Dynamic excitation type ring shear apparatus and detection method thereof

Abstract

The invention discloses a dynamic excitation type ring shear apparatus and a detection method thereof. The ring shear apparatus comprises a pile body assembly, and the pile body assembly comprises an annular pile body, an inner annular plate and an outer annular plate; the vertical supporting device comprises a clamping assembly with a clamping space, and the pile body assembly can horizontally rotate relative to the clamping assembly; the shear box assembly comprises an upper shear box and a lower shear box which are used for placing a sample to be tested; the vertical loading device comprises a vertical downward loading assembly and a vertical upward loading assembly; and the vibration excitation device is used for applying impact force perpendicular to the vertical direction to the pile body assembly or applying vibration force to the pile body assembly. Normal stress can be applied to the two faces of the pile body, and the actual dynamic pile sinking process of the pile body can be simulated.

Description

Technical Field

[0001] The invention relates to the technical field of rock and soil mechanics detection, and in particular to a dynamic excitation type ring shear instrument and a detection method thereof. Background Art

[0002] Pile foundation is a widely used foundation form for land and water structures such as buildings, bridges, ports and docks, and offshore wind power. When the pile foundation bears the vertical load of the upper pile head, a relative displacement or displacement trend occurs between the pile and the soil around the pile, which makes the friction resistance on the pile side play a role, and then gradually transfers the pile head load to the soil around the pile. It can be seen that the pile side friction resistance is an important component of the bearing capacity of a single pile. How to determine the shear properties of the interface between the pile and the soil is a key design issue and an important mechanical problem in studying the bearing capacity and settlement of pile foundations.

[0003] The dynamic excitation ring shear apparatus is a geotechnical testing equipment for determining the mechanical properties of soil under large shear displacement conditions. It is often used to detect the shear properties of the interface between piles and soil. The conventional ring shear test keeps the shear surface area of ​​the specimen unchanged during the test, and large deformation shear occurs under continuous displacement. During the test, the shear strength of the rock and soil is obtained by loading vertical pressure and torsional shear force on the annular specimen, thereby obtaining the corresponding law when the displacement changes.

[0004] Conventional dynamic excitation ring shear tester can only perform shear test on one side of the pile body, and it is under the action of continuous torsional shear force. The actual dynamic pile sinking mainly adopts two methods: impact pile sinking and vibration pile sinking. The pile body is subjected to impact force and excitation force, not continuous torsional shear force. At the same time, due to soil plugging during the sinking process, the pressure on the inner and outer walls of the pile body is not the same. Since the conventional dynamic excitation ring shear tester is difficult to use, the test results of the shear properties of the interface between the pile and the soil are inaccurate.

[0005] Therefore, it is necessary to develop a large-scale interface dynamic excitation ring shear apparatus for indoor testing of the shear characteristics of the pile-soil interface of dynamic pile driving, which is subjected to different pressures on both sides of the pile. Summary of the invention

[0006] In view of the defects of the above prior art, one of the purposes of the present invention is to provide a dynamic excitation ring shear instrument to realize the loading test of the double-sided normal stress of the pile body and simulate the actual dynamic pile sinking process of the pile body.

[0007] One of the purposes of the present invention is achieved by the following technical solution:

[0008] A dynamic excitation ring shear instrument, comprising:

[0009] A pile body assembly, the pile body assembly comprising an annular pile body, an inner annular plate and an outer annular plate, the inner annular plate being connected to the inner side of the annular pile body, and the outer annular plate being connected to the outer side of the annular pile body;

[0010] The vertical support device comprises a clamping assembly having a clamping space, the inner annular plate and the outer annular plate are clamped up and down by the clamping space, and the pile assembly can rotate horizontally in the clamping space;

[0011] A shear box assembly, comprising an upper shear box and a lower shear box for placing a sample to be tested, wherein the upper shear box is placed on the upper surface of the annular pile body, and the lower shear box is placed on the lower surface of the annular pile body;

[0012] A vertical load device, comprising a vertical downward loading assembly for applying vertical pressure to the upper shear box and a vertical upward loading assembly for applying vertical pressure to the lower shear box;

[0013] The vibration excitation device is used to apply an impact force perpendicular to the vertical direction to the pile body assembly or to apply a vibration force to the pile body assembly.

[0014] Furthermore, a load plate is provided on the outer side wall of the outer annular plate, and the impact force or vibration force generated by the excitation device acts on the load plate.

[0015] Furthermore, the vibration excitation device includes an annular track, a first connecting rod and an exciter. The annular track is located at the periphery of the pile body assembly. The outer side of the annular track is connected to the vertical support device through the first connecting rod. The exciter is slidably connected to the annular track. The exciter is used to apply impact force or vibration force to the load plate.

[0016] Furthermore, two vibration exciters are provided on the annular track, and two load plates are correspondingly provided on the outer annular plate.

[0017] Furthermore, it also includes an angular displacement sensor for detecting the rotation angle of the pile assembly, a force sensor is provided on the load plate, and a laser rangefinder is provided on the surface of the exciter opposite to the load plate.

[0018] Furthermore, it includes a vertically arranged fixed shaft, a ring is provided at one end of the fixed shaft, a plurality of connecting rods are provided along the circumferential direction of the outer periphery of the ring, a rotating wheel is rotatably provided at one end of each connecting rod away from the ring, the inner annular plate has a central through hole, a circle of annular grooves is provided on the hole wall of the central through hole, one end of the fixed shaft extends to the center position of the central through hole, and the rotating wheel is rollingly connected to the annular groove.

