Variable head permeability coefficient indoor determination test device

Abstract

The utility model relates to a variable head permeability coefficient indoor determination test device. The device comprises a permeation container and a water supply tank which are connected together, the permeation container comprises an organic glass tank with an organic glass upper cover; an upper permeable stone and a lower permeable stone arranged on the supporting baffle are arranged in the organic glass tank, and a soil sample is placed between the upper permeable stone and the lower permeable stone; an organic glass cushion block is arranged between the organic glass upper cover and the upper permeable stone; a group of upper water outlets are formed in the upper part of the organic glass tank, and a lower water outlet and a lower water inlet are respectively formed in the lower part; the lower water inlet is connected with a water supply tank through a silicone tube, and the silicone tube is connected with a water inlet and a water outlet which are formed in the bottom of the variable water head tube; the bottom of the variable water head pipe is placed on the weighing sensor; a plurality of moisture sensors and a plurality of pore water pressure sensors are uniformly distributed on the outer wall of the organic glass tank; and the weighing sensor, the moisture sensor and the pore water pressure sensor are all connected with a data acquisition instrument. According to the utility model, the permeability coefficient of a large-scale sample can be accurately measured.

Description

Technical Field

[0001] The utility model relates to the field of geotechnical tests, in particular to an indoor test device for measuring variable water head permeability coefficient. Background Art

[0002] The flow of water in the pores of rock and soil is called soil permeability. Permeability is an important engineering property of soil, which determines the strength and deformation of soil. Soil permeability can cause a series of stability problems of rock and soil, such as slope instability, slope deformation, debris flow, foundation deformation, and lava permeation collapse. Permeability coefficient is a basic indicator to measure the permeability characteristics of rock and soil, which indicates the difficulty of fluid passing through the pore skeleton. The indoor test device for measuring permeability coefficient is a common scientific test device in disciplines such as soil mechanics, hydrogeology, and engineering geology.

[0003] At present, there are many types of instruments and test methods for measuring the permeability coefficient k in the laboratory, but from the test principle, they can be roughly divided into two types: "constant head method" and "variable head method". The constant head method is suitable for measuring the permeability coefficient of coarse-grained soil with high permeability, while for fine-grained (silt and clay) soil, due to low permeability, the variable head test must be used when testing the permeability coefficient of the soil. The main component of the permeability container of the commonly used variable head test device is a ring knife with an inner diameter of 61.8mm and a height of 40mm, which has a small capacity. In fact, natural original soil is anisotropic and has a certain structure. Therefore, the permeability coefficient measured by the variable head permeability test of small-scale samples has a certain error compared with the natural original soil. In addition, for fine-grained clay soil, due to the slow infiltration of water, when conducting a permeability test, the traditional method of visually reading the water level change is used, and the reading error is large, resulting in inaccurate permeability coefficient of the tested sample, and manual measurement is time-consuming and laborious.

[0004] Chen Shihua et al. (Automatic reading test device for geotechnical variable water head permeability test CN106153523B) realizes automatic water replenishment of the variable water head permeability device by installing a water supply tee on the bottom plate and a solenoid valve connected to the lower end of the water supply pipe to form a water adding mechanism; the water head is automatically read through the reading mechanism connected to the water adding mechanism. However, there are two shortcomings in this device: 1. The preliminary debugging steps of the reading mechanism are relatively cumbersome; 2. The soil sample permeameter still uses the traditional ring knife container. Cheng Chen et al. (A soil sample variable water head permeability test device CN112697678A) changes the previous single-direction water inlet to an annular water inlet by opening a plurality of branch water inlet holes connecting the annular water inlet cavity and the water collection cavity on the inner wall of the water collection base. After the water enters the water collection cavity, it can evenly enter the test soil sample under the action of the water head pressure, thereby avoiding the penetration damage to the soil sample caused by the concentrated water flow, but the applicability to larger-scale soil samples is still not considered. He Gao et al. (A variable head multifunctional infiltration experimental device CN113640187A) realized the infiltration test of the original soil by adding a soil column inlay system and a rainfall simulation system, and realized the self-circulation of the test water by adding a water pump. However, the rainfall simulation device will bring additional scouring force to the soil column sample, change the soil structure, and cause a large error in the measured soil permeability coefficient. In addition, the equipment also has problems such as the large space occupied by the test device and the small capacity of the infiltration container.

[0005] In summary, most of the existing variable head permeability test devices are concentrated on small soil sample tests, and the data can only be read by visual inspection. The permeability coefficient calculated in this way has a certain error, and the moisture at different heights of the sample cannot be tested during the test. Utility Model Content

[0006] The technical problem to be solved by the utility model is to provide a variable water head permeability coefficient indoor measurement test device which can realize accurate measurement of the permeability coefficient of a sample with a larger scale.

