Composite foundation static load bearing plate for test and method

Abstract

The invention relates to the technical field of static load bearing plates, in particular to a composite foundation static load bearing plate for a test and a method, the bearing plate comprises an upper layer plate, a middle layer plate and a lower layer plate which are sequentially arranged from top to bottom and are coaxially arranged, and the upper layer plate and the middle layer plate are fixedly connected through a plurality of reinforcing rib plates; the middle-layer plate and the lower-layer plate are fixedly connected through a plurality of soil pressure meter mounting seats, a pile top soil pressure meter is fixedly mounted in the soil pressure meter mounting seat arranged in the center of the bearing plate, and inter-pile soil pressure meters are fixedly mounted in the soil pressure meter mounting seats uniformly distributed in the circumferential direction of the bearing plate; the pressure-bearing plate can be used for synchronously and automatically measuring the pile top and inter-pile soil pressure values, the settlement displacement of the pressure-bearing plate and the load besides the effect of transmitting the upper load, so that the quantitative values of the pile-soil stress ratio under different load levels can be obtained, and basic data are provided for the design of a composite foundation.

Description

Technical Field

[0001] The present invention relates to the technical field of static load bearing plates, and particularly to a static load bearing plate and method for a composite foundation for testing purposes. Background Art

[0002] With the continuous expansion of the scale of engineering construction in China, the composite foundation technology has been vigorously developed. However, since the load transfer mechanism between the composite foundation reinforcement and the natural foundation soil has not been fully clarified, the current feasible method is to conduct a static load test on-site to measure the settlement deformation, load magnitude, and the values of pile top and soil pressure between piles of the composite foundation. Among them, the measurement of the pile-soil stress ratio is particularly crucial for the design of the reinforcement. The pile-soil stress ratio is defined as the ratio of the average vertical stress of the pile body to the average vertical stress of the soil between piles under the action of the load. In addition to being affected by factors such as the load level, load application time, properties of the soil between piles, pile length, cushion thickness and material, etc., the placement position of the earth pressure cell and the levelness of different pressure cells during the actual testing process also have an important impact on the test results.

[0003] In traditional static load tests of composite foundations, the common method for measuring the pile-soil stress ratio is to place a number of earth pressure cells at the positions of the pile top and the soil between piles under the cushion respectively. After laying the cushion, the load is applied in stages and the readings of the earth pressure cells are taken, and the value of the pile-soil stress ratio is obtained accordingly. However, the deficiencies of this traditional method are mainly manifested in the following two aspects. Firstly, the installation position of the earth pressure cell and the levelness of different pressure cells cannot be guaranteed to be accurate, resulting in large differences in the data of the earth pressure cells at different positions even when measuring the soil pressure between piles. Secondly, a large number of studies have shown that introducing the earth pressure gauge into the soil will cause a change in the soil stress field. If the earth pressure gauge can provide a reaction force through a rigid plate, it will be more accurate than directly placing a soil pressure gauge with a large stiffness in the soil for testing. In addition, a displacement meter needs to be installed separately in the static load test to measure the settlement displacement of the load plate. When the deformation is too large, the displacement meter usually needs to be adjusted multiple times. The testing process cannot be automated and unmanned wirelessly, and the load magnitude is calculated based on the oil pressure of the jack, with deficiencies such as data asynchronization and inaccuracy.

[0004] Therefore, in order to solve the above problems, the present invention proposes a static load bearing plate and method for a composite foundation for testing purposes. Summary of the Invention

[0005] The present invention proposes a static load bearing plate and method for a composite foundation for testing purposes, so as to solve the problems of asynchronous and inaccurate test data in the static load test of the composite foundation.

[0006] The technical solution of the present invention is: a static load bearing plate and method for a composite foundation for testing. The bearing plate includes an upper plate, a middle plate, and a lower plate arranged in sequence from top to bottom, and the three are coaxially arranged. The upper plate and the middle plate are fixedly connected by a plurality of reinforcing rib plates, and the middle plate and the lower plate are fixedly connected by a plurality of earth pressure gauge mounting seats. A pile top earth pressure gauge is fixedly installed in the earth pressure gauge mounting seat arranged at the center of the bearing plate, and pile - between earth pressure gauges are fixedly installed in the earth pressure gauge mounting seats evenly distributed along the circumference of the bearing plate. If the piles are arranged in a square pattern, the center - to - center spacing of the piles is L, and the diameters of the middle plate and the lower plate are both ; If the piles are arranged in a rectangular pattern, the center - to - center spacing of the piles is or , and the diameters of the middle plate and the lower plate are both ; If the piles are arranged in an equilateral triangle pattern, the center - to - center spacing of the piles is L, and the diameters of the middle plate and the lower plate are both ; The diameter of the upper plate is smaller than the diameter of the middle plate. The bearing plate further includes a data acquisition device, and the data acquisition device is electrically connected to the pile top earth pressure gauge and all the pile - between earth pressure gauges.

