CN108414416A - A kind of more sample infiltration coefficients test and comparison means and method - Google Patents

Abstract

The invention discloses a multi-sample permeability coefficient test and comparison device and method, comprising a water supply device and a multi-pass test device. There is a water pressure sensor and a speed regulating valve. The multi-way test device includes a multi-way connector and a sample storage bin. One end of the sample storage bin is connected to the water outlet of the multi-way connector, and the other end is connected to the drainage device. The two ends of the storage bin are provided with anti-filter layers, and the drainage device is provided with a solenoid valve, a water flow sensor and a water pressure sensor in sequence, and the speed regulating valve, the water flow sensor, the water pressure sensor and the solenoid valve are connected to the computer through a connecting line. The invention has simple structure and convenient operation, can simultaneously measure and compare the permeability coefficients of multiple different samples under the same environment, and can also switch freely to measure the permeability coefficient of a single sample, greatly improving the testing efficiency and accuracy.

Description

A multi-sample permeability coefficient test and comparison device and method

technical field

The invention belongs to the technical field of testing, and in particular relates to a multi-sample permeability coefficient testing and comparison device and method.

Background technique

The permeability coefficient is an important hydrogeological parameter in hydrogeology. It represents the linear relationship between the flow rate and the hydraulic gradient in Darcy's law, and its value is a proportional constant. It is an important index to describe the permeability characteristics of soil. In geotechnical engineering, sometimes it is necessary to measure the permeability coefficient of different samples to compare the differences in permeability characteristics between them. In the process of solving this problem, whether to choose the appropriate permeability coefficient measurement method and device is directly related to the accuracy of the comparison results of the permeability characteristics of the samples.

At present, the measurement and comparison of the permeability coefficients of different samples, in the case that the accuracy of the test results is not very high, the traditional permeability coefficient measuring device is used to conduct two permeability tests respectively to achieve the permeability coefficient of different samples. for measurement and comparison purposes. It assumes that the two test environments are basically the same, and the measurement error of the permeability coefficient caused by the difference in the test environment can be ignored. However, due to slight differences in water temperature, water pressure, mineral composition in water, water flow velocity, and errors caused during the operation of the two tests, the two test environments will always be different. In addition to the influence of the degree of compactness of the soil itself, water temperature and other conditions have a great influence on the soil permeability coefficient, and the use of two tests to measure does not guarantee that these conditions are the same. Therefore, in tests that require relatively high accuracy of test results, the test methods and devices of traditional tests are no longer applicable.

Contents of the invention

In order to solve the problems in the prior art, a multi-sample permeability coefficient testing and comparison device and method are provided. During the permeability test, a variety of different samples can be tested simultaneously in the same test environment, which greatly improves the performance of the test. In order to improve the efficiency of the penetration test and the accuracy of the test results.

A multi-sample permeability coefficient test and comparison device of the present invention comprises a water supply device and a multi-pass test device, the water supply device is connected to the water inlet of the multi-pass test device, and water inlets are sequentially arranged at the outer end of the multi-pass test device. Pressure sensor and speed regulating valve, the multi-way test device includes a multi-way connector and a sample storage chamber, one end of the sample storage chamber is connected to the water outlet of the multi-way connector, and the other end is connected to the drainage device, and the drainage device is sequentially installed There are solenoid valves, water flow sensors and water pressure sensors, and the speed regulating valve, water flow sensors, water pressure sensors and solenoid valves are connected to the computer through connection lines, and reverse filter layers are arranged at both ends of the sample holding chamber.

Further, the water supply device includes a water supply tank, a water pump and a pressure water pipe.

Further, one end of the sample holding chamber is connected to the water outlet of the multi-way connector through a threaded flange, and the other end is connected to the drainage device through a threaded flange, and a sealing gasket is provided at the connection of the threaded flange.

Further, the tail end of the drainage device is connected to the collection box.

Further, the outer end of the water inlet of the multi-way test device is also provided with a water flow sensor.

Further, the multi-way test device is an equal-diameter T-shaped three-way structure.

