CN110763183A - Model test device and test method for simulating concentrated stacking load in existing tunnel - Google Patents

Model test device and test method for simulating concentrated stacking load in existing tunnel Download PDF

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Publication number
CN110763183A
CN110763183A CN201911119187.6A CN201911119187A CN110763183A CN 110763183 A CN110763183 A CN 110763183A CN 201911119187 A CN201911119187 A CN 201911119187A CN 110763183 A CN110763183 A CN 110763183A
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China
Prior art keywords
model
existing tunnel
box
water
simulating
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CN201911119187.6A
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Chinese (zh)
Inventor
魏纲
齐永洁
蒋吉清
刘亚宇
李志远
刘立源
赵得乾麟
张书鸣
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Zhejiang University City College ZUCC
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Zhejiang University City College ZUCC
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Priority to CN201911119187.6A priority Critical patent/CN110763183A/en
Publication of CN110763183A publication Critical patent/CN110763183A/en
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01BMEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B21/00Measuring arrangements or details thereof in so far as they are not adapted to particular types of measuring means of the preceding groups
    • G01B21/32Measuring arrangements or details thereof in so far as they are not adapted to particular types of measuring means of the preceding groups for measuring the deformation in a solid
    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D9/00Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
    • E21D9/06Making by using a driving shield, i.e. advanced by pushing means bearing against the already placed lining
    • GPHYSICS
    • G09EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09BEDUCATIONAL OR DEMONSTRATION APPLIANCES; APPLIANCES FOR TEACHING, OR COMMUNICATING WITH, THE BLIND, DEAF OR MUTE; MODELS; PLANETARIA; GLOBES; MAPS; DIAGRAMS
    • G09B25/00Models for purposes not provided for in G09B23/00, e.g. full-sized devices for demonstration purposes
    • G09B25/04Models for purposes not provided for in G09B23/00, e.g. full-sized devices for demonstration purposes of buildings

Abstract

The invention discloses a model test device and a test method for simulating concentrated stacking load in an existing tunnel, wherein the device comprises a model box, and a stratum loss simulation device and an existing tunnel model which are arranged up and down are arranged in the model box; the existing tunnel model comprises a pipe body and port covers arranged at two ends of the pipe body, a road bed plate, a reference beam and a closed water collecting tank are arranged in the pipe body, and two ends of the reference beam penetrate through the port covers at the two ends of the pipe body and then are fixed on a model box; the closed water collecting tanks are arranged on the road bed plate, each closed water collecting tank is independently connected with a water conveying pipe, and the water conveying pipes are led out of the model box and then are injected with water by a water supply device; the existing tunnel model is provided with a monitoring section, and a detection device is arranged at the monitoring section. By the test method, the process of loading in the tunnel can be simulated; has the advantages of rapidness and convenience; especially, under the working condition that the shield is penetrated in a short distance or an upper foundation pit is excavated to cause the existing tunnel to bulge, the anti-floating effect generated by the weight is especially suitable for being researched.

Description

Model test device and test method for simulating concentrated stacking load in existing tunnel
Technical Field
The invention belongs to the technical field of shield tunnel model tests, and particularly relates to a model test device and a test method for simulating concentrated loading in an existing tunnel, which are suitable for simulating the working condition of concentrated loading in the existing tunnel, and are particularly suitable for researching the anti-floating effect generated by weight under the working condition that the existing tunnel bulges due to short-distance upward penetration of a shield or excavation of an upper foundation pit.
Background
The shield adjacent to the existing tunnel is penetrated upwards, so that the existing tunnel at the lower part is bulged and deformed, the damages of cracks, water leakage, bolt breakage and the like between the pipe sheet rings of the existing tunnel are caused, and the use function and the safety of the operated tunnel are seriously influenced. In order to control the floating deformation of the existing tunnel, the back pressure is often performed in the tunnel by adopting a concentrated stacking mode.
