CN109632606B - Excavation surface seepage test system for river bottom shield tunnel construction under tidal load effect - Google Patents
Excavation surface seepage test system for river bottom shield tunnel construction under tidal load effect Download PDFInfo
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- CN109632606B CN109632606B CN201910020393.5A CN201910020393A CN109632606B CN 109632606 B CN109632606 B CN 109632606B CN 201910020393 A CN201910020393 A CN 201910020393A CN 109632606 B CN109632606 B CN 109632606B
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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
- G01N15/082—Investigating permeability by forcing a fluid through a sample
- G01N15/0826—Investigating permeability by forcing a fluid through a sample and measuring fluid flow rate, i.e. permeation rate or pressure change
Abstract
The invention provides an excavation surface seepage test system for river bottom shield tunnel construction under the action of tidal load. The system comprises a model box and a shield tunnel model, wherein a main body of the shield tunnel model is arranged in the model box, a soil sample and a water sample are filled in the model box in a layered mode, and a tunnel excavation surface supporting device is formed by a movable panel, a telescopic straight rod and a telescopic rod mounting seat; the invention can simulate the tidal load above the shield tunnel at the bottom of the river of the tidal bore area by using the variable frequency water pump device, and the seepage rule of the excavation surface is researched by setting the working condition combination of the tidal load with different amplitudes and different frequencies, monitoring the seepage flow change of the excavation surface, the seepage flow field change of the soil body near the excavation surface, the displacement change of the soil sample of each measuring point and the support pressure change of each measuring point, thereby optimizing the shield construction parameters and realizing the guidance design and construction.
Description
Technical Field
The invention belongs to the field of a seepage test system for an excavation surface of a shield tunnel, and particularly relates to an excavation surface seepage test system for river bottom shield tunnel construction under the action of tidal load.
Background
The shield method has the advantages of high construction speed, small influence on ground traffic and the like, is widely applied to subway tunnel excavation projects at home and abroad at present, and has unique advantages particularly for river crossing tunnel construction. The tidal bore load of the river bottom tunnel in the tidal bore area constructed by the shield method causes the pressure-bearing water of the permeable stratum to change frequently, so the tidal bore load has great influence on the stability of the excavation surface during the construction of the river bottom shield tunnel, and the seepage of the excavation surface of the shield tunnel is too large and even deformation and damage are easily caused. This problem has received widespread attention from both the academic and engineering communities.
The influence of tidal load on shield tunnel construction is mainly reflected in two aspects of excavation face seepage flow and excavation face stability, wherein the excavation face seepage flow can be directly observed through an instrument, and the excavation face stability needs to be reflected through displacement, supporting pressure and the like of soil samples of all measuring points of the excavation face.
Disclosure of Invention
The invention mainly aims to overcome the defects in the prior art and provide an excavation surface seepage test system for river bottom shield tunnel construction under the action of tidal load.
The purpose of the invention is realized by the following technical scheme: an excavation surface seepage test system for river bottom shield tunnel construction under the action of tidal load can utilize a soil sample to research a seepage test of an excavation surface of a shield tunnel, and comprises a shield tunnel model and a model box, wherein a vertical retaining glass plate and a permeable retaining steel plate are arranged in the model box, the model box is sequentially divided into a water injection cavity, a test cavity and an auxiliary cavity by the permeable retaining glass plate and the retaining glass plate, the height of the retaining glass plate is the same as that of the model box, and a semicircular hole is formed in the front end surface of the retaining glass plate;
the test chamber lower part is filled with the soil layer that permeates water, and the soil layer top that permeates water covers impervious soil layer, the shield tunnel model is the semicircle ring cylindricality structure that constitutes by semicircle ring concrete lining, the level set up in the soil layer permeates water, the one end of semicircle ring concrete lining links to each other with the semicircle orifice that keeps off native glass board front end, and the other end simulation tunnel excavation face is equipped with portable panel, and rectangular side pastes the antetheca in the mold box. The movable panel is connected with the side wall of the model box through a horizontal telescopic straight rod.
