CN212083180U - Tunnel geotechnical cloth silting-up measuring device - Google Patents
Tunnel geotechnical cloth silting-up measuring device Download PDFInfo
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- CN212083180U CN212083180U CN202020145709.1U CN202020145709U CN212083180U CN 212083180 U CN212083180 U CN 212083180U CN 202020145709 U CN202020145709 U CN 202020145709U CN 212083180 U CN212083180 U CN 212083180U
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Abstract
The utility model discloses a tunnel geotechnique cloth becomes silted up stifled measuring device. The tunnel geotechnical cloth clogging measuring device comprises a test box with a water inlet and a water outlet, wherein an arc-shaped plate is arranged on the bottom surface of the test box to simulate the arch structure of the upper half part of a tunnel, a water drainage hole is formed in the arc-shaped plate, and the test box is provided with at least two test chambers. The utility model discloses a tunnel geotechnique cloth silts up stifled measuring device has the arc of outlet through setting up in the bottom surface of proof box and passes through the route of geotechnological cloth with the water of simulation in the actual arch tunnel from the equidirectional, has avoided only simulating the rivers condition of vertical direction to can provide more true effectual data. And through set up the baffle in test box inside to divide into a plurality of the same parts with the test box, thereby can once carry out the research of a plurality of operating modes, or carry out the research of the different geotechnological cloth of the same condition simultaneously, not only can shorten test time, can also reduce the error that the repetition test brought.
Description
Technical Field
The utility model belongs to building engineering infiltration prevents stifled measurement field, concretely relates to tunnel geotechnological cloth physics silts up stifled measuring device.
Background
The functions of the geotextile in engineering can be roughly divided into a reinforcing and stabilizing function, a filtering function, an isolating function, a drainage function, a waterproof (seepage-proofing) function, a protection function and a plurality of functions.
In the clogging test of SL235-2012 geosynthetic test specification, a mesh having a certain rigidity and pore size is placed at the bottom of the geotextile to support the geotextile, and the mesh and geotextile are sealed together in a holding device. However, the aperture of the screen can affect the clogging process of the geotextile to a certain extent, and certain errors are caused to the clogging test.
In actual tunnel engineering, the annular blind pipes are arranged at intervals, water flows into the annular blind pipes through the geotextile firstly, then flows into the annular blind pipes and is discharged out of the tunnel through other drainage systems, the water flow at the position where the annular blind pipes are arranged is obviously larger than that of the annular blind pipes, silting is easy to occur, and the actual silting conditions of different cross sections are different. However, the existing clogging test does not simulate the different conditions of different cross-section clogging.
In the clogging test of SL235-2012 geosynthetic material test specification, the geotextile is horizontally placed and sealed in the holding device together with the screen, at the moment, the path of water flow is vertical permeation, and the soil pressure and the permeability on the geotextile are also vertical to the cross section of the geotextile. However, the actual tunnel is generally designed to be arched, the path of water flow not only has a vertical direction but also has a horizontal direction, the geotextile is arranged along the arched section, and the geotextile is not only influenced by the self weight of the upper soil body and the water seepage force, but also is extruded by the surrounding soil body. Therefore, the simulation of the water flow path in the existing silting test does not completely conform to the actual situation that the tunnel geotextile bears the water flow path.
In addition, in the existing silting test, when physical silting of soil particles on geotextile is researched, the filling soil is generally poured directly from the top, and the compactness and the consolidation degree of the test soil sample cannot be effectively controlled. However, in actual geological conditions, soil layers are consolidated and settled under the action of the self weight and the external pressure for a long time, and the compactness of the soil layers is increased. Therefore, the simulation of the soil sample state in the existing silting test does not completely meet the actual situation that the tunnel geotextile bears the soil sample.
SUMMERY OF THE UTILITY MODEL
In view of this, the main object of the utility model is to provide a tunnel geotechnological cloth physics becomes silted up stifled measuring device, the device can simulate the water flow path in the actual arch tunnel, accords with the atress characteristic of actual geotechnological cloth in the tunnel more to can provide more true effectual measured data.
The utility model provides a tunnel geotechnique cloth silts up stifled measuring device, the device is including the proof box that has water inlet and outlet, the bottom surface of proof box is provided with the first half domes of arc with the simulation tunnel, be provided with the outlet on the arc, the proof box has two at least test chambers.
