A dynamic excitation ring shear apparatus and a detection method thereof

Abstract

The application discloses a dynamic excitation type ring shear apparatus and a detection method thereof. The ring shear apparatus comprises a pile body assembly, the pile body assembly comprises an annular pile body, an inner annular plate and an outer annular plate; a vertical supporting device comprising a clamping assembly with a clamping space, the pile body assembly can horizontally rotate relative to the clamping assembly; a shear box assembly comprising an upper shear box and a lower shear box for placing a sample to be detected; a vertical load device comprising a vertical downward loading assembly and a vertical upward loading assembly; and an excitation device for applying an impact force perpendicular to the vertical direction to the pile body assembly or applying a vibration force to the pile body assembly. The application can apply normal stress to both sides of the pile body and simulate the actual dynamic pile sinking process of the pile body.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of geotechnical mechanics detection technology, in particular to a dynamic excitation type ring shear apparatus and a detection method thereof. BACKGROUND

[0002] Pile foundation is a widely used foundation form for buildings, bridges, ports, ocean wind power and other land and water structures. When the pile foundation bears the vertical load of the upper pile head, the relative displacement or displacement trend between the pile and the soil around the pile occurs, so that the pile side friction resistance plays a role, and then the pile head load is gradually transmitted to the soil around the pile. As can be seen, the pile side friction resistance is an important part of the single pile bearing capacity, and how to determine the interface shear properties between the pile and the soil is a key problem in design, and is also an important mechanical problem in studying the bearing capacity and settlement of pile foundation.

[0003] The dynamic excitation type ring shear apparatus is a soil test equipment for determining the mechanical properties of soil under large shear displacement, and is commonly used for detecting the interface shear properties between the pile and the soil. In the conventional ring shear test, the shear surface area of the sample is kept unchanged under continuous displacement, and large deformation shear occurs. During the test, the vertical pressure and the torsional shear are applied to the ring sample to obtain the shear strength of the rock and soil, so as to obtain the corresponding law when the displacement changes.

[0004] The conventional dynamic excitation type ring shear apparatus can only perform shear test on a single side of the pile body, and is under continuous torsional shear. However, the actual dynamic pile sinking mainly adopts impact sinking and vibration sinking, and the pile body is subjected to impact force and excitation force, rather than continuous torsional shear. At the same time, due to the soil plug, the pressure on the inner wall and the outer wall of the pile body is not the same during the sinking process. Since the conventional dynamic excitation type ring shear apparatus is difficult to, the detection result of the interface shear properties between the pile and the soil is inaccurate.

[0005] Therefore, it is necessary to develop a large-scale interface dynamic excitation type ring shear apparatus for pile-soil interface shear property indoor test of dynamic pile sinking pile body double-face different pressure action. SUMMARY

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

[0007] One of the purposes of the present application is achieved by adopting the following technical solutions:

[0008] A dynamic excitation type ring shear apparatus, comprising:

[0009] A pile body assembly comprises a ring-shaped pile body, an inner ring-shaped plate connected to the inner side of the ring-shaped pile body, and an outer ring-shaped plate connected to the outer side of the ring-shaped pile body.

[0010] A vertical support device comprises a clamping assembly having a clamping space, the inner ring-shaped plate and the outer ring-shaped plate are clamped by the clamping space, and the pile body assembly can rotate horizontally in the clamping space.

[0011] A shearing box assembly comprises an upper shearing box and a lower shearing box for placing samples to be tested, the upper shearing box is placed on the upper surface of the ring-shaped pile body, and the lower shearing box is placed on the lower surface of the ring-shaped pile body.

[0012] A vertical load device comprises a vertical downward loading assembly for applying a vertical pressure to the upper shearing box and a vertical upward loading assembly for applying a vertical pressure to the lower shearing box.

[0013] A vibration 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] Further, the outer side wall of the outer ring-shaped plate is provided with a load plate, and the impact force or the vibration force generated by the vibration device acts on the load plate.

[0015] Further, the vibration device comprises a ring-shaped track, a first connecting rod, and a vibration generator, the ring-shaped track is located at the periphery of the pile body assembly, the outer side of the ring-shaped track is connected to the vertical support device through the first connecting rod, the vibration generator is in sliding connection with the ring-shaped track, and the vibration generator is used to apply an impact force or a vibration force to the load plate.

[0016] Further, two vibration generators are arranged on the ring-shaped track, and two load plates are correspondingly arranged on the outer ring-shaped plate.

[0017] Further, an angular displacement sensor for detecting the rotation angle of the pile body assembly is further included, a force sensor is arranged on the load plate, and a laser range finder is arranged on the surface of the vibration generator opposite to the load plate.

