A model barrel device for indoor vacuum preloading model test

Abstract

A model barrel device for indoor vacuum preloading model test comprises a barrel cover, a bottom plate and a model barrel body made of transparent material, wherein the upper and lower ports of the model barrel body are respectively provided with a first flange and a second flange, the first flange is connected to the barrel cover, and the second flange is sealed and connected to the bottom plate; the bottom plate and the model barrel body form a cavity for accommodating soil; a vacuum membrane is provided at the upper end of the model barrel body, and the outer edge of the vacuum membrane is pressed between the first flange and the barrel cover; a vacuum gauge hole, a pore water pressure sensor hole and a vacuum pump connecting pipe hole are penetrated through the upper wall of the model barrel body, and a first rubber plug and a second rubber plug are respectively provided in the vacuum gauge hole and the pore water pressure sensor hole, and a vacuum probe and a pore water pressure sensor are respectively inserted from the outside; a drain plate, a vacuum probe and a pore water pressure sensor are provided in the soil body, and the drain plate is connected to a vacuum pumping system through a steel hose. The present invention adopts the form of vacuuming by opening holes on the side, thereby improving the accuracy of test data.

Description

Technical Field

[0001] The invention relates to the technical field of vacuum preloading in soft foundation treatment, and in particular to a model barrel device used for indoor vacuum preloading model test. Background Art

[0002] With the development of the national economy, in some coastal economically developed areas, the amount of land use continues to rise, and the contradiction between land supply and demand is prominent. Using artificially reclaimed sea mud as land is an effective way to alleviate the shortage of land resources. However, the foundation formed by the fill soil has unfavorable engineering characteristics such as high water content, high compressibility, certain fluidity and elasticity, and almost no bearing capacity. Reinforcement measures are required to meet the needs of subsequent engineering construction. As an effective method for treating soft soil foundations, the vacuum preloading method is to build a vertical drainage board in the soft clay, lay a sand layer on it, cover it with a geomembrane for sealing, and use a vacuum system to discharge the moisture in the soil to consolidate the soil.

[0003] When conducting a vacuum preloading model test indoors, the drain plate is connected to the external vacuum system through a hand-shaped joint and a steel hose. During the vacuuming process, the negative pressure generated by the vacuum pump discharges the water in the soil, the soil is consolidated, and the discharged water is collected by a water vapor separation bottle. When the sample soil is vacuumed, the air tightness of the model barrel will directly affect the subsequent test and the accuracy of the collected data. The model barrels used in traditional indoor vacuum preloading model tests are generally plastic model barrels or iron barrels, which are not conducive to test observations, and the sensors, vacuum probes, and vacuum tubes are introduced into the model barrel by breaking the membrane at the top. This top membrane breaking method is complicated to implement, and improper operation will cause leakage in the model barrel, causing great errors in the test results. Summary of the invention

[0004] In order to overcome the above problems, the present invention provides a model barrel device suitable for indoor vacuum preloading model test.

[0005] The technical scheme adopted by the present invention is: a model barrel device for indoor vacuum preloading model test, comprising a circular barrel cover 10, a circular plate-shaped bottom plate 11 and a cylindrical model barrel body 1 made of a transparent material, the upper end of the model barrel body 1 is provided with a first flange 3a facing outwards, and the first flange 3a is fixedly connected to the barrel cover 10 by a first fastening bolt 13a; the lower end of the model barrel body 1 is provided with a second flange 3b facing outwards, and the second flange 3b is fixedly connected to the bottom plate 11 by a second fastening bolt 13b; the model barrel body 1 and the bottom plate 11 are enclosed to form a cavity for accommodating soil, and the soil is covered with a geotextile; a first sealing gasket 5a is provided between the first flange 3a and the barrel cover 10, and a second sealing gasket 5b is provided between the second flange 3b and the bottom plate 11; a first fixed triangular support 2a is provided between the first flange 3a and the model barrel body 1, and a second fixed triangular support 2b is provided between the second flange 3b and the model barrel body 1;