According to one embodiment, the arc shape of the arc plate may correspond to the actual engineering design, for example may consist of an arc of one or more circles. Preferably, the arc-shaped plate is a semicircular arc-shaped plate.
According to an embodiment of the present invention, the radius of the semi-circular arc plate can be reduced by a ratio of 1:15 to 1:5, preferably 1:10, compared with the actual engineering.
According to another embodiment, the radius of the semi-circular arc plate may be 0.3-1.0 m, for example also 0.4 m, 0.5m, 0.6m, 0.7m, 0.8m or 0.9 m.
The longitudinal length of the arc plate is not particularly limited as long as the detection is convenient. For example, for a geotextile sample, the length of the arcuate panels can be any suitable length in the range of 0.2 to 0.8 m.
According to the utility model discloses an embodiment, the relative position that the hoop blind pipe arranged among the actual engineering of outlet simulation is arranged on the arc.
Preferably, the drainage holes are arranged on the arc-shaped section of the semicircular arc-shaped plate at intervals of 20-40 degrees, preferably 25-35 degrees, of the central angle of the circle where the arc is located.
More preferably, the drainage holes are arranged on the arc-shaped section of the semicircular arc-shaped plate at intervals of 30 degrees of the central angle of the circle on which the arc is positioned.
According to the utility model discloses an embodiment, the device still includes header tank and frequency conversion water pump, water in the header tank passes through the frequency conversion water pump carry extremely the proof box, water in the proof box warp the outlet with the outlet discharges, flows in the header tank to form hydrologic cycle. The variable-frequency water pump can adjust the water circulation rate according to the water level height required by measurement.
According to a particular embodiment, the water collection tank is arranged in the lower part of the test chamber. In this embodiment, the drain of the test chamber may be provided on its bottom surface. The water outlet can be further provided with a screen or a filter screen for preventing the soil sample from running off in the test.
The variable frequency water pump may be disposed inside the water collection tank.
The test box can be provided with a plurality of water outlets (such as 2-10) and a plurality of water inlets (such as 4-40).
According to one embodiment, the water inlet of the test chamber may be arranged at a side of the test chamber. According to a specific embodiment, the water inlets may be evenly distributed on each side wall of the test chamber.
Preferably, the at least two test chambers are formed by dividing the arc-shaped plate by a partition perpendicular to the bottom of the test chamber.
Preferably, the at least two test chambers are in fluid communication with each other so that testing in each test chamber can be performed under the same test conditions; and/or the at least two test chambers are fluidly isolated from each other to enable independent water circulation so that tests in the respective test chambers may be performed under different test conditions.
According to a specific embodiment, the fluid communication or isolation between the chambers can be switched by means of valves or the like.
The arrangement of the plurality of test chambers can implement parallel tests, for example, tests of different geotextile samples under the same condition can be realized, and tests of one geotextile sample under different conditions can also be realized.
According to the utility model discloses an embodiment, the device still includes the water knockout drum, the entry of water knockout drum with the variable frequency water pump is connected, just the water knockout drum have a plurality of distributive mouths in order respectively with the water inlet is connected.
The utility model discloses a tunnel geotechnique cloth physics silts up stifled measuring device, sets up the water in order to simulate actual arch tunnel through the route of geotechnological cloth with the arc that has the outlet through the bottom surface at the proof box, has avoided conventional measuring device only to simulate the rivers condition of vertical direction, consequently, geotechnological cloth's atress characteristic accords with actual conditions more in the device. Furthermore, the utility model discloses a tunnel geotechnological cloth physics silts up stifled measuring device through such as setting up the baffle in proof box inside to divide into a plurality of the same parts with the proof box, thereby can once carry out the research of a plurality of operating modes, or carry out the research of the different geotechnological cloth of the same condition simultaneously, not only can shorten test time, improve test efficiency, can also reduce because the error that the repetition test brought, improve experimental precision.
Drawings
Fig. 1 is a schematic structural diagram of a test apparatus according to an embodiment of the present invention;
fig. 2 is a top view of a soil sample in a test apparatus according to an embodiment of the present invention;
FIG. 3 is a graph of the physical fouling flow of a short filament geotextile for a tunnel;
FIG. 4 is a graph of physical fouling flow for a tunnel filament geotextile;
the figure includes: 1-test box, 2-water collecting tank, 3-water separator, 31-water separating port, 4-water inlet, 5-water outlet, 6-arc plate, 61-water outlet and 7-baffle plate.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the embodiments of the present invention and the accompanying drawings, and obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
The invention will be further explained below with reference to a schematic example shown in the drawings. Various advantages of the present invention will become more apparent from the following description. Like reference numerals in the drawings refer to like parts. The shapes and dimensions of the various elements in the schematic drawings are illustrative only and are not to be construed as embodying the actual shapes, dimensions and absolute positions.