[0018] Further, a fixed shaft is vertically arranged, a sleeve ring is arranged at one end of the fixed shaft, a plurality of connecting rods are arranged on the outer periphery of the sleeve ring along the circumferential direction of the sleeve ring, a rotating wheel is rotatably arranged at the end of each connecting rod away from the sleeve ring, the inner ring-shaped plate has a central through hole, a ring-shaped groove is arranged on the hole wall of the central through hole, the fixed shaft extends to the center position of the central through hole at one end, and the rotating wheel is in rolling connection with the ring-shaped groove.

[0019] Further, the vertical load device further comprises two first vertical columns, two second vertical columns, an upper vertical displacement meter and a lower vertical displacement meter, upper ends of the two first vertical columns are movably connected with a first horizontal rod, lower ends of the two second vertical columns are movably connected with a second horizontal rod, the vertical downward loading assembly is connected with the middle part of the first horizontal rod at the upper end, the vertical downward loading assembly is in contact with the top of the upper shear box at the lower end, the vertical upward loading assembly is connected with the middle part of the second horizontal rod at the lower end, the vertical upward loading assembly is in contact with the bottom of the lower shear box at the upper end, the upper vertical displacement meter is vertically arranged and the top end of the upper vertical displacement meter is connected with the first vertical column through a first connecting plate, the lower vertical displacement meter is vertically arranged and the bottom end of the lower vertical displacement meter is connected with the second vertical column through a second connecting plate.

[0020] Further, the clamping assembly comprises two oppositely arranged inner fixing members and two oppositely arranged outer fixing members, 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 member and the inner side surface of the outer fixing member, 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] The second purpose of the present application provides a detection method of the dynamic excitation type ring shear apparatus, so as to accurately simulate the actual dynamic pile driving process of the pile body.

[0022] The second purpose of the present application is achieved by the following technical solutions:

[0023] A detection method of the dynamic excitation type ring shear apparatus, comprising the dynamic excitation type ring shear apparatus, and further comprising the following steps:

[0024] S1: first, the inner annular plate, the outer annular plate and the annular pile body are assembled into a pile body assembly 20 through the fastening connecting piece, and then the inner annular plate and the outer annular plate of the pile body assembly are clamped up and down by the clamping assembly;

[0025] S2: the to-be-tested soil sample is filled and pressed in the upper shear box and the lower shear box, then 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;

[0026] S3: normal loading test: the vertical downward loading assembly applies a vertical downward pressure W1 to the upper shear box, and the vertical upward loading assembly applies a vertical upward pressure W2 to the lower shear box, so as to realize the application of double-face normal stress;

[0027] S4: ring shearing test: the distance between the exciter and the load plate is measured by a laser range finder, then the exciter is started, the exciter applies an impact force to the load plate, the pile body assembly is horizontally rotated under the action of the impact force, and the ring shearing test is realized;

[0028] Alternatively, the exciter is first made to be in close contact with the load plate, then the exciter is started, the exciter applies a vibration force to the load plate, the pile body assembly is horizontally rotated under the combined action of the vibration force and the pressure of the exciter, and the ring shearing test is realized.

[0029] S5: relevant test data are measured by the force sensor, the angular displacement sensor, the upper vertical displacement meter, the lower vertical displacement meter and the laser range finder, and the required relationship curve is obtained according to 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, the relationship curve of the normal stress and the displacement is obtained through the data of the normal stress and the vertical displacement, and the calculation formulae are respectively: and wherein R1 is the inner ring radius of the shearing box, R2 is the outer ring radius of the shearing box, and the unit is m: is the normal stress on the upper rotating surface, the unit is pa, is the normal stress on the lower rotating surface, the unit is pa;

[0031] In step S5, the impact force F or the vibration force F is obtained by the force sensor, and the rotating force couple moment M is calculated according to the impact force F or the vibration force F, wherein M=2FL, and L is the distance from the force point center to the center of the pile body assembly, the unit is m.

[0032] The average shear stress on the rotating surface is converted through the rotating force couple moment M , and the calculation formula is:

[0033]

[0034] The average shear displacement S on the rotating surface is calculated according to the average shear stress on the rotating surface and the average shear displacement on the rotating surface, and the calculation formula is: wherein is the average radius of the soil sample, the unit is m, and the calculation formula is: is the angular displacement of the rotation of the pile body assembly.

[0035] The relationship curve of the pile body interface shear stress and the shear displacement is obtained according to the data of the average shear stress on the rotating surface and the average shear displacement on the rotating surface.

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

[0037] (1) The vertical downward loading assembly applies vertical pressure to the upper shear box, and the vertical upward loading assembly applies vertical pressure to the lower shear box, so that the double-face normal stress of the ring pile body is applied, so that the change of the pile body under the action of different normal pressures is studied, and the need is beneficial. The impact force or vibration force is applied to the pile body assembly by the excitation device, so as to simulate the impact pile sinking process or vibration pile sinking process actually suffered by the pile body, so as to study the change of the pile body under the action of different impact forces and vibration forces; compared with the traditional ring shear apparatus which can only perform single-face shear test on the pile body, the pile body assembly and the clamping assembly are designed in cooperation, the impact force or vibration force acting on the pile body assembly by the excitation device is used to promote the horizontal rotation of the pile body assembly, the change of the soil sample combination surface in the upper and lower shear boxes is realized, and the double-face ring shear test of the pile body is realized.

