CN110672497A - Multifunctional infiltration piping tester - Google Patents
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- 230000008595 infiltration Effects 0.000 title claims abstract description 43
- 238000001764 infiltration Methods 0.000 title claims abstract description 43
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 272
- 239000002689 soil Substances 0.000 claims abstract description 162
- 238000001914 filtration Methods 0.000 claims abstract description 50
- 238000011068 loading method Methods 0.000 claims abstract description 38
- 238000006243 chemical reaction Methods 0.000 claims abstract description 23
- 239000000463 material Substances 0.000 claims abstract description 23
- 238000000034 method Methods 0.000 claims abstract description 23
- 239000011148 porous material Substances 0.000 claims abstract description 22
- 230000008569 process Effects 0.000 claims abstract description 20
- 230000035699 permeability Effects 0.000 claims abstract description 19
- 230000035515 penetration Effects 0.000 claims description 67
- 238000012360 testing method Methods 0.000 claims description 52
- -1 polytetrafluoroethylene Polymers 0.000 claims description 38
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims description 38
- 239000004810 polytetrafluoroethylene Substances 0.000 claims description 38
- 230000008859 change Effects 0.000 claims description 31
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- G01N15/082—Investigating permeability by forcing a fluid through a sample
- G01N15/0826—Investigating permeability by forcing a fluid through a sample and measuring fluid flow rate, i.e. permeation rate or pressure change
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
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Abstract
The invention discloses a multifunctional seepage piping tester, which comprises a loading reaction frame and a sample cylinder, wherein the sample cylinder is fixed by a support frame arranged on the loading reaction frame, the top of the loading reaction frame is fixedly provided with an axial pressurizer, the upper part of the sample cylinder is provided with a sample cylinder top cap, a water inlet of the sample cylinder top cap is connected with a pressure volume controller, the bottom of the sample cylinder is provided with a sample cylinder bottom cap funnel-shaped leak groove, the water outlet of the leak groove is connected with an external silt water filtering device, the side wall of the sample cylinder is uniformly provided with water pressure sensors from top to bottom, the upper, middle and lower parts of the side wall of the sample cylinder are provided with soil pressure gauges, and the upper and lower parts of a sample in the sample cylinder are provided with porous seepage plates. The tester is controlled by a computer and is used for measuring parameters such as seepage flow velocity, permeability coefficient, pore water pressure, hydraulic gradient, effective stress and the like in the process of infiltration of the coarse-grained soil piping and the process of action of the filter material, and the tester has high measurement precision, simple and convenient measurement procedure and simple measurement mode.
Description
Technical Field
The invention relates to the technical field of hydraulic engineering and geotechnical engineering, in particular to a multifunctional osmotic piping tester.
Background
With the development of water conservancy and hydropower and the requirement on water resource safety, the infiltration stability of coarse-grained soil is an important index of water conservancy engineering. Coarse-grained soil is a main filling material and a reverse filtration material of earth and rockfill dams and dykes, and is also one of main research objects of soil mechanics. Under the seepage action, the soil body generates internal erosion to form piping, leakage damage occurs, and engineering failure can be finally caused. Therefore, the research on the permeability, piping erosion mechanism and anti-seepage failure performance of the soil body is of great significance. The permeability is a phenomenon that liquid moves in a porous medium, the quantitative index expressed by the phenomenon is a permeability coefficient, and the permeability coefficient is measured by a constant head permeameter (sandy soil) and a variable head permeameter (clayey soil) which are recommended in the current geotechnical test regulations. The internal erosion is the scouring and erosion action of the erosion force (or erosive force) of water flow in a seepage path (such as cracks of viscous materials or pores without viscous materials) on soil particles, so that fine particles in the soil are continuously lost, and the phenomenon of soil flowing or piping occurs. The internal erosion is represented by the continuous increase of the permeability coefficient and the hydraulic gradient of the soil body, and finally a piping path is formed. At present, the existing osmotic deformation tester cannot reflect the influence of stress acting on a rock-soil body on osmotic characteristics, can not represent the microscopic mechanism of a piping formation process, and can not reasonably evaluate indexes such as critical hydraulic gradient and the like required by the design of rock-soil body seepage control engineering. The measurement of the permeability parameters of the coarse-grained soil, such as the permeability coefficient, the dry density, the porosity and the permeability gradient of the coarse-grained soil, the seepage flow velocity is generally measured manually, no systematic equipment is used for testing the permeability parameters of the coarse-grained soil, and no measuring equipment controlled by a microcomputer is provided. The existing measuring equipment has low measuring precision, complicated measuring procedure and troublesome measuring mode. Due to the existence of over-diameter particles, the permeation path of water in coarse-grained soil is much more complicated than that in fine-grained soil, the conventional permeameter has smaller size, the conventional permeameter can not avoid the size effect when being used in the coarse-grained soil, the individual coarse particles greatly reduce the water passing section of a water body in a sample, and in order to obtain a true and credible permeation coefficient, a sample cylinder body needs to be enlarged to be about several times of the maximum particle size so as to eliminate the size effect.
Some exploratory work has been carried out at home and abroad, research and development and experimental research on some related instruments are carried out aiming at a soil erosion piping mechanism under the influence of complex load, a base of a triaxial apparatus is modified mostly on the basis of the existing triaxial apparatus, and a sand water collecting container is added. The main defects of the instrument are that firstly, the size of the sample is influenced by the size of the triaxial apparatus and can only be limited within a certain range, and the test instrument cannot avoid the influence of size effect caused by the size of particles; secondly, the sample is filled in a rubber membrane with a certain size, the stress state and the pore water pressure state of the local range of the sample cannot be tested under the influence of the rubber membrane, and a test instrument cannot reflect the critical state of the local range of the sample in the piping forming process. Foreign scholars develop related piping erosion instruments aiming at the formation mechanism of soil piping erosion and the local change condition of soil in the erosion process, but the piping erosion instruments are insufficient in water supply, can only complete conventional osmotic water supply (such as a constant water head, a constant flow rate and the like), and cannot meet the specific test condition requirements of the high dam, the high water head, the large flow and the like at present. While some large-sized coarse-grained soil permeameters can avoid the size effect caused by large particles, but only can complete the conventional permeation test, and the permeameters cannot form piping paths and provide permeability parameters for preventing piping. The experimental device is similar to a penetration damage testing device commonly used in foreign countries, is only used for testing penetration damage parameters under conventional water supply conditions, is not provided with a measuring device controlled by a microcomputer, needs manual measurement on the penetration parameters, and is low in measurement precision. In addition, the device can not reflect the changes of soil body permeability and mechanical properties along with time and space in the piping forming process. In order to truly and effectively obtain the infiltration parameters and piping failure mechanism of coarse-grained soil, the method needs to consider how to effectively obtain the change rule of various infiltration parameters and mechanical parameters along with time and space in the piping formation process, formation mechanism and piping erosion process while greatly expanding the existing infiltration test device so as to provide reasonable and effective parameters for the infiltration control design of dam and embankment engineering and provide a reasonable test device for the theoretical research of piping erosion mechanism.