The movable panel is composed of a semicircular permeable stone and a semicircular rigid alloy plate, the semicircular permeable stone is arranged on one side of the test cavity, the semicircular rigid alloy plate is arranged on one side of the auxiliary cavity, a water storage tank is arranged between the semicircular permeable stone and the semicircular rigid alloy plate, and water in the water storage tank is led out to a measuring cylinder through a water outlet guide pipe.
And a soil pressure box is arranged on one side of the test cavity of the semicircular permeable stone, and an LVDT displacement sensor is arranged on the other side of the test cavity of the semicircular permeable stone.
Furthermore, the water injection device also comprises a variable frequency water pump, a water storage container and a water delivery hose, wherein the water storage container injects water into the water injection cavity through the variable frequency water pump and the water delivery hose.
A method of testing the system, the method comprising: injecting water into the water injection cavity, wherein the water surface is higher than the impermeable soil layer to simulate the river bottom environment, the water permeates into the permeable soil layer through the permeable soil retaining steel plate and generates pressure on the movable panel, the movable panel compresses the telescopic straight rod and moves towards the auxiliary cavity, and a pressure value and a displacement value are obtained through the soil pressure box and the LVDT displacement sensor respectively; meanwhile, water in the permeable soil layer permeates into the water storage tank through the semicircular permeable stones and is led out to the measuring cylinder through the water outlet guide pipe, and the water seepage amount is obtained.
Compared with the prior art, the invention has the beneficial effects that: the invention can simulate the tidal load above the shield tunnel at the bottom of the river of the tidal bore area by using the variable frequency water pump device, and the seepage rule of the excavation surface of the shield tunnel is researched by setting the working condition combination of the tidal load with different amplitudes and different frequencies, monitoring the seepage flow change of the excavation surface, the seepage flow field change of the soil body near the excavation surface, the displacement change of the soil sample of each measuring point and the support pressure change of each measuring point, thereby optimizing the shield construction parameters and realizing the guidance design and construction.
Drawings
FIG. 1 is a front perspective view of a mold box of the present invention.
FIG. 2 is a side perspective view of the mold box of the present invention.
Fig. 3 is a schematic diagram of a shield tunnel model according to the present invention.
FIG. 4 is a schematic diagram of the front and back sides of a movable baffle of the present invention.
FIG. 5 is a schematic view of a water permeable retaining steel plate according to the present invention.
The reference numbers in the figures are: 1. a model box; 2. a shield tunnel model; 3. a permeable soil layer; 4. a water impermeable soil layer; 5. water sample; 6. a variable frequency water pump; 7. a water storage container; 8. ribbed steel plate; 9. a soil-retaining glass plate; 10. a water permeable soil retaining steel plate; 11. an organic glass plate; 12. a telescopic rod mounting seat; 13. a water delivery hose; 14. a telescopic straight rod; 15. semi-circular ring concrete lining; 16. a movable panel; 17. semi-circular permeable stone; 18. a semicircular rigid alloy plate; an LVDT displacement sensor; 20. a soil pressure cell; 21. a water storage tank; 22. a water outlet; 23. a water outlet conduit; 24. a measuring cylinder.
Detailed Description
The invention will be further elucidated with reference to the following description and embodiments in which:
the system can be used for carrying out tidal load working condition combination of different amplitudes and different frequencies through a variable frequency water pump device, monitoring the seepage flow change of the excavation surface, the change of a soil body seepage flow field near the excavation surface, the change of soil sample displacement of each measuring point and the change of the supporting pressure of each measuring point, and achieving the purpose.