[0038] (2) The detection method can load the test on the pile body by the double-face normal stress, the vertical downward pressure is applied to the upper shear box by the vertical downward loading assembly, and the vertical upward pressure is applied to the lower shear box by the vertical upward loading assembly, so that the two-direction normal stress can be loaded at the same time, and the flexibility and convenience are realized; the impact force or vibration force is applied to the load plate by the excitation device, so that the stress condition of the pile body in the impact pile sinking process or vibration pile sinking process in reality can be accurately simulated, and the actual pile planting process is beneficial to be guided and optimized. The detection method is simple and convenient to operate, and the test result is accurate, and reference is provided for actual construction. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 is a schematic diagram of the dynamic excitation type ring shear apparatus of the embodiment of the present application;

[0040] Figure 2 is a sectional view of the dynamic excitation type ring shear apparatus of the embodiment of the present application;

[0041] Figure 3 is a sectional view of the dynamic excitation type ring shear apparatus of the embodiment of the present application;

[0042] Figure 4 is a schematic diagram of the vertical support device of the embodiment of the present application;

[0043] Figure 5 is a sectional view of the vertical support device of the embodiment of the present application;

[0044] Figure 6 is a schematic diagram of the pile body assembly of the embodiment of the present application;

[0045] Figure 7 is a sectional view of the pile body assembly of the embodiment of the present application;

[0046] Figure 8is a schematic view of the upper shear box and the lower shear box of the embodiment of the present application assembled on the pile body assembly;

[0047] Figure 9 is Figure 8 is a sectional view of the assembled structure;

[0048] Figure 10 is a schematic view of the vertical load device of the embodiment of the present application;

[0049] Figure 11 is a schematic view of the assembly of the vertical load device and the pile body assembly of the embodiment of the present application;

[0050] Figure 12 is a schematic view of the fixed shaft of the embodiment of the present application;

[0051] Figure 13 is a schematic view of the assembly of the rotating wheel and the pile body assembly of the embodiment of the present application;

[0052] Figure 14 is Figure 13 is a sectional view of the structure;

[0053] Figure 15 is a schematic view of the vibration excitation device of the embodiment of the present application;

[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 vertical rod; 17, lifting horizontal rod; 20, pile body assembly; 21, annular pile body; 22, inner annular plate; 23, outer annular plate; 24, fastening connecting member; 25, load plate; 26, force sensor; 27, central through hole; 28, annular groove; 30, vertical load device; 31, vertical downward loading assembly; 32, vertical upward loading assembly; 33, first vertical column; 34, second vertical column; 35, first horizontal rod; 36, second horizontal rod; 37, upper vertical displacement meter; 38, lower vertical displacement meter; 39, angular displacement sensor; 41, fixed shaft; 42, collar; 43, connecting rod; 44, rotating wheel; 50, vibration excitation device; 51, annular track; 52, first connecting rod; 53, vibration exciter; 54, laser range finder; 60, upper shear box; 70, lower shear box. DETAILED DESCRIPTION

[0055] Example implementations will now be described more fully with reference to the accompanying drawings. Example implementations can be implemented in any number of manners, and are not limited to the embodiments described herein; rather, embodiments are provided as non-limiting examples so that this disclosure will be more fully understood. Like reference numerals refer to like elements throughout the description of the figures, and description thereof will not be repeated.

[0056] The expression of position and direction described in the present application is illustrated by taking the drawings as an example, but changes can also be made as needed, and the changes made are included in the protection scope of the present application.

[0057] As shown in the drawings, the dynamic excitation type ring shear apparatus provided by the present application comprises: Figures 1-15

[0058] The pile body assembly 20 comprises a ring-shaped pile body 21, an inner ring-shaped plate 22 and an outer ring-shaped plate 23, the inner ring-shaped plate 22 is connected with the inner side of the ring-shaped pile body 21, and the outer ring-shaped plate 23 is connected with the outer side of the ring-shaped pile body 21;

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

[0060] The shear box assembly comprises an upper shear box 60 and a lower shear box 70 for placing samples to be tested, the upper shear box 60 is placed on the upper surface of the ring-shaped pile body 21, and the lower shear box 70 is placed on the lower surface of the ring-shaped pile body 21;

[0061] The vertical load device 30 comprises 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 excitation device 50 is used for applying an impact force perpendicular to the vertical direction to the pile body assembly 20 or applying a vibration force to the pile body assembly 20.