The method is applied to a plurality of projects aiming at controlling the floating deformation of the tunnel by the stacking load in the tunnel, and a plurality of scholars study the influence rule of the stacking load in the tunnel at home and abroad, and the main study methods comprise a numerical simulation method, a field actual measurement data analysis method and an indoor model test method. The numerical simulation method depends on the selection of simulation conditions to a great extent, the precision is difficult to control, and the error is often large; the field actual measurement data analysis method adopts actual engineering measurement, the measurement result is more visual and accurate, but the defects of complex field stratum shape, complex construction conditions, difficult embedding of test original components and the like exist. As an effective research method, the indoor model test method can realize the simulation of the actual engineering problem indoors on the basis of ensuring certain accuracy and intuition, thereby saving a large amount of manpower and material resources. And under the working condition of close-range upward penetration of the shield, the research on the indoor model test of the internal pressure of the existing tunnel is not yet seen and needs to be further developed.
In summary, the existing research methods generally have the problems of difficult precision control, insufficient intuition of measurement results, complex research conditions, high cost, time and labor waste, and the like, and need to be solved by improving the technology urgently.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provides a model test device and a test method for simulating the concentrated stacking load in the existing tunnel.
In order to realize the technical purpose, the invention adopts the following technical scheme:
a model test device for simulating concentrated loading in an existing tunnel comprises a model box, wherein a stratum loss simulation device and an existing tunnel model which are arranged up and down are arranged in the model box; the existing tunnel model comprises a pipe body and port covers arranged at two ends of the pipe body, a road bed plate, a reference beam and a closed water collecting tank are arranged in the pipe body, and two ends of the reference beam penetrate through the port covers at the two ends of the pipe body and then are fixed on a model box; the closed water collecting tanks are arranged on the road bed plate, each closed water collecting tank is independently connected with a water conveying pipe, and the water conveying pipes are led out of the model box and then are injected with water by a water supply device; the existing tunnel model is provided with a monitoring section, and a detection device is arranged at the monitoring section.
Furthermore, the stratum loss simulation device is composed of an outer pipe and an inner pipe nested in the outer pipe, the inner end of the inner pipe is fixed on the side wall of the model box, and the outer end of the outer pipe penetrates through a receiving hole in one side of the model box and then is connected with a traction device.
Further, detection device includes displacement meter, soil pressure cell and foil gage, and the inside both sides of existing tunnel model arch waist and vault position all set up the displacement meter, and the displacement meter is fixed on the benchmark roof beam, and outside both sides arch waist, vault and arch end position all set up soil pressure cell, and arch end position sets up the foil gage.
Furthermore, the water supply device comprises a water pump, a valve, a flowmeter and a water delivery pipe connector which are arranged in sequence.
Furthermore, the stratum loss simulation device is arranged in the upper space of the model box, the height and the crossing angle are fixed, and the height and the angle of the existing tunnel model can be adjusted in the lower space. The existing tunnel model and the stratum loss simulation device are arranged at a certain angle, the angle can be 30 degrees, 45 degrees, 60 degrees, 90 degrees and other angles, and the device is used for simulating tunnel approach construction under different burial depths and different crossing angle working conditions.
Furthermore, the length, the width and the height of the model box are respectively 4m multiplied by 3m, the front surface of the model box is made of toughened glass and marked with scales, and the other surfaces of the model box are welded by steel plates.
Furthermore, the stratum loss simulation device and the existing tunnel model are made of aluminum alloy hollow pipes, and steel balls are arranged in a gap between an outer pipe and an inner pipe of the stratum loss simulation device.
Furthermore, the road bed board is fixed in a sliding groove in the existing tunnel model, is made of a metal plate and is coated with a certain amount of lubricating oil.
Furthermore, the two ends of the pipe body are sealed by port covers, the port cover at one end is provided with a lead hole and a plastic hose, the port covers at the two ends are provided with small holes for the reference beam to pass through, and rubber ferrules are arranged inside the small holes along the annular direction.
Furthermore, the water collecting grooves are symmetrically arranged on two sides of the center of the track bed plate, each water collecting groove is of a closed box-shaped structure, the top of each water collecting groove is provided with a detachable cover plate, the water collecting grooves are as wide as the track bed plate, the length of each water collecting groove is 0.3-0.5m, the height of each water collecting groove is 10-15cm, and each water collecting groove corresponds to one water conveying pipe one by one and is numbered independently.
Furthermore, the length of the reference beam is adjustable, and two ends of the reference beam are fixed on the side wall of the model box in a detachable mode.
Furthermore, the quick sand discharge port is positioned on the rear vertical surface of the model box, a rectangular open hole is formed in a steel plate of the rear vertical surface, and a movable door is installed and can be opened and closed manually.