[0006] The upper end of the model barrel body 1 is covered with a vacuum film, and the outer edge of the vacuum film is pressed between the first flange 3a and the barrel cover 10; the upper wall surface of the model barrel body 1 is penetrated by a vacuum gauge hole 7, a pore water pressure sensor hole 8 and a vacuum pump connecting pipe hole 6;

[0007] A first reinforcing ring 9a is provided at the outer end of the vacuum pump connecting pipe hole 6, and an inlet and outlet water pipe 14 is provided in the vacuum pump connecting pipe hole 6, and one inner end of the inlet and outlet water pipe 14 is connected to a steel wire hose 16, and one outer end of the inlet and outlet water pipe 14 is connected to a vacuum system; a drain board bracket 20 is provided on the upper surface of the bottom plate 11, and a drain board 19 is vertically fixed on the drain board bracket 20 and buried in the soil; a hand-shaped joint 18 is provided at the top of the drain board 19, and the hand-shaped joint 18 is connected to the steel wire hose 16; the drain board 19 is connected to the vacuum system through the hand-shaped joint 18 and the steel wire hose 16;

[0008] A second reinforcing ring 9b is provided at the outer end of the vacuum gauge hole 7, and a first rubber plug 15a is tightly arranged in the vacuum gauge hole 7. The first rubber plug 15a is penetrated by a first fine hole, and a vacuum probe is inserted from the outside through the first fine hole, and the vacuum probe is buried in the soil;

[0009] A third reinforcing ring 9c is provided at the outer end of the pore water pressure sensor hole 8, a second rubber plug 15b is tightly arranged in the pore water pressure sensor hole 8, a second fine hole is penetrated by the second rubber plug 15b, a pore water pressure sensor is inserted into the second fine hole from the outside, and the pore water pressure sensor is buried in the soil;

[0010] A scale 12 for recording soil displacement changes is provided on the outer wall of the model barrel 1; a displacement sensor fixing bracket 21 is provided on the upper surface of the barrel cover 10, and an LVDT displacement sensor for fixing and measuring soil displacement changes is provided on the displacement sensor fixing bracket.

[0011] Furthermore, the number of the pore water pressure sensor holes 8 is 5, and the number of the vacuum gauge holes 7 is 2; the pore water pressure sensor holes 8 and the vacuum gauge holes 7 are arranged in an array on the upper wall of the model barrel body 1.

[0012] Furthermore, a first clamp 17 is provided at the connection between the hand-shaped connector 18 and the steel hose 16 , and is tightened by the first clamp 17 .

[0013] The beneficial effects of the present invention are:

[0014] 1. The model barrel is made of plexiglass and is one-piece injection molded to facilitate test observation.

[0015] 2. This model barrel adopts the form of vacuum extraction with side openings, which can effectively solve the leakage problem caused by the film coming out of the top of the pipeline during the traditional indoor vacuum pre-pressure test. It has better air tightness and improves the accuracy of the test.

[0016] 3. The test device has a simple structure and is relatively easy to operate. The model barrel can be reused, which effectively improves the working efficiency of vacuum preloading. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is the front view of the present invention.

[0018] Figure 2 It is a left side view of the present invention.

[0019] Figure 3 It is a schematic diagram of the internal structure of the present invention.

[0020] Figure 4 It is a top view of the present invention.

[0021] Figure 5 It is a structural schematic diagram of a barrel cover of the present invention.

[0022] Figure 6 It is a structural schematic diagram of the base plate of the present invention.

[0023] Figure 7 It is a schematic diagram of the structure of the pore water pressure sensor hole of the present invention.

[0024] Figure 8 It is a structural schematic diagram of the vacuum pump connecting pipe hole of the present invention.