Disclosure of Invention
The invention solves the problems that the piping infiltration erosion process and mechanism of coarse-grained soil and the microscopic change condition of local soil body in the prior art are difficult to be completely, comprehensively and systematically represented by various indoor infiltration experimental instruments, and the experimental result is difficult to objectively reflect the infiltration characteristics and the mechanical property change mechanism of the coarse-grained soil in the piping infiltration erosion process, and provides a multifunctional infiltration piping tester which can perform a reverse filtration infiltration test on protected soil (foundation soil) -reverse filter material, test the protected soil-reverse filter material composite soil layer, and realize the infiltration coefficient, the infiltration flow, the sand yield, the axial stress, the axial strain, the water pressure, the reverse filtration infiltration damage condition, the local hydraulic gradient change and the like under different loading conditions such as axial loading and non-loading. The apparatus can be used for carrying out vertical penetration test on coarse-grained soil and testing the penetration coefficients of soil bodies with different grading and the change situation of the penetration coefficients under the condition of different axial loading. The apparatus can be used for carrying out a seepage piping erosion rule test on various coarse-grained soils, and testing the migration rule of fine particles in a soil body, the change of pore water pressure and effective stress at a local position of the soil body and the change rule of a local critical hydraulic gradient under different upstream water level change modes, so that a piping erosion change mechanism of the soil body in a complex stress state is obtained.
The invention is realized by the following technical scheme:
a multifunctional seepage piping tester comprises a loading reaction frame and a sample cylinder, wherein the sample cylinder is arranged inside the loading reaction frame, the sample cylinder is fixed by a support frame arranged on the loading reaction frame, an axial pressurizer is fixedly arranged at the top of the loading reaction frame, an axial pressurizing rod is arranged at the lower part of the axial pressurizer, a displacement sensor is arranged on the axial pressurizing rod, a sample cylinder top cap is arranged at the upper part of the sample cylinder, the sample cylinder top cap and the sample cylinder are fixed together by a fixing bolt, a top cap exhaust valve, a sample cylinder top cap water inlet and a central hole are arranged on the sample cylinder top cap, the central hole can penetrate through the axial pressurizing rod, a pressure volume controller is connected with the sample cylinder top cap water inlet, an electromagnetic valve is arranged on a pipeline between the pressure volume controller and the sample cylinder top cap water inlet, and a funnel-shaped leak groove is arranged at the bottom of the sample cylinder, the bottom of the funnel-shaped leak groove of the bottom cap of the sample cylinder is provided with a leak groove water outlet, the leak groove water outlet is connected with a silt water filtering device arranged outside, the side wall of the sample cylinder is uniformly provided with water pressure sensors from top to bottom, the water inlet of the top cap of the sample cylinder and the water outlet of the leak groove are provided with water pressure sensors, the upper part, the middle part and the lower part of the side wall of the sample cylinder are provided with soil pressure gauges, a sample is arranged in the sample cylinder, the upper part and the lower part of the sample in the sample cylinder are provided with porous penetration plates, the porous penetration plates and the sample cylinder are sealed by rubber rings, the porous penetration plates are provided with penetration holes, and an axial pressure rod can be downwards contacted with the porous penetration plates and apply pressure to the.
At present, in order to actually and effectively research and obtain the expression forms, processes and mechanisms of piping formation, generation, development and damage of coarse-grained soil under different infiltration conditions and the change conditions of various infiltration parameters, manual measurement is generally carried out by a traditional infiltration instrument or a modified triaxial tester. The formation and destruction process of the piping is a very complex mechanical-hydraulic coupling process, the theory and test accumulation of the piping are not mature and complete enough, no systematic equipment is used for testing piping parameters of coarse-grained soil at present, and no measuring equipment controlled by a microcomputer is provided, so that the multifunctional seepage piping tester is provided, and the tester is mainly used for testing the piping damage mechanism of the coarse-grained soil and the performances of protected soil (foundation soil) -anti-filtering material with different grades. The device carries out axial loading through an axial pressurizer and an axial pressurizing rod arranged at the lower part, and axial displacement is measured through a displacement sensor. The test equipment sample container is of an organic glass cylinder type, the diameter of the container is 300mm and is larger than 5 times of the maximum particle size (the maximum particle size in the particle size distribution can be 60mm), and the influence of the size effect caused by the existence of over-diameter particles is effectively avoided. The equipment meets the penetration test of coarse-grained soil specified in the national industry standard of the people's republic of China's geotechnical test code ' SL 237-1999. The device adopts two pressure volume control systems connected in parallel to control the flow rate of the seepage water flow (namely, the flow rate of the seepage water flow is calculated through the head pressure difference, and a constant-flow-rate or variable-flow-rate seepage test can be carried out). The seepage mode is the seepage mode of two directions of water outlet of the top water inlet overflow port and water outlet of the bottom water inlet overflow port, namely the water supply mode of two seepage directions from bottom to top and from top to bottom can be completed. The upper and lower surfaces of the sample container are provided with porous penetration plates, the open pore design of the porous penetration plates can ensure that piping soil forms a piping path, and the upper porous penetration plates also have the function of transferring load. The system uses an automatic acquisition system to acquire and record the whole test process data and transmit the data to a calculation and hard disk, calculates various penetration parameters through self-programming software, can display various parameter curves in real time, and in addition, a pressure volume controller is communicated with a computer, and can control and record water head pressure data through the self-programming software. The self-programmed software controls the computer to automatically or manually weigh the liquid collected by the silt water filtering and separating device at regular time, weigh the running water (weight) and compare the running water with the specific gravity of pure water to obtain the soil content in the running soil, and determine the test damage time and the running soil condition. The equipment can reduce the labor intensity of operators and is a set of multifunctional infiltration piping test instrument with high automation degree. During the test, more than five layers of samples are loaded, compacted, the top surface is strickled off, non-woven fabrics are arranged, and then a porous penetration plate is arranged. And screwing a fixing bolt between the sample cylinder top cap and the sample cylinder. In order to prevent the sample from expanding upwards in the test, a 100kN loading system is adopted for loading in the axial direction, and an axial pressurizing rod acts on the upper porous permeation plate and compresses the upper porous permeation plate. After the loading, the coarse-grained soil sample was saturated and the test was started after saturation, according to the method described in geotechnical test code SL 237-1999.