The utility model discloses mainly only can measure under perpendicular rivers condition and receive the jam situation of geotechnological cloth under the soil layer pressure situation to current geotechnological cloth jam test device, and is difficult to simulate the true condition that geotechnological cloth receives multiple rivers direction and different soil layer pressure influences in the arch tunnel. From this, the utility model provides a can measure the measuring device of geotechnological cloth physics silting up stifled situation under the situation that geotechnological cloth receives perpendicular and horizontal rivers influence in the simulation tunnel.
The physical silting refers to the condition that under the action of underground water, fine particles in sandy soil are changed into free particles under the action of osmotic force and are blocked on the surface and inside of the geotextile, and the water permeability of the geotextile is greatly reduced, particularly in water-rich sandy soil strata. In Ca2+And CO3 2-In a water-rich sandy soil stratum with relatively low concentration, the clogging form of the geotextile is mainly physical clogging. The utility model discloses a measurement method is mainly silted up the measuration of stifled condition to the physics.
Chemical fouling as used herein refers to the formation of water-rich rock in a water-rich rock-soluble formation due to groundwater containing large amounts of Ca2+、Mg2 +、SO4 2-And HCO3 -Plasma, ion crystallization (mainly CaCO) during prolonged percolation3) The block is in geotechnique's cloth's surface and inside, the condition of greatly reduced geotechnique's cloth water permeability. And because the rock stratum is different from the sandy soil stratum, the cracks are not developed completely, and fine-grained soil is not easy to enter the surface and the interior of the geotextile, therefore, Ca is added2+And HCO3 -In the water-rich karst stratum with relatively high plasma concentration, the clogging form of the geotextile is mainly chemical clogging.
It should be understood by those skilled in the art that the measurement device of the present invention is not limited to the study of physical clogging, but is equally applicable to the study of geotextile clogging in any tunnel situation, including but not limited to physical clogging, chemical clogging, or coupling clogging. Through using different soil sample/water sample, adjust the velocity of flow of different hydrologic cycles, the utility model discloses a measuring device can be used to simulate multiple actual conditions to can survey under the multiple geotechnical circumstances silt up of geotechnological cloth.
The tunnel geotextile clogging measuring device of the present invention will be specifically described below by using a specific example shown in fig. 1.
Fig. 1 shows a schematic structural diagram of an example of the tunnel geotextile silting measurement device of the present invention. Referring to fig. 1, the measuring device is shown with a test chamber 1, a water collection tank 2 and a variable frequency water pump (not shown).
The bottom surface of the test box 1 is provided with an arc-shaped plate 6 and forms a part of the bottom surface, and the arc-shaped plate 6 is provided with a plurality of water drainage holes 61.
The utility model discloses a geotechnological cloth silts up stifled measuring device and the conventional geotechnological cloth and silts up stifled measuring device's main difference lies in that the bottom surface of proof box 1 has the arc 6 that is provided with a plurality of outlet 61 to can simulate the first half domes and the rivers situation in tunnel.
The cross-sectional shape of the arc-shaped plate 6 is a part of an arc of a circle. Preferably, the arc is semi-circular. In this example, the arc 6 is a semicircular arc.
The arc radius of the arc-shaped plate 6 can be reduced to 1: 15-1: 5, preferably 1:10 according to the actual engineering proportion. The arrangement of scaling down according to actual engineering can better simulate the arch structure of the tunnel and provide more real and effective measurement data. An exemplary radius of the arc may be 0.5m, but is not limited thereto, and may be set according to specific needs.
The length of the arc 6, which may be the same as the width of the test chamber, may be set according to the width of the test chamber 1. The length of the arc-shaped plate can be 1.4m for example, but is not limited to this, and can be set according to specific needs.
According to the utility model discloses, be provided with outlet 61 on the arc 6. The arrangement of the drain holes 61 simulates the design of an annular blind pipe in the existing engineering. Through set up the outlet on the arc, rather than adopting the screen cloth to constitute the arc, the actual rivers condition of the inhomogeneous distribution in the simulation engineering can be better to the stifled condition of silt of geotechnological cloth is surveyd better.