[0007] Preferably, a first round groove for accommodating the pile top earth pressure gauge and the pile - between earth pressure gauges is opened on the lower plate. The aperture of the first round groove is the same as the inner diameter of the earth pressure gauge mounting seat, and both are equal to the outer diameter of the pile top earth pressure gauge and the pile - between earth pressure gauges. The top surfaces of the pile top earth pressure gauge and the pile - between earth pressure gauges abut against the bottom surface of the middle plate.

[0008] Preferably, threaded through - holes are opened at both ends of the surface of the earth pressure gauge mounting seat, and threaded pins are threadedly connected in the threaded through - holes. The pile top earth pressure gauge or the pile - between earth pressure gauges are fixedly installed in the earth pressure gauge mounting seat through the threaded pins on the earth pressure gauge mounting seat.

[0009] Preferably, the reinforcing rib plates are arranged in a criss - cross pattern, and five are provided in the horizontal and vertical directions respectively.

[0010] Preferably, the thickness of the reinforcing rib plates is the same as that of each layer plate, and they are joined and welded in the way of a cross - brace.

[0011] Preferably, lifting holes are opened on the stiffening rib plates, and four lifting holes are opened.

[0012] Preferably, an installation groove is penetrated through the center of the upper end of the upper plate, a support plate is fixedly connected in the installation groove, and a plate - type load sensor is fixedly connected to the upper end of the support plate.

[0013] Preferably, a plurality of laser displacement sensors are provided at the upper end of the upper plate. The lower end of the laser displacement sensor is provided with a magnetic base structure, and the laser displacement sensor is electrically connected to the data acquisition device.

[0014] Preferably, circular grooves II and III are formed on both sides of the upper end of the upper plate. A fixing column I is connected to the circular groove II by internal threads, and a fixing column II is connected to the circular groove III by threads. A rotating ring I and a rotating ring II are provided on the fixing column I, wherein the rotating ring II is arranged at the upper end of the rotating ring I. A connecting plate I is fixedly connected to the surface of the rotating ring I, and a connecting plate II is fixedly connected to the surface of the rotating ring II. One end of the connecting plate I and the connecting plate II away from the fixing column I are fixedly connected to a fixing ring. One end of the fixing ring away from the fixing column I is fixedly connected to two fixing plates. One end of the two fixing plates close to each other is arranged on the surface of the fixing column II, and bolts are arranged on the two fixing plates.

[0015] Preferably, the method for the static load bearing plate of the test composite foundation: S1. When performing the static load test of the composite foundation, hoist the bearing plate through the hoisting hole onto the composite foundation cushion to be detected. Among them, the pile top earth pressure cell should be located at the center of the top of the test pile, and the inter-pile earth pressure cell should be placed at the midpoint of the connection line between two adjacent piles; S2. After placing the bearing plate in position, adsorb the laser displacement sensor on the upper surface of the upper plate through the magnetic base at a suitable position. Four sensors can be evenly arranged; S3. Place the jack at the center of the upper surface of the upper plate coaxially with the load cell. Rotate the fixing plate to clamp the jack inside the fixing ring, and use bolts to fix the fixing plate, thereby fixing the jack; S4. The laser spot hits the bottom of the reference beam, and start the data acquisition device to record the pile top earth pressure and the inter-pile earth pressure values and , and calculate the pile-soil stress ratio according to . Among them, the earth pressure measured by the bearing plate is the earth pressure value above the cushion and below the bearing plate. However, according to the diffusion law of the earth pressure, the earth pressure below the cushion is: , where is the earth pressure above the cushion, is the cushion thickness, is the cushion pressure diffusion angle.