Further, the multifunctional seepage piping tester is characterized in that the sample cylinder is arranged inside the loading reaction frame, the sample cylinder is fixed by a support frame arranged on the loading reaction frame, the top of the loading reaction frame is fixedly provided with an axial pressurizer, the lower part of the axial pressurizer is provided with an axial pressurizing rod, the axial pressurizing rod is provided with a displacement sensor, the upper part of the sample cylinder is provided with a sample cylinder top cap, the sample cylinder top cap and the sample cylinder are fixed together by a fixing bolt, the sample cylinder top cap is provided with a top cap exhaust valve, a sample cylinder top cap water inlet and a central hole, the axial pressurizing rod can penetrate through the central hole, the sample cylinder top cap water inlet is connected with a pressure volume controller, the pressure volume controller is provided with an electromagnetic valve through a pipeline between a polytetrafluoroethylene tube and the electromagnetic valve water inlet, the bottom of the sample cylinder is provided with a sample cylinder bottom cap funnel-shaped leakage groove, the bottom of funnel-shaped leak source of the sample cylinder bottom cap is provided with a leak source outlet, the leak source outlet is connected with an external silt water filtering and separating device through a polytetrafluoroethylene tube, the side wall of the sample cylinder is uniformly provided with water pressure sensors from top to bottom, the water inlet of the sample cylinder top cap and the water outlet of the leak source outlet are provided with the water pressure sensors, the upper, middle and lower parts of the side wall of the sample cylinder are provided with soil pressure gauges, a sample is arranged in the sample cylinder, the upper and lower parts of the sample in the sample cylinder are provided with porous penetration plates, the porous penetration plates and the sample cylinder are sealed through a rubber ring, and the porous penetration plates are provided with penetration holes.
Furthermore, the multifunctional seepage piping tester can connect the pressure volume controller with a water outlet of a lower leakage groove through a polytetrafluoroethylene pipe to serve as a water inlet, and a water inlet of a top cap of the sample cylinder and a silt water filtering and separating device through the polytetrafluoroethylene pipe to serve as a water outlet, so that the tester can generate vertical upward seepage flow on a sample and test the sample.
Furthermore, the multifunctional seepage piping tester is characterized in that two pressure volume controllers are arranged, each pressure volume controller is provided with an electromagnetic valve control switch, the two arranged pressure volume controllers are connected in parallel in the experiment process, and after the pressure value required by the experiment is set on computer software according to the pressure requirement of the experiment water head at each time, the two pressure volume controllers connected in parallel are operated by the computer to realize the change control of the system pressure water head. When one volume controller works, the other pump pumps water and pressurizes the water to a set pressure value, when water in the first pump permeates to a set limit value, the water is quickly switched to the second pump through the electromagnetic valve to work, so that the constant or uniform change of the water head pressure is ensured, and the infinite water supply volume can be achieved under the matching of the two pressure volume controllers.
Further, a multifunctional infiltration piping tester,
1) the pressure volume controller (9) provides a maximum pressure of: 3MPa, i.e. the maximum pressure head: 300 m. The calculation formula of the pressure head is as follows:
hp＝p/γw
wherein: h isp-a head of pressure water, m; p-pressure, kPa, provided by a pressure volume controller (9); gamma raywWater gravity, kN/m3。
2) The pressure volume controller provides: a linear pressurization mode of 0MPa → 3MPa and a linear depressurization mode of 3MPa → 0 MPa.
Further, a multifunctional infiltration piping tester, the inner wall of the organic glass sample cylinder is treated by adopting a polytetrafluoroethylene coating technology.
Furthermore, a multi-functional infiltration piping tester, 5 manometers and soil pressure meter interface hole are arranged to glass sample section of thick bamboo equidistant in proper order to be connected with water pressure sensor and soil pressure meter respectively.
Furthermore, the multifunctional seepage piping tester can be used for testing a sample by reversely using the tester by taking a water outlet of the lower leakage groove as a water inlet and a water inlet of the top cap of the sample cylinder as a water outlet.
Further, a multi-functional infiltration piping tester, water pressure sensor, axial presser, displacement sensor, soil pressure gauge all are connected with the data acquisition computer that the outside set up, by the automatic data acquisition of data acquisition appearance to carry out the data calculation and the classified storage of different operating modes by inside software.
Further, a multifunctional infiltration piping tester, the multifunctional infiltration piping tester test method is characterized by comprising the following steps:
And 2, filling the samples in layers according to the designed compactness, wherein the height of each layer of soil sample cannot exceed the bottom height of the soil pressure gauge, manually compacting, and cleaning the surfaces of the samples after the required compactness and height are achieved. A steel wire filter screen and a porous penetration plate are installed at the top of a sample cylinder, the sample cylinder is arranged on a support frame, a funnel-shaped leakage groove of a bottom cap of the sample cylinder and a top cap of the sample cylinder are installed, and the funnel-shaped leakage groove and the top cap of the sample cylinder are connected to a pressure volume controller and a sediment water filtering device respectively.
And 3, opening a water inlet valve of the pressure volume controller, opening an exhaust valve of a top cap of the sample barrel, closing a water stop valve of the sediment water filtering device, debugging the pressure volume controller through computer software, applying 10kPa pressure to the pressure volume controller, allowing water to slowly seep through the sample until water flows overflow from the exhaust valve of the top cap, connecting a polytetrafluoroethylene guide pipe to a 10L plastic barrel at the exhaust valve of the top cap, and allowing the water to slowly flow into the plastic barrel for more than 3 hours so as to completely discharge bubbles in the sample.
And 4, closing the exhaust valve of the top cap, controlling the axial pressurizer to apply 5N axial force to the porous penetration plate through the axial pressurizing rod, enabling the axial pressurizing rod to be in contact with the porous penetration plate, and enabling the porous penetration plate to be in close contact with the top of the sample.
And 5, connecting the pressure volume controller to a funnel-shaped leakage groove of a bottom cap of the sample cylinder through a polytetrafluoroethylene guide pipe, connecting the silt water filtering device to a top cap of the sample cylinder through the polytetrafluoroethylene guide pipe, and opening a water inlet valve of the pressure volume controller and a water stop valve of the silt water filtering device to form a downward-upward seepage path. The water supply pressure of the pressure volume controller is increased step by step, the data of time, a water pressure sensor, a soil pressure gauge, a displacement sensor, seepage flow Q, seepage fine particle amount and the like are recorded step by step, and the pore water pressure p of soil layers with different depths of the sample in each time period is calculatediHydraulic gradient iiPermeability coefficient kiEffective stress. Permeability coefficient k of each soil layeriAnd hydraulic gradient iiIs calculated as follows:
wherein: p is a radical ofi-pore water pressure, kPa, measured by a water pressure sensor of the ith soil layer; p is a radical ofi+1-pore water pressure, kPa, measured by a water pressure sensor of the i +1 th soil layer; gamma raywWater gravity, kN/m3；Δli-vertical thickness of the ith soil layer, m; i.e. ii-hydraulic gradient of ith soil layer; q-osmotic flow, m3S; a-cross-sectional area of soil layer, m2；ki-permeability coefficient of the ith soil layer, m/s.
