A test device and method for testing the permeability of a concrete-rock interface

Abstract

The application discloses a test device for testing the permeability of a concrete-rock interface, which comprises a permeation sample, a water pressure applying device and a measuring system; the permeation sample comprises a rock block and a concrete block poured on the surface of the rock block, a cavity is arranged at the interface between the rock block and the concrete block, and a water guide pipe is arranged in the cavity; the water guide pipe is connected with the water pressure applying device through a water pipe; the measuring system comprises a water meter, a water pressure gauge and a data acquisition instrument; the water meter and the water pressure gauge are arranged on the water pipe respectively, and the data acquisition instrument is connected with the water meter and the water pressure gauge respectively to automatically collect water quantity and water pressure data. The application further discloses a test method for testing the permeability of a concrete-rock interface. The application can make a permeation sample with a concrete-rock interface, collect the seepage flow under different water pressures, and calculate the permeability of the concrete-rock interface.

Description

Technical Field

[0001] This invention relates to a test apparatus and method for testing the permeability of concrete-rock interfaces, belonging to the field of geotechnical engineering technology. Background Technology

[0002] With urbanization, underground space development has become a trend in urban development, leading to a large number of underground buildings. For underground structures located on rock foundations, water seeping from rock fissures will affect the subbase or foundation slab. The permeability of the concrete-rock interface determines the amount of seepage, further affecting the anti-buoyancy measures adopted, and directly and significantly impacting the cost and safety of the underground structure. Existing permeability tests are either specific to rock or specific to concrete, while in actual engineering, the object to be tested is the concrete-rock interface. The permeability of a single rock or a single concrete cannot represent the permeability of the concrete-rock interface.

[0003] In summary, in order to obtain the permeability of the concrete-rock interface and meet the increasing anti-buoyancy requirements of underground structures on rock foundations, there is an urgent need for a permeability testing method and apparatus for the concrete-rock interface. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a test apparatus and method for testing the permeability of the concrete-rock interface, which can produce permeability samples with a concrete-rock interface and calculate the permeability of the concrete-rock interface by collecting seepage flow rates under different water pressures.

[0005] The technical solution of the present invention is as follows: The present invention provides a test device for testing the permeability of concrete-rock interface, including a permeability sample, a water pressure application device and a measurement system;

[0006] The permeation sample includes a rock block and a concrete block poured on the surface of the rock block. A cavity is provided at the interface between the rock block and the concrete block, and a water guide pipe is provided in the cavity.

[0007] The water pipe is connected to the water pressure application device via a water pipe;

[0008] The measurement system includes a water meter, a water pressure gauge, and a data acquisition device. The water meter and water pressure gauge are respectively installed on the water pipe, and the data acquisition device is connected to the water meter and water pressure gauge to automatically collect water volume and water pressure data.

[0009] Furthermore, the water pressure application device includes a sealed tank and an air pump. The internal space of the sealed tank is divided into a water chamber and an air chamber by an air bladder. The water chamber has a water outlet at the bottom, which is connected to a water guide pipe through a water pipe. The air chamber has an air inlet at the top, which is connected to the air pump through an air pipe.

[0010] Furthermore, the water pipe is equipped with a water valve, and the air pipe is equipped with an air valve.

[0011] Furthermore, an air tee is provided between the air inlet and the air pipe, and a pressure gauge is connected to the air tee.

[0012] Furthermore, the cavity at the interface between the rock block and the concrete block is formed by a hemispherical steel filter screen, which is fixed to the upper surface of the rock block by a fixing ring at the bottom; the hemispherical steel filter screen is provided with a waterproof layer to prevent cement slurry from seeping in during concrete pouring.

[0013] Furthermore, the water guide pipe is connected to the water pipe via a water pipe tee, and the water pressure gauge is installed on the water pipe tee.

[0014] Furthermore, the rock block is a flat rock block selected from the engineering site, transported to the laboratory for cutting, and its four sides are cut flat while the upper surface remains in its natural state.

[0015] The present invention also provides a test method for testing the permeability of the concrete-rock interface based on the above-mentioned test apparatus, comprising:

[0016] Water pressure is applied to the cavity at the interface between the rock block and the concrete block using a water pressure application device, so that water flows into the cavity and seeps into the concrete-rock interface.

