CN112627885B - Backfill load reduction structure for top shaft of large buried depth tunnel and construction method thereof - Google Patents
Backfill load reduction structure for top shaft of large buried depth tunnel and construction method thereof Download PDFInfo
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- CN112627885B CN112627885B CN202011596398.1A CN202011596398A CN112627885B CN 112627885 B CN112627885 B CN 112627885B CN 202011596398 A CN202011596398 A CN 202011596398A CN 112627885 B CN112627885 B CN 112627885B
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- 238000010276 construction Methods 0.000 title claims abstract description 23
- 230000009467 reduction Effects 0.000 title claims abstract description 10
- 230000001681 protective effect Effects 0.000 claims abstract description 66
- 238000007789 sealing Methods 0.000 claims abstract description 56
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 39
- 239000010959 steel Substances 0.000 claims abstract description 39
- 239000004567 concrete Substances 0.000 claims abstract description 27
- 239000002689 soil Substances 0.000 claims abstract description 21
- 238000003466 welding Methods 0.000 claims abstract description 6
- 238000005086 pumping Methods 0.000 claims abstract description 4
- 238000000034 method Methods 0.000 claims description 11
- 229920002635 polyurethane Polymers 0.000 claims description 11
- 239000004814 polyurethane Substances 0.000 claims description 11
- 230000008569 process Effects 0.000 claims description 11
- 229910001294 Reinforcing steel Inorganic materials 0.000 claims description 3
- 230000008878 coupling Effects 0.000 claims description 3
- 238000010168 coupling process Methods 0.000 claims description 3
- 238000005859 coupling reaction Methods 0.000 claims description 3
- 230000003014 reinforcing effect Effects 0.000 claims description 3
- 230000002787 reinforcement Effects 0.000 claims description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 8
- 230000000694 effects Effects 0.000 description 6
- 235000003181 Panax pseudoginseng Nutrition 0.000 description 4
- 244000131316 Panax pseudoginseng Species 0.000 description 4
- 239000000945 filler Substances 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 238000005187 foaming Methods 0.000 description 3
- 239000011435 rock Substances 0.000 description 3
- 238000009423 ventilation Methods 0.000 description 3
- 238000004873 anchoring Methods 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 239000011381 foam concrete Substances 0.000 description 2
- 230000007774 longterm Effects 0.000 description 2
- 239000000779 smoke Substances 0.000 description 2
- 206010021143 Hypoxia Diseases 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000003517 fume Substances 0.000 description 1
- 239000004746 geotextile Substances 0.000 description 1
- 230000008595 infiltration Effects 0.000 description 1
- 238000001764 infiltration Methods 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 239000002352 surface water Substances 0.000 description 1
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
- E21F15/00—Methods or devices for placing filling-up materials in underground workings
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/003—Linings or provisions thereon, specially adapted for traffic tunnels, e.g. with built-in cleaning devices
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D8/00—Shafts not provided for in groups E21D1/00 - E21D7/00
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
- E21F16/00—Drainage
- E21F16/02—Drainage of tunnels
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/20—Hydro energy
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- Engineering & Computer Science (AREA)
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- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- Mechanical Engineering (AREA)
- Architecture (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Lining And Supports For Tunnels (AREA)
Abstract
The invention discloses a backfill load-reducing structure of a vertical shaft at the top of a large buried tunnel and a construction method thereof, wherein the backfill load-reducing structure comprises a protective pipe which is arranged in the vertical shaft and the top end of which extends out of the vertical shaft, and a bottom sealing layer and a plurality of filling layers are arranged in the protective pipe; foldable supports are arranged between adjacent filling layers, a base, a locking opening joist and an outer wrapping layer are arranged outside the vertical shaft, and the locking opening joist and the part of the protective pipe extending out of the vertical shaft are positioned in the outer wrapping layer; the outer wrapping layer is provided with a soil sealing layer. Hoisting a plurality of sections of steel casing pipes into the vertical shaft to form a casing pipe, pouring a base, erecting a locking port joist, pouring an outer wrapping layer, arranging drainage blind pipes in an encrypted manner, and pouring a secondary lining; pumping concrete into the protective pipe, vibrating to compact the concrete into a bottom sealing layer, alternately arranging filling layers and foldable supports on the bottom sealing layer until the top surface of the finally formed filling layer is flush with the top surface of the protective pipe, and welding a well top sealing plate on the top surface of the protective pipe; and (5) piling a soil sealing layer on the outer wrapping layer to build a backfill load reduction structure of the top shaft of the large buried deep tunnel. The load reduction structure can effectively protect the safety of the underlying tunnel and fills the technical blank.
