylinder is vertically arranged on the cylinder cover, and the air outlet of the gas blasting cylinder is located at the lower end of the gas blasting cylinder. The cylinder bottom is sealed with the cylinder body, and a liquid filling space for filling liquid is formed between the cylinder bottom and the cylinder body. The pressure limiting valve includes a valve seat with a valve port, and the valve port is connected to the inner cavity of the device cylinder. A valve core for sealing the valve port is provided on the valve seat through the top of the pressure relief spring. A threaded adjustment mechanism for adjusting the compression amount of the pressure relief spring is provided between the valve seat and the pressure relief spring, and a force sensor is provided between the threaded adjustment mechanism and the pressure relief spring.

2. The gas blasting pile foundation mechanical properties testing device according to claim 1, characterized in that: The pressure limiting valve and the pressure sensor are both arranged on the cylinder cover.

3. The gas blasting pile foundation mechanical properties testing device according to claim 1, characterized in that: A counterweight structure is provided on the cylinder cover to limit the cylinder cover from moving upward when the air outlet is exhausted. The counterweight structure includes a counterweight block provided on the cylinder cover.

4. The gas blasting pile foundation mechanical properties testing device according to claim 1, characterized in that: A counterweight structure is provided on the cylinder cover to limit the upward movement of the cylinder cover when the air outlet is exhausted. The counterweight structure includes a pull rope connected to the cylinder cover through a connecting head. There are at least two pull ropes, and each pull rope is arranged at intervals along the circumference of the cylinder cover. The connecting head includes an upper connecting rod and a lower connecting sleeve. The lower end of the upper connecting rod extends into the lower connecting sleeve. A connecting rod compression spring is provided between the lower end of the upper connecting rod and the upper connecting sleeve. An adjusting nut is threadedly connected to the upper side of the lower connecting sleeve on the upper connecting rod.

5. The gas blasting pile foundation mechanical properties testing device according to claim 1, characterized in that: The gas blasting tube is a carbon dioxide liquid-gas phase conversion blasting tube.

6. The gas blasting pile foundation mechanical property testing device according to claim 1, characterized in that: The cylinder cover comprises a cylinder cover edge seated on the upper end of the cylinder body and a guide section arranged on the lower side of the cylinder cover edge and matched with the upper end of the inner hole of the cylinder body.

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