[0063] ​In this embodiment, before the test, the inner ring plate 22, the outer ring plate 23 and the ring pile body 21 are connected into a whole structure, i.e. the pile body assembly 20, and then the pile body assembly 20 is installed on the vertical support device 10. The inner ring plate 22 and the outer ring plate 23 are clamped by the clamping assembly, and the ring pile body 21 is exposed outside the clamping assembly, so as to ensure that the position of the pile body assembly 20 in the vertical direction does not change. Then, the installation of the shear box assembly is carried out: the soil sample is uniformly pressed in the upper shear box 60 and the lower surface of the soil sample is fixed, the soil sample is uniformly pressed in the lower shear box 70 and the upper surface of the soil sample is fixed, then the upper shear box 60 is placed on the upper surface of the ring pile body 21, the lower shear box 70 is placed on the lower surface of the ring pile body 21, then the vertical downward loading assembly 31 applies vertical pressure to the upper shear box 60, and the vertical upward loading assembly 32 applies vertical pressure to the lower shear box 70, so as to load the ring pile body 21 with double-face normal stress for testing, so as to study the change of the pile body under the action of different normal pressures, which is conducive to the research. 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 the actual situation to achieve dynamic adjustment. In the above embodiment, the specific form of the vertical upward loading assembly 32 and the vertical downward loading assembly 31 is not given, but those skilled in the art can know that there are many choices for this implementation, such as applying vertical pressure to the shear box through an electric cylinder, or other pressure applying means in the art, as long as the vertical pressure can be applied to the upper shear box 60 and the lower shear box 70.

[0064] When the actual dynamic pile driving process of the pile body is to be simulated, a certain pressure is applied to the lower shear box 70 by the vertical upward loading assembly 32, and a certain pressure is applied to the upper shear box 60 by the vertical downward loading assembly 31, so that the upper shear box 60 and the lower shear box 70 do not rotate relative to the pile body assembly 20. Then, the impact force perpendicular to the vertical direction is applied to the pile body assembly 20 by the excitation device 50 (the direction of the arrow F is the vertical direction), and the pile body assembly 20 rotates horizontally under the impact force, so that the soil sample combination surface of the ring pile body 21 in the upper shear box 60 and the lower shear box 70 changes, and the double-face shear test of the pile body under the impact force is realized. Figure 1 When the actual dynamic pile driving process of the pile body is to be simulated, a certain pressure is applied to the lower shear box 70 by the vertical upward loading assembly 32, and a certain pressure is applied to the upper shear box 60 by the vertical downward loading assembly 31, so that the upper shear box 60 and the lower shear box 70 do not rotate relative to the pile body assembly 20. Then, the impact force perpendicular to the vertical direction is applied to the pile body assembly 20 by the excitation device 50 (the direction of the arrow F is the vertical direction), and the pile body assembly 20 rotates horizontally under the impact force, so that the soil sample combination surface of the ring pile body 21 in the upper shear box 60 and the lower shear box 70 changes, and the double-face shear test of the pile body under the impact force is realized.

[0065] The impact force or vibration force is applied to the pile body assembly 20 by the vibration excitation device 50, so that the process of impact pile driving and vibration pile driving actually suffered by the pile body is simulated, so as to study the change of the pile body under different impact forces and vibration forces, and facilitate the research. The vibration excitation device 50 can change the size of the impact force and the vibration force according to the actual situation, and achieve dynamic controllable adjustment. In addition, compared with the traditional ring shear apparatus which can only perform single-side shear test on the pile body, the impact force or vibration force acting on the pile body assembly 20 by the vibration excitation device 50 in the application can promote the horizontal rotation of the pile body assembly 20, so that the change of the combined surface of the annular pile body 21 and the soil sample in the upper shear box 60 and the lower shear box 70 is realized, that is, the double-side shear effect is achieved.

[0066] Referring to Figure 6 and 7 , the annular pile body 21, the inner annular plate 22 and the outer annular plate 23 are connected into a whole through the fastening connecting piece 24. Specifically, the annular pile body 21, the inner annular plate 22 and the outer annular plate 23 of the embodiment are all provided with radial through holes at corresponding positions, and the fastening connecting piece 24 is sequentially inserted through the radial through holes of the outer annular plate 23, the annular pile body 21 and the inner annular plate 22 to connect the three into a whole. The fastening connecting piece 24 of the embodiment is preferably a bolt, and of course, the fastening connecting piece 24 can also be a screw or a pin shaft in other embodiments. 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] Referring to Figure 8 and Figure 9 , the upper shear box 60 and the lower shear box 70 of the embodiment are both annular steel grooves, and the groove is used for placing the soil sample. The groove of the upper shear box 60 faces downward, and the groove of the lower shear box 70 faces 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 sample is limited by the annular steel groove, so that the relative rotation of the soil sample is avoided, and the stability of the test is ensured.