Description
Technical Field
The invention belongs to the technical field of tunnels and underground engineering, and relates to a backfill load-reducing structure of a vertical shaft at the top of a large buried depth tunnel; the invention also relates to a construction method of the backfill load reduction structure.
Background
In the long and large deeply buried tunnel construction process, in order to meet the requirements of construction period, ventilation, smoke exhaust, cooling and the like, an auxiliary construction vertical shaft is generally arranged on one side or the top of the tunnel. If a vertical shaft is arranged on one side of the tunnel, a connecting channel needs to be arranged to be connected with the main tunnel, the process conversion is more, the horsehead door construction risk is high, the construction efficiency is low, and the ventilation, smoke exhaust and cooling effects are poor; set up the shaft at the tunnel top, directly link up with the earth's surface, it is efficient to slag tap, is favorable to quick ventilation, discharges fume and lower the temperature in the hole, and the effect is showing, but after the abandonment of later stage shaft, the punishment difficulty is backfilled to the big degree of depth, and the main performance is:
1) The common filler or the light filler (such as light soil and reinforced soil, graded soil stone, concrete, light foam concrete and the like) has larger volume weight, the large-depth backfilling can cause great pressure to the underlying tunnel structure to damage the tunnel structure, and the applicability of the material is invalid.
2) When the vertical shaft is locally backfilled, under the action of long-term surrounding rock pressure and underground water, the cavity body which is not backfilled in the vertical shaft collapses inwards, so that larger additional loose soil pressure is generated, the stress of the underlying tunnel structure is intensified, and the tunnel structure deforms, cracks and even collapses.
3) When the large-depth vertical shaft is backfilled, the vertical shaft is difficult to be densely filled, and long-term subsurface water seepage and surrounding rock pore water accumulation and infiltration in the vertical shaft can cause the seepage of the underlying tunnel on one hand, and soften backfilling materials on the other hand, thereby deteriorating the stress state of the tunnel.
4) When the underground backfilling operation is manually assisted, the risks of oxygen deficiency, foreign matter falling, borehole wall hole collapse and the like exist, and safety guarantee measures are difficult.
5) The tunnel structure under the tunnel needs to be reinforced by special measures, and the construction cost is high.
At present, most vertical shafts at the top of a large buried deep tunnel are permanent structures for use in an operation period, and after abandonment, the vertical shafts are backfilled with experiences and a case is blank, meanwhile, after auxiliary load shedding measures (such as backfilling of light foam concrete, applying geotextiles, applying retaining arches and the like) are carried out on the upper parts of other related underground structures, the thickness of artificial soil backfilling is extremely less than 40m, and therefore the backfilling load shedding structure and the construction method under the condition of large depth need to be solved urgently.
Disclosure of Invention
The invention aims to provide a backfill load-reducing structure of a vertical shaft at the top of a large buried-depth tunnel, which solves the problems that the existing backfill structure is heavy in weight and easy to accumulate water, the vertical shaft is easy to collapse after being abandoned for a long time, the underlying tunnel is difficult to reinforce, and risks of water leakage, cracking, crushing collapse and the like exist, and fills the technical blank in the field.
The invention also aims to provide a construction method of the backfill load-reducing structure of the top shaft of the large buried depth tunnel.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows: a backfill load reduction structure of a vertical shaft at the top of a large buried depth tunnel comprises the vertical shaft and a primary support, wherein a shaft bottom sealing plate fixedly connected with the primary support is arranged at the bottom of the vertical shaft, a protective pipe is arranged in the vertical shaft, and the top end of the protective pipe extends out of the vertical shaft; the bottom end of the protective pipe is contacted with a shaft bottom sealing plate, a bottom sealing layer and a plurality of filling layers are sequentially arranged in the protective pipe from bottom to top, and a shaft top sealing plate is fixedly connected to the top surface of the protective pipe; a foldable support is arranged between two adjacent filling layers, and a base formed by pouring concrete is arranged outside the vertical shaft; the base is provided with an outer wrapping layer formed by pouring a locking port joist and concrete, and the parts of the locking port joist and the protective pipe extending out of the vertical shaft are positioned in the outer wrapping layer; and a soil sealing layer is arranged on the outer wrapping layer.
