CN107703035B - Crack seepage tester under high water head-high stress action - Google Patents
Crack seepage tester under high water head-high stress action Download PDFInfo
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- CN107703035B CN107703035B CN201610470862.XA CN201610470862A CN107703035B CN 107703035 B CN107703035 B CN 107703035B CN 201610470862 A CN201610470862 A CN 201610470862A CN 107703035 B CN107703035 B CN 107703035B
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- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/08—Investigating permeability, pore-volume, or surface area of porous materials
- G01N15/082—Investigating permeability by forcing a fluid through a sample
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/08—Investigating permeability, pore-volume, or surface area of porous materials
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Abstract
The invention discloses a crack seepage tester under the action of high water head-high stress, which comprises a test groove, a front water collecting tank, a rear water collecting tank and a longitudinal pressurizing device, wherein the front water collecting tank and the rear water collecting tank are respectively connected with two opposite side walls of the test groove and are used for applying horizontal pressure to the test groove, and the longitudinal pressurizing device is positioned above the test groove and is used for applying longitudinal pressure to the test groove. The method can well study the water-force coupling seepage characteristics of the diaphragm wall crack and the foundation soil stone in the deep covering layer, the research result is more in line with the actual situation, and scientific basis and technical support can be provided for the reinforcing treatment of the diaphragm wall and the seepage prevention design of the deep covering layer.
Description
Technical Field
The invention belongs to the technical field of hydraulic engineering, and particularly relates to a crack seepage tester under the action of high water head-high stress.
Background
The deep covering layer is a complex geological condition which is often encountered in China in developing hydropower engineering in southwest mountainous areas in recent years, and the thickness of the deep covering layer is dozens of meters to hundreds of meters. At present, a vertical seepage-proofing mode is mostly adopted for seepage control of the foundation, and a concrete seepage-proofing wall is the most preferred and reliable engineering measure.
However, the thin wall thickness of the concrete diaphragm wall makes it easy to produce different cracks during construction and operation for various reasons: in the construction process of the impervious wall, the problems of complex foundation conditions, poor clay slurry quality, construction process and the like often cause the phenomena of splitting cracks and lower part splitting of the wall body; after the dam is built, because of the difference in material rigidity, the impervious wall can generate uneven settlement and deformation at the junction of the covering layer and the foundation, and the deformation can cause a plurality of pulling cracks on the wall body; after the reservoir stores water, under the action of the upper pressure load and the water load, the wall body is subjected to bending combined load action and will be bent under the restraint of a dam body and bedrock, and longitudinal cracks may occur; under the earthquake condition, the structure calculation result shows that the concrete impervious wall in the foundation of the deep overburden layer of the high earth-rock dam can also generate cracks with different scales under the action of dynamic load, and the like.
The cracks of the concrete impervious wall, particularly the transverse and longitudinal penetrating cracks, gradually weaken the local seepage-stopping performance of the impervious wall and aggravate seepage at the cracks along with the increase of the opening degree of the cracks, wash the downstream of the wall body, influence the seepage stability of a covering layer foundation, change the original stress and deformation state in the foundation, cause the redistribution of the local stress and deformation of the foundation and cause the influence which is difficult to estimate on the engineering safety. In addition, because the grain composition curve of the deep covering layer is mostly in a steep structure with coarse grains as main bodies to a flat fine structure, after the concrete impervious wall in the foundation cracks, fine grains can enter the cracks under the action of the pressure of upper covering soil and the permeability of underground water, and the fine grains can fill the cracks under proper reverse filtration conditions at the downstream of the impervious wall, so that a certain healing effect on the cracks of the impervious wall is achieved, the flow state of the underground water at the local cracks is improved, if no reverse filtration or a reverse filtration layer is arranged at the downstream of the impervious wall and damaged, the fine grains in the foundation can escape along the cracks of the wall and pores between coarse grains, and form piping or flowing soil damage at the downstream, thereby endangering the engineering safety.
Therefore, whether the concrete impervious wall in the foundation of the deep covering layer cracks or cracks are filled or not can affect the flow state of underground water in the foundation and the infiltration stability of a dam foundation, further great influence can be generated on the water storage effect of a reservoir and the seepage safety of engineering, and even the safety of the whole engineering can be threatened, and the influence is more serious especially in areas with frequent earthquakes.