The system for testing the seepage of the excavation surface of the river bottom shield tunnel construction under the action of tidal load, which is shown in the attached figures 1, 2 and 3, can utilize a soil sample to research the seepage test of the excavation surface of the shield tunnel, and comprises a shield tunnel model 2 and a model box 1, wherein a vertical retaining glass plate 9 and a water permeable retaining steel plate 10 are arranged in the model box 1, the model box 1 is sequentially divided into a water injection cavity, a test cavity and an auxiliary cavity by the water permeable retaining steel plate 10 and the retaining glass plate 9, the height of the retaining glass plate 9 is the same as that of the model box 1, and a semicircular hole is formed in the front end surface of the retaining glass plate 9;
the test chamber lower part is filled with the soil layer 3 that permeates water, and 3 tops on the soil layer that permeates water cover impervious soil layer 4, shield tunnel model 2 is the semicircle ring cylindricality structure that comprises semicircle ring concrete lining 15, the level set up in the soil layer 3 permeates water, the semicircle ring concrete lining 15 one end links to each other with the semicircle orifice that keeps off native glass board 9 front end, and the other end simulation tunnel excavation face is equipped with portable panel 16, and rectangular side pastes in the antetheca of mold box 1. The movable panels 16 are connected to the side walls of the mould box 1 by means of horizontal telescopic vertical bars 14.
The movable panel 16 is composed of a semicircular permeable stone 17 and a semicircular rigid alloy plate 18, the semicircular permeable stone 17 is arranged on one side of the test cavity, the semicircular rigid alloy plate 18 is arranged on one side of the auxiliary cavity, a water storage tank 21 is arranged between the semicircular permeable stone 17 and the semicircular rigid alloy plate 18, and water in the water storage tank 21 is led out to a measuring cylinder 24 through a water outlet conduit 23.
And a soil pressure box 20 is arranged on one side of the test cavity of the semicircular permeable stone 17, and an LVDT displacement sensor 19 is arranged on the other side of the test cavity.
Furthermore, the water injection device also comprises a variable frequency water pump 6, a water storage container 7 and a water delivery hose 13, wherein the water storage container 7 injects water into the water injection cavity through the variable frequency water pump and the water delivery hose 13. The variable frequency water pump 6 can control the pumping rate and the water level by adjusting the working frequency and the working time, thereby simulating the tidal load working condition combination with different amplitudes and different frequencies.
The test method of the system comprises the following steps: injecting water into the water injection cavity, wherein the water surface is higher than the impermeable soil layer 4 to simulate the river bottom environment, the water permeates into the permeable soil layer 3 through the permeable soil retaining steel plate 10 and generates pressure on the movable panel 16, the movable panel 16 compresses the telescopic straight rod 14 and moves towards the auxiliary cavity, and a pressure value and a displacement value are respectively obtained through the soil pressure box 20 and the LVDT displacement sensor 19; meanwhile, water in the permeable soil layer 3 permeates into the water storage tank 21 through the semicircular permeable stone 17 and is led out to the measuring cylinder 24 through the water outlet conduit 23, and the water seepage amount is obtained.
Example 1
The construction sequence is as follows: firstly, preparing cement mortar with a certain mixing proportion, and completing the manufacture of the semicircular concrete lining 15 through the steps of pouring, curing, form removal, installation and the like;
and secondly, installing a soil retaining glass plate 9, a permeable soil retaining steel plate 10, a telescopic rod mounting seat 12 and a measuring cylinder 24 at corresponding positions in the model box 1, and coating vaseline on the inner wall of the model box 1 to avoid a boundary effect caused by friction between a soil body and the model box. The diameter of the water filtration holes of the water permeable soil retaining steel plate 10 needs to be smaller than the median diameter of the soil sample particles of the water permeable soil layer, so as to avoid the formation loss caused by the large amount of soil particles of the water permeable soil layer entering the water sample. The water permeable retaining steel plate 10 is shown in fig. 5. And then the water delivery hose 13, the water pump 6 and the water storage container 7 are connected to realize the working condition simulation.