The invention adopts another technical scheme that: a construction method of the backfill load-shedding structure of the vertical shaft at the top of the large buried deep tunnel comprises the following steps:
1) Processing the steel casing according to the clearance in the shaft to ensure that the steel casing is closely attached to the wall of the shaft; arranging a shaft bottom sealing plate at the bottom of the vertical shaft, and anchoring the shaft bottom sealing plate on a primary support; hoisting steel casing cylinders into the vertical shaft in sections, wherein adjacent steel casing cylinders are connected through threads or welded; all the steel casing cylinders are connected with a forming casing pipe, and the top surface of the casing pipe extends out of the vertical shaft;
2) Concrete is poured outside the vertical shaft to form a base; then, erecting a lock opening joist on the base, fixedly connecting the lock opening joist and a protective pipe into a whole, pouring an outer wrapping layer on the base by using concrete, and sealing the parts of the lock opening joist and the protective pipe extending out of the vertical shaft in the outer wrapping layer;
3) Arranging a circumferential drainage blind pipe and a longitudinal drainage blind pipe behind the secondary lining in the tunnel in an encrypted manner, reinforcing the arrangement of secondary lining reinforcing steel bars, and then pouring the secondary lining of the tunnel;
4) Pumping concrete into the protective pipe from the top of the protective pipe, vibrating to compact the concrete to form a bottom sealing layer, backfilling foamed polyurethane into the protective pipe to form a filling layer, then placing a foldable support into the protective pipe, placing the foldable support on the filling layer adjacent to the bottom sealing layer, then filling the foamed polyurethane on the foldable support to form a second filling layer, then placing a second foldable support on the second filling layer in a hanging manner, forming a third filling layer on the second foldable support, and so on until the top surface of the filling layer formed by final filling is flush with the top surface of the protective pipe, and welding a well top sealing plate on the top surface of the protective pipe;
5) And (3) piling a soil sealing layer on the outer wrapping layer, wherein the height of the soil sealing layer higher than the ground surface is not less than 1m, and the construction of the backfill load reduction structure of the top shaft of the large buried depth tunnel is completed.
The backfill load shedding structure has the following advantages:
1) The strength is high, the deformation control capability of the well wall is strong, the self-weight pressure of the backfill ultra-light material is small, the effect of preventing water leakage is remarkable, the structure process is simple and convenient, the engineering implementation is convenient, and the safety of the underlying tunnel can be effectively protected.
2) The main body filler is a foaming polyurethane ultra-light material, has small density and light weight, has good adherence with the well wall after foaming, has good effect of preventing water from seeping downwards, can not cause larger pressure to the underlying tunnel structure, and can restrict the shrinkage deformation of the well wall to a certain degree.
3) The steel casing and the foldable support are arranged in the existing well wall, so that the shrinkage deformation of the well wall can be effectively restrained, hole collapse of the well wall is prevented, meanwhile, the component is convenient to process, the well wall is not clamped in the hoisting process, side turning failure is avoided, the component is closely attached to the well wall after being positioned, and the clamping performance is good.
4) The upper wellhead is provided with a locking port joist, so that the dead weight load of the steel casing can be effectively borne, and the pressure load is controlled to be transferred to the tunnel structure under the steel casing.
5) The upper well mouth is provided with a sealing steel plate and pseudo-ginseng grey soil, the well body is filled with foamed polyurethane, the lower well mouth is provided with a sealing steel plate and concrete, and the tunnel lining is provided with the drainage blind pipe.
6) Need not artifical borehole operation, construction safety risk is little.
7) The underlying tunnel structure does not require special design, over-reinforcement.
Drawings
Fig. 1 is a schematic diagram of a top shaft backfill offloading structure of the present invention.
Fig. 2 is a schematic plan view of a collapsible support in a top shaft backfill load relief structure according to the present invention.