The bleed openings 61 can be spaced at different angles for different arcs (different radii and/or different central angles). For example, they may be spaced at intervals of 20 to 40, preferably 25 to 35. In this example, the arc-shaped plate 6 is a semicircular arc-shaped plate, and the drainage holes are arranged on the cross section of the arc-shaped plate at intervals of 30 ° with the central angle of the circle where the arc is located, that is, 5 drainage holes 61 can be arranged on the semicircular arc-shaped cross section of the arc-shaped plate 6, and are respectively located at 30 °, 60 °, 90 °, 120 ° and 150 °. At this time, the drainage holes 61 positioned at 30 degrees and 150 degrees are symmetrically distributed and belong to the arch waist position; the drainage holes 61 positioned at 60 degrees and 120 degrees are symmetrically distributed and belong to the positions of arch shoulders; the drain hole 61 located at 90 ° belongs to the dome position.
To the length of different arcs, can set up multirow outlet with different spacing distance, the utility model discloses do not have special restriction to this. For example, the arrangement of the ring-shaped blind pipe in the actual engineering can be set. For example, the distance may be 15 to 35cm, preferably 20 to 30 cm. In this example, the length of the arc 6 is 1.4m, and 4 drain holes are provided at an interval of 25cm on the arc, respectively at four cross sections of 25cm, 50cm, 100cm and 125cm of the arc 6.
The shape of the drain holes 61 is not particularly limited, and may be, for example, circular, oval, square, rhombic, or the like. In this example, the shape of the drain hole is circular.
The size of the drain hole 61 can be determined according to the size of a boiling water hole of a tunnel drainage blind pipe, and generally can be 5-8 mm, and the size of the drain hole can be 5mm, 6mm, 7mm, 8mm and the like.
The exterior of the weep hole 61 is connected to the drain system and the interface needs to be sealed to prevent leakage. The connection part between the outside of the drain hole and the drainage system is a pagoda joint, and the interface is sealed by a hot melting machine, but the connection part and the sealing mode are not limited to this, and other modes can be selected according to specific situations.
With further reference to fig. 1, the water in the water collecting tank 2 is delivered to the test chamber 1 by a variable frequency water pump (not shown), and the water in the test chamber 1 is discharged through the water outlet 5 and flows into the water collecting tank 2 to form a water circulation.
The variable frequency water pump can adjust the rotating speed of the motorThe water pressure is adjusted, and the water inlet rate and the water outlet rate of the test box 1 are further controlled. In this example, the variable frequency water pump can be a submersible pump, and the submersible pump can be placed in the water collecting tank 2, with the rated lift of 36m and the rated flow of 3m3/h。
In particular, the device shown in fig. 1 also comprises a water separator 3. Wherein, the water in the header tank 2 is carried to the water knockout drum 3 through the frequency conversion water pump, and the water knockout drum 3 can be used to shift the water that the frequency conversion water pump provided to different water inlets department. The variable frequency water pump is connected with the inlet of the water separator 3 through a pipeline (such as a galvanized iron pipe). The water distributor 3 is provided with a plurality of water distribution openings 31, and the water distribution openings 31 are connected with pipelines through connecting parts and further connected with the water inlets 4 respectively. Also, a seal is required at the interface to prevent leakage. In this example, the center of the water separator 3 is a water accumulation circular groove, and 12 water separation ports 31 are arranged on the groove; the water diversion port 31 is connected with the pipeline through a pagoda joint, and a raw adhesive tape needs to be wound between the water diversion port 31 and the pagoda joint to prevent leakage; sealing between the pagoda joint and the pipeline through a hot melting machine to prevent leakage; and the other end of the pipeline is hermetically connected with the water inlet 4 by installing a quick-connection plug.
A water pressure gauge (not shown) can also be arranged at the outlet of the water diversion port 31 so as to observe different water pressures of the water inlet 4.
With further reference to fig. 1, the water inlet 4 is disposed at a side surface of the test chamber 1, and the water outlet 5 is disposed at a bottom surface of the test chamber 1. Water is poured into the test chamber 1 through the water inlet 4, and the water in the test chamber 1 is discharged through the water outlet 5 and the drain hole 61, and flows into the water collection tank 2. The number of the water inlets 4 and the water outlets 5 is respectively multiple, the specific number can be set according to the size of the test chamber 1, the distribution arrangement mode of the side surface or the bottom surface of the test chamber and other specific conditions, and the water inlet rate and the water outlet rate can be regulated and controlled (for example, through valves).