[0019] Furthermore, the vertical load device also includes two first vertical columns, two second vertical columns, an upper vertical displacement meter and a lower vertical displacement meter, the upper ends of the two first vertical columns are movably connected to the first cross bar, the lower ends of the two second vertical columns are movably connected to the second cross bar, the upper end of the vertical downward loading component is connected to the middle of the first cross bar, the lower end of the vertical downward loading component contacts the top of the upper shear box, the lower end of the vertical upward loading component is connected to the middle of the second cross bar, the upper end of the vertical upward loading component contacts the bottom of the lower shear box, the upper vertical displacement meter is vertically arranged and its top end is connected to the first vertical column through a first connecting plate, the lower vertical displacement meter is vertically arranged and its bottom end is connected to the second vertical column through a second connecting plate.

[0020] Furthermore, the clamping assembly includes two inner fixing members arranged opposite to each other up and down and two outer fixing members arranged opposite to each other up and down, the inner fixing members are located inside the outer fixing members, an annular channel is enclosed between the outer side surface of the inner fixing members and the inner side surface of the outer fixing members, the upper and lower surfaces of the inner annular plate are clamped by the two inner fixing members, the upper and lower surfaces of the outer annular plate are clamped by the two outer fixing members, and the annular pile body is located in the annular channel.

[0021] A second object of the present invention is to provide a detection method of a dynamic excitation type ring shear instrument to accurately simulate the actual dynamic pile sinking process of a pile body.

[0022] The second object of the present invention is achieved by adopting the following technical solution:

[0023] A detection method for a dynamic excitation type ring shear instrument comprises the above-mentioned dynamic excitation type ring shear instrument, and further comprises the following steps:

[0024] S1: first assemble the inner annular plate, the outer annular plate and the annular pile body into a pile body assembly 20 through fastening connectors, and then clamp the inner annular plate and the outer annular plate of the pile body assembly up and down by a clamping assembly;

[0025] S2: Fill and compact the soil sample to be tested in the upper shear box and the lower shear box, then place the upper shear box on the upper surface of the annular pile body, and place the lower shear box on the lower surface of the annular pile body;

[0026] S3: Normal loading test: A vertical downward pressure W1 is applied to the upper shear box through a vertical downward loading assembly, and a vertical upward pressure W2 is applied to the lower shear box through a vertical upward loading assembly, so as to achieve the application of double-sided normal stress;

[0027] S4: Circumferential shear test: The distance between the vibrator and the load plate is measured by a laser rangefinder, and then the vibrator is started, and the vibrator applies an impact force to the load plate. The pile assembly rotates horizontally under the impact force, thereby realizing a circumferential shear test;

[0028] Alternatively, the exciter is first brought into close contact with the load plate, and then the exciter is started, so that the exciter applies a vibration force to the load plate, and the pile assembly rotates horizontally under the combined action of the vibration force and the pressure of the exciter, thereby realizing the circumferential shear test;

[0029] S5: Relevant test data are measured by means of a force sensor, an angular displacement sensor, an upper vertical displacement meter, a lower vertical displacement meter and a laser rangefinder, and a required relationship curve is obtained based on the relevant test data.

[0030] Further, in step S3, the normal stress on the upper rotating surface and the normal stress on the lower rotating surface are obtained according to the pressure W1 and the pressure W2, and the relationship curve between the normal stress and the vertical displacement is obtained through the data of the normal stress and the vertical displacement. The calculation formulas are: and Where R1 is the inner radius of the shear box, R2 is the outer radius of the shear box, the unit is m,: σ 1n is the normal stress on the upper rotating surface, in pa, σ 2n is the normal stress on the lower rotation surface, in pa;

[0031] In step S5, the impact force F or the vibration force F is obtained by the force sensor, and the rotational torque is calculated according to the impact force F or the vibration force F. The average shear stress on the rotating surface and the average shear displacement on the rotating surface are converted by the rotational torque. The relationship curve of the shear stress-shear displacement of the pile interface is obtained according to the data of the average shear stress on the rotating surface and the average shear displacement on the rotating surface. The calculation formula is as follows:

[0032]

[0033]

[0034]

[0035] Where M is the rotational torque, τ n is the average shear stress on the rotating surface, in Pa, S is the average shear displacement on the rotating surface, in m, L is the distance from the center of the force point to the center of the pile assembly, in m, R m is the average radius of the soil sample in m, θ is the angular displacement of the pile assembly, and R is the integral variable.

[0036] Compared with the prior art, the beneficial effects of the present invention include at least:

[0037] (1) The present invention applies vertical pressure to the upper shear box through the vertical downward loading component, and applies vertical pressure to the lower shear box through the vertical upward loading component, so as to achieve the application of double-sided normal stress to the annular pile body, so as to study the changes of the pile body under the action of different normal pressures, which is beneficial to research needs. The impact force or vibration force is applied to the pile body component through the excitation device to simulate the actual impact pile sinking process or vibration pile sinking process to the pile body, so as to study the changes of the pile body under the action of different impact forces and vibration forces; compared with the traditional ring shear instrument that can only perform a single-sided shear test on the pile body, the present invention cleverly uses the matching design of the pile body component and the clamping component, and utilizes the impact force or vibration force of the excitation device on the pile body component to cause the pile body component to rotate horizontally, so as to achieve the change of the bonding surface between the annular pile body and the soil samples in the upper and lower shear boxes at the same time, so as to achieve a double-sided annular shear test of the pile body.