[0017] The water meter and pressure gauge connected to the data acquisition instrument can measure the seepage volume under different water pressures, thereby calculating and analyzing the permeability of the concrete-rock interface.

[0018] Furthermore, the method of applying water pressure to the cavity at the interface between the rock block and the concrete block using a water pressure application device is as follows: connect a water pipe tee with a water pressure gauge to the upper end of the water pipe, fill the water chamber of the sealed tank with water, connect the water pipe, water meter and sealed tank with a water pipe, and connect the sealed tank to the air pump with an air pipe; evacuate the water pipe and cavity into a vacuum, apply air pressure with the air pump, convert the air pressure into water pressure through the sealed tank, open the water valve, and under the action of water pressure, water flows into the cavity and seeps into the concrete-rock interface.

[0019] Furthermore, once the seepage rate stabilizes under a certain water pressure, the permeability coefficient of the concrete-rock interface under that water pressure can be calculated using the following formula:

[0020]

[0021] In the formula: k is the permeability coefficient of the concrete-rock interface 8, in cm / s; L is the side length of the concrete-rock interface 8, in cm; d is the diameter of the hemispherical steel filter screen 5, in cm; t is the test measurement time after the seepage volume stabilizes, in s; V is the water volume measured by the water meter 2 within the measurement time t, in cm³. 3p is the water pressure measured by the water pressure gauge 10 during the measurement time t, and the unit is kPa.

[0022] The beneficial effects achieved by this invention are as follows:

[0023] 1. The present invention provides a cavity at the interface between the rock block and the concrete block. A water pipe inserted into the cavity can transmit water pressure to the cavity and apply it to the concrete-rock interface, thus producing a permeability sample for the concrete-rock interface.

[0024] 2. The present invention uses a water pressure application device that combines an air pump and a sealed tank. This device can apply water pressure of different magnitudes to obtain the permeability of the concrete-rock interface under different water pressures, and can also prevent gas from entering the water during loading, thus solving the problem of gas affecting permeability. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the test device for testing the permeability of the concrete-rock interface according to the present invention;

[0026] Figure 2 This is a schematic diagram of the rock block structure of the present invention;

[0027] Figure 3 This is a schematic diagram of the hemispherical steel filter screen of the present invention;

[0028] Figure 4 This is a schematic diagram of the casting mold of the present invention;

[0029] Figure 5 This is a schematic diagram of the structure of the permeation sample of the present invention.

[0030] The meanings of the main reference numerals in the figure are as follows:

[0031] 1 – Permeability sample; 2 – Water meter; 3 – Water pressure application device; 4 – Rock block;

[0032] 5 – Hemispherical steel filter screen; 6 – Water guide pipe; 7 – Concrete; 8 – Concrete-rock interface;

[0033] 9 - Water pipe tee; 10 - Water pressure gauge; 11 - Water pipe; 12 - Water valve;

[0034] 13 – Sealed container; 14 – Air chamber; 15 – Air bladder; 16 – Water chamber;

[0035] 17 - Water outlet; 18 - Air hose tee; 19 - Pressure gauge; 20 - Air hose;

[0036] 21 – Air valve; 22 – Air pump; 23 – Data acquisition instrument; 24 – Casting mold;

[0037] 25 – Magnetic base; 26 – Clamp; 27 – Waterproof layer; 28 – Fixing ring. Detailed Implementation

[0038] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0039] Example 1

[0040] like Figures 1 to 5 As shown, the present invention provides a test device for testing the permeability of the concrete-rock interface, including a permeability sample 1, a water pressure application device 3, and a measurement system. The permeability sample 1 includes a rock block 4 and a concrete block 7 cast on the surface of the rock block 4. A cavity is provided at the interface between the rock block 4 and the concrete block 7, and a water guide pipe 6 is provided in the cavity. The water guide pipe 6 is connected to the water pressure application device 3 through a water pipe 11. The measurement system includes a water meter 2, a water pressure gauge 10, and a data acquisition instrument 23. The water meter 2 and the water pressure gauge 10 are respectively installed on the water pipe 11, and the data acquisition instrument 23 is connected to the water meter 2 and the water pressure gauge 10 to automatically collect water volume and water pressure data.