A second object of the present invention is to provide a test method for simulating a concentrated stacking model test apparatus in an existing tunnel, including the steps of:
(1) filling fine sand into a model box in a range below the existing tunnel model, fully compacting, and adjusting the existing tunnel model according to the angle of the test;
(2) then, uniformly filling external fine sand into the model box until the fine sand is filled to a specified height, and connecting the displacement meter, the soil pressure box and the strain gauge with corresponding instruments;
(3) starting a traction device, drawing out an outer pipe, determining water injection time, water injection position and water injection amount according to a test scheme in the tunneling process, and monitoring displacement, annular soil pressure and bending moment change data of the existing tunnel model in real time by using a displacement meter, a soil pressure box and a strain gauge;
(4) and processing test data of soil pressure, bending moment and displacement of the existing tunnel model, and drawing a relevant curve.
The invention has the beneficial effects that:
1) crossing working condition convenient for simulating different upper crossing angles and burial depths
The stratum loss simulation device is arranged at a fixed position at the upper part of the model box, 3-4 existing tunnel model embedding layers are arranged at a proper height in the lower space, and in the test process, the existing tunnel model at the lower part can be fixed in soil layers with different burial depths and can form a plurality of angles of 30 degrees, 45 degrees and 60 degrees and 90 degrees with the stratum loss simulation device, so that the stratum loss simulation device is used for simulating tunnel approach construction under the working conditions of different burial depths and different crossing angles.
2) Control effect of different loading schemes on tunnel floating convenient to simulate
Independent water collecting tanks are symmetrically arranged on two sides of an upper tunnel and a lower tunnel passing through a central point inside an existing tunnel model, one water conveying pipe is in one-to-one correspondence with each water collecting tank and leads to the outside of the model box, each water conveying pipe is respectively numbered, water only needs to be injected into the corresponding water conveying pipe and water collecting tank in the process of simulating the preloading, and the control of the floating deformation of the tunnel by different preloading lengths and preloading weights can be simulated along with the control of different positions and injection amounts of the injected water collecting tanks. In addition, water is injected before, during and after the new tunnel passes through, and the effect of loading under different passing stages can be compared.
3) High mechanization degree and simple test operation
The crossing process of the stratum loss simulation device is realized through a winch and a steel strand, fine sand in the model box is filled and compacted in a layered mode through mechanical sand sprinkling, and the sand leakage can be quickly completed through a quick sand leakage opening reserved on the model box, the mechanical degree of the test process is high, the manpower is saved, and the test operation and completion are facilitated.
4) Accurately reflecting test results for arranging measuring instruments
The LVDT displacement meters in three directions are arranged on the arch waists and the arch tops of two sides in the existing tunnel model, so that the absolute displacement and the structural convergence deformation of the whole tunnel can be measured; the soil pressure boxes arranged in four directions outside the tunnel can measure the soil pressure distribution condition of each part of the tunnel; and the strain gauge arranged on the bottom axis of the outer wall of the tunnel is used for monitoring and reflecting the change condition of the bending moment generated by the tunnel model under the influence of the upward penetration. The three parts monitor and measure the deformation condition of the existing tunnel model together, and the displacement and deformation condition of the existing tunnel model in the test process are fully reflected.
Drawings
FIG. 1 is a schematic view of the overall structure of the test apparatus of the present invention;
FIG. 2 is a plan view of an existing tunnel model arrangement;
FIG. 3 is a plan view of a formation loss simulator layout;
FIG. 4 is a schematic cross-sectional view of the internal structure of an existing tunnel model;
FIG. 5 is a schematic longitudinal sectional view of the internal structure of an existing tunnel model;
FIG. 6 is a partial detail view of the internal structure of an existing tunnel model;
description of reference numerals: a mold box 1; a formation loss simulator 2; an existing tunnel model 3; a water collection tank 4; a water delivery pipe 5; a removable cover plate 6; a port cover 7; a reference beam 8; a plastic hose 9; a water pump 10; a valve 11; a flow meter 12; a water pipe connector 13; a lead hole 14; a steel bracket 15; a tab 16; a steel strand 17; a hoist 18; a displacement meter 19; a soil pressure cell 20; a strain gauge 21; a quick sand discharge port 22; a receiving hole 23; a ballast bed plate 24; an outer tube 25; an inner tube 26.
