CN211652459U - Device for porous medium performance test experiment - Google Patents

Device for porous medium performance test experiment Download PDF

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Publication number
CN211652459U
CN211652459U CN202020190566.6U CN202020190566U CN211652459U CN 211652459 U CN211652459 U CN 211652459U CN 202020190566 U CN202020190566 U CN 202020190566U CN 211652459 U CN211652459 U CN 211652459U
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porous medium
air
water
pressure gauge
pipeline
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敖长江
郭志光
禚锦鑫
高树青
包汉营
蔡茂江
刘斌
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China Construction Civil Engineering Co Ltd
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China Construction Civil Engineering Co Ltd
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Abstract

The device for the porous medium performance test experiment comprises a porous medium earth pillar, an air inlet pipeline and an air inlet pipeline which are communicated with the upper end surface of the porous medium earth pillar, and an air outlet pipeline which is communicated with the lower end surface of the porous medium earth pillar and an air outlet pipeline on the lower side wall of the porous medium earth pillar; the inlet end of the inlet pipe is arranged in the air box, a first air delivery pump and a third pressure gauge are sequentially arranged along the airflow direction on the inlet end, the inlet end of the inlet pipe is arranged in the water box, a first peristaltic pump, a first flowmeter and a first pressure gauge are sequentially arranged along the water flow direction on the inlet end, a second pressure gauge, a second flowmeter, a second peristaltic pump and a turbidity meter are sequentially arranged along the water flow direction on the outlet pipe, and a fourth pressure gauge and a second air delivery pump are sequentially arranged along the airflow direction on the outlet pipe. The utility model discloses light, easily assemble, convenient the removal to can survey simultaneously and hold water characteristic, including saturation, permeability, fluid pressure etc. guidance construction that can be better and satisfy engineering calculation needs.

Description

Device for porous medium performance test experiment
Technical Field
The utility model relates to a device for porous medium capability test experiment.
Background
The water-holding properties (saturation, permeability, fluid pressure, etc.) of porous media (soil, permeable materials, rock, etc.) are important parameters in engineering calculations; the problem of stone migration in the process of grouting, concrete pouring and the like is an important index for judging the strength of concrete. At present, most of test instruments are porous medium water-holding characteristics or stone migration devices.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing a technical problem that prior art porous medium holds water characteristic test equipment function singleness has been solved to a device for porous medium capability test experiment.
In order to achieve the above purpose, the utility model adopts the following technical scheme:
the device for porous medium performance test experiment is characterized in that: the device comprises a porous medium earth pillar, an air inlet pipeline and a water inlet pipeline which are communicated with the upper end surface of the porous medium earth pillar, and an air outlet pipeline which is communicated with the lower end surface of the porous medium earth pillar and the lower side wall of the porous medium earth pillar; the air inlet end of the air inlet pipeline is arranged in the air box, a first air delivery pump and a third pressure gauge are sequentially arranged along the airflow direction on the air inlet pipeline, the water inlet end of the water inlet pipeline is arranged in the water box, a first peristaltic pump, a first flowmeter and a first pressure gauge are sequentially arranged along the water flow direction on the water inlet pipeline, a water inlet hose is arranged between the first pressure gauge and the porous medium soil column on the water inlet pipeline, a second pressure gauge, a second flowmeter, a second peristaltic pump and a turbidity meter are arranged along the water flow direction on the water outlet pipeline, a fourth pressure gauge and a second air delivery pump are sequentially arranged along the airflow direction on the air outlet pipeline, and an air inlet hose is arranged between the fourth pressure gauge and the second air delivery pump on the air outlet pipeline.
Further preferably, a semi-permeable membrane is arranged on a gas outlet of the porous medium soil column communicated with the gas outlet pipeline.
Furthermore, the inner diameter of the porous medium soil column is 60-100 mm, the height of the porous medium soil column is 300-500 mm, the wall thickness of the porous medium soil column is 8-15 mm, and the porous medium soil column is made of glass fiber reinforced plastics.
Furthermore, a water stop clip is arranged on the water inlet hose, and an air stop clip is arranged on the air inlet hose.
More preferably, the air inlet pipeline, the water outlet pipeline and the air outlet pipeline are communicated with the porous medium soil column through pipe hoops.