And thirdly, constructing a shield tunnel model 2 in a model box 1, arranging a semicircular opening with the same diameter as the shield tunnel model 2 on a retaining glass plate 9, sequentially filling a permeable soil layer 3, an impermeable soil layer 4 and a water sample 5 into the model box 1 to a certain height, arranging white fine sand with similar soil physical and mechanical properties to the permeable soil layer 3 for testing on one side of an organic glass plate 11 in the permeable soil layer 3 as a mark point, and shooting in real time by using a shooting device in the testing process to more clearly capture the change process of a soil body seepage field near an excavation surface. Then, excavating a permeable soil layer 3 through a semicircular opening on a retaining glass plate 9, and simultaneously installing a semicircular concrete lining 15 prepared in advance on the inner wall of the excavated part of the shield tunnel model 2;
fourthly, the semi-circular permeable stone 17 and the semi-circular rigid alloy plate 18 are installed to form the movable panel 16, the semi-circular permeable stone 17 is arranged at one side of the test chamber, and the semi-circular rigid alloy plate 18 is arranged at one side of the auxiliary chamber, as shown in the attached figure 4. Installing an LVDT displacement sensor 19 and a soil pressure cell 20 at a corresponding measuring point, and firmly attaching the installed movable panel 16 to an excavation surface;
fifthly, one end of the telescopic straight rod 14 is arranged on the movable panel 16, the other end of the telescopic straight rod is arranged on the telescopic rod mounting seat 12, and water in a water storage tank 21 between the semicircular permeable stone 17 and the semicircular rigid alloy plate 18 is led out to the measuring cylinder 24 through a water outlet conduit 23.
After the test system is installed and debugged, the working frequency and the working time are adjusted through the variable frequency water pump 6 to control the pumping speed and the water level, tidal load combinations with different frequencies and different amplitudes are set in different test groups, the water seepage amount under different working conditions and the pressure value and the displacement value obtained by the soil pressure cell 20 and the LVDT displacement sensor 19 are obtained, a large amount of detailed monitoring data are obtained, the seepage rule of the excavation surface of the shield tunnel can be obtained under different tidal load working conditions through the contrastive analysis of the data, further the shield construction parameters are optimized, and the guidance design and construction are realized.
The reasonability and the applicability of the method are verified by a project example of construction of a Hangzhou subway No. 8 line first-stage project SG8-2 standard large-diameter slurry shield tunnel through Qiantangjiang, the seepage rule of the excavation surface of the shield tunnel simulated by the method is compared with a result obtained by numerical simulation in the project, and the error is found to be small.
Finally, it should be noted that the above-mentioned list is only a specific embodiment of the present invention. It is obvious that the present invention is not limited to the above embodiments, but many variations are possible. All modifications which can be derived or suggested by a person skilled in the art from the disclosure of the present invention are to be considered within the scope of the invention.
Claims (5)
1. An excavation surface seepage test system for river bottom shield tunnel construction under the action of tidal load can utilize a soil sample to research a shield tunnel excavation surface seepage test, and is characterized by comprising a shield tunnel model (2) and a model box (1), wherein a vertical retaining glass plate (9) and a permeable retaining steel plate (10) are arranged in the model box (1), the model box (1) is sequentially divided into a water injection cavity, a test cavity and an auxiliary cavity by the permeable retaining glass plate (10) and the retaining glass plate (9), the height of the retaining glass plate (9) is the same as that of the model box (1), and a semicircular hole is formed in the front end surface of the retaining glass plate (9);
the lower part of the test cavity is filled with a permeable soil layer (3), an impermeable soil layer (4) covers the permeable soil layer (3), the shield tunnel model (2) is of a semicircular cylindrical structure formed by semicircular concrete linings (15) and is horizontally arranged in the permeable soil layer (3), one end of each semicircular concrete lining (15) is connected with a semicircular hole in the front end of a retaining glass plate (9), the other end of each semicircular concrete lining simulates a tunnel excavation surface, a movable panel (16) is arranged, and the rectangular side surface is attached to the front wall of the model box (1); the movable panel (16) is connected with the side wall of the model box (1) through a horizontal telescopic straight rod (14);
the movable panel (16) is composed of a semicircular pervious stone (17) and a semicircular rigid alloy plate (18), the semicircular pervious stone (17) is arranged on one side of the test cavity, the semicircular rigid alloy plate (18) is arranged on one side of the auxiliary cavity, a water storage tank (21) is arranged between the semicircular pervious stone (17) and the semicircular rigid alloy plate (18), and water in the water storage tank (21) is led out to a measuring cylinder (24) through a water outlet conduit (23).