FIG. 3 is a view I-I of FIG. 2;
FIG. 4 is a schematic view of a shackle joist of the present invention;
FIG. 5 is a view II-II of FIG. 5;
FIG. 6 is a schematic view of a collapsible support well entry of the present invention;
in the figure: 1. the vertical shaft, 2. A protective pipe, 3. A filling layer, 4. A bottom sealing layer, 5. A foldable support, 6. A locking port joist, 7. A soil sealing layer, 8. A shaft bottom sealing plate, 9. A primary support, 10. A secondary lining, 11. A circumferential drainage blind pipe, 12. A longitudinal drainage blind pipe, 13. A base, 14. An outer wrapping layer, 15. A shaft top sealing plate, 16. A first support, 17. A first connecting plate, 18. A rotating shaft, 19. A first lifting ring, 20. A second lifting ring, 21. A second connecting plate, 22. A second support, 23. A section steel beam and 24. A beam support;
l1, the height of the steel casing, L2, the thickness of bottom sealing concrete, L3, the thickness of base concrete, L4, the thickness of externally wrapped concrete, L5, the thickness of pseudo-ginseng gray soil, L6, the distance between every two adjacent foldable supports, and D, the inner diameter of the steel casing.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
As shown in fig. 1, the backfill load-shedding structure of the top vertical shaft comprises an existing vertical shaft 1, wherein a shaft bottom sealing plate 8 is arranged at the bottom of the vertical shaft 1, the shaft bottom sealing plate 8 is an arc-shaped plate, and the concave surface of the arc-shaped plate is matched with the outer edge of a primary support 9 of a tunnel; a protective pipe 2 which is tightly attached to the inner wall of the vertical shaft 1 and has the height of L1 is arranged in the vertical shaft 1; the top end of the protective pipe 2 extends out of the vertical shaft 1, and the top surface of the protective pipe 2 is flush with the ground surface; the protective pipe 2 is formed by fixedly connecting a plurality of cylindrical steel protective cylinders with the inner diameter D in sequence, and two adjacent steel protective cylinders are connected or welded through threads; the bottom end of the protective pipe 2 is contacted with a shaft bottom sealing plate 8, a bottom sealing layer 4 and a plurality of filling layers 3 are sequentially arranged in the protective pipe 2 from bottom to top, and a shaft top sealing plate 15 is fixedly connected to the top surface of the protective pipe 2; the height of the bottom sealing layer 4 is L2 and is formed by concrete; the filling layer 3 is formed of foamed polyurethane; a foldable support 5 is arranged between two adjacent layers of filling layers 3, a base 13 formed by pouring concrete with the thickness of L3 is arranged outside the vertical shaft 1, the L3 is more than or equal to 1m, and the upper end surface of the base 13 is flush with the top surface of the vertical shaft 1; the base 13 is provided with a locking joist 6 and an outer wrapping layer 14 which is formed by pouring concrete and has the thickness of L4, the L4 is more than or equal to 1m, the locking joist 6 and the part of the protective pipe 2 extending out of the vertical shaft 1 are both positioned in the outer wrapping layer 14, and the upper end surface of the outer wrapping layer 14 is flush with the top surface of the protective pipe 2; the outer wrapping layer 14 is provided with a soil sealing layer 7 which is formed by piling up the pseudo-ginseng gray soil and has a height of L5, wherein L5 is more than or equal to 1m.
As shown in fig. 2 and 3, the foldable support 5 in the top shaft backfill load reduction structure of the invention comprises a first support 16 and a second support 22 which are arranged side by side and have the same structure, a first connecting plate 17 is fixedly connected to the top surface of the first support 16, a second connecting plate 21 is fixedly connected to the top surface of the second support 22, the first connecting plate 17 and the second connecting plate 21 are connected through a rotating shaft 18, the first connecting plate 17, the second connecting plate 21 and the rotating shaft 18 form a hinge, the length of the rotating shaft 18 is greater than that of the first connecting plate 17 and that of the second connecting plate 21, a first hanging ring 19 is fixedly connected to each of two ends of the rotating shaft 18, and a second hanging ring 20 is fixedly connected to each of the first support 16 and the second support 22; first support 16 and second support 22 are hollow box, and the lateral wall that pivot 18 was kept away from to second support 22 and the lateral wall that pivot 18 was kept away from to first support 16 are the arc to with the internal wall looks adaptation of pillar 2, first support 16 sets up towards the lateral wall slope of second support 22, and second support 22 sets up towards the lateral wall slope of first support 16. Both the first support 16 and the second support 22 are reciprocally rotatable about the rotation axis 18.
As shown in fig. 4 and 5, the locking joist 6 in the backfill load-reducing structure of the top vertical shaft of the invention comprises four section steel beams 23, two of the four section steel beams 23 are arranged side by side, the other two section steel beams 23 are arranged on the two section steel beams 23 arranged side by side in parallel, the four section steel beams 23 form a shape like a Chinese character 'jing', and the two section steel beams 23 which are contacted with each other are fixedly connected; every shaped steel roof beam 23 is last all to be rigid coupling has the beam holder 24, and the beam holder 24 is right angle trapezoidal piece, and the right angle waist of beam holder 24 and the outer wall rigid coupling of pillar 2, beam holder 24 equipartition are on pillar 2 outer wall.