In this example, the test chamber 1 is provided with 28 water inlets 4, two rows of water inlets 4 are arranged on both the front and back side surfaces of the test chamber 1, the height of the first row of water inlets 4 from the bottom surface of the test chamber 1 is 25cm, and the height of the second row of water inlets 4 from the bottom surface of the test chamber 1 is 75 cm. Three rows of water inlets 4 are arranged on the left side surface and the right side surface of the test box 1, and each row is provided with 3 water inlets 4; the second row of water inlets 4 is located in the middle of the test chamber 1 in the width direction, and the first and third rows of water inlets 4 are respectively 25cm away from the boundary of the test chamber 1. The diameter of the water inlet 4 can be 15-25 cm, and is preferably 20 cm.
The water inlet 4 needs to be fitted with a sealing member to be sealed. The sealing means of the water inlet 4 can be exemplified by a quick-connect coupling seal.
In this example, the bottom surface of the test chamber 1 is provided with 4 water outlets 5, and the diameter of the water outlets 5 may be 20-30 cm, preferably 25 cm.
The test chamber of the measuring device of the present invention may further have a top cover (not shown in the figure). The top cover and the box body need to be fixed and sealed. In this embodiment, the top cover and the box body can be fixed by screws, but not limited thereto; meanwhile, the top cover and the box body can be sealed through a sealing bead, but the sealing bead is not limited to the top cover and the box body.
The utility model discloses measuring device's proof box can have two or more test chamber. The arrangement of two or more test chambers can simultaneously research the clogging conditions of two or more kinds of geotextiles, thereby not only shortening the test time and improving the test efficiency, but also reducing the errors caused by repeated tests and improving the test precision. For example, the test chamber may have 2 to 10, preferably 2 to 5, more preferably 2 or 3 chambers.
The at least two testing chambers may be in fluid communication with each other, thereby ensuring that the water circulation conditions between the different chambers are the same and allowing parallel test testing.
The at least two test chambers may also be fluidly isolated from each other to enable independent water circulation, so that different water circulation conditions can be simulated in the same test.
The test chamber 1 may be divided into a plurality of chambers by providing partitions 7 in the test chamber 1, but is not limited thereto.
The fluid communication or fluid isolation between adjacent chambers can be controlled by providing on-off devices (e.g., valves) between the chambers.
As shown in fig. 1, in this example, the test chamber 1 is divided into two test chambers having the same area by providing a partition plate 7 at 75cm in the longitudinal direction of the arc-shaped plate 6. The height of the partition 7 may be, for example, 60cm, but is not limited thereto.
The shape of the test chamber 1 is not particularly limited, and may be a rectangular parallelepiped in general. The size of the test chamber 1 is set according to actual needs, and may be, for example, 2m × 1.5m × 1m (length × width × height), but is not limited thereto.
The shape of the header tank 2 is not particularly limited, and may be, for example, a rectangular parallelepiped. The size of the header tank 2 may be, for example, 3m × 1m × 0.9m (length × width × height), but is not limited thereto.
The material of the test box 1 of the present invention is not particularly limited, but it is required to be able to bear the pressure required by the test. For example, the stainless steel plate may be welded, and the thickness of the stainless steel plate may be 5 to 15mm, preferably 10 mm.
Be suitable for the utility model discloses a header tank 2's material can be the same with proof box 1's material, also can be different. For example, the stainless steel plate is welded, and the thickness of the stainless steel plate can be 3-7 mm, preferably 5 mm.
Because the utility model discloses the material of pilot test case 1 and header tank 2 all can be the stainless steel, and after stainless steel contacted with water and air for a long time, the box inboard can produce a large amount of iron rusts (Fe)2O3) The specific chemical reaction equation is as follows:
4Fe+6H2O+3O2＝4Fe(OH)3
2Fe(OH)3＝Fe2O3+3H2O
the generated rust can adhere to the surface of the geotextile along with water and cause certain clogging of the geotextile. In order to prevent the formation of a large amount of rust, the inside of the test chamber 1 and the header tank 2 was entirely painted before the test to isolate air and water.
The device for measuring the clogging of the geotechnical cloth of the tunnel is suitable for the research on the clogging of the geotechnical cloth under any tunnel condition, including but not limited to the conditions of physical clogging, chemical clogging or coupling clogging. Through using different soil sample/water sample, adjust the velocity of flow of different hydrologic cycles, the utility model discloses a measuring device can be used to simulate multiple actual conditions to can survey under the multiple geotechnical circumstances silt up of geotechnological cloth.