[0016] The beneficial effects of the present invention: 1. In addition to transmitting the upper load, the bearing plate can also synchronously and automatically measure the pile top and inter-pile earth pressure values, the settlement displacement of the bearing plate and the load magnitude, and then be able to obtain the quantitative values of the pile-soil stress ratio under different load levels, providing basic data for the design of the composite foundation.

[0017] 2. The position of the soil pressure cell under the bearing plate is accurately set, with uniform levelness, and the rigid bearing plate can provide a reaction force for the soil pressure cell, thereby making the measured value of the pile-soil stress ratio more accurate. Brief Description of the Drawings

[0018] Figure 1 It shows a schematic diagram of the overall three-dimensional structure of the present invention; Figure 2 It shows a schematic diagram of the upper plate structure of the present invention; Figure 3 It shows a schematic diagram of the reinforcing rib plate structure of the present invention; Figure 4 It shows a schematic diagram of the square pile layout structure of the present invention; Figure 5 It shows a schematic diagram of the triangular pile layout structure of the present invention; Figure 6 It shows a schematic diagram of the connection structure of the clamping device of the present invention; Figure 7 It shows a schematic diagram of the sectional structure of the present invention; Figure 8 It shows a schematic diagram of the design dimensions of the bearing plate for square pile layout and the pile-soil pressure test of the present invention; Figure 9 It shows a schematic diagram of the design dimensions of the bearing plate for triangular pile layout and the pile-soil pressure test of the present invention; Figure 10 It shows a schematic diagram of the top view of the bearing plate of the present invention and the opening positions of the soil pressure cells.

[0019] Description of the reference numerals: 1. Upper plate; 2. Middle plate; 3. Lower plate; 4. Reinforcing rib plate; 5. Pile top soil pressure gauge; 6. Inter-pile soil pressure gauge; 7. Lifting hole; 8. Data acquisition device; 9. Pressure gauge mounting seat; 10. First circular groove; 11. Threaded pin; 12. Installation groove; 13. Support plate; 14. Plate type load sensor; 15. Second circular groove; 16. Third circular groove; 17. First fixed column; 18. First rotating ring; 19. Second rotating ring; 20. First connecting plate; 21. Second connecting plate; 22. Fixed ring; 23. Fixed plate; 24. Second fixed column; 25. Bolt; 26. Laser displacement sensor. Detailed Description of the Invention

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0021] Please refer to Figures 1-7 Figures 1-7 , the present invention provides an embodiment: a static load bearing plate for a composite foundation for testing, which includes an upper plate 1, a middle plate 2, and a lower plate 3 arranged in sequence from top to bottom. The three are coaxially arranged. The upper plate 1 and the middle plate 2 are fixedly connected by a plurality of reinforcing rib plates 4. The middle plate 2 and the lower plate 3 are fixedly connected by a plurality of earth pressure gauge mounting seats 9. A pile top earth pressure gauge 5 is fixedly installed in the earth pressure gauge mounting seat 9 arranged at the center of the bearing plate. Earth pressure gauges 6 for between piles are fixedly installed in the earth pressure gauge mounting seats 9 evenly distributed along the circumference of the bearing plate. The diameter of the upper plate 1 is smaller than the diameter of the middle plate 2.

[0022] The bearing plate further includes a data acquisition device 8, and the data acquisition device 8 is electrically connected to the pile top earth pressure gauge 5 and all the earth pressure gauges 6 for between piles.

[0023] A first circular groove 10 for accommodating the pile top earth pressure gauge 5 and the earth pressure gauges 6 for between piles is formed on the lower plate 3. The aperture of the first circular groove 10 is the same as the inner diameter of the earth pressure gauge mounting seat 9, and is equal to the outer diameter of the pile top earth pressure gauge 5 and the earth pressure gauges 6 for between piles. The top surfaces of the pile top earth pressure gauge 5 and the earth pressure gauges 6 for between piles abut against the bottom surface of the middle plate 2.

[0024] Threaded through holes are formed at both ends of the surface of the earth pressure gauge mounting seat 9. Threaded pins 11 are threadedly connected in the threaded through holes. The pile top earth pressure gauge 5 or the earth pressure gauges 6 for between piles are fixedly installed in the earth pressure gauge mounting seat 9 through the threaded pins 11 on the earth pressure gauge mounting seat 9.