[0038] (2) The detection method of the present invention can perform a double-sided normal stress loading test on the pile body. By applying vertical downward pressure to the upper shear box through the vertical downward loading component and applying vertical upward pressure to the lower shear box through the vertical upward loading component, it can realize the simultaneous loading of normal stress in two directions, which is flexible and convenient; by applying impact force or vibration force to the load plate through the exciter, it can accurately simulate the stress condition of the pile body in the impact pile sinking process or vibration pile sinking process in reality, which is conducive to guiding and optimizing the actual pile planting process. The detection method is simple and easy to operate, which can not only ensure the accuracy of the test results, but also provide a reference for actual construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Schematic diagram of a dynamic excitation ring shear apparatus according to an embodiment of the present invention;

[0040] Figure 2 It is one of the cross-sectional views of the dynamic excitation type ring shear apparatus according to an embodiment of the present invention;

[0041] Figure 3 is a second cross-sectional view of the dynamic excitation type ring shear apparatus according to an embodiment of the present invention;

[0042] Figure 4 is a schematic diagram of a vertical support device according to an embodiment of the present invention;

[0043] Figure 5 is a cross-sectional view of a vertical support device according to an embodiment of the present invention;

[0044] Figure 6 is a schematic diagram of a pile assembly according to an embodiment of the present invention;

[0045] Figure 7 is a cross-sectional view of a pile assembly according to an embodiment of the present invention;

[0046] Figure 8It is a schematic diagram of an upper shear box and a lower shear box assembled on a pile body assembly according to an embodiment of the present invention;

[0047] Fig. 9 yes Figure 8 A cross-sectional view of the assembly structure;

[0048] Fig.10 is a schematic diagram of a vertical load device according to an embodiment of the present invention;

[0049] Fig.11 is a schematic diagram of the assembly of a vertical load device and a pile assembly according to an embodiment of the present invention;

[0050] Fig.12 is a schematic diagram of a fixed shaft according to an embodiment of the present invention;

[0051] Fig.13 is a schematic diagram of the assembly of a runner and a pile body assembly according to an embodiment of the present invention;

[0052] Fig.14 yes Fig.13 Cross-sectional view of the structure;

[0053] Fig.15 is a schematic diagram of an excitation device according to an embodiment of the present invention;

[0054] In the figure: 10, vertical support device; 11, inner fixing member; 110, inner clamping space; 12, outer fixing member; 120, outer clamping space; 13, annular channel; 14, rolling body; 15, lower support rod; 16, lifting pole; 17, lifting cross bar; 20, pile body assembly; 21, annular pile body; 22, inner annular plate; 23, outer annular plate; 24, fastening connector; 25, load plate; 26, force sensor; 27, center through hole; 28, annular groove; 30, vertical load device; 3 1. Vertical downward loading assembly; 32. Vertical upward loading assembly; 33. First vertical column; 34. Second vertical column; 35. First cross bar; 36. Second cross bar; 37. Upper vertical displacement meter; 38. Lower vertical displacement meter; 39. Angular displacement sensor; 41. Fixed shaft; 42. Ring; 43. Connecting rod; 44. Rotating wheel; 50. Excitation device; 51. Annular track; 52. First connecting rod; 53. Exciter; 54. Laser rangefinder; 60. Upper shear box; 70. Lower shear box. DETAILED DESCRIPTION

[0055] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided to make the present invention more comprehensive and complete and to fully convey the concepts of example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar structures, and thus their repeated description will be omitted.

[0056] The words expressing positions and directions described in the present invention are all explained with reference to the accompanying drawings as examples, but they can be changed as needed, and all such changes are included in the protection scope of the present invention.

[0057] like Figure 1-15 As shown, a dynamic excitation ring shear instrument provided by the present invention comprises:

[0058] The pile assembly 20 includes an annular pile body 21, an inner annular plate 22 and an outer annular plate 23, wherein the inner annular plate 22 is connected to the inner side of the annular pile body 21, and the outer annular plate 23 is connected to the outer side of the annular pile body 21;

[0059] The vertical support device 10 comprises a clamping assembly having a clamping space, the inner annular plate 22 and the outer annular plate 23 are clamped up and down by the clamping space, and the pile assembly 20 can rotate horizontally in the clamping space;

[0060] A shear box assembly, comprising an upper shear box 60 and a lower shear box 70 for placing a sample to be tested, wherein the upper shear box 60 is placed on the upper surface of the annular pile body 21, and the lower shear box 70 is placed on the lower surface of the annular pile body 21;

[0061] A vertical load device 30, comprising a vertical downward loading assembly 31 for applying vertical pressure to the upper shear box 60 and a vertical upward loading assembly 32 for applying vertical pressure to the lower shear box 70;

[0062] The vibration excitation device 50 is used to apply an impact force perpendicular to the vertical direction to the pile body assembly 20 or to apply a vibration force to the pile body assembly 20 .

[0063] In this embodiment, before the test, the inner annular plate 22, the outer annular plate 23 and the annular pile body 21 are first connected into an integral structure, namely the pile body assembly 20, and then the pile body assembly 20 is installed on the vertical support device 10, and the inner annular plate 22 and the outer annular plate 23 are clamped up and down by the clamping assembly, and the annular pile body 21 is exposed outside the clamping assembly to ensure that the position of the pile body assembly 20 in the vertical direction does not change. Afterwards, the shear box assembly is installed: first, the soil sample is evenly compacted in the upper shear box 60 and the lower surface of the soil sample is fixed, and then the soil sample is evenly compacted in the lower shear box 70 and the upper surface of the soil sample is fixed, and then the upper shear box 60 is placed on the upper surface of the annular pile body 21, and the lower shear box 70 is placed on the lower surface of the annular pile body 21, and then the vertical downward loading assembly 31 is used to apply vertical pressure to the upper shear box 60, and the vertical upward loading assembly 32 is used to apply vertical pressure to the lower shear box 70, so as to perform a double-sided normal stress loading test on the annular pile body 21, so as to study the changes of the pile body under the action of different normal pressures, which is beneficial to research needs. In other embodiments, the vertical upward loading assembly 32 and the vertical downward loading assembly 31 can change the size of the applied pressure according to actual conditions to achieve dynamic adjustment. In the above embodiment, the present application does not give the specific forms of the vertical upward loading component 32 and the vertical downward loading component 31, but those skilled in the art will know that there are a variety of options for implementation, such as applying vertical pressure to the shear box through an electric cylinder, or other pressure-applying means in the field, as long as it is possible to apply vertical pressure to the upper shear box 60 and the lower shear box 70.

