A device and method for testing effective stress of unsaturated frozen soil

Abstract

The present invention relates to the technical field of unsaturated frozen soil testing, and specifically discloses an unsaturated frozen soil effective stress testing device, including a test box, a box cover is provided on one side of the test box, a horizontally arranged slide is provided on the inner wall of the test box, a first sliding beam and a second sliding beam are slidably connected on the slide, an unsaturated frozen soil layer making device is installed on the first sliding beam, a test assembly is installed on the second sliding beam, the test assembly includes a sliding sleeve, the sliding sleeve reciprocates on the second sliding beam, a hydraulic cylinder is installed on one side of the sliding sleeve, and the telescopic end of the hydraulic cylinder is vertically arranged downward and fixedly connected to an extrusion test wheel group. The unsaturated frozen soil effective stress testing device provided by the present invention simulates an effective stress test on an unsaturated frozen soil roadbed in the test box, and can also change the temperature in the test box during the test process, thereby obtaining the influence of temperature on the effective stress of the unsaturated frozen soil foundation.

Description

Technical Field

[0001] The invention belongs to the technical field of unsaturated frozen soil testing, and in particular relates to an unsaturated frozen soil effective stress testing device and method. Background Art

[0002] Unsaturated soil refers to soil whose pores are filled with water and air, that is, soil when the saturation is less than 100% but greater than 0. Frozen soil refers to various rocks and soils below zero degrees Celsius and containing ice. The strength of frozen soil is indeed determined by the bonding strength between soil particles and ice, among which ice content (or initial water content) and dry bulk density are the main factors affecting the strength of unsaturated frozen soil. Due to the presence of gas, the properties of unsaturated soil are significantly different from those of saturated soil. The traditional saturated soil theory cannot truly reflect the nature of roadbed soil, and it is difficult to establish a complete design method and propose reasonable disease prevention and control measures. Therefore, from the perspective of unsaturated soil, it is very necessary to use the theory and method of unsaturated soil to study the basic properties of unsaturated roadbed soil and solve the theoretical and related engineering and technical problems of roadbed design. The main manifestation of unsaturated frozen soil roadbed engineering diseases is road pavement damage caused by uneven settlement and embankment instability, and the appearance is uneven deformation. Therefore, when encountering unsaturated frozen soil roadbed, testing the effective stress of the unsaturated frozen soil roadbed is an indispensable link. CN116244920A discloses a method and device for predicting the thermal conductivity of ultra-low temperature unsaturated frozen soil, which can test various properties of unsaturated frozen soil, but cannot test the roadbed formed by unsaturated frozen soil. Summary of the invention

[0003] The purpose of the present invention is to provide a device for testing effective stress of unsaturated frozen soil to solve the problems existing in the prior art.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A device for testing effective stress of unsaturated frozen soil comprises a test box, a box cover is provided on one side of the test box, a horizontally arranged slide is provided on the inner wall of the test box, a first sliding beam and a second sliding beam are slidably connected on the slide, an unsaturated frozen soil layer making device is installed on the first sliding beam, a test assembly is installed on the second sliding beam, the test assembly comprises a sliding sleeve, the sliding sleeve reciprocates on the second sliding beam, a hydraulic cylinder is installed on one side of the sliding sleeve, the telescopic end of the hydraulic cylinder is vertically downwardly arranged and fixedly connected to an extrusion test wheel group, a strain type pressure sensor is installed on one side of the extrusion test wheel group, a bracket is installed on one side of the extrusion test wheel group, a paintbrush is installed on one side of the bracket, a drawing board is installed on the inner wall of the test box, and the paintbrush is in contact with the drawing board.

[0006] Preferably, the extrusion test wheel group includes a fixed block, which is installed at the telescopic end of the hydraulic cylinder. The lower side of the fixed block is fixedly connected to the wheel frame, and the extrusion wheel is rotatably connected inside the wheel frame. The strain type pressure sensor is installed on one side of the fixed block.

[0007] Preferably, the telescopic end of the hydraulic cylinder is fixedly connected to the circular ring through a cable-stayed beam, and a plurality of radars are installed below the circular ring.

[0008] Preferably, the unsaturated frozen soil layer making device includes a laying device and a rolling device, and the laying device and the rolling device are both installed on the first sliding beam.

[0009] Preferably, the laying device includes an elastic hanger, one side of which is fixedly connected to a barrel, a discharge port is provided at the bottom of the barrel, large particles of frozen soil, small particles of frozen soil and ice particles are placed in the barrel, and the large particles of frozen soil, small particles of frozen soil and ice particles fall from the discharge port and are compacted by a compaction device to form a frozen soil layer.

[0010] Preferably, optical fiber sensors are buried in the frozen soil layer.