Compared with the prior art the utility model has the following characteristics and beneficial effect:
the utility model discloses effectively, swiftly obtain porous medium osmotic coefficient, the migration law of building stones in VG model relevant parameter and the concrete, better guidance construction. The utility model discloses simple structure, light, the cost is cheap, and the practicality is strong, to porous medium hold water characteristic and penetration test, can play the effect of generally using widely.
The utility model discloses light, easily assemble, convenient the removal to can survey simultaneously and hold water characteristic, including saturation, permeability, fluid pressure etc. guidance construction that can be better and satisfy engineering calculation needs.
Drawings
Fig. 1 is a schematic structural diagram of the present invention.
Detailed Description
In order to make the technical means, innovative features, objectives and functions realized by the present invention easy to understand, the present invention will be further described below.
The embodiments described herein are specific embodiments of the present invention, and are intended to be illustrative of the concepts of the present invention, which are intended to be illustrative and exemplary, and should not be construed as limiting the scope of the embodiments of the present invention. In addition to the embodiments described herein, those skilled in the art will be able to employ other technical solutions which are obvious based on the disclosure of the claims and the specification of the present application, and these technical solutions include technical solutions which make any obvious replacement or modification for the embodiments described herein.
The device for the porous medium performance test experiment comprises a porous medium earth pillar 1, an air inlet pipeline 2 and an air inlet pipeline 3 which are communicated with the upper end surface of the porous medium earth pillar 1, and an air outlet pipeline 4 which is communicated with the lower end surface of the porous medium earth pillar 1 and an air outlet pipeline 5 on the lower side wall, as shown in figure 1; the air inlet end of the air inlet pipeline 2 is arranged in the air box 6, a first air delivery pump 7 and a third pressure gauge 8 are sequentially arranged on the air inlet pipeline in the air flow direction, the water inlet end of the water inlet pipeline 3 is arranged in the water box 9, a first peristaltic pump 10, a first flowmeter 11 and a first pressure gauge 12 are sequentially arranged on the water inlet pipeline in the water flow direction, a water inlet hose 19 is arranged on the water inlet pipeline 3 and between the first pressure gauge 12 and the porous medium earth pillar 1, a second pressure gauge 15, a second flowmeter 16, a second peristaltic pump 17 and a turbidity meter 18 are arranged on the water outlet pipeline 4 in the water flow direction, a fourth pressure gauge 13 and a second air delivery pump 14 are sequentially arranged on the air outlet pipeline 5 in the air flow direction, an air inlet hose 20 is arranged on the air outlet pipeline 5 and between the fourth pressure gauge 13 and the second air delivery pump 14, a semipermeable membrane is arranged on an air outlet of the porous medium earth pillar 1 communicated with the, the height is 300-500 mm, the wall thickness is 8-15 mm, the material is glass steel, the last stagnant water clamp that is equipped with of water inlet hose 19 is equipped with the stagnant water clamp on the air inlet hose 20, is equipped with the stagnant air clamp on the air inlet hose 20, and inlet channel 2, inlet channel 3, outlet conduit 4 and outlet conduit 5 all communicate with porous medium earth pillar 1 through ferrule and porous medium earth pillar 1.