Further, a multifunctional infiltration piping tester, the multifunctional infiltration piping tester test method is characterized by comprising the following steps:
And 2, sequentially filling the foundation soil samples in a layered manner according to the designed thickness and compactness of the foundation soil, wherein the height of each layer of soil sample cannot exceed the bottom height of the soil pressure gauge, manually compacting, and cleaning the surface of the foundation soil sample after the required compactness and height are achieved to enable the surface of the sample to be flat. And sequentially filling the anti-filtering material samples on the surface of the foundation soil sample in layers, and respectively leveling and compacting the samples until the thickness of the anti-filtering material is designed. And a pebble layer with a certain thickness is filled on the top of the filter material in a layered mode. A steel wire filter screen and a porous penetration plate are installed at the top of a sample cylinder, the sample cylinder is arranged on a support frame, a funnel-shaped leakage groove of a bottom cap of the sample cylinder and a top cap of the sample cylinder are installed, and the funnel-shaped leakage groove and the top cap of the sample cylinder are connected to a pressure volume controller and a sediment water filtering device respectively.
And 3, opening a water inlet valve of the pressure volume controller, opening an exhaust valve of a top cap of the sample barrel, closing a water stop valve of the sediment water filtering device, debugging the pressure volume controller through computer software, applying 10kPa pressure to the pressure volume controller, allowing water to slowly seep through the sample until water flows overflow from the exhaust valve of the top cap, connecting a polytetrafluoroethylene guide pipe to a 10L plastic barrel at the exhaust valve of the top cap, and allowing the water to slowly flow into the plastic barrel for more than 3 hours so as to completely discharge bubbles in the sample.
And 4, closing the exhaust valve of the top cap, controlling the axial pressurizer to apply 5N axial force to the porous penetration plate through the axial pressurizing rod, enabling the axial pressurizing rod to be in contact with the porous penetration plate, and enabling the porous penetration plate to be in close contact with the top of the sample.
And 5, connecting the pressure volume controller to a funnel-shaped leakage groove of a bottom cap of the sample cylinder through a polytetrafluoroethylene guide pipe, connecting the silt water filtering device to a top cap of the sample cylinder through the polytetrafluoroethylene guide pipe, and opening a water inlet valve of the pressure volume controller and a water stop valve of the silt water filtering device to form a downward-upward seepage path. The water supply pressure of the pressure volume controller is increased step by step, the data of time, a water pressure sensor, a soil pressure gauge, a displacement sensor, seepage flow Q, seepage fine particle amount and the like are recorded step by step, and the pore water pressure p of soil layers with different depths of the sample in each time period is calculatediHydraulic gradient iiPermeability coefficient kiEffective stress. Permeability coefficient k of each soil layeriAnd hydraulic gradient iiIs calculated as follows:
wherein: p is a radical ofi-pore water pressure, kPa, measured by a water pressure sensor of the ith soil layer; p is a radical ofi+1-pore water pressure, kPa, measured by a water pressure sensor of the i +1 th soil layer; gamma raywWater gravity, kN/m3；Δli-vertical thickness of the ith soil layer, m; i.e. iiOf the ith layerHydraulic gradient; q-osmotic flow, m3S; a-cross-sectional area of soil layer, m2；ki-permeability coefficient of the ith soil layer, m/s.
In summary, the following beneficial effects of the invention are:
1. the invention relates to a multifunctional infiltration piping tester, which can perform an anti-filtration infiltration test on a plurality of soil bodies and anti-filtration layers, test the infiltration coefficients, the infiltration flow, the sand output, the axial stress, the axial strain, the pore water pressure, the anti-filtration infiltration damage conditions, the local hydraulic gradient change and the like of the composite soil layers of the soil bodies and the anti-filtration layers under different loading conditions of axial loading, non-loading and the like. The apparatus can be used for carrying out vertical penetration test on coarse-grained soil and testing the penetration coefficients of soil bodies with different grading and the change situation of the penetration coefficients under the condition of different axial loading. The apparatus can be used for carrying out a seepage piping erosion rule test on various coarse-grained soils, and testing the migration rule of fine particles in a soil body, the change of pore water pressure and effective stress at a local position of the soil body and the change rule of a local critical hydraulic gradient under different upstream water level change modes, so that a piping erosion change mechanism of the soil body in a complex stress state is obtained.
2. The invention relates to a multifunctional seepage piping tester, which solves the problems that the piping seepage erosion generation process and mechanism of coarse-grained soil and the microscopic change condition of local soil are difficult to be completely, comprehensively and systematically represented by various indoor seepage experimental instruments, the experimental result is difficult to objectively reflect the seepage characteristic and the mechanical property change mechanism of the coarse-grained soil in the piping seepage erosion process, and the like, can test the change condition of the seepage parameters of different positions of the soil from top to bottom along with time in the stages of piping initiation, generation, development, damage and the like, and provides a powerful tool for the theoretical research and experimental research of piping.
3. The invention relates to a multifunctional seepage piping tester, which solves the problems that the existing soil body piping-stress testing device is influenced by the size of a sample, the stress change condition of coarse-grained soil in the piping process can not be effectively tested, and the size effect influence exists due to the influence of oversized particles.
4. The multifunctional seepage piping tester has the advantages that the combination mode of all the components is ingenious, efficient and compact, the tester is controlled by a computer, the seepage water flow can be from bottom to top or from top to bottom, the tester is suitable for coarse-grained soil and various scattered-grained soils and used for measuring parameters such as pore water pressure, permeability coefficient, hydraulic gradient, seepage flow rate and the like of the coarse-grained soil, the measurement precision is high, the measurement program is simple and convenient, and the measurement mode is simple.
5. The multifunctional infiltration piping tester provided by the invention overcomes the defect that the traditional permeameter judges the reverse filtration performance only through the sand output, and can test parameters such as the permeability coefficient, the permeation flow, the sand output, the axial stress, the axial strain, the pore water pressure, the local hydraulic gradient and the like of a protected soil (foundation soil) -filter material composite soil layer under different loading conditions such as axial loading and non-loading, so that the application range of various reverse filtration layers of the protected soil layer can be reasonably judged through various composite parameters.
6. According to the multifunctional infiltration piping tester, due to the two pressure volume controllers connected in parallel, an unlimited water supply volume can be provided for the tester, and the defect that the conventional coarse-grained soil permeameter needs to be repeatedly supplemented with water manually is overcome; the maximum 3MPa of osmotic pressure can be provided through the pressure volume controller, and the osmotic pressure can be linearly increased (reduced) to carry out cyclic reciprocating change, thereby truly simulating the specific test conditions of high water head, large flow rate and water level lifting change faced by the existing hydraulic engineering.
Drawings
The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:
FIG. 1 is a schematic view of the structure of the present invention.
FIG. 2 is a schematic diagram of a porous membrane structure according to the present invention.