[0068] As a preferred embodiment, referring to 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 vibration excitation device 50 acts on the load plate 25. In the embodiment, the impact force or vibration force generated by the vibration 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 body assembly 20, so that the generation of the impact load or the vibration load is simpler and safer.

[0069] As a preferred embodiment, referring to Figure 15The exciting 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 with the vertical support device 10 through the first connecting rod 52, the exciter 53 is slidably connected with the annular track 51, and the outer side wall of the outer annular plate 23 is provided with a load plate 25, and the exciter 53 is used for applying an impact force or a vibration force to the load plate 25.

[0070] In the embodiment, the load plate 25 is perpendicular to the outer side wall of the outer annular plate 23 and extends in the direction of the annular track 51, and the stress surface of the load plate 25 is opposite to the exciter 53; the exciter 53 is slidably connected on the annular track 51, and the exciter 53 can slide along the track of the annular track 51; when it is needed 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 away from the load plate 25 by a preset distance, to simulate the jumping height of the impact hammer, then the exciter 53 applies an impact force to the load plate 25, under the action of the impact force, the pile assembly 20 rotates horizontally, to achieve a double-shear test; when it is needed to apply a vibration force to the pile, the exciter 53 is first slid to be close to the load plate 25, in the process of close, the exciter 53 applies a pressure to the load plate 25, then the exciter 53 applies a vibration force to the load plate 25, so that the pile assembly 20 rotates horizontally under the joint action of the vibration force and the pressure, to achieve a double-shear effect. Through the sliding installation of the exciter 53 on the annular track 51, the position between the exciter 53 and the load plate 25 can be flexibly adjusted, the process that the actual pile assembly 20 is subjected to impact sinking and vibration sinking in different directions is simulated, different test purposes are achieved, and the flexibility is high.

[0071] In the above embodiment, the specific form that the exciter 53 is slidably connected with the annular track 51 is not given, but those skilled in the art can know that there are various choices for the implementation mode, for example, the exciter 53 is slidably connected with the annular track 51 through a pulley, or other fixing means in the art can be selected, as long as the exciter 53 can be slidably connected with the annular track 51.

[0072] In the above embodiment, the specific structure of the exciter 53 is not given, but those skilled in the art can know that the exciter 53 can be an electric exciter 53, the electric exciter 53 is suitable for generating an exciting force when an alternating voltage is input, and the exciting force can be transmitted to the pile assembly 20 through the load plate 25, of course, the exciter 53 can also be selected as other structures in the art, as long as the exciter 53 can apply an impact force or a vibration force to the load plate 25.

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

[0074] As a preferred embodiment, the present application further comprises an angular displacement sensor 39 for detecting the rotation angle of the pile body assembly 20. The angular displacement sensor 39 can detect the rotation angle of the pile body assembly 20 in real time, improving the convenience of the test. Specifically, the angular displacement sensor 39 is fixed on the second vertical column 34 by a support, 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 body assembly 20.

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

[0076] As a preferred embodiment, referring to Figure 12 , Figure 13 and Figure 14 , the present application further comprises a vertically arranged fixed shaft 41, one end of the fixed shaft 41 is provided with a collar 42, a plurality of connecting rods 43 are arranged on the outer periphery of the collar 42 along the circumferential direction thereof, one end of each connecting rod 43 away from the collar 42 is rotatably provided with a rotating wheel 44, the inner annular plate 22 has a central through hole 27, a ring groove 28 is arranged on the hole wall of the central through hole 27, 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 ring groove 28.

[0077] In this embodiment, when the pile body assembly 20 rotates horizontally, the inner annular plate 22 is rollingly connected with the rotating wheel 44, so that the rotation axis of the pile body assembly 20 coincides with the vertical axis of the fixed shaft 41, so that the rotation axis of the pile body assembly 20 does not change, and eccentric motion is avoided. The rotating wheel 44 is rollingly connected with the ring 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, refer to Figure 10 and Figure 11 , 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 with a first horizontal rod 35, the lower ends of the two second vertical columns 34 are movably connected with a second horizontal rod 36, the upper end of the vertical downward loading assembly 31 is connected with the middle part of the first horizontal rod 35, the lower end of the vertical downward loading assembly 31 is in contact with the top of the upper shear box 60, the lower end of the vertical upward loading assembly 32 is connected with the middle part of the second horizontal rod 36, the upper end of the vertical upward loading assembly 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 with 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 with the second vertical column 34 through a second connecting plate.