[0007] In order to solve the above problems, the utility model discloses a variable head permeability coefficient indoor determination test device, which is characterized in that: the device comprises a permeation container and a water supply box connected together; the permeation container comprises a plexiglass tank with a plexiglass upper cover; the plexiglass tank is provided with an upper permeable stone and a lower permeable stone placed on a supporting baffle, and a soil sample is placed between the upper permeable stone and the lower permeable stone; a plexiglass pad is provided between the plexiglass upper cover and the upper permeable stone; an annular sealing rubber ring I is provided between the upper permeable stone and the plexiglass tank, and a plexiglass gasket is provided between the annular sealing rubber ring I and the plexiglass upper cover; the plexiglass gasket is provided on the Drain holes are arranged; an annular sealing rubber ring II is arranged between the lower permeable stone and the organic glass tank; a group of upper drain ports are symmetrically arranged on the upper part of the organic glass tank, and a lower drain port and a lower water inlet are respectively arranged on the lower part; the lower water inlet is connected to the water supply tank through a silicone tube, and the silicone tube is respectively connected to the water inlet and the drain port arranged at the bottom of the variable head pipe; the bottom of the variable head pipe is placed on a weighing sensor; a plurality of moisture sensors and a plurality of pore water pressure sensors are evenly arranged on the outer wall of the organic glass tank between the upper permeable stone and the lower permeable stone; the weighing sensor, the moisture sensor and the pore water pressure sensor are all connected to a data acquisition instrument.

[0008] The water supply box is connected to the water supply pipe.

[0009] The organic glass spacer is located at the center of the upper permeable stone.

[0010] A group of upper drainage ports are arranged on the tank body of the organic glass tank above the upper permeable stone, and the positions of the upper drainage ports and the drainage holes arranged on the organic glass gasket are consistent.

[0011] A group of upper drain outlets are respectively provided with a water stop clamp I and a water stop clamp II.

[0012] The lower drain port and the lower water inlet are symmetrically arranged on the tank body of the organic glass tank below the lower permeable stone, and the positions of the lower drain port and the lower water inlet are consistent with the positions of the reserved holes arranged on the supporting baffle.

[0013] A water stop clamp III is provided on the lower drain outlet.

[0014] The silicone tube is respectively provided with a water stop clamp IV, a water stop clamp V and a water stop clamp VI.

[0015] The organic glass tank is provided with a sensor hole, through which the moisture sensor and the pore water pressure sensor are inserted.

[0016] Compared with the prior art, the utility model has the following advantages:

[0017] 1. The permeation container in the utility model comprises an organic glass jar with an organic glass upper cover, and the bottom of the organic glass jar is provided with a supporting baffle. Not only does the permeation container have a large capacity, but it also has good sealing and heat preservation properties, so that the measured permeability coefficient is closer to the "true value".

[0018] 2. The utility model arranges sensor holes on the organic glass tank, through which moisture sensors and pore water pressure sensors are inserted, so as to test the change of moisture at different sample heights over time during the penetration test.

[0019] 3. In the utility model, an organic glass pad is provided between the organic glass upper cover and the upper permeable stone, an annular sealing rubber ring Ⅰ is provided between the upper permeable stone and the organic glass tank 1, and an organic glass gasket is provided between the annular sealing rubber ring Ⅰ and the organic glass upper cover. By screwing the organic glass upper cover, the annular sealing rubber ring Ⅰ and the upper permeable stone can be fully contacted to increase the sealing performance. At the same time, the pressure transmitted by the upper permeable stone can be fully contacted with the surface of the soil sample through the organic glass pad.

[0020] 4. The utility model is provided with a weighing sensor, which is connected to a data acquisition instrument to realize the function of automatically measuring and reading the data of water head changes over time, thereby reducing labor and saving time and effort.

[0021] 5. The utility model has good sealing performance and is simple and convenient to operate. It can successfully solve the system error caused by the small volume of the soil sample, thereby realizing the accurate determination of the permeability coefficient of larger-scale samples. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The specific implementation of the utility model is further described in detail below with reference to the accompanying drawings.

[0023] Figure 1 It is a schematic diagram of the utility model.

[0024] Figure 2 It is a top view of the permeation container in the utility model.

[0025] Figure 3 This is a detailed diagram of the glass upper cover in the present invention.