[0025] An installation groove 12 is formed through the center of the upper end of the upper plate 1. A support plate 13 is fixedly connected in the installation groove 12. A plate type load sensor 14 is fixedly connected to the upper end of the support plate 13. The diameter of the plate type load sensor 14 should be larger than the outer diameter of the loading jack. During the test, the center of the jack and the plate type load sensor 14 are coaxial, so that the load value can be directly and accurately measured. The tail wire of the plate type load sensor 14 is also connected to the data acquisition device 8.

[0026] The laser displacement sensor 26 is adsorbed on the upper surface of the upper plate 1 through a magnetic adsorption base. The laser displacement sensor 26 is electrically connected to the data acquisition device 8. After the bearing plate is placed in position, the laser displacement sensor 26 is placed and fixed at a suitable position on the bearing plate through the visible laser displacement sensor 26. Four can be evenly placed, and the laser spot is hit at the bottom of the reference beam. Since it is a non-contact measurement, no manual adjustment is required during the test, and unmanned and automated testing can be achieved.

[0027] On both sides of the upper end of the upper layer plate 1, there are provided a second circular groove 15 and a third circular groove 16. A first fixing column 17 is threadedly connected in the second circular groove 15, and a second fixing column 24 is threadedly connected in the third circular groove 16. There are provided a first rotating ring 18 and a second rotating ring 19 on the first fixing column 17, wherein the second rotating ring 19 is arranged at the upper end of the first rotating ring 18. A first connecting plate 20 is fixedly connected to the surface of the first rotating ring 18, and a second connecting plate 21 is fixedly connected to the surface of the second rotating ring 19. One ends of the first connecting plate 20 and the second connecting plate 21 away from the first fixing column 17 are fixedly connected to a fixing ring 22. One end of the fixing ring 22 away from the first fixing column 17 is fixedly connected to two fixing plates 23. One ends of the two fixing plates 23 close to each other are arranged on the surface of the second fixing column 24, and a bolt 25 is provided on the two fixing plates 23.

[0028] It can be disassembled by rotating the first fixing column 17 and the second fixing column 24, so as to disassemble the first rotating ring 18, the second rotating ring 19, the first connecting plate 20, the second connecting plate 21, the fixing ring 22 and the fixing plate 23.

[0029] According to the Technical Code for Composite Foundation (GB / T 50783), the bearing plate for vertical compressive load test can be circular or square. The shape of the bearing plate in the present invention is preferably circular. The thickness of each layer plate is determined according to the overall outer diameter of the bearing plate, and a Q235 steel plate with a thickness of 10 - 20 mm can be selected for cutting and processing. The larger the overall outer diameter of the bearing plate, the larger the thickness of the selected steel plate should be.

[0030] The bearing plate for static load test of composite foundation with earth pressure test function in this case includes an upper layer plate 1, a middle layer plate 2, a lower layer plate 3 and a plurality of stiffening rib plates 4 which are fixedly connected by welding. First, according to the pile layout form and pile center spacing Determine the diameter of the bearing plate ; As Figure 4 And Figure 8 Shown, if the piles are arranged in a square or rectangular pattern, the diameter of the bearing plate is Or ; As Figure 5 And Figure 9 Shown, if the piles are arranged in an equilateral triangle pattern, the diameter of the bearing plate is ; Among them, the processing diameters of the lower layer plate 3 and the middle layer plate 2 are both , the upper layer plate 1 is appropriately reduced in diameter and processed with a diameter less than .

[0031] Furthermore, to enhance the overall bending stiffness of the bearing plate, five stiffening rib plates 4 are arranged in both the longitudinal and transverse directions. The stiffening rib plates 4 are connected to each layer plate by welding, and the thickness of the stiffening rib plates 4 is the same as that of each layer plate, and they are welded in a cross-brace manner; On this basis, as Figure 7 and Figure 10 shown, a circular groove 10 with a diameter slightly larger than the pile top earth pressure gauge 5 is opened on the lower layer plate 3 at the center position of the bearing plate. The wire outlet hole of the pile top earth pressure gauge 5 is opened on the middle layer plate 2 at the corresponding position. The distance between the lower layer plate 3 and the middle layer plate 2 is equal to the height of the pile top earth pressure gauge 5. At the same time, the lower layer plate 3 and the middle layer plate 2 are welded together along the circular groove 10 of the pile top earth pressure gauge with steel plates of equal thickness, and two holes are symmetrically opened and tapped around the circular groove 10 to facilitate the fixing of the pile top earth pressure gauge 5 with the threaded pin 11.