At present, the research on seepage analysis test instruments under the cracking condition of the concrete diaphragm wall is few at home and abroad, and the cubic law reflecting the seepage of fractured rock mass is still adopted in most cases. The existing instrument is used for simulating cracks or is parallel to a glass plate, and water supply equipment is still an upstream water tank and a downstream water tank, so that the tester has the following problems:
①, the crack simulation is insufficient, the smooth crack simulation can adopt a parallel glass plate, but the cracks with different types, roughness and the like cannot be simulated, and the cracks of the actual impervious wall are rough and have various crack forms;
② can only singly reflect the influence of underground water on the seepage characteristic of the crack, but can not reflect the actual seepage of the crack under the stress coupling condition, and can not reflect the coupling effect under the high water head-high stress, which is far away from the actual engineering, the test result can not well reflect the actual water-force environment of the diaphragm wall in the deep covering layer, and the engineering guidance significance is not great;
③ can not reflect the condition and process of filling cracks under different grading soils from the microscopic view, and only can only consider the filling effect of fine particles on slab cracks, so the relation between the actual crack filling and the load, water pressure, crack opening and particle diameter of the concrete impervious wall is not clear, and the method is not enough to provide scientific basis and technical support for the reinforcing treatment of the impervious wall and the impervious design of deep and thick covering layers.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide a crack seepage tester under the action of high water head-high stress, which is used for simulating the action of high-pressure groundwater and high overburden load.
In order to achieve the above object, the present invention provides a crack seepage tester under high head-high stress action, which comprises a test tank, a front water collecting tank, a rear water collecting tank and a longitudinal pressurizing device, wherein the front water collecting tank and the rear water collecting tank are respectively connected to two opposite sidewalls of the test tank for applying a horizontal pressure to the test tank, and the longitudinal pressurizing device is located above the test tank for applying an axial pressure to the test tank.
In some embodiments, the front header tank is connected to the upstream reservoir vessel and the rear header tank is connected to the downstream reservoir vessel, the upstream reservoir vessel supplying water to the front header tank so that the water continues to enter the test tank, then flows out through the rear header tank and finally flows into the downstream reservoir vessel for collection.
In some embodiments, the side wall of the test tank connected with the front water collecting tank is provided with a plurality of water passing holes, the top of the front water collecting tank is provided with an exhaust valve, and a front water collecting cavity for collecting water is arranged in the front water collecting tank;
the side wall of the test tank connected with the rear water collecting tank is provided with a plurality of water passing holes, and a rear water collecting cavity for collecting water is arranged in the rear water collecting tank.
In some embodiments, the test tank is further provided with a reinforcing plate on the side wall connected with the front header tank, the reinforcing plate is used for limiting the lateral deformation of the earth and rock materials under high water head and high stress;
the side wall of the test tank connected with the rear water collecting tank is also provided with a reinforcing plate, and the reinforcing plate is used for limiting the lateral deformation of soil and stone materials under high water head high stress.
In some embodiments, the bottom of the rear header tank is provided with a pellet outlet for discharging soil and stone materials entering the rear header tank;
the top of the rear water collecting tank is provided with a water outlet for discharging water in the rear water collecting cavity, and the water outlet is communicated to a downstream reservoir container through a pipeline.
In some embodiments, the system further comprises a load sensor connected with the downstream reservoir container and a support frame for supporting the downstream reservoir container, wherein the top of the downstream reservoir container is provided with an exhaust valve, and the bottom of the downstream reservoir container is communicated with the water outlet of the rear water collecting tank.
In some embodiments, the longitudinal pressing device comprises an oil cylinder for providing axial pressure, a pressure transfer plate, and a pressure bearing seat arranged on the upper surface of the pressure transfer plate, the lower surface of the pressure transfer plate faces the test groove, and the pressure bearing seat is used for transferring the pressure of the oil cylinder to the pressure transfer plate.
In some embodiments, the upper surface of the pressure bearing seat is recessed inwards to form a spherical groove, and correspondingly, the lower surface of the oil cylinder is provided with a spherical pressure transmission head which can be embedded into the spherical groove and is used for transmitting the loading pressure of the oil cylinder to the pressure bearing seat.