The blocking condition of the geotechnical cloth in the tunnel can be measured by utilizing the blocking measuring device for the geotechnical cloth in the tunnel. The method for measuring physical clogging of geotextiles in a tunnel is described in detail below.
The measuring method comprises the following steps:
laying geotextile to be measured on the arc-shaped plate of the measuring device, covering the geotextile with a soil sample and tamping the geotextile;
starting water circulation by keeping the water level in the test box at a predetermined height;
the amount of water discharged from each of the drain holes is measured at regular intervals.
In the method of the present invention, the tamping is performed by adding the soil sample in batches to tamp the soil sample in batches so that the density of the soil sample is uniform. Preferably, the consistency of the compactness of the soil sample is determined by measuring and controlling the height change of each batch of soil sample before and after tamping. More preferably, the soil sample is tamped to make the compactness of the soil sample close to the compactness of the soil layer on the upper part of the actual tunnel when measured.
The compactness of the soil sample within test chamber 1 can be characterized by quantifying the density of the soil sample, but is not limited thereto.
The preset height is not limited, and the physical clogging conditions of different types of geotextiles at the same water level height can be researched by controlling a variable method; similarly, physical clogging conditions at different water level heights can be studied by a controlled variable method with the same type of geotextile. In general, the larger the water level height, the larger the water head above the drain hole 61, the larger the water pressure, and the larger the flow rate, and finally the more clogging of the drain hole becomes.
The expression of the data result needs to be considered in the setting of the certain time interval, and the shorter the time interval is, the more data points are collected, and the more accurate the test result is. Meanwhile, the time interval is too long, which may cause inaccurate trend of test result expression. The certain time interval can be 2-4 h, and is preferably 3 h.
And when the water discharge is stable, taking out the measured geotextile, and cutting the geotextile after drying to obtain the geotextile corresponding to different positions of the water discharge holes. And weighing the mass of the dried geotextile, and comparing the mass of the geotextile with the mass of the geotextile before the physical clogging test is carried out, so that the clogging conditions corresponding to the drainage holes at different positions can be analyzed.
The embodiment adopts the tunnel geotextile measuring device to carry out the physical silting measurement
Firstly, the tunnel geotextile physical clogging measuring device is checked to ensure that the phenomena of water leakage and blockage do not occur. This is because water leakage and clogging of the test apparatus significantly affect the test results, and therefore, it is necessary to inspect the test apparatus before the start of the actual test.
The inspection process was as follows: first, the water collection tank 2 is checked for water leakage. Injecting water into the water collecting tank 2 to a specified height, observing and measuring the height of the water level after 1h, and if the height of the water level is not changed, proving that the water collecting tank 2 does not leak water; if the water level is lowered, it is proved that the water collection tank 2 has a water leakage phenomenon, and the water collection tank 2 needs to be inspected and maintained. Next, the test chamber 1 is checked for water leakage or clogging at the water inlet 4, the water outlet 5, the drain hole 61, and the like. Switching on a transformer power supply, switching on a water pump to the transformer, adjusting the rotating speed of the water pump to a proper value, conveying water in a water collecting tank 2 to a test box 1 through a water separator 3 (checking whether water leakage exists at each joint in the process, if water leakage is found, starting a test after water stopping treatment is needed), turning off the water pump after the water level of the test box 1 reaches a specified water level height, and checking whether water drainage of each water outlet 5 is smooth one by one in the process; if there is a clogged drain opening 5, the test is continued after cleaning in time and normally. Observing and measuring the water level height in the test box 1 after 1h, and if the water level height is not changed, proving that the test box 1 is watertight; if the water level is lowered, the water leakage phenomenon of the test box 1 is proved, and the test box 1 needs to be checked and maintained again. Finally, after the inspection is completed, the drain port 5 of the test chamber 1 and the header tank 2 is opened to drain all the water.
Then, the mass per unit area of the geotextile was measured.
The procedure for determining mass was as follows: since the test chamber 1 has dimensions of 2m × 1.5m × 1m (length × width × height), the thickness of the stainless steel plate on each side of the test chamber 1 is 10mm, and the radius of the arc-shaped plate 6 is 0.5 m. At this time, the geotextile laid on the arc-shaped plate 6 has a length of 0.5 pi (about 1.57m), a width of 0.65m, and an area of about 1m2. Specifically, the cutting of the geotextile sample should be accurate to 1 mm. The samples were divided into 3 groups, each group having 10 specimens and numbered. And weighing the geotextile samples one by one on a balance, wherein the reading precision of the balance is accurate to 0.1 g.