[0064] When the actual dynamic pile sinking process of the pile body is to be simulated, a certain pressure is first applied to the lower shear box 70 by the vertical upward loading component 32, and a certain pressure is applied to the upper shear box 60 by the vertical downward loading component 31, so as to keep the upper shear box 60 and the lower shear box 70 from rotating relative to the pile body component 20. Then, an impact force perpendicular to the vertical direction is applied to the pile body component 20 by the vibration excitation device 50 ( Figure 1 The direction indicated by the arrow F in the middle is the vertical direction), the pile body assembly 20 rotates horizontally under the action of the impact force, so that the bonding surface between the annular pile body 21 and the soil samples in the upper shear box 60 and the lower shear box 70 changes, thereby realizing a double-sided shear test of the pile body under the impact force; when the excitation device 50 applies a vibration force to the pile body assembly 20, the pile body assembly 20 rotates horizontally under the vibration force, so that the bonding surface between the annular pile body 21 and the soil samples in the upper shear box 60 and the lower shear box 70 changes, thereby realizing a double-sided shear test of the pile body under the vibration force.

[0065] The present invention applies impact force or vibration force to the pile body assembly 20 through the vibration device 50, thereby simulating the process of impact pile sinking and vibration pile sinking of the actual pile body, so as to study the changes of the pile body under different impact forces and vibration forces, which is beneficial to research needs. Among them, the vibration device 50 can change the magnitude of the impact force and the vibration force according to the actual situation to achieve dynamic controllable adjustment. In addition, compared with the traditional ring shear instrument that can only perform a single-sided shear test on the pile body, the present invention cleverly uses the matching design of the pile body assembly 20 and the clamping assembly, and utilizes the impact force or vibration force of the vibration device 50 acting on the pile body assembly 20 to cause the pile body assembly 20 to rotate horizontally, so that the annular pile body 21 simultaneously changes the bonding surface with the soil samples in the upper shear box 60 and the lower shear box 70, that is, to achieve a double-sided shear effect.

[0066] See also Figure 6 and 7 The annular pile body 21, the inner annular plate 22 and the outer annular plate 23 of the present invention are connected into a whole by a fastening connector 24. Specifically, radial through holes are reserved at corresponding positions of the annular pile body 21, the inner annular plate 22 and the outer annular plate 23 in this embodiment. The fastening connector 24 passes through the radial through holes of the outer annular plate 23, the annular pile body 21 and the inner annular plate 22 in sequence to connect the three into a whole. The fastening connector 24 of this embodiment is preferably a bolt. Of course, in other embodiments, the fastening connector 24 can also be a screw or a pin. In addition, the thickness of the inner annular plate 22 and the outer annular plate 23 is less than the thickness of the annular pile body 21.

[0067] See also Figure 8 and Fig. 9 In this embodiment, the upper shear box 60 and the lower shear box 70 are both annular steel grooves, and the grooves are used to place soil samples. The grooves of the upper shear box 60 face downward, and the grooves of the lower shear box 70 face upward. The upper shear box 60 and the lower shear box 70 both include an outer plate, an inner plate, and a top plate. The soil samples are limited by the annular steel grooves to prevent the soil samples from rotating relative to each other, thereby ensuring the stability of the test.

[0068] As a preferred embodiment, see Figure 1 The outer side wall of the outer annular plate 23 is provided with a load plate 25, and the impact force or vibration force generated by the excitation device 50 acts on the load plate 25. In this embodiment, the impact force or vibration force generated by the excitation device 50 acts on the load plate 25, and the load plate 25 can transmit the impact force or vibration force to the pile assembly 20, so that the generation of impact load or vibration load is simpler and safer.

[0069] As a preferred embodiment, see Fig.15The vibration excitation device 50 includes an annular track 51, a first connecting rod 52 and an exciter 53. The annular track 51 is located at the periphery of the pile body assembly 20. The outer side of the annular track 51 is connected to the vertical support device 10 through the first connecting rod 52. The exciter 53 is slidably connected to the annular track 51. The outer side wall of the outer annular plate 23 is provided with a load plate 25. The exciter 53 is used to apply impact force or vibration force to the load plate 25.