A multi-sample permeability coefficient test and comparison method based on a multi-sample permeability coefficient test and comparison device comprises the following steps:

a. Prepare the penetration sample;

b. Place the infiltration sample in the sample holding chamber;

c. Turn on the water supply device and adjust the water flow speed through the computer-controlled speed regulating valve. The water flow flows into the three-way test device and flows to the infiltration samples on both sides respectively. The water flow passes through the reverse filter layer to penetrate the infiltration sample, and finally passes through the reverse filter layer along The drainage device flows out, and after a period of time, the water flow tends to be stable, and the computer shows that the values measured by the three water pressure sensors are basically unchanged. At this time, the computer controls the water flow sensor to start working and simultaneously performs a stopwatch on the computer;

d. After t time, the water pressure sensor outside the water inlet of the tee test device transmits the detected pressure to the computer, and the pressure value P _C is measured. The water pressure sensor and water flow sensor on the drainage device will detect the pressure and the flow rate are transmitted to the computer, and the pressure values PA, P _B and flow values Q _A , Q _B are measured _;

e. Calculate the permeability coefficient according to the preset calculation program in the computer. The formula for calculating the permeability coefficient is:

In the formula: and Respectively, the permeability coefficient cm/s of the penetration sample 1 and the penetration sample 2 at the test temperature T°C;

Q _A and Q _B are respectively the flow values cm ³ measured by the water flow sensors at both ends of the three-way experimental device;

L is the length cm of the penetration sample;

A is the cross-sectional area cm ² of the sample holding chamber;

Δ ₁ h and Δ ₂ h are the water head difference cm between the position C of the upper water flow sensor and the positions A and B of the water flow sensors at both ends of the lower part respectively;

P _C , P _A and P _B are the pressure values kpa measured by the upper water pressure sensor and the water pressure sensor at both ends of the lower part respectively;

γ _W is the weight of water, its value is 9.8×10 ^-6 KN/cm ³ ;

Z _A , Z _B and Z _C are the distances from the three water pressure sensors to the bottom of the collection box in cm;

K ₂₀ is the permeability coefficient cm/s of the penetration sample at standard temperature;

η _T , η ₂₀ are the dynamic viscosity coefficient kpa s of water at T°C and 20°C respectively;

Substitute the data P _A P _B P _C , Q _A Q _B and t into the permeability coefficient calculation formula to calculate the permeability coefficients K _{20 sample 1} and K _{20 sample 2} of the permeability samples at the standard temperature of 20°C, and according to the obtained The permeability coefficients are compared to the permeability characteristics of the permeable samples.

In step a, the method for preparing the penetration test sample includes the following steps:

1) Collect penetration samples, and avoid mixing other non-tested soil samples into the soil samples during the sampling and transportation process;

2) Sand washing, air-drying, and grinding of the infiltration sample;

3) sieve the crushed permeation sample to obtain the required quantity for the test;

4) Put the obtained permeation samples into different dry containers according to the order of particle size and mark them with labels.

In step b, the method for placing the penetration sample in the sample holding chamber includes the following steps:

1) Put the first reverse filter layer into the water inlet end of the sample holding chamber;

2) Put the marked penetration sample into the sample holding chamber;

3) Compact the infiltration sample layer by layer, pour 1/2 of the infiltration sample with the volume of 72 volumes in the sample storage bin for the first time and compact it, and pour 1/4 of the volume with the volume of 72 volumes in the sample storage bin for the second time. Infiltrate the sample and compact it. For the third time, fill the infiltration sample with the volume of 1/8 of the sample holding chamber 72 and compact it. For the fourth time, fill the volume of the remaining sample holding chamber 72 and compact it;

4) After compacting the infiltration sample, put the second reverse filter layer into the water outlet end of the sample holding chamber;

5) Repeat the above steps for placement and compaction of the penetration sample.

Beneficial effects: the present invention has simple structure and wide application, and can simultaneously measure and compare the permeability coefficients of various samples during the permeability test, which reduces the influence caused by different test environment factors. The test saves time and labor and greatly improves the test accuracy. Of course, the present invention is also compatible with the traditional permeability coefficient measurement device. By controlling the closure of the solenoid valve, it can be freely adjusted to the traditional permeability coefficient measurement mode for a single sample. In addition, the sample can be different types of soil, or the same soil with different particle gradation, compactness and soil structure, etc., which has a wide range of applications and has strong practicability and promotion value.