The raw material of the geotextile should be selected in consideration of physical properties, chemical properties, service life and cost required in the application environment. In general, natural fibers are inferior to synthetic fibers in strength, aging resistance, acid and alkali resistance, corrosion resistance, etc., and therefore synthetic fibers such as polyester fibers (dacron), polypropylene fibers (polypropylene fibers), polyamide fibers (chinlon), polyvinyl acetal fibers (vinylon), polyacrylonitrile fibers (acrylon), etc., are mostly used as raw materials for geotextiles, and among them, polyester fibers and polypropylene fibers are mostly used. In this embodiment, two types of geotextiles, namely, a polyester filament geotextile and a polyester staple geotextile, are used.
And finally, carrying out a physical clogging test of the geotextile.
The procedure for the physical fouling test was as follows: first, the water collecting tank 2 is connected to a tap water tap by a water pipe, and the water collecting tank 2 is filled with water to a predetermined height by turning on a switch.
Then, tailor geotechnological cloth according to the size of mold box, tile geotechnological cloth on the arch face of proof box 1 inboard, extrude the inside air that exists to the tunnel bottom in proper order from the vault to simultaneously from the middle unnecessary air of discharging to both sides, pay attention to avoid producing the space in geotechnological cloth and proof box 1 inboard as far as possible, this can produce great influence to experimental, and the waterproof adhesive tape is fixed for the edge of geotechnological cloth, prevents that solution from flowing in from marginal space.
Secondly, a sand barrel is used for loading a test soil sample, the test soil sample is placed on an electronic scale for weighing and recording the weight of the test soil sample, the test soil sample is slowly poured into the test box 1 along the inner wall of the test box 1, and the height change of the soil sample after each pouring is recorded by a graduated scale. After the height change of the soil sample poured each time is repeatedly recorded by the graduated scale until the soil sample in the test box 1 reaches the position of 30cm, firstly treading the deficient soil by feet once, then determining a ramming point every 20cm, ramming each ramming point by a rammer for 8 times, lifting the soil to the chest by two hands for the first seven times, and lifting the soil to the head by the hands for the last time. And (5) ramming the excessive soil between rammed points for 8 times at each position. And after the ramming is repeated for three times, leveling the upper layer of the rammed soil by using a flat shovel. And then sprinkling water to wet the ramming layer, wherein the standard is that the ramming layer is completely wetted, and then beating 4 times at each ramming point by using a rammer. And repeating the operation of determining the tamping point, tamping and tamping point beating until the height of the tamping layer is 60 cm.
Further, referring to fig. 2, a top view of a soil sample of a test chamber in a test apparatus according to an embodiment of the present invention is shown.
And (3) switching on a transformer power supply, switching on the water pump to the transformer, adjusting the rotating speed of the water pump, conveying the solution in the water collecting tank 2 to the test box 1 through the water distributor 3, adjusting the rotating speed of the water pump according to the flow of the water outlet 5 after the water level reaches the specified water level height, controlling the water level height in the test box 1 to be unchanged, and controlling the water level height in the test box 1 to be 75cm away from the box bottom at the moment. After water circulation for 1h, the rotating speed of the water pump is adjusted according to the flow change of the water outlet hole, and the height of the water level in the test box 1 is kept unchanged. After every 1h, the rotating speed of the water pump is repeatedly adjusted, and the height of the water level in the test box 1 is kept unchanged. If the water level in the test box 1 is lowered after the test is started, and a water leakage phenomenon exists, a waterproof spray gun can be used for local leakage compensation, so that the influence of the water leakage condition on the test is reduced as much as possible.
After the start of the water circulation, the water discharge amount at the drain hole 61 for a certain period of time was measured by a timer measuring cylinder at intervals of 3 hours, and the data of the test was recorded. The flow rates of the drain holes 61 at different positions are calculated, and the function relation of the flow rate and the time is obtained.