[0079] In this embodiment, the vertical downward loading assembly 31 is connected with the first vertical column 33 through the first horizontal rod 35, the first vertical column 33 plays a guiding role in the downward movement of the vertical downward loading assembly 31, and similarly, the vertical upward loading assembly 32 is connected with the second vertical column 34 through the second horizontal rod 36, the second vertical column 34 plays a guiding role in the upward movement of the vertical upward loading assembly 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 assembly 31 exerts vertical pressure on 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 assembly 32 exerts vertical pressure on the lower shear box 70. Preferably, the upper vertical displacement meter 37 of this embodiment is provided with two, and the two upper vertical displacement meters 37 are distributed at different positions of the upper shear box 60 to improve the measurement accuracy, and similarly, the lower vertical displacement meter 38 is also provided with two.

[0080] As a preferred embodiment, refer to Figure 4 and Figure 5 , the clamping assembly comprises two inner fixed parts 11 arranged oppositely in up and down and two outer fixed parts 12 arranged oppositely in up and down, the inner fixed part 11 is located inside the outer fixed part 12, an annular channel 13 is enclosed between the outer side surface of the inner fixed part 11 and the inner side surface of the outer fixed part 12, the upper and lower surfaces of the inner annular plate 22 are clamped by the two inner fixed parts 11, the upper and lower surfaces of the outer annular plate 23 are clamped by the two outer fixed parts 12, and the annular pile body 21 is located in the annular channel 13.

[0081] In the embodiment, the inner clamping space 110 is formed between the upper and lower end faces of the two inner fixing members 11, the outer clamping space 120 is formed between the upper and lower end faces of the two outer fixing members 12, the inner annular plate 22 is clamped by the inner clamping space 110, the outer annular plate 23 is clamped by the outer clamping space 120, and the annular pile body 21 is located in the annular channel 13. In this way, the inner fixing members 11 and the outer fixing members 12 limit the up-down displacement of the pile body assembly 20 in the vertical direction. In addition, in the present application, 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. The inner annular fixing groove and the outer annular fixing groove each have 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 arranged between the two inner fixing members 11 and the two outer fixing members 12, the resistance to horizontal rotation of the pile body assembly 20 is effectively reduced. The rolling body 14 in the embodiment is preferably a rolling 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 members 11, the outer fixing members 12, and the inner annular plate 22 and the outer annular plate 23.

[0082] As a preferred embodiment, referring to Figure 4 and Figure 5 , the vertical support device 10 further comprises a plurality of lower support rods 15 and a plurality of lifting vertical 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 vertical rod 16 is connected to the top of the clamping assembly.

[0083] In the 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, 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. In this way, the lifting vertical rod 16 lifts the inner fixing member 11 and the outer fixing member 12 of the upper part, so as to facilitate the placement of the pile body assembly 20 on the upper surface of the inner fixing member 11 and the outer fixing member 12 of the lower part, and the lower support rod 15 is used to fix the clamping assembly to the ground. More specifically, the upper ends of the plurality of lifting vertical rods 16 are jointly connected to a lifting cross rod 17, and the two ends of the lifting cross rod 17 are respectively connected to two second vertical columns 34. Therefore, the plurality of lifting vertical rods 16 can be simultaneously lifted or simultaneously pressed by the lifting cross rod 17, which is simple and convenient to operate.

[0084] The present application also provides a detection method of the dynamic excitation type ring shear apparatus, which comprises the dynamic excitation type ring shear apparatus and the following steps:

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

[0086] S2: the soil sample to be tested is filled and pressed in the upper shear box 60 and the lower shear box 70, and then the upper shear box 60 is placed on the upper surface of the ring pile body 21, and the lower shear box 70 is placed on the lower surface of the ring pile body 21;

[0087] S3: normal loading test: the vertical downward loading assembly 31 applies a vertical downward pressure W1 to the upper shear box 60, and the vertical upward loading assembly 32 applies a vertical upward pressure W2 to the lower shear box 70, so as to realize the application of double-face normal stress;

[0088] S4: circumferential shear test: the distance between the impact generator 53 and the load plate 25 is measured by the laser range finder 54, then the impact generator 53 is started, the impact generator 53 applies an impact force to the load plate 25, and the pile body assembly 20 rotates horizontally under the action of the impact force, so as to realize the circumferential shear test;

[0089] Or, the impact generator 53 is in close contact with the load plate 25, then the impact generator 53 is started, the impact generator 53 applies a vibration force to the load plate 25, and the pile body assembly 20 rotates horizontally under the combined action of the vibration force and the pressure of the impact generator 53, so as to realize the circumferential shear test;

[0090] S5: the 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 range finder 54, and the required relationship curve is obtained according to the relevant test data.