[0026] In the figure: 1—plexiglass jar; 2—plexiglass upper cover; 3—plexiglass pad; 4—plexiglass gasket; 5—upper drain outlet; 6—upper permeable stone; 7—annular sealing rubber ring Ⅰ; 8—water sensor; 9—pore water pressure sensor; 10—lower permeable stone; 11—annular sealing rubber ring Ⅱ; 121—water stop clamp Ⅰ; 122—water stop clamp Ⅱ; 123—water stop clamp Ⅲ; 124—water stop clamp Ⅳ; 125—water stop clamp Ⅴ; 126—water stop clamp Ⅵ; 13—lower drain outlet; 14—lower water inlet; 15—support baffle; 16—soil sample; 17—weighing sensor; 18—water inlet; 19—drain outlet; 20—variable head pipe; 21—water supply tank; 22—water supply pipe; 23—silicone tube. DETAILED DESCRIPTION

[0027] like Figures 1 to 3 As shown, a variable head permeability coefficient indoor determination test device comprises a permeation container and a water supply box 21 connected together. The permeation container comprises an organic glass tank 1 with an organic glass upper cover 2; an upper permeable stone 6 and a lower permeable stone 10 placed on a supporting baffle 15 are arranged in the organic glass tank 1, and a soil sample 16 is placed between the upper permeable stone 6 and the lower permeable stone 10; an organic glass pad 3 is arranged between the organic glass upper cover 2 and the upper permeable stone 6; an annular sealing rubber ring Ⅰ7 is arranged between the upper permeable stone 6 and the organic glass tank 1, and an organic glass gasket 4 is arranged between the annular sealing rubber ring Ⅰ7 and the organic glass upper cover 2; drainage holes are arranged on the organic glass gasket 4; an annular sealing rubber ring Ⅱ11 is arranged between the lower permeable stone 10 and the organic glass tank 1; A group of upper drain outlets 5 are symmetrically provided on the upper part of the organic glass tank 1, and a lower drain outlet 13 and a lower water inlet 14 are respectively provided on the lower part; the lower water inlet 14 is connected to the water supply tank 21 through a silicone tube 23, and the silicone tube 23 is respectively connected to the water inlet 18 and the drain outlet 19 arranged at the bottom of the variable head pipe 20; the bottom of the variable head pipe 20 is placed on the weighing sensor 17; a plurality of moisture sensors 8 and a plurality of pore water pressure sensors 9 are evenly distributed on the outer wall of the organic glass tank 1 between the upper permeable stone 6 and the lower permeable stone 10; the weighing sensor 17, the moisture sensor 8 and the pore water pressure sensor 9 are all connected to the data acquisition instrument.

[0028] Wherein: the water supply box 21 is connected to the water supply pipe 22, and water is supplied through the water supply pipe 22.

[0029] The organic glass spacer 3 is located at the center of the upper permeable stone 6.

[0030] A set of upper drainage ports 5 is arranged on the tank body of the organic glass tank 1 above the upper permeable stone 6 , and the positions of the upper drainage ports 5 and the drainage holes arranged on the organic glass gasket 4 are consistent.

[0031] A set of upper drain outlets 5 are respectively provided with a water stop clamp Ⅰ 121 and a water stop clamp Ⅱ 122 .

[0032] The lower drain port 13 and the lower water inlet 14 are symmetrically arranged on the tank body of the organic glass tank 1 below the lower permeable stone 10 , and the positions of the lower drain port 13 and the lower water inlet 14 are consistent with the positions of the reserved holes arranged on the supporting baffle 15 .

[0033] A water stop clamp III 123 is provided on the lower drain outlet 13 .

[0034] The silicone tube 23 is provided with a water stop clamp IV 124 , a water stop clamp V 125 , and a water stop clamp VI 126 , respectively.

[0035] The organic glass jar 1 is provided with sensor holes, through which the moisture sensor 8 and the pore water pressure sensor 9 are inserted.

[0036] The weighing sensor 17 is used to measure the change of water head in real time.

[0037] All interface connections are sealed with glue.

[0038] The method of using the utility model is as follows:

[0039] First, vaseline is evenly applied on the inner wall of the plexiglass jar 1 to enhance the sealing between the soil and the inner wall. Then, the lower permeable stone 10 is placed on the upper edge of the bottom support baffle 15 of the plexiglass jar 1, and the lower permeable stone 10 is tightly fitted to the interior of the plexiglass jar 1 with an annular sealing rubber ring Ⅱ11.

[0040] Then, the soil sample 16 is compacted in layers and loaded into the organic glass tank 1, and the upper permeable stone 6 is placed on the upper surface of the sample, and the annular sealing rubber ring Ⅰ7 is used for sealing; and the organic glass gasket 4 is placed on the annular sealing rubber ring Ⅰ7, and the organic glass upper cover 2 is screwed and pressed, so that the annular sealing rubber ring Ⅰ7 is in close contact with the upper permeable stone 6 through the pressure transmitted by the organic glass gasket 4, thereby increasing its sealing performance. In addition, when the organic glass upper cover 2 is screwed and pressed, the upper permeable stone 6 can be fully in contact with the upper surface of the soil sample 16 through the pressure transmitted by the organic glass pad 3, until the upper surface height of the upper permeable stone 6 is consistent with the bottom of the upper drain port 5, so that the water that seeps out can be discharged smoothly.