2. Excavation face seepage test system of claim 1, characterized in that, the test chamber of semicircular permeable stone (17) is provided with soil pressure cell (20) on one side, and displacement sensor (19) on the other side.
3. Excavation face seepage test system of claim 2, characterized in that, the displacement sensor (19) is an LVDT displacement sensor.
4. The excavation face seepage test system of claim 1, further comprising a variable frequency water pump (6), a water storage container (7) and a water delivery hose (13), wherein the water storage container (7) injects water into the water injection cavity through the variable frequency water pump and the water delivery hose (13).
5. A method of testing the system of claim 1, the method comprising: injecting water into the water injection cavity, wherein the water surface is higher than the impermeable soil layer (4) to simulate the river bottom environment, water permeates into the permeable soil layer (3) through the permeable soil retaining steel plate (10) and generates pressure on the movable panel (16), the movable panel (16) compresses the telescopic straight rod (14) and moves towards the auxiliary cavity, and a pressure value and a displacement value are obtained through the soil pressure box (20) and the displacement sensor (19) respectively; meanwhile, water in the permeable soil layer (3) permeates into the water storage tank (21) through the semicircular permeable stone (17) and is led out to the measuring cylinder (24) through the water outlet conduit (23), and the water seepage amount is obtained.
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| CN201910020393.5A CN109632606B (en) | 2019-01-09 | 2019-01-09 | Excavation surface seepage test system for river bottom shield tunnel construction under tidal load effect |
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| CN110398414A (en) * | 2019-07-12 | 2019-11-01 | 广西大学 | The model test apparatus and test method of excavation face unstability under the conditions of seepage flow artesian water |
| CN111983191B (en) * | 2020-08-20 | 2022-09-13 | 中铁二十局集团有限公司 | Tunnel excavation gushing water simulation device and simulation method |
| CN115902169B (en) * | 2023-03-10 | 2023-05-19 | 四川藏区高速公路有限责任公司 | Diversion test simulation device for treating water gushing and mud bursting of tunnel |
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| JPH08120261A (en) * | 1994-10-27 | 1996-05-14 | Konoike Constr Ltd | Shield excavation method in shield tunneling method |
| CN203287239U (en) * | 2013-05-29 | 2013-11-13 | 浙江大学 | Earth pressure balance shield excavation face stability control model test device |
| CN204422499U (en) * | 2015-01-21 | 2015-06-24 | 同济大学 | For the rigid protection face device of Shield Tunneling face seepage erosion model test |
| CN108956935A (en) * | 2018-04-26 | 2018-12-07 | 长安大学 | A kind of centrifugal device and test method that simulation rich water soft clay tunnel tunnel face is stable |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103278376B (en) * | 2013-05-29 | 2015-01-14 | 浙江大学 | Test device of stability control model of earth pressure balance shield excavation surface |
| CN108072749A (en) * | 2017-07-05 | 2018-05-25 | 同济大学 | A kind of tunneling shield excavates high-precision seepage flow simulation by tracing experimental rig |
| CN108489892B (en) * | 2018-03-29 | 2020-06-05 | 华东交通大学 | Submarine shield tunnel excavation test device and method under seepage condition |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08120261A (en) * | 1994-10-27 | 1996-05-14 | Konoike Constr Ltd | Shield excavation method in shield tunneling method |
| CN203287239U (en) * | 2013-05-29 | 2013-11-13 | 浙江大学 | Earth pressure balance shield excavation face stability control model test device |
| CN204422499U (en) * | 2015-01-21 | 2015-06-24 | 同济大学 | For the rigid protection face device of Shield Tunneling face seepage erosion model test |
| CN108956935A (en) * | 2018-04-26 | 2018-12-07 | 长安大学 | A kind of centrifugal device and test method that simulation rich water soft clay tunnel tunnel face is stable |
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