[0011] Preferably, the material barrel is rotatably connected to the inner barrel, and three cross-arranged partitions are provided in the inner barrel. The three partitions divide the inner barrel into a large-particle frozen soil bin, a small-particle frozen soil bin and an ice particle bin. The inner barrel is provided with three openings corresponding to the large-particle frozen soil bin, the small-particle frozen soil bin and the ice particle bin. A motor is installed on one side of the elastic hanger, and the motor is used to drive the inner barrel to rotate.

[0012] Preferably, the elastic hanger includes a first hanger plate and a second hanger plate, one side of the first hanger plate is fixedly connected to the first flat plate, one side of the second hanger plate is fixedly connected to the second flat plate, a guide rod is slidably connected in the center hole of the second flat plate, the upper end of the guide rod is fixed to the first flat plate, the lower end of the guide rod is fixedly connected to a support plate, a spring is fixedly connected between the support plate and the second flat plate, and a vibration motor is installed on one side of the second hanger plate.

[0013] Preferably, a nozzle is provided on one side of the discharge port.

[0014] Preferably, the rolling device comprises a swing beam, which is hinged to the first sliding beam, one end of the swing beam is fixedly connected to a roller frame, and a rolling roller is rotatably connected inside the roller frame.

[0015] The invention also discloses a method for testing the effective stress of unsaturated frozen soil, and adopts the above-mentioned testing device to test the effective stress of the unsaturated frozen soil roadbed.

[0016] The technical effects and advantages of the present invention are as follows: the present invention provides an unsaturated frozen soil effective stress testing device which simulates the effective stress test of the unsaturated frozen soil roadbed in the test box, and can also change the temperature in the test box during the test, thereby obtaining the influence of temperature on the effective stress of the unsaturated frozen soil foundation.

[0017] The pressure of the extrusion wheel on the frozen soil layer is adjustable. When the extrusion wheel moves forward, the radar under the ring can detect the deformation of the frozen soil layer around the extrusion wheel. However, the frozen soil layer under the extrusion wheel is blocked by the extrusion wheel and cannot be detected by the radar. Therefore, a line will be drawn on the drawing board with a brush during the extrusion wheel's forward movement, and a deformation curve of the frozen soil layer under the extrusion wheel can be drawn on the drawing board. The position of the extrusion wheel can be changed by the reciprocating sliding of the sleeve on the second sliding beam, so that different positions of the frozen soil layer can be tested. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a basic structural schematic diagram of the present invention;

[0019] Figure 2 for Figure 1 Schematic diagram of the internal structure;

[0020] Figure 3 Schematic diagram of the basic structure of the device for making unsaturated frozen soil;

[0021] Figure 4 for Figure 3 A magnified view of part A;

[0022] Figure 5 It is a basic structural diagram of the laying device;

[0023] Figure 6 The figure is a schematic diagram of the basic structure of the test component. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] The present invention provides Figure 1-Figure 6 An unsaturated frozen soil effective stress testing device is shown, comprising a test box 1, a ventilation pipe and an exhaust pipe are provided on one side of the test box 1, and cold air or hot air is introduced through the ventilation pipe to change the temperature in the test box 1, so that the present invention can perform tests at different temperatures, and a box cover 11 is provided on one side of the test box 1, and the box cover 11 can ensure the sealing of the test box 1.

[0026] A horizontally arranged slide 12 is provided on the inner wall of the test box 1. The slide 12 is a prior art and will not be described in detail here. The slide 12 is slidably connected to the first sliding beam 13 and the second sliding beam 14. The first sliding beam 13 and the second sliding beam 14 are respectively equipped with walking devices, which can drive the corresponding first sliding beam 13 or the second sliding beam 14 to move back and forth horizontally along the slide 12.

[0027] The first sliding beam 13 is provided with an unsaturated frozen soil layer making device, and the second sliding beam 14 is provided with a test assembly 6. When in use, the unsaturated frozen soil layer making device is used to make a frozen soil layer 3 in the test box 1, and the frozen soil layer 3 simulates an unsaturated frozen soil roadbed, and at the same time, an optical fiber sensor 31 is buried in the frozen soil layer 3. The test assembly 6 is used to test the effective stress of the frozen soil layer 3.