A method for obtaining a soil-water characteristic curve of a porous medium by using the device is characterized by comprising the following steps:
(a) filling a porous medium soil column (1): in the filling process of the soil column, the complete water saturation state is ensured, after the filling is finished, the first peristaltic pump 10, the second peristaltic pump 17, the first air transmission pump 7 and the second air transmission pump 8 are closed, and the water inlet hose 19 and the air inlet hose 20 are respectively subjected to water stopping and air stopping through a water stop clamp and an air stop clamp;
(b) calculating initial pore water pressure: adjusting the first peristaltic pump 10 and the second peristaltic pump 17 to the same required rotating speed, and after the first pressure gauge 12 and the second pressure gauge 15 are stabilized, recording the values of the first flow meter 11, the second flow meter 16, the first pressure gauge 12 and the second pressure gauge 15 as vq1,0、vq2,0、P1,0And P2,0At the moment, the water seepage speed in the porous medium is constant, the gradient of the pore water pressure is constant according to the formula (1), and the initial pore air pressure P in the porous mediumg,0=0Pa,
Figure DEST_PATH_GDA0002655272740000041
Wherein Sw is the water saturation; v. ofwThe actual seepage velocity vector of pore water in the porous medium is shown; u. ofwRespectively are pore horizontal uniform seepage velocity vectors on the section of the porous medium; mu.swIs the viscosity coefficient of pore water; k is the permeability of the porous medium, is related to the porosity and is the inherent property of the porous medium; krwPore water relative permeability;
Figure DEST_PATH_GDA0002655272740000043
ρwpore water density; pwPore water pressure; g is the acceleration of gravity, m/s2(ii) a n is the porosity of the porous medium;
then, an initial pore water pressure of p is obtainedw,0
Figure DEST_PATH_GDA0002655272740000042
Wherein L is the length of the porous medium; z is suspended particle penetrationDistance from the location to the top of the porous media earth column; pw,0Is the initial pore water pressure in the porous medium; p1,0The pore water pressure value of the pressure gauge-1 at the moment is recorded initially; p2,0The pore water pressure value of the pressure gauge-2 at the moment is recorded initially;
(c) calculating the average saturation of the porous water, the pore air pressure and the whole porous medium in the porous medium: opening the first air delivery pump 7 and the air inlet hose 20, adjusting the rotating speed of the second peristaltic pump 17 to be higher than that of the first peristaltic pump 10, and simultaneously recording the changes v of the first flowmeter 11 and the second flowmeter 16 along with the timeq1,1(t)、vq2,1(t), starting to record the moment as the moment when t is 0s, starting the second air delivery pump 8 and closing the air inlet hose 20 when the fluid at the air inlet hose 20 to be switched is changed from water to air, and adjusting the second air delivery pump 8 to the required power; after the first pressure gauge 12, the second pressure gauge 15, the third pressure gauge 8 and the fourth pressure gauge 13 are stabilized, the value of each pressure gauge is recorded as P1,1、P2,1、P3,1And P4,1Recording the time when all pressure gauges are stable as t ═ t0At the moment s, the stable seepage velocity of the pore water is recorded as vqAt this time, the pore water and pore air pressure in the porous medium are:
Figure DEST_PATH_GDA0002655272740000051
Figure DEST_PATH_GDA0002655272740000052
wherein L is the length of the porous medium; z is the distance from the penetration position of the suspended particles to the top of the porous medium soil column; pw,1To achieve the set saturation (i.e. all gauges were stable during the test, t ═ t-0Time of day) average pore water pressure; pg,1To the average pore gas pressure at which the set saturation is reached; p1,1Is t ═ t0Pore water pressure value of the pressure gauge-1 at the moment; p2,1Is t ═ t0Pore water pressure value of the pressure gauge-2 at that moment; p3,1Is t ═ t0Pressure of time of dayMeasuring the pore gas pressure value of-3; p4,1Is t ═ t0Pore gas pressure value of the pressure gauge-4 at the moment;
the average saturation of the porous medium as a whole is
Figure DEST_PATH_GDA0002655272740000053
In the formula, Vw and V are respectively the pore water volume and the total volume of the porous medium when the porous medium is completely saturated; t time variable; v. ofq1,1(t)、vq2,1(t) is the function of the change of the flowmeter-1 and the flowmeter-2 with time from the moment starting to record the moment 0 to the end of the test respectively; t is t0The time when all the pressure gauges are stable, namely the time when the set saturation is reached;
the relation of saturation, matrix suction and matrix suction head can be known from soil mechanics knowledge, and the matrix suction at different positions in a stable state is known as formula (3) and formula (4)
Figure DEST_PATH_GDA0002655272740000054