[0070] In this embodiment, the load plate 25 is perpendicular to the outer wall of the outer annular plate 23 and extends in the direction of the annular track 51. The force-bearing surface of the load plate 25 is opposite to the exciter 53. The exciter 53 is slidably connected to the annular track 51, and the exciter 53 can slide along the track of the annular track 51. When it is necessary to apply an impact force to the pile assembly 20, the exciter 53 is slid to a preset position so that the exciter 53 is at a preset distance from the load plate 25 to simulate the high jump of the impact hammer. Afterwards, the vibrator 53 applies an impact force to the load plate 25. Under the action of the impact force, the pile body assembly 20 rotates horizontally to achieve a double-sided shear test; when it is necessary to apply a vibration force to the pile body, the vibrator 53 is first slid to be in close contact with the load plate 25. During the close contact process, the vibrator 53 applies a pressure to the load plate 25. Then, the vibrator 53 applies a vibration force to the load plate 25, so that the pile body assembly 20 rotates horizontally under the combined action of the vibration force and the pressure, achieving a double-sided shear effect. The present invention facilitates flexible adjustment of the position between the vibrator 53 and the load plate 25 by slidingly installing the vibrator 53 on the annular track 51, simulating the process of impact pile sinking and vibration pile sinking of the actual pile body assembly 20 in different directions, achieving different test purposes, and having strong flexibility.

[0071] In the above embodiment, the present invention does not give a specific form of the sliding connection between the exciter 53 and the annular track 51, but those skilled in the art will know that there are a variety of options for this implementation, such as: the exciter 53 and the annular track 51 are slidably connected via a pulley, or other fixing means in the art can be selected to achieve the sliding connection between the exciter 53 and the annular track 51.

[0072] In the above-mentioned embodiment, the present invention does not give a specific structure of the vibrator 53, but those skilled in the art will know that the vibrator 53 can be an electric vibrator 53, which is suitable for generating an exciting force when an alternating voltage is input, and can transmit the exciting force to the pile assembly 20 through the load plate 25. Of course, the vibrator 53 can also be selected as other structures in the art to enable the vibrator 53 to apply impact force or vibration force to the load plate 25.

[0073] As a preferred embodiment, two exciters 53 are provided on the annular track 51, and two load plates 25 are correspondingly provided on the outer annular plate 23. In this embodiment, the two exciters 53 are arranged roughly symmetrically, and the two exciters 53 respectively apply the same magnitude of impact force or vibration force to the corresponding load plates 25, so that the impact force or vibration force received by the pile body assembly 20 is roughly symmetrical, ensuring that the pile body assembly 20 is subjected to force balance.

[0074] As a preferred embodiment, the present invention further includes an angular displacement sensor 39 for detecting the rotation angle of the pile assembly 20. The angular displacement sensor 39 can detect the rotation angle of the pile assembly 20 in real time, thereby improving the convenience of the test. Specifically, the angular displacement sensor 39 of the present invention is fixed to the second vertical column 34 through a bracket, and the angular displacement sensor 39 is located on the outer circumferential path of the outer annular plate 23, so as to accurately detect the rotation angle of the pile assembly 20.

[0075] The load plate 25 is provided with a force sensor 26, and the surface of the exciter 53 opposite to the load plate 25 is provided with a laser rangefinder 54. In this embodiment, since the impact force or vibration force generated by the exciter 53 is transmitted to the pile assembly 20 through the load plate 25, the impact force or vibration force can be detected in real time through the force sensor 26 on the load plate 25, and the test data can be flexibly adjusted to improve the convenience of the test. The laser rangefinder 54 is used to measure the vertical distance between the exciter 53 and the load plate 25, so as to correctly simulate the height jump of the impact hammer.

[0076] As a preferred embodiment, see Fig.12 , Fig.13 and Fig.14 The present invention also includes a vertically arranged fixed shaft 41, one end of which is provided with a collar 42, and the outer periphery of the collar 42 is provided with a plurality of connecting rods 43 along its circumferential direction, and each connecting rod 43 is rotatably provided with a rotating wheel 44 at one end away from the collar 42, the inner annular plate 22 has a central through hole 27, and the hole wall of the central through hole 27 is provided with a circle of annular grooves 28, one end of the fixed shaft 41 extends to the center position of the central through hole 27, and the rotating wheel 44 is rollingly connected with the annular groove 28.

[0077] In this embodiment, when the pile assembly 20 rotates horizontally, the rotation axis of the pile assembly 20 coincides with the vertical axis of the fixed shaft 41 due to the rolling connection between the inner annular plate 22 and the rotating wheel 44, so that the rotation axis of the pile assembly 20 is kept unchanged and eccentric motion is avoided. The rotating wheel 44 is rollingly connected to the annular groove 28, so that the inner annular plate 22 and the rotating wheel 44 are in rolling contact, reducing the friction between the inner annular plate 22 and the rotating wheel 44.

[0078] As a preferred embodiment, see Fig.10 and Fig.11 The vertical load device 30 also includes two first vertical columns 33, two second vertical columns 34, an upper vertical displacement meter 37 and a lower vertical displacement meter 38. The upper ends of the two first vertical columns 33 are movably connected to the first cross bar 35, and the lower ends of the two second vertical columns 34 are movably connected to the second cross bar 36. The upper end of the vertical downward loading component 31 is connected to the middle of the first cross bar 35, and the lower end of the vertical downward loading component 31 contacts the top of the upper shear box 60. The lower end of the vertical upward loading component 32 is connected to the middle of the second cross bar 36, and the upper end of the vertical upward loading component 32 contacts the bottom of the lower shear box 70. The upper vertical displacement meter 37 is vertically arranged and its top end is connected to the first vertical column 33 through a first connecting plate. The lower vertical displacement meter 38 is vertically arranged and its bottom end is connected to the second vertical column 34 through a second connecting plate.