[0091] In the embodiment, in step S1, before the pile body assembly 20 is installed, the upper inner fixing member 11 and the outer fixing member 12 are lifted upward by the lifting 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 lifting vertical rod 16 is lowered, 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 the values thereof can be adjusted according to research requirements, so that the change of the pile body under different normal stresses can be simulated; in step S4, the impact force or the vibration force applied by the exciter 53 can be adjusted according to research requirements. The detection method of the present application can perform a double-face normal stress experiment on the pile body, the vertical downward pressure applied to the upper shear box 60 by the vertical downward loading assembly 31 and the vertical upward pressure applied to the lower shear box 70 by the vertical upward loading assembly 32 can realize the simultaneous loading of the normal stresses in two directions, and the operation is convenient; the impact force or the vibration force applied to the load plate 25 by the exciter 53 can accurately simulate the stress condition of the pile body in the impact pile driving process or the vibration pile driving process in reality, and is beneficial to guiding and optimizing the actual pile driving process. The detection method is simple and convenient to operate, and can ensure the accuracy of the test results and provide a reference for actual construction.

[0092] As a preferred embodiment, in step S3, the upper normal stress on the upper rotary surface and the lower normal stress on the lower rotary surface are obtained according to the pressure W1 and the pressure W2, and the relationship curve between the normal stress and the displacement is obtained through the data of the normal stress and the vertical displacement, and the calculation formulas are respectively: and wherein R1 is the inner ring radius of the shear box, R2 is the outer ring radius of the shear box, and the unit is m, is the upper normal stress on the upper rotary surface, the unit is pa, is the lower normal stress on the lower rotary surface, the unit is pa;

[0093] In step S5, the impact force F or the vibration force F is obtained by the force sensor 26, and the rotary couple moment M is calculated according to the impact force F or the vibration force F, wherein M=2FL, L is the distance from the force point center to the center of the pile body assembly 20, and the unit is m;

[0094] The average shear stress on the rotary surface is converted by the rotary couple moment M , and the calculation formula is:

[0095]

[0096] And the average shear displacement S on the rotation surface, the calculation formula is: Wherein, The average radius of the soil sample, the unit is m, the calculation formula is: , theta is the angular displacement of the pile body assembly 20;

[0097] According to the average shear stress on the rotation surface and the average shear displacement on the rotation surface, the relationship curve of the pile body interface shear stress and shear displacement is obtained.

[0098] In the application, the relationship curve of the normal stress and displacement is obtained through the data of the normal stress and the vertical displacement, the relationship curve of the pile body interface shear stress and shear displacement is obtained through the data of the average shear stress on the rotation surface and the average shear displacement on the rotation surface, and the obtained relationship curves are analyzed, so that a theoretical basis can be provided for the subsequent related research of the pile body sinking process.

[0099] Although the embodiments of the application have been shown and described above, it can be understood that the above-mentioned embodiments are exemplary and cannot be understood as limiting the application, and the ordinary skilled in the art can make changes, modifications, replacements and modifications to the above-mentioned embodiments without departing from the principles and purposes of the application within the scope of the application, and all these changes should belong to the protection scope of the claims of the application.

Claims

1. A dynamic resonant ring shear apparatus, characterised in that, The utility model relates to a vertical loading test device for pile body, which comprises: a pile body assembly (20) comprising a ring-shaped pile body (21), an inner ring-shaped plate (22) connected to the inner side of the ring-shaped pile body (21), and an outer ring-shaped plate (23) connected to the outer side of the ring-shaped pile body (21); a vertical support device (10) comprising a clamping assembly with a clamping space, the inner ring-shaped plate (22) and the outer ring-shaped plate (23) being clamped by the clamping space, and the pile body assembly (20) being capable of rotating horizontally in the clamping space; a shearing box assembly comprising an upper shearing box (60) and a lower shearing box (70) for placing samples to be tested, the upper shearing box (60) being placed on the upper surface of the ring-shaped pile body (21), and the lower shearing box (70) being placed on the lower surface of the ring-shaped pile body (21); a vertical loading device (30) comprising a vertical downward loading assembly (31) for applying vertical pressure to the upper shearing box (60) and a vertical upward loading assembly (32) for applying vertical pressure to the lower shearing box (70); a vibration device (50) for applying impact force perpendicular to the vertical direction to the pile body assembly (20) or applying vibration force to the pile body assembly (20); the clamping assembly comprises two inner side fixing members (11) arranged oppositely and two outer side fixing members (12) arranged oppositely, the inner side fixing members (11) being located inside the outer side fixing members (12), a ring-shaped channel (13) being enclosed between the outer side of the inner side fixing members (11) and the inner side of the outer side fixing members (12), the upper and lower surfaces of the inner ring-shaped plate (22) being clamped by the two inner side fixing members (11), the upper and lower surfaces of the outer ring-shaped plate (23) being clamped by the two outer side fixing members (12), and the ring-shaped pile body (21) being located in the ring-shaped channel (13).

2. The dynamic resonant ring shear apparatus of claim 1, wherein, The outer side wall of the outer ring-shaped plate (23) is provided with a load plate (25), and the impact force or vibration force generated by the vibration device (50) acts on the load plate (25).

