Device for detecting permeability coefficient of cement soil

Abstract

A device for detecting permeability coefficient of cement soil is characterized in that a box body is arranged on a support, a water tank and a gas tank are arranged on the rear side of the top, the top of the water tank is communicated with the top of the gas tank, an air inlet pipe is communicated with the gas tank through a fine adjustment device arranged at the front end of the box body, and the water inlet pipe is communicated with the water tank through a main valve arranged on a pipeline; a first branch pipe, a second branch pipe and a third branch pipe are arranged on the water inlet pipe in parallel, three groups of test mold holes are formed in the front end in the box body, a first test mold, a second test mold and a third test mold are respectively arranged in the test mold holes, and the first branch pipe, the second branch pipe and the third branch pipe are respectively communicated with the first test mold, the second test mold and the third test mold; according to the utility model, the situation of pipeline air leakage caused by frequent disassembly and assembly of the test mold is avoided, the stability of constant pressure is improved, the error influence on test results is avoided, and the test accuracy is ensured.

Description

Technical Field

[0001] The utility model belongs to the technical field of soil sample testing equipment or devices for water conservancy and hydropower civil engineering, and particularly relates to a device for detecting the permeability coefficient of cement soil. Background Technique

[0002] At present, in the construction of using cement soil formed with cement as a seepage prevention body, it is often necessary to detect the permeability coefficient of the cement soil after curing. During the detection, the cement soil cured to the age is loaded into a permeameter mold, the mold is sealed with a sealing material, then the pressure gauge is adjusted, and pressure is applied step by step. The last-stage pressure should be increased until water comes out on the surface of the cement soil, and the permeation pressure and the amount of water seeping out are recorded at this time to calculate the permeability coefficient of the cement soil. However, there is no standard or test procedure for such a method in the water conservancy industry, and this device can only test one specimen at a time, and the pressure gauge is unstable when reading the permeation pressure, affecting the accuracy and speed of the test. The reasons for the above problems are as follows: First, there is only one set of the mold and its corresponding supporting pipelines, so only one specimen can be tested each time. Generally, there are three specimens in a group for this test, and the cost of the specimens is relatively high. Moreover, this device has high requirements for sealing, so air leakage is likely to occur during frequent installation and disassembly of the mold pipelines, resulting in test failure; Second, when reading the permeation pressure, due to the lack of a fine-tuning device, the pressure gauge shows instability, which is extremely likely to cause error effects on the test results and cannot ensure the test accuracy. Summary of the Invention

[0003] The technical problem to be solved by the utility model is to overcome the above-mentioned deficiencies of the prior art and provide a device for detecting the permeability coefficient of cement soil with reasonable design, simple structure, small test error and high test accuracy.

[0004] The technical solution adopted to solve the above technical problem is: A device for detecting the permeability coefficient of cement soil, a box body is arranged on a bracket, a water tank and an air tank are arranged at the rear side of the top, the water tank and the air tank are connected at the top, an air inlet pipe is connected to the air tank through a fine-tuning device installed at the front end of the box body, a water inlet pipe is connected to the water tank through a main valve installed on the pipeline, a first branch pipe, a second branch pipe and a third branch pipe are arranged in parallel on the water inlet pipe, three sets of mold holes are arranged at the front end in the box body, a first mold, a second mold and a third mold are respectively arranged in the mold holes, and the first branch pipe, the second branch pipe and the third branch pipe are respectively connected to the first mold, the second mold and the third mold.

[0005] A first valve, a second valve and a third valve are respectively arranged on the first branch pipe, the second branch pipe and the third branch pipe of the utility model.

[0006] A water tank liquid indicating pipe connected to the water inlet pipe is connected to the water tank of the utility model.

[0007] The fine-tuning device of the present utility model is composed of a first fine-tuning valve and a second fine-tuning valve connected in series.

[0008] Fine-tuning pressure gauges are provided on both the first fine-tuning valve and the second fine-tuning valve of the present utility model.

[0009] A water tank pressure gauge is provided on the water tank of the present utility model.

[0010] Measuring cups are provided at the bottoms of the first test mold, the second test mold, and the third test mold of the present utility model.