Figures 3 and 4 show flow charts of physical fouling of the short and long filament geotextiles, respectively, of a tunnel. The semi-arc section is divided into three parts of arch waist (30 degrees and 150 degrees), arch shoulder (60 degrees and 120 degrees) and arch crown (90 degrees), the water displacement of different positions of the same geotextile is averaged, and a water flow change curve graph of the drainage holes of the two geotextiles at each position is obtained. As shown in fig. 3 and 4, the flow rates at the three positions were constantly decreasing with time (initial decreasing phase) and remained at a substantially constant value after 24 hours (steady phase). Obviously, the flow at the haunch is greater at each time interval than at the spandrel, and the flow at the spandrel is greater at each time interval than at the spandrel, which may be due to hydraulic slopes at different locations. Under the condition that the water level is the same, the hydraulic gradient at the arch waist is larger than the arch shoulder and larger than the arch top, and the flow of each position is increased along with the increase of the hydraulic gradient at different positions. Although the drainage flow rates at different positions are different, the drainage flow rates of the drainage holes at different positions have the same trend of decreasing with time.
And finally, after waiting for 36 hours, closing a water pump switch, opening a water outlet 5 in the test box 1, completely discharging water in the test box 1, taking the geotextile out of the test box 1, and placing the geotextile in a ventilated place for air drying. And further cutting the geotextile by using a pair of scissors after the geotextile is completely air-dried, measuring the mass change of the geotextile at different positions after physical clogging by using an electronic scale, and measuring and recording the mass per unit area and the thickness of the geotextile at the positions after clogging by using a graduated scale.
The above is only the preferred embodiment of the present invention, not limiting the scope of the present invention, all of which are under the concept of the present invention, the equivalent structure transformation made by the contents of the specification and the drawings is utilized, or the direct/indirect application is included in other related technical fields in the protection scope of the present invention.
Claims (13)
1. The device for measuring the clogging of the geotechnical cloth of the tunnel comprises a test box with a water inlet and a water outlet, wherein an arc-shaped plate is arranged on the bottom surface of the test box to simulate the arch structure of the upper half part of the tunnel, and a water drainage hole is formed in the arc-shaped plate.
2. The apparatus of claim 1, wherein the arcuate shape of the arcuate plate conforms to actual engineering design.
3. The apparatus of claim 1, wherein the curved plate is a semi-circular curved plate.
4. The apparatus for measuring clogging of geotechnical cloth of a tunnel of claim 3, wherein the radius of said semi-circular arc plate is reduced in proportion of 1:15 to 1:5 compared with the actual engineering.
5. The apparatus of claim 3, wherein the radius of the semi-circular arc plate is 0.3-1.0 m.
6. The apparatus for measuring clogging of geotechnical cloth for tunnel according to claim 1, wherein said drain hole is disposed on said arc-shaped plate in a position relative to the circumferential blind pipe arrangement in the actual engineering.
7. The apparatus for measuring clogging of geotextile of claim 6, wherein said drainage holes are arranged at intervals of 20 ° to 40 ° at the central angle of the circle on which the arc is located on the arc-shaped cross section of said arc-shaped plate.
8. The apparatus for measuring clogging of geotextile of claim 7, wherein said drainage holes are arranged at intervals of 30 ° at a central angle of a circle on which said arc is located on an arc-shaped section of said arc-shaped plate.
9. The apparatus for measuring clogging of geotechnical cloth for tunnel according to any one of claims 1 to 8, wherein said apparatus further comprises a water collecting tank and a variable frequency water pump, wherein water in said water collecting tank is transported to said test chamber by said variable frequency water pump, and water in said test chamber is discharged through said water discharge opening and said water discharge hole, and flows into said water collecting tank to form water circulation.
10. The apparatus of claim 1, wherein the at least two test chambers are formed by dividing the curved plates by a partition perpendicular to the bottom of the test chamber.
11. The tunnel geotextile fouling measurement device of claim 1, wherein the at least two testing chambers are in fluid communication with each other or are fluidly isolated from each other to enable independent water circulation.
12. The apparatus of claim 1, wherein the water inlet is disposed at a side of the test chamber and the water outlet is disposed at a bottom of the test chamber.
13. The apparatus of claim 9, further comprising a water separator having an inlet connected to the variable frequency water pump and having a plurality of water separation ports connected to the water inlet, respectively.
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| CN111103225A (en) * | 2020-01-23 | 2020-05-05 | 中铁第四勘察设计院集团有限公司 | Tunnel geotextile physical clogging measuring device and method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111103225A (en) * | 2020-01-23 | 2020-05-05 | 中铁第四勘察设计院集团有限公司 | Tunnel geotextile physical clogging measuring device and method |
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