[0028] See also Figure 6 As a preferred embodiment of the present invention, the test assembly 6 includes a sleeve 61, which slides back and forth on the second sliding beam 14. A hydraulic cylinder 62 is installed on one side of the sleeve 61. The telescopic end of the hydraulic cylinder 62 is vertically downwardly arranged and fixedly connected to the extrusion test wheel group. The extrusion test wheel group includes a fixed block 60, which is installed on the telescopic end of the hydraulic cylinder 62. The lower side of the fixed block 60 is fixedly connected to the wheel frame 63, and the wheel frame 63 is rotatably connected to the extrusion wheel 64. A strain gauge pressure sensor 65 is installed on one side of the fixed block 60. The telescopic end of the hydraulic cylinder 62 is fixedly connected to the ring 67 through the inclined beam 66, and multiple radars are installed below the ring 67. When testing the frozen soil layer 3, the hydraulic cylinder 62 pushes the extrusion test wheel group downward, so that the extrusion wheel 64 generates pressure on the frozen soil layer 3, and the strain type pressure sensor 65 can measure the pressure of the frozen soil layer 3. The frozen soil layer 3 may or may not be deformed after being subjected to the pressure of the extrusion wheel 64. The second sliding beam 14 is driven to move by the walking device, so that the extrusion wheel 64 moves on the frozen soil layer 3, thereby testing the stress deformation of the frozen soil layer 3. The pressure of the extrusion wheel 64 on the frozen soil layer 3 is adjustable. When the extrusion wheel 64 moves forward, the radar under the ring 67 can detect the deformation of the frozen soil layer 3 around the extrusion wheel 64, while the frozen soil layer 3 under the extrusion wheel 64 is blocked by the extrusion wheel 64 and cannot be detected by the radar. Therefore, a bracket 68 is fixedly connected to one side of the wheel frame 63, and a paintbrush 69 is installed on one side of the bracket 68. A drawing board 9 is installed on the inner wall of the test box 1, and the paintbrush 69 is in contact with the drawing board 9. During the process of the extrusion wheel 64 moving forward, the drawing brush 69 will draw a line on the drawing board 9. If the frozen soil layer 3 sinks and deforms, the extrusion wheel 64 will inevitably move up and down, so that a deformation curve diagram below the extrusion wheel 64 can be drawn on the drawing board 9. The position of the extrusion wheel 64 can be changed by the reciprocating sliding of the sliding sleeve 61 on the second sliding beam 14, so as to test different positions of the frozen soil layer 3. At the same time, the temperature in the test box 1 can also be changed during the test process, so as to obtain the influence of temperature on the effective stress of the unsaturated frozen soil foundation.

[0029] See also Figure 3-Figure 5 As a preferred embodiment of the present invention, the unsaturated frozen soil layer making device includes a laying device 5 and a rolling device 4, and the laying device 5 and the rolling device 4 are both installed on the first sliding beam 13. The laying device 5 includes an elastic hanger, and the elastic hanger includes a first hanging plate 43 and a second hanging plate 49. One side of the first hanging plate 43 is fixedly connected to the first flat plate 44, and one side of the second hanging plate 49 is fixedly connected to the second flat plate 47. The guide rod 45 is slidably connected in the center hole of the second flat plate 47. The upper end of the guide rod 45 is fixed to the first flat plate 44, and the lower end of the guide rod 45 is fixedly connected to the supporting plate 46. A spring 48 is fixedly connected between the supporting plate 46 and the second flat plate 47, and a vibration motor 40 is installed on one side of the second hanging plate 49. One side of the second hanging plate 49 is fixedly connected to the material barrel 51, and a discharge port 52 is provided at the bottom of the material barrel 51. The material barrel 51 is rotatably connected to the inner barrel 53. Three cross-arranged partitions 54 are provided in the inner barrel 53. The three partitions 54 divide the inner barrel 53 into a large-grain frozen soil bin, a small-grain frozen soil bin and an ice grain bin. The inner barrel 53 is provided with three openings corresponding to the large-grain frozen soil bin, the small-grain frozen soil bin and the ice grain bin. Each opening is provided with a corresponding filter 55. A motor 56 is installed on one side of the elastic hanger, and the motor 56 is used to drive the inner barrel 53 to rotate. During the rotation of the inner barrel 53, large-grain frozen soil, small-grain frozen soil and ice grains fall evenly and slowly from the discharge port 52 and are rolled by the rolling device 4 to form a frozen soil layer 3. A nozzle 57 is provided on one side of the discharge port 52. When large frozen soil particles, small frozen soil particles and ice particles fall, water mist is sprayed through the nozzle 57, so that water mist is formed on the surface of the large frozen soil particles and small frozen soil particles, which is equivalent to wrapping a layer of skeleton or ice crystals around the outside of the large frozen soil particles and small frozen soil particles, so that the frozen soil roadbed can be better simulated.

[0030] The rolling device 4 includes a swing beam 41, which is hinged to the first sliding beam 13, and one end of the swing beam 41 is fixedly connected to a roller frame 42, which is rotatably connected to a rolling roller 431. The rolling can be performed by the self-gravity of the rolling roller 431 and the swing beam 41. Of course, an electric telescopic rod can be hinged between the swing beam 41 and the first sliding beam 13, and the rolling roller 431 can generate a rolling force on the large-grain frozen soil and the small-grain frozen soil through the electric telescopic rod.