Wherein L is the length of the porous medium; z is the distance from the penetration position of the suspended particles to the top of the porous medium soil column; p1,1Is t ═ t0Pore water pressure value of the pressure gauge-1 at the moment; p2,1Is t ═ t0Pore water pressure value of the pressure gauge-2 at that moment; p3,1Is t ═ t0Pore gas pressure value of the pressure gauge-3 at the moment; p4,1Is t ═ t0Pore gas pressure value of the pressure gauge-4 at the moment;
if steady state, if the inlet pressure P is3,1Pressure P of water inlet1,1The difference being equal to the outlet pressure P4,1With the pressure P of the water outlet2,1Difference, then substrate suction at different positions becomes
Pc,1(z)=P3,1-P1,1=P4,1-P2,1(7)
According to the relation between the relative saturation calculation formula and the matrix suction head and the formula (7), the saturation at different positions in the porous medium is the same; when the test process is considered to be a one-dimensional seepage process, the formula (3) is substituted into the formula (1)
Figure DEST_PATH_GDA0002655272740000061
In the formula, SDIs the cross-sectional area of the porous medium; u. ofwRespectively is a pore horizontal average seepage velocity vector and a pore gas average seepage velocity vector on the section of the porous medium; k is the permeability (m) of the porous medium2) Porosity-related, intrinsic properties of the porous media; l is the porous medium length; pwPore water pressure; v. ofwActual seepage velocity vector of pore water in the porous medium; v. ofqThe steady seepage velocity of pore water;
(d) calculating corresponding saturation degrees under different water outlet, air inlet and air treatment rates; changing the speed of the second peristaltic pump 17, and simultaneously adjusting the power of the first air delivery pump 7 and the second air delivery pump 8 until the substrate suction in the formula (7) is different, and calculating to obtain the corresponding saturation through the formula (1);
(e) obtaining a soil-water characteristic curve of the porous medium: repeating the step (d) to obtain saturation values, matrix suction values and pore water seepage velocities v under different stable statesq
According to the relation between the relative saturation and the matrix suction head, the parameter T of the corresponding porous medium in VG models with different filling particle sizes, different porosities and different temperatures can be obtained by adopting a least square method parameter fitting methodα、Tn、Tm
And (3) obtaining a parameter L in the porous medium permeability K and VG models by a parameter fitting method according to the relation between the relative permeability and saturation of the pore water and the relation between the seepage velocity and the permeability of the porous medium and the relative permeability of the pore water in the formula (8), so as to obtain the soil-water characteristic curve of the porous medium.
A method for carrying out a suspended particle penetration experiment by using the device is characterized in that: the porous medium in the porous medium soil column 1 is in a saturated state, and the method comprises the following steps:
a. the filling process of the porous medium soil column 1 needs to ensure a complete water saturation state, after the filling is finished, the first peristaltic pump 10, the second peristaltic pump 17, the first air transmission pump 7 and the second air transmission pump 8 are closed, and the water inlet hose 19 and the air inlet hose 20 are respectively subjected to water stopping and air stopping through a water stopping clamp and an air stopping clamp;
b. simultaneously starting the first peristaltic pump 10 and the second peristaltic pump 17, adjusting the peristaltic pumps to the required rotating speed, and recording the values of the first pressure gauge 12 and the second pressure gauge 15 as P after the first pressure gauge 12 and the second pressure gauge 15 are stabilized1,1And P2,1And simultaneously recording the stable seepage velocity of pore water as vq(ii) a Obtaining an initial void pressure Pw.1
c. Opening a water inlet hose 19, injecting a suspended particle solution with a certain concentration by using an injector, simultaneously taking a water outlet solution, recording the t as 0s at the moment, and indirectly calculating by using a turbidity meter 18 to obtain the penetration concentration C of the suspended particles at the bottom of the porous mediumi,L(t);
d. Repeating the steps a-b, and carrying out suspended particle penetration tests with different injection concentrations and pore water seepage speeds;
e. using C obtained in step Ci,L(t), v obtained by the formula (8)wAdjusting related calculation parameters of the following formula (9) by using a parameter optimization method, performing fitting evaluation by using a least square method, and finally finding out the optimal solution of the parameters so as to obtain penetration test parameter values with different injection concentrations and pore water seepage speeds;
Figure DEST_PATH_GDA0002655272740000081
in the formula, kNFIs the equilibrium coefficient in the adsorption and desorption process; rhobIs the volume dry density, pb=(1-n)ρs(ii) a n is the porosity of the soil body; ciIs the solute concentration, which represents the concentration of suspended particles in the fluid;<vw>is pore water velocity tensor; sw is the water saturation; t is a time variable; z is the distance from the suspended particle penetration site to the top of the column of porous media.