Reference numbers and corresponding part names in the drawings:
1-axial pressurizer, 2-axial pressurizing rod, 3-sample cylinder top cap, 4-porous penetration plate, 5-sample, 6-hydraulic pressure sensor, 7-soil pressure gauge, 8-sample cylinder top cap water inlet, 9-pressure volume controller, 10-electromagnetic valve, 11-sample cylinder, 12-sample cylinder bottom cap funnel-shaped leak groove, 13-leak groove water outlet, 14-fixing bolt, 15-loading reaction frame, 16-silt water filtering and separating device, 17-rubber ring, 18-penetration hole, 19-top cap exhaust valve, 20-support frame, 21-displacement sensor and 22-center hole.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not meant to limit the present invention.
Example 1
As shown in fig. 1-2, a multifunctional osmotic piping tester comprises a loading reaction frame 15 and a sample tube 11, wherein the sample tube 11 is arranged inside the loading reaction frame 15, the sample tube 11 is fixed by a support frame 20 arranged on the loading reaction frame 15, an axial pressurizer 1 is fixedly arranged at the top of the loading reaction frame 15, an axial pressure rod 2 is arranged at the lower part of the axial pressurizer 1, a displacement sensor 21 is arranged on the axial pressure rod 2, a sample tube top cap 3 is arranged at the upper part of the sample tube 11, the sample tube top cap 3 and the sample tube 11 are fixed together by a fixing bolt 14, an exhaust valve 19, a water inlet 8 and a central hole 22 of the sample tube top cap are arranged on the sample tube top cap 3, the axial pressure rod 2 can pass through the central hole 22, and the water inlet 8 of the sample tube top cap is connected with a pressure volume controller 9, the pressure volume controller 9 is provided with an electromagnetic valve 10 through a pipeline between a polytetrafluoroethylene tube and a sample tube top cap water inlet 8, the bottom of the sample tube 11 is provided with a sample tube bottom cap funnel-shaped leak groove 12, the bottom of the sample tube bottom cap funnel-shaped leak groove 12 is provided with a leak groove water outlet 13, the leak groove water outlet 13 is connected with an external silt water filtering and separating device 16 through the polytetrafluoroethylene tube, the side wall of the sample tube 11 is uniformly provided with water pressure sensors 6 from top to bottom, the sample tube top cap water inlet 8 and the leak groove water outlet 13 are provided with the water pressure sensors 6, the upper, middle and lower parts of the side wall of the sample tube 11 are provided with soil pressure gauges 7, the sample tube 11 is internally provided with a sampleThe device comprises a product 5, wherein porous penetration plates 4 are arranged at the upper part and the lower part of a sample 5 in a sample cylinder 11, the porous penetration plates 4 and the sample cylinder 11 are sealed by rubber rings 17, the porous penetration plates 4 are provided with penetration holes 18, a tester can connect a pressure volume controller 9 with a lower leakage groove water outlet 13 through a polytetrafluoroethylene tube to be used as a water inlet, a sample cylinder top cap water inlet 8 and a silt water filtering and separating device 16 are used as water outlets through the polytetrafluoroethylene tube to enable the tester to generate vertical upward seepage flow for the sample and test, the pressure volume controller 9 is provided with two sets, each pressure volume controller 9 is provided with a solenoid valve 10 control switch, the two set pressure volume controllers 9 are connected in parallel in the test process, and after the pressure value required by the test is set on computer software according to the requirement of the water head pressure of each time, the change control of the system pressure head is realized by operating two pressure volume controllers 10 connected in parallel through a computer. When one volume controller is in work, the other pump pumps water and pressurizes to a set pressure value, when water in the first station permeates to a set limit value, the water in the first station is quickly switched to the second station to work through the electromagnetic valve, so that the constant or uniform change of the water head pressure is ensured, the infinite water supply volume can be reached under the matching of the two pressure volume controllers 10, and the pressure volume controller 9 provides the maximum pressure as follows: 3MPa, i.e. the maximum pressure head: 300 m; the calculation formula of the pressure head is as follows: h isp＝p/γwWherein: h isp-a head of pressure water, m; p-pressure supplied by the pressure volume controller 9, kPa; gamma raywWater gravity, kN/m3(ii) a The pressure volume controller 9 provides: the pressure measuring device comprises a linear pressurizing mode of 0MPa → 3MPa and a linear depressurizing mode of 3MPa → 0MPa, wherein the inner wall of an organic glass sample cylinder 11 is treated by adopting a polytetrafluoroethylene coating technology, the glass sample cylinder 11 is sequentially provided with 3-5 pressure measuring holes and 3-5 soil pressure meter interface holes at equal intervals and is respectively connected with a water pressure sensor 6 and a soil pressure meter 7, the water pressure sensor 6, an axial pressurizer 1, a displacement sensor 21 and the soil pressure meter 7 are all connected with a data acquisition computer arranged outside, the data acquisition instrument automatically acquires data, and internal software is used for carrying out data meters with different working conditionsCalculation and classified storage, a multifunctional test method of a permeability piping tester, comprising the following steps:
and 2, filling the samples in layers according to the designed compactness, wherein the height of each layer of soil sample cannot exceed the height of the bottom of the soil pressure gauge 7, manually compacting, and cleaning the surfaces of the samples after the required compactness and height are achieved. Installing a steel wire filter screen and a porous penetration plate 4 on the top of a sample cylinder 4, placing the sample cylinder 4 on a support frame 20, installing a funnel-shaped leakage groove 12 of a bottom cap of the sample cylinder and a top cap 3 of the sample cylinder, and respectively connecting the funnel-shaped leakage groove 12 and the top cap 3 of the sample cylinder to a pressure volume controller 9 and a sediment water filtering device 16;
and 5, connecting the pressure volume controller 9 to a funnel-shaped leakage groove 12 of a bottom cap of the sample cylinder through a polytetrafluoroethylene guide pipe, connecting the silt water filtering device 16 to a top cap 3 of the sample cylinder through the polytetrafluoroethylene guide pipe, and opening a water inlet valve of the pressure volume controller 9 and a water stop valve of the silt water filtering device 16 to form a downward-upward seepage path. The water supply pressure of the pressure volume controller 9 is increased step by step, the data of time, a water pressure sensor 6, a soil pressure gauge 7, a displacement sensor, an osmotic flow Q, the amount of exuded fine particles and the like are recorded step by step, and the pore water pressure p, the osmotic coefficient ki, the water conservancy gradient and the effective stress of soil layers with different depths of the sample in each time period are calculated;
the water pressure sensor 6, the axial pressurizer 1, the displacement sensor 21 and the soil pressure gauge 7 are all connected with a data acquisition computer arranged outside, data are automatically acquired by a data acquisition instrument, and data calculation and classified storage under different working conditions are performed by internal software.