[0041] The water pressure application device 3 includes a sealed tank 13 and an air pump 22. The internal space of the sealed tank 13 is divided into a water chamber 16 and an air chamber 14 by an air bag 15. The water chamber 16 is provided with a water outlet 17, which is connected to the water guide pipe 6 through a water pipe 11. The air chamber 14 is provided with an air inlet, which is connected to the air pump 22 through an air pipe 20.

[0042] The water pipe 11 is equipped with a water valve 12, and the air pipe 20 is equipped with an air valve 21.

[0043] An air pipe tee 18 is provided between the air inlet and the air pipe 20, and a pressure gauge 19 is connected to the air pipe tee 18.

[0044] The cavity at the interface between the rock block 4 and the concrete block 7 is formed by a hemispherical steel mesh 5, which is fixed to the upper surface of the rock block by a fixing ring 28 at the bottom. The hemispherical steel mesh 5 is provided with a waterproof layer 27 to prevent cement slurry from seeping in during concrete pouring.

[0045] The water pipe 6 is connected to the water pipe 11 via a water pipe tee 9, and the water pressure gauge 10 is installed on the water pipe tee 9.

[0046] The rock block 4 is a flat rock block selected from the engineering site, transported to the laboratory for cutting, and its four sides are cut flat while the upper surface remains in its natural state.

[0047] The present invention has a cavity at the interface between the rock block and the concrete block. A water pipe inserted into the cavity can transmit water pressure to the cavity and apply it to the concrete-rock interface, thus creating a permeation sample for the concrete-rock interface.

[0048] This invention employs a water pressure application device combining an air pump and a sealed tank. This device can apply water pressure of different magnitudes to obtain the permeability of the concrete-rock interface under different water pressures, while also preventing gas from entering the water during loading, thus solving the problem of gas affecting permeability.

[0049] Example 2

[0050] This invention provides a method for preparing the permeation sample 1 in the test apparatus of Example 1, comprising:

[0051] Rock blocks 4 were selected and cut from the engineering site. A water-proof layer 27 was set inside a hemispherical steel filter 5 and fixed at the center of the upper surface of the rock block 4. The casting mold 24 was placed in the mold, the water pipe 6 was connected and fixed with a clamp 26, and concrete 7 was poured to obtain a permeable sample 1 containing cavities on the concrete-rock interface 8.

[0052] Before the permeation test, a miniature endoscope can be inserted into the water pipe 6 to check the molding quality of the cavity. During the permeation test, the water pipe 6 can deliver water volume and transmit water pressure.

[0053] This invention provides a test method for testing the permeability of the concrete-rock interface, comprising:

[0054] Connect a water pipe tee 9 with a water pressure gauge 10 to the upper end of the water pipe 6. After filling the water chamber 14 of the sealed tank 13 with water, connect the water pipe 6, water meter 2 and sealed tank 13 with water pipe 11. Connect the sealed tank 13 to the air pump 22 with air pipe 20.

[0055] The water pipe 11 and the cavity are evacuated into a vacuum. The air pump 22 applies air pressure, which is converted into water pressure through the sealed tank 13. The water valve 12 is opened, and water flows into the cavity and seeps into the concrete-rock interface 8 under the action of water pressure.

[0056] The water meter 2 and water pressure gauge 10 connected to the data acquisition instrument 23 can measure the seepage volume under different water pressures, thereby calculating and analyzing the permeability of the concrete-rock interface.

[0057] Once the seepage rate stabilizes under a certain water pressure, the permeability coefficient of the concrete-rock interface under that water pressure can be calculated using the following formula:

[0058]

[0059] In the formula: k is the permeability coefficient of the concrete-rock interface 8, in cm / s; L is the side length of the concrete-rock interface 8, in cm; d is the diameter of the hemispherical steel filter screen 5, in cm; t is the test measurement time after the seepage volume stabilizes, in s; V is the water volume measured by the water meter 2 within the measurement time t, in cm³. 3 p is the water pressure measured by the water pressure gauge 10 during the measurement time t, and the unit is kPa.