In some embodiments, the longitudinal pressurizing device further comprises a connecting seat and a load sensor for feeding back load data, wherein the upper surface of the connecting seat is connected to the oil cylinder, the lower surface of the connecting seat is connected to the load sensor, and the load sensor is connected with the spherical pressure transmission head.
In some embodiments, the longitudinal pressurizing device further comprises a pressure regulating cylinder, the pressure regulating cylinder is connected with the oil cylinder through a high-pressure oil pipe, and the required axial load is provided for the longitudinal pressurizing device;
and the displacement sensor clamp and the displacement sensor are arranged on the upper part of the test groove, and the displacement sensor clamp is used for mounting the displacement sensor on the upper part of the test groove.
Therefore, aiming at the high water head and high stress environment in the deep covering layer, the seepage characteristic under the impervious wall crack is solved, the defects of the existing equipment are completely overcome, and the following technical effects can be achieved:
(1) the test groove is internally provided with a clamping groove, so that the spatial position of the concrete slab can be well controlled; meanwhile, the concrete slab used in the test is poured according to the process, so that different cracks of the concrete impervious wall can be set according to the actual situation, wherein the cracks comprise form, opening degree, roughness and the like;
(2) the instrument is provided with an upstream reservoir container and a longitudinal pressurizing device, and can well simulate the action of high-pressure underground water and high overburden load respectively, wherein the height of a test seepage head can reach 50m, the axial loading stress can reach 1000kN (converted into axial load of about 3MPa), and the high-water-pressure and high-ground-stress environment existing in a deep covering layer foundation and a concrete impervious wall can be reflected more truly;
(3) in a large-scale test tank, soil and stone materials with different grain compositions can be filled in the upper part and the lower part of a concrete slab, so that the healing effect of cracks under different grain compositions can be reflected, meanwhile, the side wall of the test tank is formed by organic glass and a steel plate, the crack filling process can be observed from a microscopic angle, the research on the relation characteristics between the actual crack filling and load, water pressure, crack opening and grain diameter of the concrete impervious wall can be more scientifically and effectively carried out, the research result is more in line with the actual situation, and scientific basis and technical support can be provided for the reinforcement treatment of the impervious wall and the impervious design of a deep covering layer.
(4) The side wall of the test tank is made of organic glass and steel plates, the crack filling process can be observed from a microscopic angle, and the research on the relation characteristics between the actual crack filling and load, water pressure, crack opening and particle diameter of the concrete impervious wall can be developed more scientifically and effectively.
(5) The downstream side of the test tank is also provided with a fine aggregate collecting device, so that the loss condition of different-grade soil aggregate after cracking can be collected, and the inner piping phenomenon under the cracking condition of the impervious wall can be well researched.
In addition, if the test tank is not provided with the concrete slab, the test tank becomes a high-water-head and high-stress coupling seepage tester for the soil and stone, and can be used for researching the real seepage characteristics of the soil and stone with different grades in the foundation of the soil and stone dam.
In conclusion, the method can well research the water-force coupling seepage characteristics of the diaphragm wall crack and the foundation soil stone in the deep covering layer, the research result is more in line with the actual situation, and scientific basis and technical support can be provided for the reinforcing treatment of the diaphragm wall and the seepage prevention design of the deep covering layer.
Drawings
For a better understanding of the objects, aspects and advantages of the present invention, reference will now be made in detail to the following description, taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a schematic structural diagram of a fracture seepage tester under the action of a high water head and high stress according to an embodiment of the invention;
fig. 2 is a side view of a fracture seepage tester under high head-high stress action according to an embodiment of the invention.
Detailed Description
The invention is described in further detail below with reference to the figures and specific examples.
In order to solve the seepage characteristic of the cracked impervious wall under the coupling action of high water head and high stress in a deep covering layer, the invention provides the tester for the seepage of the crack under the high water head-high stress action, which can be used for researching the local seepage evolution mechanism of the cracked concrete impervious wall and revealing the influence rule of the influence factors such as high stress, high hydraulic ratio drop, crack opening, roughness, crack number, filling condition and the like on the seepage of the crack.