[0025] Explanation of the reference numerals: 1. Model barrel body; 2a. First fixed triangular support; 2b. Second fixed triangular support; 3a. First flange; 3b. Second flange; 4a. First bolt hole; 4b. Second bolt hole; 5a. First sealing gasket; 5b. Second sealing gasket; 6. Vacuum pump connecting pipe hole; 7. Vacuum gauge hole; 8. Pore water pressure sensor hole; 9a. First reinforcement ring; 9b. Second reinforcement ring; 9c. Third reinforcement ring; 10. Barrel cover; 11. Bottom plate; 12. Scale; 13a. First fastening bolt; 13b. Second fastening bolt 14. Inlet and outlet water pipes; 15a. First rubber plug; 15b. Second rubber plug; 16. Steel wire hose; 17. First clamp; 18. Hand-shaped joint; 19. Drain board; 20. Drain board bracket; 21. Displacement sensor fixing bracket. DETAILED DESCRIPTION

[0026] The present invention is further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto:

[0027] Referring to the accompanying drawings, a model barrel device for indoor vacuum preloading model test includes a circular barrel cover 10, a circular plate-shaped bottom plate 11 made of thick steel plate, and a cylindrical model barrel body 1 made of organic glass. The thickness of the model barrel body 1 is 15 mm, the width of the barrel cover 10 is 65 mm, and the upper end of the model barrel body 1 is provided with an outward first flange 3a, and the first flange 3a is provided with 24 first bolt holes 4a with a diameter of 10 mm at positions corresponding to the barrel cover 10; the first bolt holes 4a are distributed at equal intervals along the circumference of the first flange 3a, and the first flange 3a is fixedly connected to the barrel cover 10 by first fastening bolts 13a;

[0028] The lower port of the model barrel body 1 is provided with an outward second flange 3b, and 24 second bolt holes 4b with a diameter of 10 mm are provided at positions corresponding to the second flange 3b and the bottom plate 11. The second bolt holes 4b are evenly spaced along the circumference of the second flange 3b, and the second flange 3b is fixedly connected to the bottom plate 11 by second fastening bolts 13b; the width of the first flange 3a and the second flange 3b are both 50 mm, the thickness of the first flange 3a is 20 mm, and the thickness of the second flange 3b is 30 mm;

[0029] The model barrel body 1 and the bottom plate 11 are enclosed to form a cavity for accommodating soil, and the soil is covered with a geotextile; a first sealing gasket 5a is provided between the first flange 3a and the barrel cover 10, and a second sealing gasket 5b is provided between the second flange 3b and the bottom plate 11; a first fixed triangular support 2a is provided between the first flange 3a and the model barrel body 1, and a second fixed triangular support 2b is provided between the second flange 3b and the model barrel body 1;

[0030] The upper end of the model barrel body 1 is covered with a vacuum film, and the outer edge of the vacuum film is pressed between the first flange 3 and the barrel cover 10; the upper wall of the model barrel body 1 is penetrated by a vacuum gauge hole 7, a pore water pressure sensor hole 8 and a vacuum pump connecting pipe hole 6; the number of the pore water pressure sensor holes 8 is 5, and the number of the vacuum gauge holes 7 is 2; the pore water pressure sensor holes 8 and the vacuum gauge holes 7 are arranged in an array on the upper wall of the model barrel body 1;

[0031] A first reinforcing ring 9a is provided at the outer end of the vacuum pump connecting pipe hole 6, and an inlet and outlet water pipe 14 is provided in the vacuum pump connecting pipe hole 6, and one inner end of the inlet and outlet water pipe 14 is connected to a steel wire hose 16, and one outer end of the inlet and outlet water pipe 14 is connected to a vacuum system; a drain board bracket 20 is provided on the upper surface of the bottom plate 11, and a drain board 19 is vertically fixed on the drain board bracket 20 and buried in the soil; a hand-shaped joint 18 is provided at the top of the drain board 19, and the hand-shaped joint 18 is connected to the steel wire hose 16; a first clamp 17 is provided at the connection between the hand-shaped joint 18 and the steel wire hose 16, and is clamped by the first clamp 17; the drain board 19 is connected to the vacuum system through the steel wire hose 16;