[0060] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A test apparatus for testing the permeability of the concrete-rock interface, characterized in that, It includes a permeation sample (1), a water pressure application device (3), and a measurement system; The permeation sample (1) includes a rock block (4) and a concrete block (7) poured on the surface of the rock block (4). A cavity is provided at the interface between the rock block (4) and the concrete block (7), and a water pipe (6) is provided in the cavity. The water pipe (6) is connected to the water pressure application device (3) via the water pipe (11); The measurement system includes a water meter (2), a water pressure gauge (10), and a data acquisition device (23). The water meter (2) and the water pressure gauge (10) are respectively installed on the water pipe (11). The data acquisition device (23) is connected to the water meter (2) and the water pressure gauge (10) respectively, and automatically collects water volume and water pressure data. The water pressure application device (3) includes a sealed tank (13) and an air pump (22). The internal space of the sealed tank (13) is divided into a water chamber (16) and an air chamber (14) by an air bag (15). The water chamber (16) has a water outlet (17) at the bottom, and the water outlet (17) is connected to the water guide pipe (6) through a water pipe (11). The air chamber (14) has an air inlet at the top, and the air inlet is connected to the air pump (22) through an air pipe (20). The cavity at the interface between the rock block (4) and the concrete block (7) is formed by a hemispherical steel mesh (5), which is fixed to the upper surface of the rock block by a fixing ring (28) at the bottom; the hemispherical steel mesh (5) is provided with a water-proof layer (27) to prevent cement slurry from seeping in during concrete pouring.

2. The test apparatus for testing the permeability of the concrete-rock interface according to claim 1, characterized in that, The water pipe (11) is equipped with a water valve (12), and the air pipe (20) is equipped with an air valve (21).

3. The test apparatus for testing the permeability of the concrete-rock interface according to claim 1, characterized in that, An air tee (18) is provided between the air inlet and the air pipe (20), and a pressure gauge (19) is connected to the air tee (18).

4. The test apparatus for testing the permeability of the concrete-rock interface according to claim 1, characterized in that, The water pipe (6) is connected to the water pipe (11) through the water pipe tee (9), and the water pressure gauge (10) is installed on the water pipe tee (9).

5. The test apparatus for testing the permeability of the concrete-rock interface according to claim 1, characterized in that, The rock block (4) is a flat rock block selected from the engineering site, transported to the laboratory for cutting, and its four sides are cut flat while the upper surface remains in its natural state.

6. A test method for testing the permeability of the concrete-rock interface based on the test apparatus according to any one of claims 1-5, characterized in that, include: Water pressure is applied to the cavity at the interface between the rock block (4) and the concrete block (7) using a water pressure application device (3), so that water flows into the cavity and seeps into the concrete-rock interface (8). The water meter (2) and water pressure gauge (10) connected to the data acquisition instrument (23) can measure the seepage volume under different water pressures, thereby calculating and analyzing the permeability of the concrete-rock interface.

7. The test method according to claim 6, characterized in that, The method of applying water pressure to the cavity at the interface between the rock block (4) and the concrete block (7) using the water pressure application device (3) is as follows: Connect a water pipe tee (9) with a water pressure gauge (10) to the upper end of the water pipe (6), fill the water chamber (16) of the sealed tank (13) with water, connect the water pipe (6), water meter (2) and sealed tank (13) with water pipe (11), and connect the sealed tank (13) with air pump (22) with air pipe (20); evacuate the water pipe (11) and the cavity into a vacuum, apply air pressure with air pump (22), convert the air pressure into water pressure through the sealed tank (13), open the water valve (12), and under the action of water pressure, water flows into the cavity and seeps into the concrete-rock interface (8).

8. The test method according to claim 6, characterized in that, Once the seepage rate stabilizes under a certain water pressure, the permeability coefficient of the concrete-rock interface under that water pressure can be calculated using the following formula: ； In the formula: k It is the permeability coefficient of the concrete-rock interface 8, in cm / s; L It is the side length of the concrete-rock interface 8, in cm; d This refers to the diameter of the hemispherical steel filter screen 5, in centimeters. t It is the test measurement time after the seepage volume stabilizes, in seconds; V Water meter 2 during measurement time t The internal water volume is measured in cm³. 3 ; p The water pressure gauge 10 measures the duration of the measurement. t The internal water pressure is measured in kPa.

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