Detailed Description
The present invention will be further described with reference to the following examples. The following examples are set forth merely to aid in the understanding of the invention. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.
It should be noted that all the directional indications (such as up, down, left, right, front, and rear … …) in the embodiment of the present application are only used to explain the relative position relationship between the components, the movement situation, and the like in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indication is changed accordingly.
As shown in figure 1, the invention provides a model test device for simulating concentrated stacking in an existing tunnel, which comprises a model box 1, wherein the model box 1 is reduced in proportion of 15:1, the length, the width and the height are respectively 4m multiplied by 3m, the interior of the model box comprises a stratum loss simulation device 2 and an existing tunnel model 3, the stratum loss simulation device 2 is arranged in the upper space, a steel bracket 15 is arranged on the right side of the model box 1, the top surface of the steel bracket 15 is as high as the lowest point of a receiving hole 23, and the traction device and an outer pipe 25 can be conveniently placed after being drawn out; the left end of the stratum loss simulator 2 is fixed on the left side wall of the model box 1, and the right end of the stratum loss simulator passes through the right receiving hole 23; a pull ring 16 is arranged at the right end of the stratum loss simulation device 2, the pull ring 16 is connected to a traction device through a steel strand 17 (as a winch 18 has the advantages of simple mechanical equipment, easy operation, wide application range and the like, the winch 18 is adopted in the embodiment), and the outer pipe 2 can be pulled rightwards through the work of the winch 18 to simulate shield tunneling; a rear vertical surface of the model box 1 is provided with a quick sand discharge port 22 at a position which is positioned on the left side of the existing tunnel model 3 and is inclined downwards, the quick sand discharge port 22 is closed in the test process, and is manually opened when an upper sand layer needs to be removed, the upper sand layer is quickly discharged, and the consumption of manual soil unloading is reduced; the water pipe 5 in the existing tunnel model 3 is led out from the interior of the model box 1 through the lead hole 14 and the plastic hose 9, and then the water pipe connector 13, the flowmeter 12, the valve 11 and the water pump 10 are sequentially connected, wherein the water pipe connector 13 is used as a connecting device of the water pipe 5, the water pipe connector 13 can be detached or connected with the water pipe 5 with corresponding numbers at any time and is used for injecting water into the water collecting tanks 4 at different positions, and the flowmeter 12 is used for displaying and controlling the amount of the injected water.
As shown in fig. 2, 3-4 embedding depths of the existing tunnel models 3 are selected from the lower space of the stratum loss simulation device 2 in the model box 1, the existing tunnel models 3 can be fixed according to included angles of 90 degrees, 60 degrees, 45 degrees or 30 degrees under the same embedding depth, different shield crossing working conditions can be simulated through adjustment of the embedding depth and the arrangement angle of the existing tunnel models 3, and the research content of the test device is increased; the length of the existing tunnel model 3 is unchanged, but with the change of the included angle degree, the distance between the two ends of the existing tunnel model 3 and the side wall of the model box 1 is changed, and the length of the reference beam 8 needs to be adjusted; the two ends of the existing tunnel model 3 are provided with port covers 7, the port cover 7 of the front section is provided with a lead hole 14, and the internal water delivery pipe 5 and the measuring line can be led out of the model box 1 through the lead hole 14 and the plastic hose 9.
As shown in fig. 3, the formation loss simulation device 2 is transversely arranged in the model box 1 from left to right, the formation loss simulation device 2 is composed of an outer pipe 25 and an inner pipe 26, the outer pipe 25 is sleeved outside the inner pipe 26, and steel balls are filled in gaps between the outer pipe 25 and the inner pipe 26, so that the outer pipe 25 can be conveniently pulled out in a subsequent process; the left end of the inner pipe 26 is fixed on the left side wall of the model box 1, the outer pipe 25 is not fixed with the left side wall, and the right ends of the outer pipe 25 and the inner pipe 26 are erected on the receiving hole 23; a pull ring 16 is welded at the right end of the outer pipe 25, the pull ring 16 is pulled by a winch 18 through a steel strand 17 in the test process, the outer pipe 25 is slowly pulled out, and due to the fact that the diameter difference exists between the outer pipe 25 and the inner pipe 26, the existing gap is used for simulating the soil loss influence caused by the shield crossing process.