Example 2
As shown in fig. 1-2, a multifunctional osmotic piping tester comprises a loading reaction frame 15 and a sample tube 11, wherein the sample tube 11 is arranged inside the loading reaction frame 15, the sample tube 11 is fixed by a support frame 20 arranged on the loading reaction frame 15, an axial pressurizer 1 is fixedly arranged at the top of the loading reaction frame 15, an axial pressure rod 2 is arranged at the lower part of the axial pressurizer 1, a displacement sensor 21 is arranged on the axial pressure rod 2, a sample tube top cap 3 is arranged at the upper part of the sample tube 11, the sample tube top cap 3 and the sample tube 11 are fixed together by a fixing bolt 14, an exhaust valve 19, a water inlet 8 and a central hole 22 of the sample tube top cap are arranged on the sample tube top cap 3, the axial pressure rod 2 can pass through the central hole 22, and the water inlet 8 of the sample tube top cap is connected with a pressure volume controller 9, the pressure volume controller 9 is provided with an electromagnetic valve 10 through a pipeline between a polytetrafluoroethylene tube and a sample tube top cap water inlet 8, the bottom of the sample tube 11 is provided with a sample tube bottom cap funnel-shaped leak groove 12, the bottom of the sample tube bottom cap funnel-shaped leak groove 12 is provided with a leak groove water outlet 13, the leak groove water outlet 13 is connected with an externally arranged silt water filtering and separating device 16 through the polytetrafluoroethylene tube, the side wall of the sample tube 11 is uniformly provided with water pressure sensors 6 from top to bottom, the top cap water inlet 8 and the leak groove water outlet 13 of the sample tube are provided with the water pressure sensors 6, the upper, middle and lower parts of the side wall of the sample tube 11 are provided with soil pressure gauges 7, the sample tube 11 is internally provided with a sample 5, the upper and lower parts of the sample 5 in the sample tube 11 are provided with porous permeation plates 4, and the porous permeation plates 4 are sealed with the sample tube 11 through a rubber ring 17, the porous penetration plate 4 is provided with penetration holes 18,the tester can connect the pressure volume controller 9 with a lower leakage groove water outlet 13 through a polytetrafluoroethylene pipe to be used as a water inlet, and the sample cylinder top cap water inlet 8 is used as a water outlet through the polytetrafluoroethylene pipe and a silt water filtering and separating device 16, so that the tester can produce vertical upward seepage and test on a sample, the pressure volume controller 9 is provided with two pressure volume controllers, each pressure volume controller 9 is provided with a control switch of an electromagnetic valve 10, the two pressure volume controllers 9 are connected in parallel in the experiment process, and after the pressure value required by the experiment is set on computer software according to the pressure requirement of the water head experiment at each time, the two pressure volume controllers 10 connected in parallel are operated by the computer to realize the change control of the system pressure water head. When one volume controller is in work, the other pump pumps water and pressurizes to a set pressure value, when water in the first station permeates to a set limit value, the water in the first station is quickly switched to the second station to work through the electromagnetic valve, so that the constant or uniform change of the water head pressure is ensured, the infinite water supply volume can be reached under the matching of the two pressure volume controllers 10, and the pressure volume controller 9 provides the maximum pressure as follows: 3MPa, i.e. the maximum pressure head: 300 m; the calculation formula of the pressure head is as follows: h isp＝p/γwWherein: h isp-a head of pressure water, m; p-pressure supplied by the pressure volume controller 9, kPa; gamma raywWater gravity, kN/m3(ii) a The pressure volume controller 9 provides: the pressure measuring device comprises a linear pressurizing mode of 0MPa → 3MPa and a linear depressurizing mode of 3MPa → 0MPa, wherein the inner wall of an organic glass sample cylinder 11 is processed by adopting a polytetrafluoroethylene coating technology, 3-5 pressure measuring holes and 3-5 soil pressure meter interface holes are sequentially arranged at equal intervals on the glass sample cylinder 11 and are respectively connected with a water pressure sensor 6 and a soil pressure meter 7, the water pressure sensor 6, an axial pressurizer 1, a displacement sensor 21 and the soil pressure meter 7 are all connected with a data acquisition computer arranged outside, data are automatically acquired by a data acquisition instrument, and data calculation and classified storage of different working conditions are carried out by internal software.
A test method of a multifunctional infiltration piping tester comprises the following steps:
and 2, sequentially filling the foundation soil samples in a layered manner according to the designed thickness and compactness of the foundation soil, wherein the height of each layer of soil sample cannot exceed the height of the bottom of the soil pressure gauge 7, manually compacting, and cleaning the surface of the foundation soil sample after the required compactness and height are achieved to enable the surface of the sample to be flat. And sequentially filling the anti-filtering material samples on the surface of the foundation soil sample in layers, and respectively leveling and compacting the samples until the thickness of the anti-filtering material is designed. And a pebble layer with a certain thickness is filled on the top of the filter material in a layered mode. Installing a steel wire filter screen and a porous penetration plate 4 on the top of a sample cylinder 4, placing the sample cylinder 4 on a support frame 20, installing a funnel-shaped leakage groove 12 of a bottom cap of the sample cylinder and a top cap 3 of the sample cylinder, and respectively connecting the funnel-shaped leakage groove 12 and the top cap 3 of the sample cylinder to a pressure volume controller 9 and a sediment water filtering device 16;
and 5, connecting the pressure volume controller 9 to a funnel-shaped leakage groove 12 of a bottom cap of the sample cylinder through a polytetrafluoroethylene guide pipe, connecting the silt water filtering device 16 to a top cap 3 of the sample cylinder through the polytetrafluoroethylene guide pipe, and opening a water inlet valve of the pressure volume controller 9 and a water stop valve of the silt water filtering device 16 to form a downward-upward seepage path. The water supply pressure of the pressure volume controller 9 is increased step by step, data such as time, water pressure sensor 6, soil pressure meter 7, displacement sensor, seepage flow Q, seepage fine particle amount and the like are recorded step by step, pore water pressure p, seepage coefficient ki, water conservancy gradient and effective stress of soil layers with different depths of the sample are calculated in each time period, the water pressure sensor 6, the axial pressurizer 1, the displacement sensor 21 and the soil pressure meter 7 are all connected with a data acquisition computer arranged outside, data are automatically acquired by a data acquisition instrument, and data calculation and classified storage of different working conditions are carried out by internal software.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (10)
1. The multifunctional seepage piping tester comprises a loading reaction frame (15) and a sample cylinder (11), and is characterized in that the sample cylinder (11) is arranged inside the loading reaction frame (15), the sample cylinder (11) is fixed by a support frame (20) arranged on the loading reaction frame (15), an axial pressurizer (1) is fixedly arranged at the top of the loading reaction frame (15), an axial pressurizing rod (2) is arranged at the lower part of the axial pressurizer (1), a displacement sensor (21) is arranged on the axial pressurizing rod (2), a sample cylinder top cap (3) is arranged at the upper part of the sample cylinder (11), the sample cylinder top cap (3) and the sample cylinder (11) are fixed together by a fixing bolt (14), a top cap exhaust valve (19), a sample cylinder top cap water inlet (8) and a central hole (22) are arranged on the sample cylinder top cap (3), the axial pressurizing rod (2) can penetrate through a center hole (22), the sample cylinder top cap water inlet (8) is connected with a pressure volume controller (9), the pressure volume controller (9) is provided with an electromagnetic valve (10) through a pipeline between a polytetrafluoroethylene tube and the sample cylinder top cap water inlet (8), the bottom of the sample cylinder (11) is provided with a sample cylinder bottom cap funnel-shaped leakage groove (12), the bottom of the sample cylinder bottom cap funnel-shaped leakage groove (12) is provided with a leakage groove water outlet (13), the leakage groove water outlet (13) is connected with a silt water filtering and separating device (16) arranged outside through the polytetrafluoroethylene tube, the side wall of the sample cylinder (11) is uniformly provided with water pressure sensors (6) from top to bottom, and the sample cylinder top cap water inlet (8) and the leakage groove water outlet (13) are provided with water pressure sensors (6), the soil pressure gauge (7) is arranged at the upper, middle and lower parts of the side wall of the sample cylinder (11), a sample (5) is arranged in the sample cylinder (11), porous permeation plates (4) are arranged at the upper and lower parts of the sample (5) in the sample cylinder (11), the porous permeation plates (4) and the sample cylinder (11) are sealed through arranged rubber bands (17), and permeation holes (18) are formed in the porous permeation plates (4).