[0031] The invention also discloses a method for testing the effective stress of unsaturated frozen soil, and adopts the above-mentioned testing device to test the effective stress of the unsaturated frozen soil roadbed.

[0032] In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "up", "down", "left", "right", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0033] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An unsaturated frozen soil effective stress testing device, comprising a test box (1), wherein a box cover (11) is provided on one side of the test box (1), and wherein: A horizontally arranged slideway (12) is provided on the inner wall of the test box (1), a first sliding beam (13) and a second sliding beam (14) are slidably connected on the slideway (12), an unsaturated frozen soil layer making device is installed on the first sliding beam (13), a test assembly (6) is installed on the second sliding beam (14), the test assembly (6) comprises a sliding sleeve (61), the sliding sleeve (61) slides back and forth on the second sliding beam (14), a hydraulic cylinder (62) is installed on one side of the sliding sleeve (61), the telescopic end of the hydraulic cylinder (62) is vertically arranged downward and fixedly connected to an extrusion test wheel group, a strain gauge pressure sensor (65) is installed on one side of the extrusion test wheel group, a bracket (68) is installed on one side of the extrusion test wheel group, a paintbrush (69) is installed on one side of the bracket (68), a drawing board (9) is installed on the inner wall of the test box (1), and the paintbrush (69) is in contact with the drawing board (9); The extrusion test wheel assembly comprises a fixed block (60), the fixed block (60) being mounted on the telescopic end of the hydraulic cylinder (62), the lower side of the fixed block (60) being fixedly connected to a wheel frame (63), the wheel frame (63) being rotatably connected to an extrusion wheel (64), and the strain gauge pressure sensor (65) being mounted on one side of the fixed block (60); The telescopic end of the hydraulic cylinder (62) is fixedly connected to a circular ring (67) via a cable-stayed beam (66), and a plurality of radars are installed below the circular ring (67).

2. The unsaturated frozen soil effective stress testing device according to claim 1, characterized in that: The unsaturated frozen soil layer making device comprises a laying device (5) and a rolling device (4), and the laying device (5) and the rolling device (4) are both installed on the first sliding beam (13).

3. The unsaturated frozen soil effective stress testing device according to claim 2, characterized in that: The laying device (5) comprises an elastic hanger, one side of the elastic hanger is fixedly connected to a material barrel (51), a discharge port (52) is provided at the bottom of the material barrel (51), large frozen soil particles, small frozen soil particles and ice particles are placed in the material barrel (51), and the large frozen soil particles, small frozen soil particles and ice particles fall from the discharge port (52) and are rolled by the rolling device (4) to form a frozen soil layer (3).

4. The unsaturated frozen soil effective stress testing device according to claim 3, characterized in that: An optical fiber sensor (31) is buried in the frozen soil layer (3).

5. The unsaturated frozen soil effective stress testing device according to claim 3, characterized in that: The material barrel (51) is rotatably connected to the inner barrel (53), and three cross-arranged partitions (54) are provided in the inner barrel (53). The three partitions (54) divide the inner barrel (53) into a large-grain frozen soil bin, a small-grain frozen soil bin, and an ice grain bin. The inner barrel (53) is provided with three openings corresponding to the large-grain frozen soil bin, the small-grain frozen soil bin, and the ice grain bin. A motor (56) is installed on one side of the elastic hanger, and the motor (56) is used to drive the inner barrel (53) to rotate.

6. The unsaturated frozen soil effective stress testing device according to claim 3, characterized in that: The elastic hanger comprises a first hanger plate (43) and a second hanger plate (49), one side of the first hanger plate (43) is fixedly connected to the first flat plate (44), one side of the second hanger plate (49) is fixedly connected to the second flat plate (47), a guide rod (45) is slidably connected in the center hole of the second flat plate (47), the upper end of the guide rod (45) is fixedly connected to the first flat plate (44), the lower end of the guide rod (45) is fixedly connected to the supporting plate (46), a spring (48) is fixedly connected between the supporting plate (46) and the second flat plate (47), and a vibration motor (40) is installed on one side of the second hanger plate (49).

7. The unsaturated frozen soil effective stress testing device according to claim 2, characterized in that: The rolling device (4) comprises a swing beam (41), the swing beam (41) being hinged to the first sliding beam (13), one end of the swing beam (41) being fixedly connected to a roller frame (42), and a rolling roller (431) being rotatably connected inside the roller frame (42).

8. A method for testing effective stress of unsaturated frozen soil, characterized in that: The effective stress of an unsaturated frozen soil roadbed is tested using the testing device as described in any one of claims 1 to 7.

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