Referring to fig. 1, a schematic structural diagram of a crack seepage tester under high water head-high stress action according to an embodiment of the present invention is shown, and the crack seepage tester comprises a test tank 1, a front header tank 30, a rear header tank 23, and a longitudinal pressurizing device, wherein the front header tank 30 and the rear header tank 23 are respectively connected to two opposite sidewalls of the test tank 1, and are used for applying a horizontal pressure to the test tank 1, and the longitudinal pressurizing device is located above the test tank 1 and is used for applying an axial pressure to the test tank 1.
The front water collection tank 30 is connected with the upstream reservoir container 31, the rear water collection tank 23 is connected with the downstream reservoir container 36, and the upstream reservoir container 31 supplies water to the front water collection tank 30, so that the water continuously enters the test slot 1, flows out through the rear water collection tank 23 and finally flows into the downstream reservoir container 36 to be collected. It can be seen that the present invention applies a horizontal pressure to the test cell 1 via the upstream reservoir tank 31 and the downstream reservoir tank 36. As shown in fig. 1, a concrete plate 4 is installed in a test bath 1 filled with a soil material, and the concrete plate 4 is faced to a front header tank 30 and a rear header tank 23 for the purpose of testing a cut-off wall.
In a preferred embodiment of the present invention, the test tank 1 is provided with a plurality of water through holes 7 on the side wall connected to the front water collecting tank 30, the top of the front water collecting tank 30 is provided with an exhaust valve 9, and the front water collecting tank 30 is internally provided with a front water collecting cavity 8 for collecting water. Therefore, the water in the upstream reservoir tank 31 flows into the front water collecting chamber 8 of the front water collecting tank 30, and then penetrates into the test tank 1 through the water passing holes 7. Preferably, the test tank 1 is further provided with a reinforcing plate 32 on the side wall connected to the front header tank 30, the reinforcing plate 32 being used to limit lateral deformation of the soil material under high head stress. Further, a water inlet ball valve 33 is further disposed on a pipe connecting the front water collecting tank 30 and the upstream reservoir container 31, for controlling the water inlet amount of the front water collecting tank 30.
In another preferred embodiment of the present invention, the test tank 1 is provided with a plurality of water through holes 7 on the side wall connected with the rear water collecting tank 23, and a rear water collecting cavity 35 for collecting water is arranged in the rear water collecting tank 23. Therefore, the water in the test tank 1 penetrates into the rear water collecting chamber 35 of the rear water collecting tank 23 through the water passing holes 7, and then flows into the downstream reservoir tank 36. Preferably, the test cell 1 is also provided with a reinforcing plate 32 on the side wall connected to the rear header tank 23.
In a preferred embodiment of the present invention, the bottom of the rear header tank 23 is provided with a pellet outlet 24 for discharging the soil material introduced into the rear header tank 23. The top of the rear water collecting tank 23 is provided with a water outlet for discharging water in the rear water collecting chamber 35, and the water outlet is communicated to the downstream reservoir container 36 through a pipeline, so that water in the water collecting tank 23 flows into the downstream reservoir container 36. Furthermore, a water outlet ball valve 33 is also arranged on the pipeline.
The tester also comprises a load sensor 3 connected with the downstream reservoir container 36 and a support frame 6 used for supporting the downstream reservoir container 36, wherein the top of the downstream reservoir container 36 is provided with an exhaust valve 37, and the bottom of the downstream reservoir container 36 is communicated with the water outlet of the rear water collecting tank 23. The support frame 6 suspends the downstream reservoir tank 36 by the load sensor 3, and the load sensor 3 is used for measuring the weight of the downstream reservoir tank 36 and the water therein. Preferably, the bottom of the downstream reservoir container 36 is opened with a water inlet 12, and the water inlet 12 is communicated to the water outlet of the rear water collecting tank 23.