[0079] In this embodiment, the vertical downward loading component 31 is connected to the first vertical column 33 through the first cross bar 35, and the first vertical column 33 guides the downward movement of the vertical downward loading component 31. Similarly, the vertical upward loading component 32 is connected to the second vertical column 34 through the second cross bar 36, and the second vertical column 34 guides the upward movement of the vertical upward loading component 32. The upper vertical displacement meter 37 is used to measure the vertical displacement of the upper shear box 60 after the vertical downward loading component 31 applies vertical pressure to the upper shear box 60, and the lower vertical displacement meter 38 is used to measure the vertical displacement of the lower shear box 70 after the vertical upward loading component 32 applies vertical pressure to the lower shear box 70. Preferably, two upper vertical displacement meters 37 are provided in this embodiment, and the two upper vertical displacement meters 37 are distributed at different positions of the upper shear box 60 to improve the measurement accuracy. Similarly, two lower vertical displacement meters 38 are also provided.

[0080] As a preferred embodiment, see Figure 4 and Figure 5 The clamping assembly includes two inner fixing members 11 disposed opposite to each other up and down and two outer fixing members 12 disposed opposite to each other up and down, the inner fixing member 11 is located inside the outer fixing member, and an annular channel 13 is enclosed between the outer side surface of the inner fixing member 11 and the inner side surface of the outer fixing member. The upper and lower surfaces of the inner annular plate 22 are clamped by the two inner fixing members 11, and the upper and lower surfaces of the outer annular plate 23 are clamped by the two outer fixing members 12, and the annular pile body 21 is located in the annular channel 13.

[0081] In this embodiment, an inner clamping space 110 is formed between the upper and lower end surfaces of the two inner fixing members 11, an outer clamping space 120 is formed between the upper and lower end surfaces of the two outer fixing members 12, the inner annular plate 22 is clamped up and down by the inner clamping space 110, the outer annular plate 23 is clamped up and down by the outer clamping space 120, and the annular pile body 21 is located in the annular channel 13. In this way, the vertical displacement of the pile body assembly 20 is limited by the inner fixing member 11 and the outer fixing member 12. In addition, in the present invention, the two inner fixing members 11 each have an inner annular fixing groove, and the two outer fixing members 12 each have an outer annular fixing groove, and the inner annular fixing groove and the outer annular fixing groove are both provided with a rolling body 14 for rolling contact with the surface of the inner annular plate 22 and the outer annular plate 23. Since the rolling body 14 for rolling contact with the surface of the inner annular plate 22 and the outer annular plate 23 is provided between the two inner fixing members 11 and the two outer fixing members 12, the resistance of the pile body assembly 20 to horizontal rotation is effectively reduced. The rolling body 14 of this embodiment is preferably a ball. Of course, in other embodiments, the rolling body 14 can also be other rolling structures as long as rolling contact is ensured between the inner fixing member 11, the outer fixing member 12 and the inner annular plate 22 and the outer annular plate 23.

[0082] As a preferred embodiment, see Figure 4 and Figure 5 The vertical support device 10 also includes a plurality of lower support rods 15 and a plurality of lifting rods 16, the top of each lower support rod 15 is connected to the bottom of the clamping assembly, and the lower end of each lifting rod 16 is connected to the top of the clamping assembly.

[0083] In this embodiment, the top of the lower support rod 15 is connected to the bottom surface of the inner fixing member 11 and the outer fixing member 12 at the lower part, and the lower part of the lifting vertical rod 16 is connected to the top surface of the inner fixing member 11 and the outer fixing member 12 at the upper part. In this way, the lifting vertical rod 16 lifts the inner fixing member 11 and the outer fixing member 12 at the upper part, so as to place the pile body assembly 20 on the upper surface of the inner fixing member 11 and the outer fixing member 12 at the lower part, and the lower support rod 15 is used to fix the clamping assembly on the ground. More specifically, the upper ends of multiple lifting vertical rods 16 are commonly connected to a lifting cross bar 17, and the two ends of the lifting cross bar 17 are respectively connected to two second vertical columns 34. Therefore, multiple lifting vertical rods 16 can be lifted up or pressed down at the same time by the lifting cross bar 17, and the operation is simple and convenient.

[0084] The present invention also provides a detection method of a dynamic excitation type ring shear instrument, comprising the above-mentioned dynamic excitation type ring shear instrument, and further comprising the following steps:

[0085] S1: First, the inner annular plate 22, the outer annular plate 23 and the annular pile body 21 are assembled into a pile body assembly 20 through the fastening connector 24, and then the inner annular plate 22 and the outer annular plate 23 of the pile body assembly 20 are clamped up and down by the clamping assembly;

[0086] S2: Fill and compact the soil sample to be tested in the upper shear box 60 and the lower shear box 70, and then place the upper shear box 60 on the upper surface of the annular pile body 21, and place the lower shear box 70 on the lower surface of the annular pile body 21;

[0087] S3: Normal loading test: A vertical downward pressure W1 is applied to the upper shear box 60 through the vertical downward loading component 31, and a vertical upward pressure W2 is applied to the lower shear box 70 through the vertical upward loading component 32, so as to achieve the application of double-sided normal stress;

[0088] S4: Circumferential shear test: The distance between the vibrator 53 and the load plate 25 is measured by a laser rangefinder 54, and then the vibrator 53 is started, and the vibrator 53 applies an impact force to the load plate 25, and the pile assembly 20 rotates horizontally under the impact force, thereby realizing a circumferential shear test;

[0089] Alternatively, the exciter 53 is brought into close contact with the load plate 25, and then the exciter 53 is started, so that the exciter 53 applies a vibration force to the load plate 25, and the pile assembly 20 rotates horizontally under the combined action of the vibration force and the pressure of the exciter 53, thereby realizing a hoop shear test;

[0090] S5: Relevant test data are measured by the force sensor 26, the angular displacement sensor 39, the upper vertical displacement meter 37, the lower vertical displacement meter 38 and the laser rangefinder 54, and the required relationship curve is obtained according to the relevant test data.