Description of drawings

Fig. 1 is the structural diagram of multi-sample permeability coefficient test and comparison device;

Fig. 2 is the structural representation of multi-pass test device;

Figure 3 is a schematic diagram of the structure of a multi-sample permeability coefficient test and comparison device using a three-way test device.

In the figure: 1-water supply tank, 2-pressure water pipe, 3-water pump, 4-speed regulating valve, 5-water flow sensor, 5A-water flow sensor, 5B-water flow sensor, 5C-water flow sensor, 6-water Pressure sensor, 6A-water pressure sensor, 6B-water pressure sensor, 6C-water pressure sensor, 7-multi-way test device, 71-multi-way connector, 72-sample storage chamber, 8-reverse filter layer, 9 - threaded flange, 10 - sealing gasket, 11 - drainage device, 12 - solenoid valve, 13 - collection box.

Detailed ways

An embodiment of the present invention will be further described below in conjunction with the accompanying drawings.

As shown in Figure 3, a multi-sample permeability coefficient test and comparison device, a water supply device and a three-way test device, the three-way test device is an equal-diameter T-shaped three-way structure, and the water supply device includes a water supply tank 1, a water pump 3 and a pressure The water pipe 2 and the pressure water pipe 2 are connected to the water inlet of the three-way test device 7, and the outer end of the water inlet of the three-way test device is provided with a water flow sensor 5C, a water pressure sensor 6C and a speed regulating valve 4 in sequence. The three-way test device includes three Through connector 71 and sample storage bin 72, one end of sample storage bin 72 is connected with the water outlet of the three-way connector through threaded flange 9, and the other end is connected with drainage device through threaded flange 9, and at the threaded flange 9 A sealing gasket 10 is provided at the joint, reverse filter layers 81, 82 are provided at both ends of the sample holding chamber 72, and a solenoid valve 12, a water flow sensor 5A (5B) and a water pressure sensor 6A ( 6B), speed regulating valve 4, water flow sensors 5A, 5B, 5C, water pressure sensors 6A, 6B, 6C and electromagnetic valve 12 are connected to the computer through connecting wires, and the tail end of the drainage device 11 is connected to the collection box 13.

A multi-sample permeability coefficient test and comparison method based on a multi-sample permeability coefficient test and comparison device comprises the following steps:

a. Prepare the penetration sample, including the following steps:

1) Collect permeation samples according to the soil requirements of the coarse-grained group in GB/T 50145-2007 "Engineering Classification Standards for Soils", and avoid mixing other non-tested soil samples into the soil samples during the sampling and transportation process;

2) Sand washing, air-drying, and grinding of the infiltration sample;

3) sieve the crushed permeation sample to obtain the required quantity for the test;

4) Put the obtained permeation samples into different dry containers according to the order of particle size and mark them with labels.

b. Place the penetration sample in the sample holding chamber 72, including the following steps:

1) Put the first reverse filter layer 81 into the water inlet end of the sample holding chamber 72;

2) Put the marked penetration sample into the sample holding chamber 72;

3) Compact the penetration sample in layers according to the requirements of GB/T50123-1999 "Standards for Geotechnical Test Methods". Take the penetration sample that is poured into 1/2 of the sample storage bin with a volume of 72 for the first time and compact it. Fill in 1/4 of the infiltration sample with a volume of 72 in the sample storage bin for the second time and compact it; fill in the third time with 1/8 of the infiltration sample with a volume of 72 in the sample storage bin and compact it, and fill it up for the fourth time. The volume of the remaining sample storage bin 72 is compacted;

4) After compacting the infiltration sample, put the second reverse filter layer 82 into the outlet end of the sample holding chamber 72;

5) Repeat the above steps for placement and compaction of the penetration sample.