In a further embodiment of the present invention, the longitudinal pressing device comprises an oil cylinder 18 for providing axial pressure, a pressure transmission plate 5, and a pressure bearing seat 14 mounted on the upper surface of the pressure transmission plate 5, the lower surface of the pressure transmission plate 5 is opposite to the test chamber 1, and the pressure bearing seat 14 is used for transmitting the pressure of the oil cylinder 18 to the pressure transmission plate 5. Preferably, the upper surface of the pressure bearing seat 14 is recessed inwards to form a spherical groove, and correspondingly, the lower surface of the oil cylinder 18 is provided with a spherical pressure transmission head 15, the spherical pressure transmission head 15 can be embedded into the spherical groove, and the spherical pressure transmission head 15 is used for transmitting the loading pressure of the oil cylinder 18 to the pressure bearing seat 14. In the test process, the pressure transmission plate may incline due to different densities and particles of all parts in the soil and stone material filling process in the test tank 1, so that the spherical groove is arranged on the upper surface of the pressure bearing seat 14 to ensure the perpendicularity of the axial force in the test process and prevent the axial force from being influenced by the inclination, and the spherical surface can automatically adjust the center, thereby ensuring the accuracy of the axial force.
Preferably, the longitudinal pressurizing device further comprises a connecting seat 16 and a load sensor 17 for feeding back load data, wherein the upper surface of the connecting seat 16 is connected to an oil cylinder 18, the lower surface of the connecting seat is connected to the load sensor 17, and the load sensor 17 is connected with the spherical pressure transmission head 15. Therefore, the pressure of the oil cylinder 18 is transmitted to the bearing seat 14 through the connecting seat 16, the load sensor 17 and the spherical pressure transmission head 15 in sequence.
In another embodiment of the invention, the longitudinal pressurizing device further comprises a pressure regulating cylinder 2, the pressure regulating cylinder 2 is connected with a cylinder 18 through a high-pressure oil pipe, the required axial load is provided for the longitudinal pressurizing device, and the axial pressure and the axial speed are controlled through feedback of a load sensor 17 on the cylinder 18 and a displacement sensor 20 arranged on the test groove 1. Optionally, the pressure regulating cylinder 2 is a 90-type electric pressure regulating cylinder, and the load of the oil cylinder 18 is 500 kN.
In a preferred embodiment of the present invention, a displacement sensor holder 19 and a displacement sensor 20 are mounted on the upper portion of the test chamber 1, and the displacement sensor holder 19 is used to mount the displacement sensor 20 on the upper portion of the test chamber 1. During the test, the thimble of the displacement sensor 20 is pressed against the pressure transmission plate 5 and moves along with the displacement of the pressure transmission plate 5, so as to measure the deformation of the sample. The water stop 10 is arranged in a clamping groove on the side surface of the pressure transmission plate 5, and lubricant is smeared on the surface during a test and is pressed into the pressure to realize the sealing between the pressure transmission plate 5 and the side wall of the test tank 1.
In another embodiment of the present invention, a pull rod seat 11 is further installed on the upper portion of the test tank 1, and when the axial pressure is too high, in order to prevent the test tank from deforming and affecting the sealing performance between the pressure transmitting plate 5 and the test tank 1, a pull rod can be further installed on the pull rod seat 11 to play a role in strengthening protection.
As shown in FIG. 2, the bottom of the test tank 1 is provided with a lower beam 29, which is connected and fixed with the upper beam 22 into a whole through a column 25 and a column nut 21 to provide a rigid reaction frame for the axial pressure of the equipment. And four rollers 28 are arranged at the bottom of the lower beam 29, so that the test tank 1 can be moved out when the test tank is not used or a test sample is assembled and disassembled, and construction is convenient. The simulated concrete plate 4 is divided into an upper block and a lower block, different height sizes can be prepared according to test requirements, and the simulated concrete plate is respectively connected with the test groove 1 and the pressure transmission plate 5 and is used for simulating the actual conditions of different cracks. The fracture 27 can be simulated by the cut-off wall, and the fracture 27 will change size under the action of axial pressure or be tightly filled under the action of axial force and seepage.
A liquid flow meter is further installed between the upstream reservoir container 31 and the test tank 1 for measuring the liquid flow rate of the upstream reservoir flowing to the test tank 1. Also, a liquid flow meter is installed between the test tank 1 and the downstream reservoir tank 36 to measure the seepage amount.
Further, the tester also comprises a high-pressure air source, and the upstream reservoir container 31 is connected with the high-pressure air source through an air pipe and is used for providing larger water pressure by blowing air into the upstream pressurizing device and the downstream pressurizing device.