3. The dynamic resonant ring shear apparatus of claim 2, wherein, The vibration device (50) comprises a ring-shaped track (51), a first connecting rod (52), and a vibration generator (53), the ring-shaped track (51) being located at the periphery of the pile body assembly (20), the outer side of the ring-shaped track (51) being connected to the vertical support device (10) through the first connecting rod (52), and the vibration generator (53) being in sliding connection with the ring-shaped track (51), the vibration generator (53) being used for applying impact force or vibration force to the load plate (25).

4. The dynamic resonant ring shear apparatus of claim 3, wherein, Two vibration generators (53) are arranged on the ring-shaped track (51), and two load plates (25) are correspondingly arranged on the outer ring-shaped plate (23).

5. The dynamic resonant ring shear apparatus of claim 4, wherein, An angle displacement sensor (39) for detecting the rotation angle of the pile body assembly (20) is further included, a force sensor (26) is arranged on the load plate (25), and a laser range finder (54) is arranged on the surface of the vibration generator (53) opposite to the load plate (25).

6. The dynamic resonant ring shear apparatus of claim 5, wherein, Further comprising a vertically arranged fixed shaft (41), one end of the fixed shaft (41) is provided with a collar (42), the outer periphery of the collar (42) is provided with a plurality of connecting rods (43) along the circumferential direction, one end of each of the connecting rods (43) away from the collar (42) is provided with a rotating wheel (44), the inner annular plate (22) has a central through hole (27), the hole wall of the central through hole (27) is provided with a ring groove (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 in rolling connection with the ring groove (28).

7. The dynamic resonant ring shear apparatus of claim 6, wherein, 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 with a first horizontal rod (35), the lower ends of the two second vertical columns (34) are movably connected with a second horizontal rod (36), the upper end of the vertical downward loading assembly (31) is connected with the middle part of the first horizontal rod (35), the lower end of the vertical downward loading assembly (31) is in contact with the top of the upper shear box (60), the lower end of the vertical upward loading assembly (32) is connected with the middle part of the second horizontal rod (36), and the upper end of the vertical upward loading assembly (32) is in contact with the bottom of the lower shear box (70), the upper vertical displacement meter (37) is vertically arranged and the top end thereof is connected with the first vertical column (33) through a first connecting plate, and the lower vertical displacement meter (38) is vertically arranged and the bottom end thereof is connected with the second vertical column (34) through a second connecting plate.

8. A detection method of a dynamic excitation type ring shear apparatus, characterized by, The dynamic excitation ring shear apparatus comprises the steps of: 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 fastening connectors (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 a clamping assembly; S2: the soil sample to be measured is filled and pressed in the upper shear box (60) and the lower shear box (70), 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); S3: normal load test: a vertical downward pressure W1 is applied to the upper shear box (60) by the vertical downward loading assembly (31), and a vertical upward pressure W2 is applied to the lower shear box (70) by the vertical upward loading assembly (32), so as to realize the application of double-face normal stress; S4: ring shear test: the distance between the exciter (53) and the load plate (25) is measured by a laser range finder (54), then the exciter (53) is started, the exciter (53) applies an impact force to the load plate (25), the pile body assembly (20) rotates horizontally under the action of the impact force, and the ring shear test is realized. Alternatively, the exciter (53) is first brought into close contact with the load plate (25), and then the exciter (53) is started to apply a vibration force to the load plate (25), and the pile body assembly (20) is horizontally rotated under the combined action of the vibration force and the pressure of the exciter, so as to realize the ring shear test; S5: The 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 range finder (54), and the required relationship curve is obtained according to the relevant test data.

9. The method of claim 8, wherein the dynamic ring shear apparatus is a dynamic simple shear apparatus. In step S3, the normal stress on the upper rotary surface and the normal stress on the lower rotary surface are derived according to the pressure W1 and the pressure W2, the relationship curve between the normal stress and the displacement is obtained through the data of the normal stress and the vertical displacement, and the calculation formula is respectively: and wherein R1 is the inner ring radius of the shear box, R2 is the outer ring radius of the shear box, and the unit is m, is the normal stress on the upper rotary surface, and the unit is pa, is the normal stress on the lower rotary surface, and the unit is pa. In step S5, the impact force F or the vibration force F is obtained by the force sensor (26), and the rotational couple moment M is calculated according to the impact force F or the vibration force F, wherein M=2FL, and L is the distance from the center of the force point to the center of the pile body assembly (20), and the unit is m; The average shear stress on the plane of rotation is obtained by converting the moment of the couple M The formula is: and the average shear displacement S on the rotating surface, the calculation formula is: wherein, is the average radius of the soil sample, the unit is m, and the calculation formula is: is the average radius of the soil sample, the unit is m, and the calculation formula is: is the angular displacement of the pile assembly (20) rotation; The relationship curve of the pile body interface shear stress and the shear displacement is obtained according to the data of the average shear stress on the rotation surface and the average shear displacement on the rotation surface.

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