c. Turn on the water supply device, and adjust the water flow speed through the computer-controlled speed regulating valve 4. The water flow flows from the water supply tank 1 along the pressure water pipe 2 into the three-way test device through the water pump 3, and flows to the penetration samples on both sides respectively, and the water flow passes through the first layer. The anti-filter layer 81 penetrates the infiltration sample, and finally passes through the second layer of anti-filter layer 82 and flows into the collection box 13 along the drainage device 11. After a period of time, the water flow tends to be stable, and the computer displays three water pressure sensors 6A, 6B and 6C The measured value is basically unchanged, and at this moment, the water flow sensors 5A, 5B and 5C are controlled by the computer to start working and simultaneously carry out the stopwatch timing on the computer;

d. After t time, the water pressure sensor 6C and water flow sensor 5C outside the water inlet of the three-way test device will transmit the detected pressure and flow to the computer, and the measured pressure value P _C and flow value Q _C , the drainage device 13 The water pressure sensors 6A, 6B and water flow sensors 5A, 5B on the upper part transmit the detected pressure and flow to the computer, measure the pressure values P _A , P _B and flow values Q _A , Q _B , and calculate whether Q _C satisfies Q _C ＝Q _A +Q _B , if it is satisfied, the test can be carried out normally, if not, it is necessary to check whether there is any fault in the test device;

e. Calculate the permeability coefficient according to the preset calculation program in the computer. The formula for calculating the permeability coefficient is:

In the formula: and Respectively, the permeability coefficient cm/s of the penetration sample 1 and the penetration sample 2 at the test temperature T°C;

Q _A and Q _B are respectively the flow values cm ³ measured by the water flow sensors at both ends of the three-way experimental device;

L is the length cm of the penetration sample;

A is the cross-sectional area cm ² of the sample holding chamber;

Δ ₁ h and Δ ₂ h are the water head difference cm between the upper water flow sensor position 5C and the lower water flow sensor positions 5A and 5B respectively;

P _C , P _A and P _B are the pressure values kpa measured by the upper water pressure sensor and the water pressure sensor at both ends of the lower part respectively;

γ _W is the weight of water, its value is 9.8×10 ^-6 KN/cm ³ ;

Z _A , Z _B and Z _C are the distances from the three water pressure sensors to the bottom of the collection box in cm;

K ₂₀ is the permeability coefficient cm/s of the penetration sample at standard temperature;

η _T , η ₂₀ are the dynamic viscosity coefficient kpa s of water at T°C and 20°C respectively;

Substitute the data P _A P _B P _C , Q _A Q _B and t into the permeability coefficient calculation formula to calculate the permeability coefficients K _{20 sample 1} and K _{20 sample 2} of the permeability samples at the standard temperature of 20°C, and according to the obtained The permeability coefficients are compared to the permeability characteristics of the permeable samples.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (9)