2. The multifunctional infiltration piping tester of claim 1, wherein the tester can connect the pressure volume controller (9) with the lower leak tank water outlet (13) through a polytetrafluoroethylene tube to be used as a water inlet, and the sample cylinder top cap water inlet (8) with the silt water filtering and separating device (16) through a polytetrafluoroethylene tube to be used as a water outlet, so that the tester can produce vertical upward seepage flow to the sample and test the sample.
3. The multifunctional infiltration piping tester as claimed in claim 1, wherein the pressure volume controllers (9) are provided with two, each pressure volume controller (9) is provided with a solenoid valve (10) control switch, the two pressure volume controllers (9) are connected in parallel in the process of experiment, according to the requirement of water head pressure of each experiment, after the pressure value required by the experiment is set on the computer software, the change control of the system pressure water head is realized by operating the two pressure volume controllers (9) connected in parallel through the computer; when one volume controller works, the other one pumps water and pressurizes to a set pressure value, when water in the first one permeates to a set limit value, the water in the first one is quickly switched to the second one to work through the electromagnetic valve, so that the constant or uniform change of the water head pressure is ensured, and the infinite water supply volume can be achieved under the matching of the two pressure volume controllers (9).
4. A multifunctional osmotic piping tester according to claim 3, characterized in that the pressure volume controller (9) provides a maximum pressure of: 3MPa, i.e. the maximum pressure head: 300 m; the calculation formula of the pressure head is as follows:
hp＝p/γw
wherein: h isp-a head of pressure water, m; p-pressure, kPa, provided by a pressure volume controller (9); gamma raywWater gravity, kN/m3(ii) a The pressure volume controller (9) provides: a linear pressurization mode of 0MPa → 3MPa and a linear depressurization mode of 3MPa → 0 MPa.
5. The multifunctional infiltration piping tester of claim 1, wherein the inner wall of the organic glass sample cylinder (11) is treated by polytetrafluoroethylene coating technology.
6. The multifunctional infiltration piping tester of claim 5, characterized in that the sample cylinder (11) is sequentially provided with 3-5 pressure measuring holes and 3-5 soil pressure meter interface holes at equal intervals and is respectively connected with the water pressure sensor (6) and the soil pressure meter (7).
7. The multifunctional infiltration piping tester as claimed in claim 1, wherein the water pressure sensor (6), the axial pressurizer (1), the displacement sensor (21) and the soil pressure gauge (7) are all connected with an externally arranged data acquisition computer, data are automatically acquired by the data acquisition computer, and data calculation and classified storage under different working conditions are performed by internal software.
8. The multifunctional osmotic piping tester test method according to any one of claims 1 to 7, characterized by comprising the following steps:
step 1, selecting a representative sample, drying, carrying out a particle analysis test, drawing a sample grading curve, installing a porous penetration plate (4) to the bottom of a sample cylinder (11) by using an O-shaped sealing ring, and installing a metal filter screen on the upper part of the porous penetration plate;
step 2, filling the samples in layers according to the designed compactness, wherein the height of each layer of soil sample cannot exceed the bottom height of the soil pressure gauge (7), manually compacting, and cleaning the surfaces of the samples after the required compactness and height are achieved; a steel wire filter screen and a porous penetration plate (4) are arranged at the top of a sample cylinder (11), the sample cylinder (11) is arranged on a support frame (20), a funnel-shaped leak groove (12) of a bottom cap of the sample cylinder and a top cap (3) of the sample cylinder are arranged, and the funnel-shaped leak groove and the top cap are respectively connected to a pressure volume controller (9) and a silt water filtering and separating device (16);
step 3, opening a water inlet valve of the pressure volume controller (9), opening a top cap exhaust valve (19) of the sample barrel, closing a water stop valve of the muddy water filtering and separating device (16), debugging the pressure volume controller (9) through computer software, applying pressure of 10kPa to the pressure volume controller (9), allowing water to slowly seep through the sample until water overflows from the top cap exhaust valve (19), connecting a polytetrafluoroethylene conduit to a 10L plastic barrel on the top cap exhaust valve (19), and allowing the water to slowly flow into the plastic barrel for more than 3h so as to completely discharge bubbles in the sample;
step 4, closing the top cap exhaust valve (19), controlling the axial pressurizer (1) to apply 5N axial force to the porous penetration plate (4) through the axial pressurizing rod (2), enabling the axial pressurizing rod (2) to be in contact with the porous penetration plate (4), and enabling the porous penetration plate (4) to be in close contact with the top of the sample;
step 5, connecting the pressure volume controller (9) to a funnel-shaped leakage groove (12) of a bottom cap of a sample cylinder through a polytetrafluoroethylene guide pipe, connecting a silt water filtering and separating device (16) to a top cap (3) of the sample cylinder through the polytetrafluoroethylene guide pipe, and opening a water inlet valve of the pressure volume controller (9) and a water stop valve of the silt water filtering and separating device (16) to form a seepage path from bottom to top; the water supply pressure of the pressure volume controller (9) is increased step by step, the data of time, a water pressure sensor (6), a soil pressure gauge (7), a displacement sensor, seepage flow Q, seepage fine particle quantity and the like are recorded step by step, and the pore water pressure p of soil layers with different depths of the sample in each time period is calculatediHydraulic gradient iiPermeability coefficient kiEffective stress; permeability coefficient k of each soil layeriAnd hydraulic gradient iiIs calculated as follows:
wherein: p is a radical ofi-pore water pressure, kPa, measured by a water pressure sensor (6) of the ith soil layer; p is a radical ofi+1-pore water pressure, kPa, measured by a water pressure sensor (6) of the i +1 th soil layer; gamma raywWater gravity, kN/m3；Δli-vertical thickness of the ith soil layer, m; i.e. ii-hydraulic gradient of ith soil layer; q-osmotic flow, m3S; a-cross-sectional area of soil layer, m2；ki-permeability coefficient of the ith soil layer, m/s.