[0011] Since the present utility model integrates three sets of test molds in a box body, all three specimens can be directly loaded into the test molds during one assembly, avoiding the air leakage of pipelines caused by frequent disassembly and assembly of the test molds. The water inlet pipes of each test mold are connected side by side with the water inlet pipe of the water tank, and a valve is provided on the water inlet pipe of each test mold for individual control; two fine-tuning valves are provided on the air inlet pipe of the air tank, both of the two fine-tuning valves are equipped with pressure gauges, and they are connected in series with the air inlet pipe of the air tank, increasing the stability of the constant pressure, avoiding the error influence on the test results, and ensuring the test accuracy. Description of the Drawings

[0012] Figure 1 is a schematic structural diagram of an embodiment of the present utility model.

[0013] Figure 2 is Figure 1 the top view of

[0014] In the figure: 1, support; 2, box body; 3, first fine-tuning valve; 4, air inlet pipe; 5, first test mold; 6, water inlet pipe; 7, first branch pipe; 8, water tank liquid indicating pipe; 9, water tank; 10, water tank pressure gauge; 11, air tank; 12, second fine-tuning valve; 13, main valve; 14, second valve; 15, third valve; 16, second test mold; 17, third branch pipe; 18, third test mold; 19, second branch pipe; 20, first valve. Detailed Embodiment

[0015] The following further describes the present utility model in detail with reference to the drawings and embodiments, but the present utility model is not limited to these embodiments.

[0016] Embodiment 1

[0017] In Figure 1 , 2Among them, the device for detecting the permeability coefficient of cement soil involved in the present utility model is provided with a box body 2 on a bracket 1. The box body 2 is of a cylindrical or rectangular structure. A water tank 9 and an air tank 11 are installed at the rear side of the top of the box body 2. The top of the water tank 9 and the air tank 11 are connected. After pressurization, air enters the air tank 11 to pressurize the water in the water tank 9. An air inlet pipe 4 is connected to the air tank 11 through a fine-tuning device installed at the front end of the box body 2. The fine-tuning device in this embodiment is composed of a first fine-tuning valve 3 and a second fine-tuning valve 12 connected in series. Fine-tuning pressure gauges are provided on both the first fine-tuning valve 3 and the second fine-tuning valve 12. Three sets of test mold holes are provided at the front end inside the box body 2. A first test mold 5, a second test mold 16, and a third test mold 18 are respectively arranged in the test mold holes. Measuring cups are arranged at the bottoms of the first test mold 5, the second test mold 16, and the third test mold 18. The measuring cups are used to collect the seepage liquid in the test molds and calculate the seepage flow rate. A water inlet pipe 6 is connected to the water tank 9 through a main valve 13 installed on the pipeline. A first branch pipe 7, a second branch pipe 19, and a third branch pipe 15 are connected in parallel on the water inlet pipe 6 behind the main valve 13. The first branch pipe 7, the second branch pipe 19, and the third branch pipe 15 are respectively connected to the first test mold 5, the second test mold 16, and the third test mold 18. First valves 20, second valves 14, and third valves 15 are respectively provided on the first branch pipe 7, the second branch pipe 19, and the third branch pipe 15. The water in each branch is independently controlled for water inlet. In order to facilitate observing the water surface height in the water tank 9, a water tank liquid indicating pipe 8 connected to the water inlet pipe 6 is connected to the water tank 9. A water tank pressure gauge 10 is provided on the water tank 9 for reading the seepage pressure of each branch. During the test, a constant pressure is required during the step-by-step pressurization process. The air pressure is finely adjusted and stabilized through the first fine-tuning valve 3 and the second fine-tuning valve 12. After the pressure is constant for a period of time, the reading of the water tank pressure gauge 10 is taken as the parameter for calculating the permeability coefficient. First, close the main valve 13, open the first valve 20, and the water in the water tank 9 enters the first test mold 5 under the action of pressure. After the test of the first test mold 5 is completed, close the first valve 20, open the second valve 14, and test the specimen in the second test mold 16. Correspondingly, after the test of the specimen in the second test mold 16 is completed, close the second valve 14, open the third valve 15, and test the specimen in the third test mold 18. After all three specimens are tested, the collected parameters are calculated to obtain the final permeability coefficient result.