[0032] A second reinforcing ring 9b is provided at the outer end of the vacuum gauge hole 7, and a first rubber plug 15a is tightly arranged in the vacuum gauge hole 7. The first rubber plug 15a is penetrated by a first fine hole, and a vacuum probe is inserted from the outside through the first fine hole, and the vacuum probe is buried in the soil;

[0033] A third reinforcing ring 9c is provided at the outer end of the pore water pressure sensor hole 8, a second rubber plug 15b is tightly arranged in the pore water pressure sensor hole 8, a second fine hole is penetrated by the second rubber plug 15b, a pore water pressure sensor is inserted into the second fine hole from the outside, and the pore water pressure sensor is buried in the soil;

[0034] A scale 12 for recording soil displacement changes is provided on the outer wall of the model barrel body 1; a displacement sensor fixing bracket 21 is provided on the upper surface of the barrel cover 10, and the displacement sensor fixing bracket 21 includes a horizontally arranged plate-like fixing plate and two tubular supporting cylinders vertically arranged in the middle of the plate-like fixing plate. Screw holes are provided at both ends of the displacement sensor fixing bracket 21 at positions corresponding to the first bolt holes 4a on the barrel cover 10, and are fixed by first bolts 13a. An LVDT displacement sensor for fixing and measuring soil displacement changes is provided on the displacement sensor fixing bracket.

[0035] The working steps of this embodiment are:

[0036] Step 1: Check whether the test device, the model barrel device and each component are normal, test whether each sensor is working normally, whether the vacuum membrane is damaged, etc.;

[0037] Step 2: The top of the drain board 19 is connected to the hand-shaped joint 18, and the drain board bracket 20 is set on the bottom plate. The interface between the drain board 19 and the hand-shaped joint 18 and the bottom of the drain board 19 are respectively bonded with AB glue, and the drain board 19 is vertically bound to the drain board bracket 20. Holes are opened on the first rubber plug 15a and the second rubber plug 15b respectively, and the vacuum probe and its connecting wire, the pore water pressure sensor and its data wire are introduced into the model barrel through their corresponding rubber plugs. The vacuum probe and the pore water pressure sensor are respectively fixed on the drain board bracket 20, and the side wall opening is plugged with a rubber plug, and glass glue is used to seal it;

[0038] Step three, an inlet and outlet water pipe 14 is arranged in the vacuum pump connecting pipe hole 6, the inner end of the inlet and outlet water pipe 14 is connected to the hand-shaped joint 18 through the steel hose 16, and the outer end of the inlet and outlet water pipe 14 is connected to the vacuum system through the steel hose 16, and the interfaces of each pipeline are tightened and fixed with a clamp; add a test soil sample, i.e., soil, into the model barrel 1, attach a geotextile on the top of the soil, lay a vacuum membrane with a large enough area on top of the geotextile, place the first sealing gasket 5a on the outer edge of the vacuum membrane, place the barrel cover 10 on the first sealing gasket 5a, arrange the displacement sensor bracket 21 on the barrel cover 10, align with the first bolt hole 4a, first fix the displacement sensor bracket 21 with the first bolt 13a, and then fix the remaining first bolts 13a;

[0039] Step 4: Arrange other test instruments; turn on the vacuum system and start the data acquisition software on the computer. The negative pressure generated by the vacuum system will discharge the water in the soil through the drainage board 19. The pore water pressure and soil settlement of the soil during the vacuum preloading test are obtained through data acquisition, and the changes in the vacuum degree of the soil are recorded.