[0041] Secondly, after the sample is installed, open water-stop clamp IV124 and water-stop clamp III123, and close water-stop clamp I121, water-stop clamp II122, water-stop clamp V125, and water-stop clamp VI126, so that the water in the water supply tank 21 flows along the silicone tube 23 into the bottom of the plexiglass jar 1 until water flows out of the lower drain port 13 (mainly to exhaust the air at the bottom of the plexiglass jar 1), and then close water-stop clamp IV124 and water-stop clamp III123.

[0042] Finally, open water stop clamp VI 126, and inject the water in the water supply tank 21 into the variable head pipe 20. After the water level in the pipe stabilizes, close water stop clamp VI 126, and open water stop clamps V125, I121, and II122 to start the penetration experiment. After the water flows out of the upper drain outlet 5, start recording the value of the weighing sensor 17.

Claims

1. A variable head permeability coefficient indoor test device, characterized in that: The device comprises an infiltration container and a water supply box (21) connected together; the infiltration container comprises an organic glass tank (1) with an organic glass upper cover (2); an upper permeable stone (6) and a lower permeable stone (10) placed on a supporting baffle (15) are arranged in the organic glass tank (1); a soil sample (16) is placed between the upper permeable stone (6) and the lower permeable stone (10); an organic glass pad (3) is arranged between the organic glass upper cover (2) and the upper permeable stone (6); an annular sealing rubber ring I (7) is arranged between the upper permeable stone (6) and the organic glass tank (1); an organic glass gasket (4) is arranged between the annular sealing rubber ring I (7) and the organic glass upper cover (2); a drainage hole is arranged on the organic glass gasket (4); a drainage hole is arranged between the lower permeable stone (10) and the organic glass tank (1 ... An annular sealing rubber ring II (11) is provided; a group of upper drain ports (5) are symmetrically provided on the upper part of the organic glass tank (1), and a lower drain port (13) and a lower water inlet (14) are provided on the lower part; the lower water inlet (14) is connected to the water supply box (21) via a silicone tube (23), and the silicone tube (23) is respectively connected to the water inlet (18) and the drain port (19) provided at the bottom of the variable water head tube (20); the bottom of the variable water head tube (20) is placed on the weighing sensor (17); a plurality of moisture sensors (8) and a plurality of pore water pressure sensors (9) are uniformly distributed on the outer wall of the organic glass tank (1) between the upper permeable stone (6) and the lower permeable stone (10); the weighing sensor (17), the moisture sensor (8) and the pore water pressure sensor (9) are all connected to a data acquisition instrument.

2. A variable head permeability indoor test device as claimed in claim 1, characterized in that: The water supply box (21) is connected to the water supply pipe (22).

3. A variable head permeability coefficient indoor measurement test device as claimed in claim 1, characterized in that: The organic glass spacer (3) is located at the center of the upper permeable stone (6).

4. A variable head permeability coefficient indoor measurement test device as claimed in claim 1, characterized in that: A group of upper drainage ports (5) are arranged on the tank body of the organic glass tank (1) above the upper permeable stone (6), and the positions of the upper drainage ports (5) and the drainage holes arranged on the organic glass gasket (4) are consistent.

5. A variable head permeability indoor test device as claimed in claim 1 or 4, characterized in that: A set of upper drain outlets (5) are provided with a water stop clamp I (121) and a water stop clamp II (122), respectively.

6. The variable head permeability coefficient indoor test device according to claim 1, characterized in that: The lower drain port (13) and the lower water inlet (14) are symmetrically arranged on the tank body of the organic glass tank (1) below the lower permeable stone (10), and the positions of the lower drain port (13) and the lower water inlet (14) are consistent with those of the reserved holes arranged on the supporting baffle (15).

7. A variable head permeability coefficient indoor measurement test device as claimed in claim 1 or 6, characterized in that: A water stop clamp III (123) is provided on the lower drain outlet (13).

8. The variable head permeability coefficient indoor test device according to claim 1, characterized in that: The silicone tube (23) is provided with a water stop clamp IV (124), a water stop clamp V (125), and a water stop clamp VI (126), respectively.

9. The variable head permeability coefficient indoor test device according to claim 1, characterized in that: The organic glass tank (1) is provided with a sensor hole, through which the moisture sensor (8) and the pore water pressure sensor (9) are inserted.

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