1. A multi-sample permeability coefficient test and comparison device is characterized in that it comprises a water supply device and a multi-pass test device (7), it is characterized in that the water supply device is connected to the water inlet of the multi-pass test device (7), and multiple The outer end of the water inlet of the through test device (7) is provided with a water pressure sensor (6C) and a speed regulating valve (4) in sequence, and the multi-way test device (7) includes a multi-way connector (71) and a sample container warehouse (72), one end of the sample storage chamber (72) is connected to the water outlet of the multi-way connector (71), and the other end is connected to the drainage device (11). The drainage device (11) is sequentially provided with a solenoid valve ( 12), water flow sensor (5) and water pressure sensor (6), described speed regulating valve (4), water flow sensor (5), water pressure sensor (6) and solenoid valve (12) are connected with computer by connection line connected to each other, and reverse filter layers (81, 82) are also provided at both ends of the sample holding chamber (72). 2. A multi-sample permeability coefficient test and comparison device according to claim 1, characterized in that the water supply device comprises a water supply tank (1), a water pump (3) and a pressure water pipe (2). 3. A multi-sample permeability coefficient test and comparison device according to claim 1, characterized in that, one end of the sample holding chamber (72) and the water outlet of the multi-way connector (7) pass through a threaded flange (9) connection, the other end is connected with the drainage device through a threaded flange (9), and a sealing gasket (10) is provided at the connection of the threaded flange (9). 4. A multi-sample permeability coefficient test and comparison device according to claim 1, characterized in that, the tail end of the drainage device (11) is connected to a collection box (13). 5. A multi-sample permeability coefficient test and comparison device according to claim 1, characterized in that, the outer end of the water inlet of the multi-pass test device (7) is also provided with a water flow sensor (5C). 6 . A multi-sample permeability coefficient test and comparison device according to claim 1 , characterized in that, the multi-way test device ( 7 ) is an equal-diameter T-shaped three-way structure. 7. A multi-sample permeability coefficient test and comparison method is characterized in that, the method is based on the multi-sample permeability coefficient test and comparison device described in claim 6, comprising the following steps: a. Prepare the penetration sample; b. Place the infiltration sample in the sample holding chamber (72); c. Turn on the water supply device, adjust the water flow speed through the computer-controlled speed regulating valve (4), the water flow flows into the three-way test device, and flows to the permeation samples on both sides respectively, and the water flow passes through the reverse filter layer (81) to penetrate the permeation sample, Finally, flow out along the drainage device (13) through the reverse filter layer (82). After a period of time, the water flow tends to be stable, and the computer shows that the values recorded by the three water pressure (6A, 6B, 6C) sensors are basically unchanged. At this time, The computer controls the water flow sensor (5A, 5B) to start working and simultaneously carries out the stopwatch timing on the computer; d, after t time, the water pressure sensor (6C) outside the water inlet of the three-way test device transmits the detected pressure to the computer, and the pressure value PC is measured, and the water pressure sensor ( _6A , 6C) on the drainage device (13) 6B) and water flow sensors (5A, 5B) transmit the detected pressure and flow to _{the computer, and measure the pressure values PA, P B and} flow values Q _A , Q _B ; e. Calculate the permeability coefficient according to the preset calculation program in the computer. The formula for calculating the permeability coefficient is: In the formula: and Respectively, the permeability coefficient cm/s of the penetration sample 1 and the penetration sample 2 at the test temperature T°C; Q _A and Q _B are respectively the flow values cm ³ measured by the water flow sensors at both ends of the three-way experimental device; L is the length cm of the penetration sample; A is the cross-sectional area cm ² of the sample holding chamber; Δ ₁ h and Δ ₂ h are the water head difference cm between the position C of the upper water flow sensor and the positions A and B of the water flow sensors at both ends of the lower part respectively; P _C , P _A and P _B are the pressure values kpa measured by the upper water pressure sensor and the water pressure sensor at both ends of the lower part respectively; γ _W is the weight of water, its value is 9.8×10 ^-6 KN/cm ³ ; Z _A , Z _B and Z _C are the distances from the three water pressure sensors to the bottom of the collection box in cm; K ₂₀ is the permeability coefficient cm/s of the penetration sample at standard temperature; η _T , η ₂₀ are the dynamic viscosity coefficient kpa s of water at T°C and 20°C respectively; Substitute the data P _A P _B P _C , Q _A Q _B and t into the permeability coefficient calculation formula to calculate the permeability coefficients K _{20 sample 1} and K _{20 sample 2} of the permeability samples at the standard temperature of 20°C, and according to the obtained The permeability coefficients are compared to the permeability characteristics of the permeable samples. 8. the comparison method of a kind of multi-sample permeability coefficient test according to claim 7 is characterized in that in a step, the method for preparing the penetration sample comprises the steps: 1) Collect penetration samples, and avoid mixing other non-tested soil samples into the soil samples during the sampling and transportation process; 2) Sand washing, air-drying, and grinding of the infiltration sample; 3) sieve the crushed permeation sample to obtain the required quantity for the test; 4) Put the obtained permeation samples into different dry containers according to the order of particle size and mark them with labels. 9. The comparison method of a kind of multi-sample permeability coefficient test according to claim 7, characterized in that in step b, the method of placing the penetration sample in the sample holding chamber comprises the following steps: 1) Put the first reverse filter layer (81) into the water inlet end of the sample holding chamber (72); 2) Put the marked penetration sample into the sample holding chamber (72); 3) Compact the infiltration sample layer by layer, pour the infiltration sample into 1/2 of the volume of the sample holding chamber (72) for the first time and compact it, and pour it into 1/4 of the sample holding chamber (72) for the second time. 72) the volume of the infiltration sample and compact it, fill the penetration sample with the volume of 1/8 of the sample holding chamber (72) for the third time and compact it, and fill the remaining sample holding chamber (72) for the fourth time volume and compaction; 4) After compacting the infiltration sample, put the second reverse filter layer (82) into the water outlet end of the sample holding chamber (72); 5) Repeat the above steps for placement and compaction of the penetration sample.