As shown in fig. 4, closed water collecting tanks 4 are arranged on a track bed plate 24 in the existing tunnel model 3, and a detachable cover plate 6 is arranged at the top of each water collecting tank 4 and correspondingly connected with a water conveying pipe 5; arranging LVDT displacement meters 19 in three directions on the arch waists and the arch tops of two sides in the existing tunnel model 3, wherein the LVDT displacement meters 19 are all arranged on the reference beam 8 and used for measuring the displacement change of the existing tunnel model 3; and soil pressure boxes 20 are pasted in four directions outside the existing tunnel model 3 and used for measuring the annular soil pressure change of the existing tunnel model 3.
As shown in fig. 5, monitoring sections are arranged at intervals inside and outside the existing tunnel model 3, and LVDT displacement meters 19 are arranged at the arch waist and the arch crown positions at two sides of the inside for measuring the displacement change of the existing tunnel model 3; the positions of the waist, the arch top and the arch bottom at two sides of the exterior are all provided with soil pressure boxes 20 for measuring the annular soil pressure change of the existing tunnel model 3, and the position of the arch bottom is provided with a strain gauge 21 for measuring the bending moment change generated by the exterior; 6 water collecting tanks 4 are symmetrically arranged on the track bed plate 24 along the center, each water collecting tank 4 is equal to the track bed plate 24 in width, 0.5m in length and 15cm in height, and each water collecting tank 4 corresponds to one water conveying pipe 5 one by one for carrying out independent numbering; the two ends of the existing tunnel model 3 are provided with port covers 7, and the port cover 7 on the left side is provided with a lead hole 14 and a plastic hose 9 for leading the internal water delivery pipe 5 and the measuring line out of the model box 1; the reference beam 8 is used for installing the LVDT displacement meter 19 and is located in the center of the existing tunnel model 3, small holes with rubber ferrules are reserved in the annular direction on the port covers 7 at the two ends, the reference beam 8 is convenient to penetrate through the small holes and is fixed on the side wall of the model box 1, and the rubber ferrules have certain elasticity in the radial direction, so that the existing tunnel model 3 is allowed to generate a certain range of heave displacement when blocking sand enters the inside of the existing tunnel model 3.
As shown in fig. 6, the port cover 7 can be opened, the road bed plate 24 can be drawn out along the preset chute on the inner wall of the existing tunnel model 3, so that the installation and replacement of internal devices and instruments are facilitated, and meanwhile, the detachable cover plate 6 at the top of the water collecting tank 4 can be lifted, so that accumulated water injected inside is convenient to clear.
In addition, the detailed description will be given with reference to specific cases.
The size of the model related to the invention can be flexibly adjusted according to the selected reduced size proportion and the simulated engineering actual condition. The ratio of 15:1 is selected, the outer diameter of the existing tunnel model 3 is 41.3cm (the actual diameter is selected to be 6.2m), the length of one water collecting tank 4 is 0.5m, the width is 0.3m, the height is 15cm, and 6 water collecting tanks 4 are arranged on the track bed plate 24 in total, so that the total length covered by the water collecting tanks 4 is 3 m. Because the stacking in the tunnel is usually carried out symmetrically along the stacking center, if water is injected into the two water collecting grooves 4 at the middle, the simulated actual stacking length is 15 m; if water is injected into the four water collecting grooves 4 in the middle, the simulated actual stacking length is 30 m; if water is injected into the six water collecting tanks 4 at the same time, the simulated actual stacking length is 45 m. The maximum water injection amount of the single water collecting tank 4 is 22.5L, if the density of water is 1kg/L, the maximum water injection mass of the single water collecting tank 4 is 22.5kg, the maximum water injection mass of the six water collecting tanks 4 is 135kg, and the maximum loading amount in the simulated actual engineering is 675 kg/m. As the water injection amount can be flexibly controlled, in conclusion, the test device can simulate the actual engineering stacking ranges of 15m, 30m and 45m, and the simulated concentrated stacking amount in the tunnel is 0-675 kg/m.
The structure of the formation loss simulation apparatus 3 according to the present invention is manufactured with reference to "an apparatus for simulating formation loss caused by propulsion of a rectangular shield" (application No. 201720664274X), and the detailed structure and function introduction is described in the original text.