The operation steps of the tester are as follows:
1. cleaning up sundries in the test tank, and checking the opening and closing of each valve. Various sensors required for the test were installed. And move the loading reaction frame to the far left. The upstream reservoir container is filled with water and is added to the required water level according to the water level indicator.
2. And (4) installing the bottom impervious wall, checking whether the sealing strip is installed or not before installation, and coating the sealing glue on two sides and the bottom, particularly coating more glue on two right-angle parts of the bottom. After coating, the coating is evenly fastened at the bottom of the test groove by bolts, and then each side seam is coated by silica gel to ensure no leakage. (the diaphragm walls have various height dimensions and can be selected according to the test requirements).
3. And (3) loading the test samples according to the test requirements, inserting the lower impervious wall into the middle part of the test tank in advance, filling the test samples on two sides, and compacting the test samples in layers. Stopping compacting when the test sample is loaded to be about 100mm away from the top of the test tank, and flattening the upper part of the test sample. And pulling out the upper anti-seepage wall, installing the upper anti-seepage wall on the pressure transmission plate, cleaning the pressure transmission plate before installation, cleaning the groove on the pressure transmission plate, coating silicone grease, installing the upper stop water belt, and paying attention to the position of the air tap. And coating silicone grease on the sealing tube. And unscrews the vent screw. And (4) checking whether the sealing strip is installed or not, cleaning sample residues on four walls in the groove, and cleaning residues on the top of the upper impervious wall to ensure cleanness. And coating silica gel on the top of the four walls and the impervious wall, coating sealant on two sides and the upper part of the walls, and screwing bolts. (also the upper diaphragm wall has various height dimensions, which can be selected according to the test requirements).
4. The pressure transmission plate is lifted by the portal frame and the chain block and moved to the test groove position, the pressure transmission plate is slowly placed into the test groove, the protruding part of the sealing tube is noticed not to be broken by a card when the pressure transmission plate is placed, and the sealing rubber strip is pressed in and fixed by the pressure plate bolt when the pressure transmission plate is placed to be flush with the test groove. And continuously placing the container to the top of the upper impervious wall, fastening the pressure transmission plate and the upper impervious wall by using bolts and a sealing rubber sheet, slowly pressing the container along the grooves of the two side walls, smearing two side seams by using silica gel, pressing a special sealing strip, and then placing the gourd.
5. And moving the portal frame away, pushing the reaction frame to the central position of the test groove, controlling the electric pressure regulating cylinder to move to enable the piston of the hydraulic cylinder to move downwards, stopping when the piston is in quick contact, slightly moving the reaction frame forwards, backwards, leftwards and rightwards to enable the two pressure transmission heads to be aligned with the centers of the pressure bearing seats on the pressure transmission plate, connecting the sensors, starting the electric pressure regulating cylinder until the numerical value of the sensors is changed and stopped, and enabling the pressure transmission plate to be in contact with the sample at the moment. The sensor is set to zero. And installing and resetting the displacement sensor.
6. Inflating the water stop belt with an inflator under 0.2MPa.
7. Connecting water inlet and outlet pipes, opening the valve, and filling water according to the required upstream water head. And closing the exhaust valve until the exhaust valve on the test groove and the exhaust hole on the pressure transmission plate continuously discharge water, and screwing the exhaust screw.
10. Setting a pressure value, starting pressurizing the pressure regulating cylinder to the pressure required by the test, opening a downstream valve, and starting measuring the seepage flow after the stable water flow flows out. The axial pressure can be increased or decreased at any time during the test. Or increase, decrease the upstream head.
11. After the test is finished, the electric pressure regulating cylinder is reversely controlled to return the piston to the top, the pressure regulating valve on the control cabinet can be adjusted to help the piston to ascend when the piston returns, the reaction frame is pushed out, all parts are detached in sequence after the air pressure in the sealing pipe is discharged, the sample is removed, the sewage is discharged, and the piston is wiped dry after being washed clean.