[0032] Secondly, measure outwards from the center of the bearing plate the distance. If the pile layout form is square or rectangular, four installation holes for the inter-pile earth pressure gauges 6 are symmetrically opened along the four sides of the bearing plate. For example, four holes are opened at positions three, six, nine, and twelve as shown in Figure 10 ; if the pile layout form is triangular, five installation holes for the inter-pile earth pressure gauges 6 are equally spaced along the circumference of the bearing plate. For example, six holes are opened at optional positions one, three, five, seven, nine, eleven or positions two, four, six, eight, ten, twelve as shown in Figure 10 ; the fixing methods of these openings and the inter-pile earth pressure gauges 6 are exactly the same as those of the pile top earth pressure gauge 5.

[0033] When using the test composite foundation static load bearing plate: S1. When conducting the composite foundation static load test, the bearing plate is hoisted to the composite foundation cushion to be tested through the hoisting hole 7. Among them, the pile top earth pressure cell 5 should be located at the center of the test pile pile top, and the inter-pile earth pressure cell 6 should be placed at the midpoint position of the connection line between two adjacent piles; S2. After placing the bearing plate in position, the laser displacement sensor 26 is adsorbed on the upper surface of the upper layer plate 1 through the magnetic adsorption base at a suitable position, and four can be evenly placed; S3. The jack is placed coaxially with the load cell at the center of the upper surface of the upper layer plate 1. The fixing plate 23 is rotated to clamp the jack inside the fixing ring 22, and the fixing plate 23 is fixed with the bolt 25 to fix the jack and prevent the jack from shifting; S4. The laser point is hit on the bottom of the reference beam, and the data acquisition device 8 is started to record the values of the pile top earth pressure 5 and the inter-pile earth pressure 6 and , and the pile-soil stress ratio is calculated according to . Among them, the earth pressure measured by the bearing plate is the earth pressure value above the cushion and below the bearing plate. However, according to the diffusion law of the earth pressure, the earth pressure magnitude under the cushion is: .

[0034] is the earth pressure magnitude above the cushion; is the cushion thickness

[0035] is the pressure diffusion angle of the cushion

[0036] It can be seen that there is a linear relationship between the soil pressures above and below the cushion. Therefore, the pile-soil stress ratio measured above is the true ratio of the pile top pressure to the soil pressure between piles below the cushion

Claims

1. The composite foundation static load bearing plate for testing is characterized by: The pressure-bearing plate comprises an upper plate (1), a middle plate (2) and a lower plate (3) which are arranged in sequence from top to bottom, and the three are arranged coaxially, the upper plate (1) and the middle plate (2) are fixedly connected via a plurality of reinforcing ribs (4), and the middle plate (2) and the lower plate (3) are fixedly connected via a plurality of soil pressure gauge mounting seats (9); A pile top soil pressure gauge (5) is fixedly mounted in a soil pressure gauge mounting seat (9) arranged at the center of the pressure bearing plate, and inter-pile soil pressure gauges (6) are fixedly mounted in soil pressure gauge mounting seats (9) uniformly distributed along the circumference of the pressure bearing plate; If the piles are arranged in a square shape, the distance between the pile centers is L, and the diameters of the middle plate (2) and the lower plate (3) are both ; If the piles are arranged in a rectangular shape, the distance between the pile centers is or , the diameters of the middle plate (2) and the lower plate (3) are ; If the piles are arranged in an equilateral triangle, the distance between the pile centers is L, and the diameters of the middle plate (2) and the lower plate (3) are both ; The diameter of the upper plate (1) is smaller than the diameter of the middle plate (2); The pressure bearing plate further comprises a data acquisition device (8), wherein the data acquisition device (8) is electrically connected to the pile top soil pressure gauge (5) and all the inter-pile soil pressure gauges (6).

2. The test composite foundation static load bearing plate according to claim 1, characterized in that: The lower plate (3) is provided with a circular groove (10) for accommodating a pile top soil pressure gauge (5) and an inter-pile soil pressure gauge (6); the hole diameter of the circular groove (10) is consistent with the inner diameter of the soil pressure gauge mounting seat (9), and is equal to the outer diameter of the pile top soil pressure gauge (5) and the inter-pile soil pressure gauge (6); the top surfaces of the pile top soil pressure gauge (5) and the inter-pile soil pressure gauge (6) are against the bottom surface of the middle plate (2).