A method for carrying out a suspended particle penetration experiment by utilizing the device comprises the following steps that:
a, ensuring a complete water saturation state in the filling process of the porous medium soil column 1, closing a first peristaltic pump 10, a second peristaltic pump 17, a first air transmission pump 7 and a second air transmission pump 8 after filling, and stopping water and air through a water stop clamp and an air stop clamp respectively by a water inlet hose 19 and an air inlet hose 20;
b. simultaneously starting the first peristaltic pump 10 and the second peristaltic pump 17, adjusting the peristaltic pumps to the required rotating speed, and recording the values of the first pressure gauge 12 and the second pressure gauge 15 as P after the first pressure gauge 12 and the second pressure gauge 15 are stabilized1,1And P2,1And simultaneously recording the stable seepage velocity of pore water as vq(ii) a Obtaining an initial void pressure Pw.1
c. Opening a water inlet hose 19, injecting a suspended particle solution with a certain concentration by using an injector, simultaneously taking a water outlet solution, recording the t as 0s at the moment, and indirectly calculating by using a turbidity meter 18 to obtain the penetration concentration C of the suspended particles at the bottom of the porous mediumi,L(t);
d. Repeating the steps a-b, and carrying out suspended particle penetration tests with different injection concentrations and pore water seepage speeds;
e. using C obtained in step Ci,L(t) average saturation S obtained by the formula (5)w,1V obtained by the formula (8)w. Adjusting the related calculation parameters of the formula (9) by using a parameter optimization method, performing fitting evaluation by using a least square method, and finally finding out the optimal solution of the parameters so as to obtain penetration test parameter values with different injection concentrations and pore water seepage speeds; through numerical simulation analysis and calculation, parameters are obtained by utilizing the seepage differential equation of formula pore water and pore gas, the coupling model of formula (10) and test fitting, and the test result of pollutant penetration concentration and the numerical analysis result can be compared and verified by utilizing experimental data, so that the suspended particle penetration test under the unsaturated condition is completed;
Figure DEST_PATH_GDA0002655272740000091
in the formula: rhobIs the bulk dry density; n is the porosity of the soil body; k is a radical ofNFIs the equilibrium coefficient in the adsorption and desorption process; t is a time variable; sw is the water saturation; ciConcentration of solute representing the concentration of suspended particles in the fluid αdIs hydrodynamic dispersivity;<vw>is the pore water velocity tensor.
The above description is only for the preferred embodiment of the present invention, and is not intended to limit the present invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included within the protection scope of the present invention.

Claims (5)

1. The device for porous medium performance test experiment is characterized in that: comprises a porous medium earth pillar (1), an air inlet pipeline (2) and a water inlet pipeline (3) which are communicated with the upper end surface of the porous medium earth pillar (1), and a water outlet pipeline (4) which is communicated with the lower end surface of the porous medium earth pillar (1) and an air outlet pipeline (5) on the lower side wall; the air inlet end of the air inlet pipeline (2) is arranged in the air box (6), a first air delivery pump (7) and a third pressure gauge (8) are sequentially arranged on the air inlet pipeline along the air flow direction, the water inlet end of the water inlet pipeline (3) is arranged in the water box (9), a first peristaltic pump (10), a first flowmeter (11) and a first pressure gauge (12) are sequentially arranged on the water flow direction, a water inlet hose (19) is arranged on the water inlet pipeline (3) and between the first pressure gauge (12) and the porous medium soil column (1), a second pressure gauge (15), a second flowmeter (16), a second peristaltic pump (17) and a turbidity meter (18) are arranged on the water outlet pipeline (4) along the water flow direction, a fourth pressure gauge (13) and a second air delivery pump (14) are sequentially arranged on the air outlet pipeline (5) along the air flow direction, and an air inlet hose (20) is arranged on the air outlet pipeline (5) and between the fourth pressure gauge (13) and the second air delivery pump (14).
2. The apparatus for porous media performance testing experiments according to claim 1, wherein: and a semi-permeable membrane is arranged on a gas outlet of the porous medium soil column (1) communicated with the gas outlet pipeline (5).
3. The apparatus for porous media performance testing experiments according to claim 1, wherein: the inner diameter of the porous medium soil column (1) is 60-100 mm, the height is 300-500 mm, the wall thickness is 8-15 mm, and the porous medium soil column is made of glass fiber reinforced plastics.
4. The apparatus for porous media performance testing experiments according to claim 1, wherein: the water inlet hose (19) is provided with a water stop clip, and the air inlet hose (20) is provided with an air stop clip.
5. The apparatus according to any one of claims 1 to 4, wherein: the air inlet pipeline (2), the water inlet pipeline (3), the water outlet pipeline (4), the air outlet pipeline (5) and the porous medium soil column (1) are communicated with the porous medium soil column (1) through pipe hoops.
CN202020190566.6U 2020-02-20 2020-02-20 Device for porous medium performance test experiment Expired - Fee Related CN211652459U (en)

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