Therefore, aiming at the high water head and high stress environment in a deep covering layer, the seepage characteristic under the impervious wall crack is solved, the defects of the existing equipment are completely overcome, and the following technical effects can be achieved:
(1) the test groove is internally provided with a clamping groove, so that the spatial position of the concrete slab can be well controlled; meanwhile, the concrete slab used in the test is poured according to the process, so that different cracks of the concrete impervious wall can be set according to the actual situation, wherein the cracks comprise form, opening degree, roughness and the like;
(2) the instrument is provided with an upstream reservoir container and a longitudinal pressurizing device, and can well simulate the action of high-pressure underground water and high overburden load respectively, wherein the height of a test seepage head can reach 50m, the axial loading stress can reach 1000kN (converted into axial load of about 3MPa), and the high-water-pressure and high-ground-stress environment existing in a deep covering layer foundation and a concrete impervious wall can be reflected more truly;
(3) in a large-scale test tank, soil and stone materials with different grain compositions can be filled in the upper part and the lower part of a concrete slab, so that the healing effect of cracks under different grain compositions can be reflected, meanwhile, the side wall of the test tank is formed by organic glass and a steel plate, the crack filling process can be observed from a microscopic angle, the research on the relation characteristics between the actual crack filling and load, water pressure, crack opening and grain diameter of the concrete impervious wall can be more scientifically and effectively carried out, the research result is more in line with the actual situation, and scientific basis and technical support can be provided for the reinforcement treatment of the impervious wall and the impervious design of a deep covering layer.
(4) The side wall of the test tank is made of organic glass and steel plates, the crack filling process can be observed from a microscopic angle, and the research on the relation characteristics between the actual crack filling and load, water pressure, crack opening and particle diameter of the concrete impervious wall can be developed more scientifically and effectively.
(5) The downstream side of the test tank is also provided with a fine aggregate collecting device, so that the loss condition of different-grade soil aggregate after cracking can be collected, and the inner piping phenomenon under the cracking condition of the impervious wall can be well researched.
In addition, if the test tank is not provided with the concrete slab, the test tank becomes a high-water-head and high-stress coupling seepage tester for the soil and stone, and can be used for researching the real seepage characteristics of the soil and stone with different grades in the foundation of the soil and stone dam.
In conclusion, the method can well research the water-force coupling seepage characteristics of the diaphragm wall crack and the foundation soil stone in the deep covering layer, the research result is more in line with the actual situation, and scientific basis and technical support can be provided for the reinforcing treatment of the diaphragm wall and the seepage prevention design of the deep covering layer.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.
Claims (9)
1. The crack seepage tester under the action of high water head-high stress is characterized by comprising a test groove, a front water collecting tank, a rear water collecting tank and a longitudinal pressurizing device, wherein the front water collecting tank and the rear water collecting tank are respectively connected with two opposite side walls of the test groove and are used for applying horizontal pressure to the test groove;
the test groove is internally provided with a clamping groove, so that the spatial position of the concrete slab can be well controlled;
the instrument is provided with an upstream reservoir container and a longitudinal pressurizing device, and can well simulate the effects of high-pressure underground water and high overlying load respectively;
the bottom of the test tank is provided with a lower cross beam, and the lower cross beam is connected and fixed with an upper cross beam into a whole through an upright post and an upright post nut to provide a rigid reaction frame for the axial pressure of the equipment; the concrete slab is divided into an upper block and a lower block, different height sizes are prepared according to test requirements, and the concrete slab is respectively connected with the test groove and the pressure transmission plate and used for simulating the actual conditions of different cracks;
the front water collecting tank is connected with the upstream reservoir container, the rear water collecting tank is connected with the downstream reservoir container, and the upstream reservoir container supplies water to the front water collecting tank, so that the water continuously enters the test groove, flows out through the rear water collecting tank and finally flows into the downstream reservoir container to be collected.
2. The apparatus for testing seepage of cracks under the action of high water head-high stress as claimed in claim 1, wherein the side wall of the test tank connected with the front water collecting tank is provided with a plurality of water through holes, the top of the front water collecting tank is provided with an exhaust valve, and a front water collecting cavity for collecting water is arranged in the front water collecting tank;
the side wall of the test tank connected with the rear water collecting tank is provided with a plurality of water passing holes, and a rear water collecting cavity for collecting water is arranged in the rear water collecting tank.