[0091] In this embodiment, in step S1, before installing the pile body assembly 20, the upper inner fixing member 11 and the outer fixing member 12 are first lifted upward by lifting the vertical rod 16, and then the pile body assembly 20 is placed on the upper surface of the lower inner fixing member 11 and the outer fixing member 12, and then the vertical rod 16 is lowered and lifted, so that the pile body assembly 20 can be fixed in the vertical direction; in step S2, after the upper shear box 60 and the lower shear box 70 are placed, the lower shear box 70 is fixed by the vertical upward loading assembly 32, and the upper shear box 60 is fixed by the vertical upward loading assembly 32; in step S3, the pressure W1 and the pressure W2 can be the same or different, and their values ​​can be adjusted according to research requirements, so as to simulate the changes of the pile body under different normal stresses; in step S4, the impact force or vibration force applied by the exciter 53 can be adjusted according to research requirements. The detection method of the present invention can conduct a double-sided normal stress experiment on the pile body. By applying vertical downward pressure to the upper shear box 60 through the vertical downward loading component 31 and applying vertical upward pressure to the lower shear box 70 through the vertical upward loading component 32, it can realize the simultaneous loading of normal stress in two directions, and the operation is convenient; by applying impact force or vibration force to the load plate 25 through the exciter 53, it can accurately simulate the stress conditions of the impact pile sinking process or vibration pile sinking process of the pile body in reality, which is conducive to guiding and optimizing the actual pile planting process. The detection method is simple and easy to operate, which can not only ensure the accuracy of the test results, but also provide a reference for actual construction.

[0092] As a preferred embodiment, in step S3, the normal stress on the upper rotating surface and the normal stress on the lower rotating surface are obtained according to the pressure W1 and the pressure W2, and the relationship curve between the normal stress and the vertical displacement is obtained through the data of the normal stress and the vertical displacement. The calculation formulas are: and Where R1 is the inner radius of the shear box, R2 is the outer radius of the shear box, the unit is m, σ 1n is the normal stress on the upper rotating surface, in pa, σ 2n is the normal stress on the lower rotation surface, in pa;

[0093] In step S5, the impact force F or the vibration force F is obtained by the force sensor 26, and the rotational torque is calculated according to the impact force or the vibration force F. The average shear stress on the rotating surface and the average shear displacement on the rotating surface are converted by the rotational torque. The relationship curve of the shear stress-shear displacement of the pile body interface is obtained according to the data of the average shear stress on the rotating surface and the average shear displacement on the rotating surface. The calculation formula is as follows:

[0094]

[0095]

[0096]

[0097] Where M is the rotational torque, τ n is the average shear stress on the rotating surface, in Pa, S is the average shear displacement on the rotating surface, in m, L is the distance from the center of the force point to the center of the pile assembly 20, in m, R m is the average radius of the soil sample, in m, θ is the angular displacement of the pile assembly 20, and R is the integral variable.

[0098] In the present invention, a relationship curve between normal stress and displacement is obtained through the data of normal stress and vertical displacement, and a relationship curve between shear stress and shear displacement at the pile interface is obtained through the data of average shear stress on the rotating surface and average shear displacement on the rotating surface. Analysis of the obtained relationship curves can provide a theoretical basis for subsequent related research on the pile sinking process.

[0099] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, substitute and modify the above embodiments within the scope of the invention without departing from the principles and purpose of the present invention. All such changes should fall within the scope of protection of the claims of the present invention.

Claims

1. A dynamic excitation ring shear instrument, characterized in that: include: A pile body assembly (20) comprises an annular pile body (21), an inner annular plate (22) and an outer annular plate (23), wherein the inner annular plate (22) is connected to the inner side of the annular pile body (21), and the outer annular plate (23) is connected to the outer side of the annular pile body (21); The vertical support device (10) comprises a clamping assembly having a clamping space, wherein the inner annular plate (22) and the outer annular plate (23) are clamped up and down by the clamping space, and the pile assembly (20) can rotate horizontally in the clamping space; A shear box assembly, comprising an upper shear box (60) and a lower shear box (70) for placing a sample to be tested, wherein the upper shear box (60) is placed on the upper surface of the annular pile body (21), and the lower shear box (70) is placed on the lower surface of the annular pile body (21); A vertical load device (30) comprising a vertical downward loading component (31) for applying vertical pressure to the upper shear box (60) and a vertical upward loading component (32) for applying vertical pressure to the lower shear box (70); The vibration excitation device (50) is used to apply an impact force perpendicular to the vertical direction to the pile body component (20) or to apply a vibration force to the pile body component (20).

2. The dynamic excitation ring shear instrument according to claim 1, characterized in that: A load plate (25) is provided on the outer side wall of the outer annular plate (23), and the impact force or vibration force generated by the vibration excitation device (50) acts on the load plate (25).

3. The dynamic excitation ring shear instrument according to claim 2, characterized in that: The vibration excitation device (50) comprises an annular track (51), a first connecting rod (52) and an exciter (53); the annular track (51) is located at the periphery of the pile assembly 20; the outer side of the annular track (51) is connected to the vertical support device (10) via the first connecting rod (52); the exciter (53) is slidably connected to the annular track (51); and the exciter (53) is used to apply impact force or vibration force to the load plate (25).

4. The dynamic excitation ring shear instrument according to claim 3, characterized in that: Two vibration exciters (53) are arranged on the annular track (51), and two load plates (25) are correspondingly arranged on the outer annular plate (23).