The invention also provides a construction method of the vertical shaft backfill load reduction structure, which comprises the following steps:
1) Processing the steel casing according to the clearance in the vertical shaft 1 to ensure that the steel casing is closely attached to the wall of the vertical shaft 1; arranging a shaft bottom sealing plate 8 at the bottom of the shaft 1, and anchoring the shaft bottom sealing plate 8 on a primary support 9 of the tunnel through bolts; the steel casing is hoisted into the vertical shaft 1 in sections, and adjacent steel casings are connected through threads or welding; all the steel casing pipes are connected to form a casing pipe 2, and the top surface of the casing pipe 2 extends out of the vertical shaft 1 and is level with the ground surface;
2) Pouring a base 13 with the thickness not less than 1m by using concrete outside the vertical shaft 1, wherein the top surface of the base 13 is flush with the top surface of the vertical shaft 1; then, erecting a lock opening joist 6 on a base 13, fixedly connecting the lock opening joist 6 and a protective pipe 2 into a whole, pouring an outer wrapping layer 14 with the thickness not less than 1m on the base 13 by using concrete, and sealing the parts of the lock opening joist 6 and the protective pipe 2 extending out of the vertical shaft 1 in the outer wrapping layer 14;
3) Arranging in a tunnel in an encrypted manner (the distance between the original drainage blind pipes at the back of the tunnel is about 9m, the distance is adjusted to be 2-3 m in the construction method of the invention), arranging reinforcing steel bars of the secondary lining 10 (the diameter of the original lining stressed main bar is 22 mm, the distance is 250mm, the diameter of the lining stressed main bar is 25 mm, and the distance is 200 mm) on the back of the secondary lining 10, and then pouring the secondary lining 10 of the tunnel;
4) Pumping concrete into the protecting pipe 2 from the top of the protecting pipe 2, vibrating to be compact, forming a bottom sealing layer 4 with the height L2 of 1-3 m, backfilling foamed polyurethane into the protecting pipe 2, forming a filling layer 3 which is not more than 5m and is adjacent to the bottom sealing layer 4, and then hanging the foldable support 5 into the protecting pipe 2, wherein the concrete hanging process comprises the following steps: before the foldable support 5 is hung, a lifting rope is tied on the two first hanging rings 19 and the two second hanging rings 20 respectively, the foldable support 5 is hung in the protective pipe 2 and falls downwards, in the falling process, the lifting rope tied on the two first hanging rings 19 is tightened, the lifting rope tied on the two second hanging rings 20 is loosened, the first support 16 and the second support 22 are prevented from being opened in advance, the wall clamping phenomenon occurs, when the foldable support 5 is lowered to a preset design position, the lifting rope tied on the two second hanging rings 20 is tightened, the first support 16 and the second support 22 rotate reversely, the foldable support 5 is unfolded, the side wall of the first support 16 far away from the rotating shaft 18 and the side wall of the second support 22 far away from the rotating shaft 18 are tightly adhered and clamped with the inside of the protective pipe 2, at the moment, the first support 16 and the second support 22 are in a horizontal state, and the upper portion of the side wall of the first support 16 facing the second support 22 is contacted with the upper portion of the side wall of the second support 22 facing the first support 16, as shown in fig. 6. Before the first support 16 and the second support 22 are clamped and stabilized, the lifting rope tied on the first lifting ring 19 cannot be completely loosened, so that the component can be timely adjusted in the clamping and fixing process of the component; then filling foamed polyurethane on the foldable support 5 to form a second filling layer 3 with the height not more than 5m, then hanging the second foldable support 5 on the second filling layer 3, forming a third filling layer 3 on the second foldable support 5, and so on until the top surface of the filling layer 3 formed by final filling is flush with the top surface of the protective pipe 2, and welding a well top sealing plate 15 on the top surface of the protective pipe 2;
when the foaming polyurethane is backfilled, the actual backfilling engineering quantity is compared and checked with the volume engineering quantity of the protective pipe 2, the difference value is less than 3%, and the backfilling compactness can be confirmed.
5) And (3) piling a soil sealing layer 7 on the outer wrapping layer 14 by using the pseudo-ginseng gray soil, wherein the height of the soil sealing layer 7 higher than the ground surface is not less than 1m, and then arranging a protective fence enclosure on the ground surface to prevent the backfill structure from being artificially damaged.
The invention has been applied to Yinxi high-speed railway early-surpassing first tunnel engineering, has the advantages of high strength of the retaining wall structure, strong capability of controlling the deformation of the well wall, ultra-light dead weight pressure of main body filler, obvious effect of preventing water leakage, no need of special reinforcement for the tunnel structure, no potential safety hazard, simple and convenient structure process, convenient engineering implementation, overcoming the problems in the prior art, filling the technical blank in the field and strong practicability.