3. The high head-high stress under crack seepage tester of claim 2, wherein the test tank is further provided with a reinforcing plate on the side wall connected with the front header tank, and the reinforcing plate is used for limiting the lateral deformation of the earth and rock material under high head-high stress;
the side wall of the test tank connected with the rear water collecting tank is also provided with a reinforcing plate, and the reinforcing plate is used for limiting the lateral deformation of soil and stone materials under high water head high stress.
4. The high water head-high stress action fracture seepage tester as claimed in claim 1, wherein the bottom of the rear header tank is provided with an aggregate outlet for discharging the earth and stone materials entering the rear header tank;
the top of the rear water collecting tank is provided with a water outlet for discharging water in the rear water collecting cavity, and the water outlet is communicated to a downstream reservoir container through a pipeline.
5. The high water head-high stress action fracture seepage tester as claimed in claim 1, further comprising a load sensor connected with the downstream reservoir container and a support frame for supporting the downstream reservoir container, wherein the top of the downstream reservoir container is provided with an exhaust valve, and the bottom of the downstream reservoir container is communicated with a water outlet of the rear water collecting tank.
6. The high head-high stress crack seepage tester according to claim 1, wherein the longitudinal pressurizing device comprises an oil cylinder for providing axial pressure, a pressure transmitting plate, and a pressure bearing seat arranged on the upper surface of the pressure transmitting plate, the lower surface of the pressure transmitting plate is opposite to the test groove, and the pressure bearing seat is used for transmitting the pressure of the oil cylinder to the pressure transmitting plate.
7. The high water head-high stress action fracture seepage tester as claimed in claim 6, wherein the upper surface of the bearing seat is recessed inwards to form a spherical groove, and correspondingly, the lower surface of the oil cylinder is provided with a spherical pressure transmission head which can be embedded into the spherical groove and is used for transmitting the loading pressure of the oil cylinder to the bearing seat.
8. The high water head-high stress action fracture seepage tester as claimed in claim 7, wherein the longitudinal pressurizing device further comprises a connecting seat and a load sensor for feeding back load data, the upper surface of the connecting seat is connected to the oil cylinder, the lower surface of the connecting seat is connected to the load sensor, and the load sensor is connected with the spherical pressure transmitting head.
9. The high water head-high stress action fracture seepage tester as claimed in claim 8, wherein the longitudinal pressurizing device further comprises a pressure regulating cylinder, the pressure regulating cylinder is connected with the oil cylinder through a high pressure oil pipe, and the required axial load is provided for the longitudinal pressurizing device;
and the displacement sensor clamp and the displacement sensor are arranged on the upper part of the test groove, and the displacement sensor clamp is used for mounting the displacement sensor on the upper part of the test groove.
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| CN112630121B (en) * | 2020-11-30 | 2021-10-12 | 中国矿业大学 | Device and method for testing permeability of fractured surrounding rock of deep chamber under stress action |
| CN113109230B (en) * | 2021-03-30 | 2022-11-04 | 中国电建集团西北勘测设计研究院有限公司 | Novel earth and rockfill dam construction material seepage deformation test system and method |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101514978A (en) * | 2009-04-02 | 2009-08-26 | 河海大学 | Test method for studying phenomenon of permeable damage on soil body and test device thereof |
| CN201765222U (en) * | 2010-07-08 | 2011-03-16 | 贵州师范大学 | Water level control water supply device with adjustable water level |
| CN102419298A (en) * | 2011-10-28 | 2012-04-18 | 西安理工大学 | Seepage device for slurry of coarse grained soil |
| CN104897539A (en) * | 2015-04-30 | 2015-09-09 | 四川大学 | Horizontal permeameter suitable for soil horizontal contact surface shearing deformation |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101514978A (en) * | 2009-04-02 | 2009-08-26 | 河海大学 | Test method for studying phenomenon of permeable damage on soil body and test device thereof |
| CN201765222U (en) * | 2010-07-08 | 2011-03-16 | 贵州师范大学 | Water level control water supply device with adjustable water level |
| CN102419298A (en) * | 2011-10-28 | 2012-04-18 | 西安理工大学 | Seepage device for slurry of coarse grained soil |
| CN104897539A (en) * | 2015-04-30 | 2015-09-09 | 四川大学 | Horizontal permeameter suitable for soil horizontal contact surface shearing deformation |
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