3. The test composite foundation static load bearing plate according to claim 1, characterized in that: Threaded through holes are provided at both ends of the surface of the soil pressure gauge mounting seat (9), threaded pins (11) are threadedly connected in the threaded through holes, and the pile top soil pressure gauge (5) or the inter-pile soil pressure gauge (6) is fixedly mounted in the soil pressure gauge mounting seat (9) via the threaded pins (11) on the soil pressure gauge mounting seat (9).

4. The test composite foundation static load bearing plate according to claim 1, characterized in that: The reinforcing ribs (4) are arranged in a crisscross pattern, and five ribs are provided in the transverse direction and the longitudinal direction respectively.

5. The test composite foundation static load bearing plate according to claim 1, characterized in that: The thickness of the reinforcing ribs (4) is consistent with that of each layer plate, and they are overlapped and welded in a cross-beam manner.

6. The test composite foundation static load bearing plate according to claim 1, characterized in that: The stiffening rib plate (4) is provided with lifting holes (7), and four lifting holes (7) are provided.

7. The test composite foundation static load bearing plate according to claim 1, characterized in that: A mounting groove (12) is provided through the center of the upper end of the upper plate (1), a support plate (13) is fixedly connected in the mounting groove (12), and a plate-type load sensor (14) is fixedly connected to the upper end of the support plate (13).

8. The test composite foundation static load bearing plate according to claim 1, characterized in that: A plurality of laser displacement sensors (26) are arranged at the upper end of the upper plate (1), and a magnetic base structure is arranged at the lower end of the laser displacement sensor (26). The laser displacement sensor (26) is electrically connected to the data acquisition device (8).

9. The test composite foundation static load bearing plate according to claim 1, characterized in that: A second circular groove (15) and a third circular groove (16) are provided on both sides of the upper end of the upper plate (1). The second circular groove (15) is internally threadedly connected to a first fixing column (17). The third circular groove (16) is threadedly connected to a second fixing column (24). The first fixing column (17) is provided with a rotating ring (18) and a second rotating ring (19). The second rotating ring (19) is arranged at the upper end of the first rotating ring (18). The surface of the first rotating ring (18) is fixedly connected to a connecting plate (20). The surface of the second rotating ring (19) is fixedly connected to a connecting plate (21). The ends of the connecting plates (20) and (21) away from the first fixing column (17) are fixedly connected to a fixing ring (22). The ends of the fixing ring (22) away from the first fixing column (17) are fixedly connected to two fixing plates (23). The ends of the two fixing plates (23) close to each other are arranged on the surface of the second fixing column (24). Bolts (25) are arranged on the two fixing plates (23).

10. The method for using the composite foundation static load bearing plate for testing according to any one of claims 1 to 9 is characterized by the following steps: S1, when performing a static load test on a composite foundation, the bearing plate is hoisted onto the composite foundation cushion layer to be tested through the hoisting hole (7), wherein the pile top soil pressure box (5) should be located at the center of the top of the test pile, and the inter-pile soil pressure box (6) should be placed at the midpoint of the line connecting two adjacent piles; S2, after the pressure plate is positioned, the laser displacement sensor (26) is adsorbed to a suitable position on the upper surface of the upper plate (1) through a magnetic base, and four sensors may be evenly distributed; S3, placing the jack at the center of the upper surface of the upper plate (1) coaxially with the load cell, rotating the fixing plate (23) to clamp the jack inside the fixing ring (22), and fixing the fixing plate (23) with bolts (25), thereby fixing the jack; S4, the laser point is hit at the bottom of the reference beam, and the data acquisition device (8) is started to record the values ​​of the soil pressure on the pile top (5) and the soil pressure between piles (6) and ,according to The pile-soil stress ratio is calculated, where the soil pressure measured by the bearing plate is the soil pressure value above the cushion layer and below the bearing plate. However, according to the diffusion law of soil pressure, the soil pressure under the cushion layer is: ,in is the soil pressure above the cushion layer, is the cushion thickness, is the cushion pressure diffusion angle.

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