5. The dynamic excitation ring shear instrument according to claim 3, characterized in that: It also includes an angular displacement sensor (39) for detecting the rotation angle of the pile assembly (20), a force sensor (26) is provided on the load plate (25), and a laser rangefinder (54) is provided on the surface of the exciter (53) opposite to the load plate (25).

6. The dynamic excitation ring shear instrument according to claim 1, characterized in that: It also includes a vertically arranged fixed shaft (41), one end of which is provided with a collar (42), the outer periphery of which is provided with a plurality of connecting rods (43) along its circumferential direction, and each connecting rod (43) is provided with a rotating wheel (44) at one end away from the collar (42), the inner annular plate (22) has a central through hole (27), the hole wall of which is provided with a circle of annular grooves (28), one end of which extends to the center of the central through hole (27), and the rotating wheel (44) is rollingly connected to the annular groove (28).

7. The dynamic excitation ring shear instrument according to claim 1, characterized in that: The vertical load device (30) further comprises two first vertical columns (33), two second vertical columns (34), an upper vertical displacement meter (37) and a lower vertical displacement meter (38); the upper ends of the two first vertical columns (33) are movably connected to a first cross bar (35); the lower ends of the two second vertical columns (34) are movably connected to a second cross bar (36); the upper end of the vertical downward loading component (31) is connected to the middle of the first cross bar (35); the vertical downward loading component (31) The lower end is in contact with the top of the upper shear box (60), the lower end of the vertical upward loading component (32) is connected to the middle of the second cross bar (36), the upper end of the vertical upward loading component (32) is in contact with the bottom of the lower shear box (70), the upper vertical displacement meter (37) is vertically arranged and its top end is connected to the first vertical column (33) through a first connecting plate, and the lower vertical displacement meter (38) is vertically arranged and its bottom end is connected to the second vertical column (34) through a second connecting plate.

8. The dynamic excitation ring shear instrument according to claim 1, characterized in that: The clamping assembly comprises two inner fixing members (11) arranged opposite to each other in the upper and lower parts and two outer fixing members (12) arranged opposite to each other in the upper and lower parts, wherein the inner fixing member (11) is located inside the outer fixing member, and an annular channel (13) is enclosed between the outer side surface of the inner fixing member (11) and the inner side surface of the outer fixing member, the upper and lower surfaces of the inner annular plate (22) are clamped by the two inner fixing members (11), and the upper and lower surfaces of the outer annular plate (23) are clamped by the two outer fixing members (12), and the annular pile body (21) is located in the annular channel (13).

9. A detection method for a dynamic excitation ring shear instrument, characterized in that: The method comprises the dynamic excitation ring shearing apparatus according to any one of claims 1 to 8, further comprising the following steps: S1: first assembling the inner annular plate (22), the outer annular plate (23) and the annular pile body (21) into a pile body assembly (20) through a fastening connector (24), and then clamping the inner annular plate (22) and the outer annular plate (23) of the pile body assembly (20) up and down by a clamping assembly; S2: Fill and compact the soil sample to be tested in the upper shear box (60) and the lower shear box (70), then place the upper shear box (60) on the upper surface of the annular pile body (21), and place the lower shear box (70) on the lower surface of the annular pile body (21); S3: Normal loading test: applying a vertical downward pressure W1 to the upper shear box (60) through the vertical downward loading component (31), and applying a vertical upward pressure W2 to the lower shear box (70) through the vertical upward loading component (32), so as to achieve the application of double-sided normal stress; S4: Circumferential shear test: The distance between the vibrator (53) and the load plate (25) is measured by a laser rangefinder (54), and then the vibrator (53) is started, and the vibrator (53) applies an impact force to the load plate (25), and the pile assembly (20) rotates horizontally under the impact force, thereby realizing a circumferential shear test; Alternatively, the vibration exciter (53) is first brought into close contact with the load plate (25), and then the vibration exciter (53) is started, so that the vibration exciter (53) applies a vibration force to the load plate (25), and the pile assembly (20) rotates horizontally under the combined action of the vibration force and the pressure of the vibration exciter, thereby realizing a circumferential shear test; S5: Relevant test data are measured by the force sensor (26), the angular displacement sensor (39), the upper vertical displacement meter (37), the lower vertical displacement meter (38) and the laser rangefinder (54), and the required relationship curve is obtained according to the relevant test data.

10. The detection method of the dynamic excitation ring shear instrument according to claim 9, characterized in that: In step S3, the normal stress on the upper rotating surface and the normal stress on the lower rotating surface are obtained according to the pressure W1 and the pressure W2, and the relationship curve between the normal stress and the vertical displacement is obtained through the data of the normal stress and the vertical displacement. The calculation formulas are: and Where R1 is the inner radius of the shear box, R2 is the outer radius of the shear box, the unit is m, σ 1n is the normal stress on the upper rotating surface, in pa, σ 2n is the normal stress on the lower rotation surface, in pa; In step S4, the impact force F or the vibration force F is obtained by the force sensor (26), and the rotational torque is calculated according to the impact force F or the vibration force F. The average shear stress on the rotating surface and the average shear displacement on the rotating surface are obtained by converting the rotational torque. The relationship curve between the shear stress and the shear displacement of the pile interface is obtained according to the data of the average shear stress on the rotating surface and the average shear displacement on the rotating surface. The calculation formula is as follows: M=2FL, S=R m I, Where M is the rotational torque, τ n is the average shear stress on the rotating surface, in Pa, S is the average shear displacement on the rotating surface, in m, L is the distance from the center of the force point to the center of the pile assembly (20), in m, R m is the average radius of the soil sample, in m, θ is the angular displacement of the pile assembly (20), and R is the integral variable.

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