[0040] The contents described in the embodiments of this specification are merely an enumeration of the implementation forms of the inventive concept. The protection scope of the present invention should not be regarded as limited to the specific forms described in the embodiments. The protection scope of the present invention also extends to equivalent technical means that can be conceived by those skilled in the art based on the inventive concept.

Claims

1. A model barrel device for indoor vacuum preloading model test, characterized in that: The invention comprises a circular barrel cover (10), a circular plate-shaped bottom plate (11) and a cylindrical model barrel body (1) made of a transparent material, wherein the upper end of the model barrel body (1) is provided with a first flange (3a) facing outwards, and the first flange (3a) is fixedly connected to the barrel cover (10) via a first fastening bolt (13a); the lower end of the model barrel body (1) is provided with a second flange (3b) facing outwards, and the second flange (3b) is fixedly connected to the bottom plate (11) via a second fastening bolt (13b); and the model barrel body (1) and the bottom plate (11) are combined to form a cavity for accommodating soil, and the soil is covered with a geotextile; a first sealing gasket (5a) is provided between the first flange (3a) and the barrel cover (10), and a second sealing gasket (5b) is provided between the second flange (3b) and the bottom plate (11); a first fixed triangular support (2a) is provided between the first flange (3a) and the model barrel body (1), and a second fixed triangular support (2b) is provided between the second flange (3b) and the model barrel body (1); The upper end of the model barrel body (1) is covered with a vacuum membrane, and the outer edge of the vacuum membrane is pressed tightly between the first flange (3a) and the barrel cover (10); the upper wall surface of the model barrel body (1) is penetrated by a vacuum gauge hole (7), a pore water pressure sensor hole (8) and a vacuum pump connecting pipe hole (6); A first reinforcing ring (9a) is provided at the outer end of the vacuum pump connecting pipe hole (6), an inlet and outlet water pipe (14) is provided in the vacuum pump connecting pipe hole (6), an inner end of the inlet and outlet water pipe (14) is connected to a steel wire hose (16), and an outer end of the inlet and outlet water pipe (14) is connected to a vacuum pumping system; a drain board bracket (20) is provided on the upper surface of the bottom plate (11), and the drain board (19) is vertically fixed on the drain board bracket (20) and buried in the soil; a hand-shaped joint (18) is provided at the top of the drain board (19), and the hand-shaped joint (18) is connected to the steel wire hose (16); the drain board (19) is connected to the vacuum pumping system through the hand-shaped joint (18) and the steel wire hose (16); A second reinforcing ring (9b) is provided at the outer end of the vacuum gauge hole (7), a first rubber plug (15a) is tightly arranged in the vacuum gauge hole (7), a first fine hole is penetrated through the first rubber plug (15a), a vacuum probe is inserted from the outside through the first fine hole, and the vacuum probe is buried in the soil; A third reinforcing ring (9c) is provided at the outer end of the pore water pressure sensor hole (8), a second rubber plug (15b) is tightly arranged in the pore water pressure sensor hole (8), a second fine hole is penetrated by the second rubber plug (15b), the pore water pressure sensor is inserted into the second fine hole from the outside, and the pore water pressure sensor is buried in the soil; A scale (12) for recording soil displacement changes is provided on the outer wall of the model barrel (1); a displacement sensor fixing bracket (21) is provided on the upper surface of the barrel cover (10); and an LVDT displacement sensor for fixing and measuring soil displacement changes is provided on the displacement sensor fixing bracket (21).

2. A model barrel device for indoor vacuum preloading model test as claimed in claim 1, characterized in that: The number of the pore water pressure sensor holes (8) is 5, and the number of the vacuum gauge holes (7) is 2; the pore water pressure sensor holes (8) and the vacuum gauge holes (7) are arranged in an array on the upper wall surface of the model barrel body (1).

3. A model barrel device for indoor vacuum preloading model test according to claim 1, characterized in that: A first clamp (17) is provided at the connection between the hand-shaped connector (18) and the steel hose (16), and the connection is tightened by the first clamp (17).

Images