9. The multifunctional osmotic piping tester test method according to any one of claims 1 to 7, characterized by comprising the following steps:
step 1, selecting representative base soil and filter material samples, drying, performing a particle analysis test, and respectively drawing grading curves of the base soil and the filter material samples; mounting a porous penetration plate (4) to the bottom of a sample cylinder (11) by using an O-shaped sealing ring, and mounting a metal filter screen on the upper part of the porous penetration plate;
step 2, sequentially filling foundation soil samples in a layered mode according to the designed thickness and compactness of the foundation soil, enabling the height of each layer of soil sample to be not more than the bottom height of the soil pressure gauge (7), manually compacting, and cleaning the surface of the foundation soil sample after the required compactness and height are achieved to enable the surface of the sample to be flat; sequentially filling anti-filter material samples on the surface of the foundation soil sample in layers, and respectively leveling and compacting the anti-filter material samples until the thickness of the anti-filter material is designed; filling a pebble layer with a certain thickness on the top of the filter material in a layered manner; a steel wire filter screen and a porous penetration plate (4) are arranged at the top of a sample cylinder (11), the sample cylinder (11) is arranged on a support frame (20), a funnel-shaped leak groove (12) of a bottom cap of the sample cylinder and a top cap (3) of the sample cylinder are arranged, and the funnel-shaped leak groove and the top cap are respectively connected to a pressure volume controller (9) and a silt water filtering and separating device (16);
step 3, opening a water inlet valve of the pressure volume controller (9), opening a top cap exhaust valve (19) of the sample barrel, closing a water stop valve of the muddy water filtering and separating device (16), debugging the pressure volume controller (9) through computer software, applying pressure of 10kPa to the pressure volume controller (9), allowing water to slowly seep through the sample until water overflows from the top cap exhaust valve (19), connecting a polytetrafluoroethylene conduit to a 10L plastic barrel on the top cap exhaust valve (19), and allowing the water to slowly flow into the plastic barrel for more than 3h so as to completely discharge bubbles in the sample;
step 4, closing the top cap exhaust valve (19), controlling the axial pressurizer (1) to apply 5N axial force to the porous penetration plate (4) through the axial pressurizing rod (2), enabling the axial pressurizing rod (2) to be in contact with the porous penetration plate (4), and enabling the porous penetration plate (4) to be in close contact with the top of the sample;
step 5, connecting the pressure volume controller (9) to a funnel-shaped leakage groove (12) of a bottom cap of a sample cylinder through a polytetrafluoroethylene guide pipe, connecting a silt water filtering and separating device (16) to a top cap (3) of the sample cylinder through the polytetrafluoroethylene guide pipe, and opening a water inlet valve of the pressure volume controller (9) and a water stop valve of the silt water filtering and separating device (16) to form a seepage path from bottom to top; the water supply pressure of the pressure volume controller (9) is increased step by step, the data of time, a water pressure sensor (6), a soil pressure gauge (7), a displacement sensor, seepage flow Q, seepage fine particle quantity and the like are recorded step by step, and the pore water pressure p of soil layers with different depths of the sample in each time period is calculatediHydraulic gradient iiPermeability coefficient kiEffective stress; permeability coefficient k of each soil layeriAnd hydraulic gradient iiIs calculated as follows:
wherein: p is a radical ofi-pore water pressure, kPa, measured by a water pressure sensor (6) of the ith soil layer; p is a radical ofi+1Of the (i + 1) th soil layerPore water pressure, kPa, measured by a water pressure sensor (6); gamma raywWater gravity, kN/m3；Δli-vertical thickness of the ith soil layer, m; i.e. ii-hydraulic gradient of ith soil layer; q-osmotic flow, m3S; a-cross-sectional area of soil layer, m2；ki-permeability coefficient of the ith soil layer, m/s.
10. The multifunctional infiltration piping tester as claimed in claim 1, wherein the water pressure sensor (6), the axial pressurizer (1), the displacement sensor (21) and the soil pressure gauge (7) are all connected with an externally arranged data acquisition computer, data are automatically acquired by the data acquisition computer, and data calculation and classified storage under different working conditions are performed by internal software.
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| CN111239020A (en) * | 2020-02-10 | 2020-06-05 | 山东大学 | Soil permeability coefficient measuring device and method capable of considering rainfall and vegetation influence |
| CN112268844A (en) * | 2020-10-14 | 2021-01-26 | 浙大城市学院 | Seepage erosion control system and test method under GDS triaxial apparatus drainage condition |
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| CN112630126A (en) * | 2021-01-13 | 2021-04-09 | 大连理工大学 | Nondestructive in-situ permeability testing device and method suitable for cemented soil |
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| CN112268844A (en) * | 2020-10-14 | 2021-01-26 | 浙大城市学院 | Seepage erosion control system and test method under GDS triaxial apparatus drainage condition |
| CN112268816A (en) * | 2020-10-14 | 2021-01-26 | 浙大城市学院 | Back pressure control system of GDS triaxial apparatus under condition of no drainage and operation method thereof |
| CN112798488A (en) * | 2020-12-29 | 2021-05-14 | 苏州汇才土水工程科技有限公司 | Device and method for transient measurement of permeability coefficient |
| CN112630126A (en) * | 2021-01-13 | 2021-04-09 | 大连理工大学 | Nondestructive in-situ permeability testing device and method suitable for cemented soil |
| CN112964623A (en) * | 2021-03-23 | 2021-06-15 | 哈尔滨工业大学 | Experimental device for axial permeation of annular tissue engineering scaffold and use method |
| CN113203671B (en) * | 2021-04-30 | 2024-03-01 | 长安大学 | Laser type permeable pavement permeability coefficient testing device and method |
| CN113203671A (en) * | 2021-04-30 | 2021-08-03 | 长安大学 | Laser type permeable pavement permeability coefficient testing device and method |
| CN113739984A (en) * | 2021-08-18 | 2021-12-03 | 中国科学院西北生态环境资源研究院 | Device for measuring frozen soil pore water pressure change |
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| CN115046892A (en) * | 2022-06-30 | 2022-09-13 | 重庆大学 | Testing device for soil-rock mixture seepage model test under dry-wet cycle condition |
| CN115493985A (en) * | 2022-09-23 | 2022-12-20 | 浙江大学 | Supergravity temperature control variable water head seepage test device and method |
| CN115493985B (en) * | 2022-09-23 | 2024-02-27 | 浙江大学 | Supergravity temperature control variable head seepage test device and method |
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