[0018] The operation steps of the present utility model are as follows:

[0019] Step 1. Water addition: Connect an external water source to the water inlet pipe 6, open the main valve 13, and close the branch valves. After the water enters the water tank 9, observe the water tank liquid indicating pipe 8. When the liquid level height in the water tank liquid indicating pipe 8 reaches the top, close the main valve 13.

[0020] Step 2. Specimen installation: Load the cement soil cured to the age into the first test mold 5, the second test mold 16, and the third test mold 18, and make good seals.

[0021] Step 3. Pressurization: Connect an external air source to the air inlet pipe 4, open the first fine-tuning valve 3 and the second fine-tuning valve 12. The pressurized air enters the air tank 11, and the air tank 11 is communicated with the water tank 9, thereby pressurizing the water tank 9.

[0022] Step 4. Water injection: Open the first valve 13. After being pressurized, the water enters the first test mold 5 through the first branch pipe 20, seeps out through the gaps in the cement soil, and finally is collected in the measuring cup at the drainage outlet at the bottom of the test mold.

[0023] Step 5. Stepwise pressurization: The first-stage pressure is 0.02 MPa. After pressurization, observe the pressure gauge 10 of the water tank, and fine-tune through the first fine-tuning valve 3 and the second fine-tuning valve 12 until the pointer of the pressure gauge 10 of the water tank no longer shakes, then keep the pressure constant for a period of time. The pressurization levels are 0.02 MPa, 0.04 MPa, 0.06 MPa, 0.08 MPa, 0.1 MPa, and then increase in increments of 0.1 MPa. The constant pressure time for each stage of seepage pressure should be 1 h. The last stage of pressure is increased until water seeps out from the surface of the cement soil specimen. Record the seepage pressure at this time, and measure the amount of water seeping out from the cement soil specimen under the constant pressure. Repeat steps 4 and 5 to test the other two specimens.

Claims

1. A device for detecting cement soil permeability coefficient, characterized in that: A box body (2) is arranged on a support (1), a water tank (9) and an air tank (11) are arranged on the rear side of the top, the tops of the water tank (9) and the air tank (11) are connected, an air inlet pipe (4) is connected to the air tank (11) via a fine adjustment device installed at the front end of the box body (2), a water inlet pipe (6) is connected to the water tank (9) via a main valve (13) installed on the pipe, a first branch pipe (7), a second branch pipe (19), and a third branch pipe (17) are arranged in parallel on the water inlet pipe (6), three groups of test mold holes are arranged at the front end of the box body (2), a first test mold (5), a second test mold (16), and a third test mold (18) are respectively arranged in the test mold holes, and the first branch pipe (7), the second branch pipe (19), and the third branch pipe (17) are respectively connected to the first test mold (5), the second test mold (16), and the third test mold (18).

2. The device for detecting cement soil permeability coefficient according to claim 1, characterized in that: The first branch pipe (7), the second branch pipe (19) and the third branch pipe (17) are respectively provided with a first valve (20), a second valve (14) and a third valve (15).

3. The device for detecting cement soil permeability coefficient according to claim 1, characterized in that: The water tank (9) is provided with a water tank liquid indicator tube (8) which is connected to the water inlet pipe (6).

4. The device for detecting cement soil permeability coefficient according to claim 1, characterized in that: The fine-tuning device is composed of a first fine-tuning valve (3) and a second fine-tuning valve (12) connected in series.

5. The device for detecting cement soil permeability coefficient according to claim 4, characterized in that: The first fine-tuning valve (3) and the second fine-tuning valve (12) are both provided with fine-tuning pressure gauges.

6. The device for detecting cement soil permeability coefficient according to claim 1, characterized in that: The water tank (9) is provided with a water tank pressure gauge (10).

7. The device for detecting cement soil permeability coefficient according to claim 1, characterized in that: Measuring cups are arranged at the bottom of the first test mold (5), the second test mold (16), and the third test mold (18).

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