The concentrated stacking model test device for simulating the concentrated stacking model in the existing tunnel is used for carrying out concentrated stacking model test, and comprises the following steps:
1) making a model: manufacturing a stratum loss simulation device 2 and an existing tunnel model 3 by using an aluminum alloy hollow pipe according to a ratio of 15:1, welding a metal pull ring 16 at one end of an outer pipe 25, arranging two sliding grooves at the installation position of a track bed plate 24 in the existing tunnel model 3, symmetrically installing water collecting grooves 4 along two sides of the midpoint of the track bed plate 24, connecting water conveying pipes 5, and numbering respectively;
2) installing an instrument: temporarily fixing reference beams 8 at two ends of the existing tunnel model 3, installing an LVDT displacement meter 19 on the reference beams 8, pasting a soil pressure box 20 and a strain gauge 21 outside the existing tunnel model 3, numbering all measuring lines, and arranging the measuring lines into bundles to avoid the problems that the measuring lines are disordered and cannot be identified in the test process;
3) installing the existing tunnel model 3: the method comprises the steps that a track bed plate 24 is arranged in an existing tunnel model 3 along a sliding groove, end covers 7 are arranged at two ends of the existing tunnel model 3, in the installation process, a measuring line of an LVDT displacement meter 19 and a water delivery pipe 5 pass through a lead hole 14 and a plastic hose 9, two ends of a reference beam 8 pass through small holes, the reference beam 8 is placed aside for later use after the installation is finished, fine sand is filled in a model box 1 in the range below the existing tunnel model 3 and is fully compacted, the existing tunnel model 3 is placed in the model box 1 according to the test angle, the reference beam 8 is fixed on the side wall of the model box 1 in a detachable mode, the plastic hose 9 is fixedly connected to the small holes reserved in the model box 1, and the measuring line of the LVDT displacement meter 19 is led out of the model box 1;
4) installing a stratum loss simulation device 2: fixing one end of an inner pipe 26 on the side wall of the model box 1, erecting the other end on a receiving hole 23, coating a lubricant on the surface of the inner pipe 26 and wrapping a PE film, then sheathing an outer pipe 25 from the outside by using the receiving hole 23, adding steel balls into a gap between the inner pipe 26 and the outer pipe 25, coating the lubricant on the surface of the outer pipe 25 and sheathing the smooth PE film;
5) filling fine sand and installing an instrument: uniformly filling external fine sand into the model box 1 by using a sand sprinkling system, tamping once every 100mm of fine sand is filled, repeating the operation until the fine sand is filled to a specified height, leading out a sand layer along the inner wall of the model box 1 by using the measuring lines of the soil pressure box 20 and the strain gauge 21, connecting the sand layer with a corresponding instrument, sequentially connecting the water pipe 5 led out from the interior of the existing tunnel model 3 with the water pipe connector 13, the flowmeter 12, the valve 11 and the water pump 10, and connecting the measuring line of the LVDT displacement meter 19 with the corresponding instrument;
6) a single set of experiments was performed: connecting a pull ring 16 at one end of an outer pipe 25 to a winch 18 through a steel strand 17, starting the winch 18, pulling the outer pipe 25 to move rightwards by using the steel strand 17, determining water injection time, water injection position and water injection amount according to a test scheme in the tunneling process, and monitoring settlement and deformation data of the existing tunnel model 3 in real time by using related measuring elements;
7) subsequent further sets of experiments: after the single-group crossing test is finished, opening a quick sand discharge port 22 on the model box 1 to finish quick removal of a sand layer on the upper part of the existing tunnel model 3, detaching a reference beam 8 fixed at two ends, opening a port cover 7, drawing out a ballast bed plate 24, opening a detachable cover plate on the water collecting tank 4, removing accumulated water in the tunnel model, reassembling the tunnel model, readjusting the embedding angle or depth of the existing tunnel model 3 according to a test scheme, cleaning the surface of an inner pipe 26, re-smearing the lubricant, sleeving the outer pipe 25 into a receiving hole 23 again, smearing the lubricant, repeating the sand filling process after the operation is finished, and performing the next group of tests;
8) and (3) post-processing: and processing test data of soil pressure, bending moment and displacement of the existing tunnel model 3, drawing a relevant curve, and researching the displacement and deformation rule of the existing tunnel model 3 under the combined action of crossing and stacking.
The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims (10)

1. A model test device for simulating concentrated stacking load in an existing tunnel is characterized by comprising a model box, wherein a stratum loss simulation device and an existing tunnel model which are arranged up and down are arranged in the model box; the existing tunnel model comprises a pipe body and port covers arranged at two ends of the pipe body, a road bed plate, a reference beam and a closed water collecting tank are arranged in the pipe body, and two ends of the reference beam penetrate through the port covers at the two ends of the pipe body and then are fixed on a model box; the closed water collecting tanks are arranged on the road bed plate, each closed water collecting tank is independently connected with a water conveying pipe, and the water conveying pipes are led out of the model box and then are injected with water by a water supply device; the existing tunnel model is provided with a monitoring section, and a detection device is arranged at the monitoring section.
2. The apparatus of claim 1, wherein the newly constructed tunnel model comprises an outer tube and an inner tube nested within the outer tube, the inner end of the inner tube being secured to the sidewall of the mold box, and the outer end of the outer tube being received through a receiving hole in one side of the mold box and then coupled to the pulling device.
3. The model test device for simulating the concentrated stacking load in the existing tunnel according to claim 1 or 2, wherein the detection device comprises a displacement meter, a soil pressure cell and a strain gauge, the displacement meter is arranged at the position of the arch waist and the arch top at two sides in the existing tunnel model and is fixed on the reference beam, the soil pressure cell is arranged at the position of the arch waist, the arch top and the arch bottom at two sides outside the existing tunnel model, and the strain gauge is arranged at the position of the arch bottom.
4. The model test device for simulating the concentrated surcharge in the existing tunnel according to claim 1, wherein the water supply device comprises a water pump, a valve, a flow meter and a water pipe connector which are arranged in sequence.
5. The model test device for simulating the concentrated stacking load in the existing tunnel according to claim 1, wherein the front surface of the model box is made of toughened glass and marked with scales, and the other surfaces of the model box are welded by steel plates.
6. The model test device for simulating the concentrated stacking load in the existing tunnel according to claim 1, wherein two ends of the tube body are sealed by port covers, a lead hole and a plastic hose are arranged on the port cover at one end, a small hole for a reference beam to pass through is arranged on each port cover at two ends, and a rubber ferrule is arranged inside the small hole along the annular direction.
7. The model test device for simulating the concentrated stacking load in the existing tunnel according to claim 1, wherein the water collecting grooves are symmetrically arranged on two sides of the center of the track bed plate, each water collecting groove is of a closed box-shaped structure, a detachable cover plate is arranged at the top of each water collecting groove, and each water collecting groove corresponds to one water conveying pipe one by one and is numbered independently.
8. The model test device for simulating the concentrated stacking load in the existing tunnel according to claim 1, wherein the length of the reference beam is adjustable, and two ends of the reference beam are detachably fixed on the side wall of the model box.
9. The model test device for simulating the concentrated surcharge load in the existing tunnel according to claim 1, wherein the fast sand-discharging port is positioned on the rear vertical surface of the model box, a rectangular opening is formed by using a steel plate on the rear vertical surface, and a movable door is installed.
10. A test method for simulating a concentrated stacking model test device in an existing tunnel according to claim 3, characterized in that: the method comprises the following steps:
(1) filling fine sand into a model box in a range below the existing tunnel model, fully compacting, and adjusting the existing tunnel model according to the angle of the test;
(2) then, uniformly filling external fine sand into the model box until the fine sand is filled to a specified height, and connecting the displacement meter, the soil pressure box and the strain gauge with corresponding instruments;
(3) starting a traction device, drawing out an outer pipe, determining water injection time, water injection position and water injection amount according to a test scheme in the tunneling process, and monitoring displacement, annular soil pressure and bending moment change data of the existing tunnel model in real time by using a displacement meter, a soil pressure box and a strain gauge;
(4) and processing test data of soil pressure, bending moment and displacement of the existing tunnel model, and drawing a relevant curve.
CN201911119187.6A 2019-11-15 2019-11-15 Model test device and test method for simulating concentrated stacking load in existing tunnel Pending CN110763183A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112065415A (en) * 2020-10-13 2020-12-11 重庆交通大学 Test device and method for simulating stratum displacement caused by double-circular shield tunnel construction

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112065415A (en) * 2020-10-13 2020-12-11 重庆交通大学 Test device and method for simulating stratum displacement caused by double-circular shield tunnel construction

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