For preventing hole collapse after existing shaft 1 abandons for a long time, ensure that the wall of a well is stable, paste the inboard pillar 2 that sets up of the wall of a well, pillar 2 embeds collapsible support 5 to reinforcing wall of a well resistance prevents to shrink deformation under the surrounding rock pressure effect. After the protective pipe 2 is arranged, in order to reduce the large pressure caused by the dead weight pressure of the protective pipe 2 under the condition of large depth to the underlying lining structure, a locking port supporting beam 6 reliably connected with the protective pipe 2 is arranged at the top of the vertical shaft 1 so as to control the falling force of the protective pipe 2, the locking port supporting beam 6 is arranged on the base 13, and the upper part of the locking port supporting beam is covered with concrete for wrapping.
After a shaft bottom sealing plate 8 is arranged at the joint of the bottom of the shaft 1 and a primary support 9 of the tunnel, a tunnel secondary lining 10 is poured and reinforced with a shaft connecting section tunnel secondary lining steel bar to improve the bearing capacity of the lining, and a circumferential and longitudinal drainage blind pipe behind the lining is encrypted to enhance the drainage preventing capacity of the tunnel.
The shaft top sealing plate 15 is provided to prevent surface water from flowing backward into the shaft 1.
Claims (8)
1. A backfill load reduction structure of a vertical shaft at the top of a large buried-depth tunnel comprises a vertical shaft (1) and a primary support (9), and is characterized in that a shaft bottom sealing plate (8) fixedly connected with the primary support (9) is arranged at the bottom of the vertical shaft (1), a protective pipe (2) is arranged in the vertical shaft (1), and the top end of the protective pipe (2) extends out of the vertical shaft (1); the bottom end of the protective pipe (2) is contacted with a shaft bottom sealing plate (8), a bottom sealing layer (4) and a plurality of filling layers (3) are sequentially arranged in the protective pipe (2) from bottom to top, and a shaft top sealing plate (15) is fixedly connected to the top surface of the protective pipe (2); a foldable support (5) is arranged between two adjacent layers of filling layers (3), and a base (13) formed by pouring concrete is arranged outside the vertical shaft (1); the base (13) is provided with a locking joist (6) and an outer wrapping layer (14) formed by pouring concrete, and the parts of the locking joist (6) and the protective pipe (2) extending out of the vertical shaft (1) are positioned in the outer wrapping layer (14); a soil sealing layer (7) is arranged on the outer wrapping layer (14);
the foldable support (5) comprises a first support (16) and a second support (22) which are arranged side by side and have the same structure, a first connecting plate (17) is fixedly connected to the first support (16), a second connecting plate (21) is fixedly connected to the second support (22), the first connecting plate (17) and the second connecting plate (21) are connected through a rotating shaft (18), the first connecting plate (17), the second connecting plate (21) and the rotating shaft (18) form a hinge, first hanging rings (19) are fixedly connected to two ends of the rotating shaft (18) respectively, and second hanging rings (20) are fixedly connected to the first support (16) and the second support (22); the first support (16) and the second support (22) are both hollow boxes, the first support (16) is obliquely arranged towards the side wall of the second support (22), and the second support (22) is obliquely arranged towards the side wall of the first support (16); the other side wall of the second support (22) and the other side wall of the first support (16) are both arc-shaped and are matched with the inner wall surface of the protective pipe (2).
2. The backfill load-reducing structure for the vertical shaft at the top of the large buried deep tunnel according to claim 1, characterized in that the locking bracket beam (6) comprises four section steel beams (23), the four section steel beams (23) form a shape like a Chinese character 'jing', and two contact section steel beams (23) are fixedly connected; every shaped steel roof beam (23) all is connected with the beam support (24) firmly, beam support (24) and pillar (2) outer wall rigid coupling, all beam supports (24) equipartition are on pillar (2) outer wall.
3. The backfill load-reducing structure for the vertical shaft at the top of the large buried deep tunnel according to claim 2, characterized in that the beam support (24) is a right-angle trapezoidal block, and the right-angle waist of the beam support (24) is fixedly connected with the outer wall of the protective pipe (2).
4. The construction method of the backfill load-reducing structure of the top shaft of the large buried deep tunnel according to claim 1, characterized by comprising the following steps:
1) Processing the steel casing according to clearance in the vertical shaft (1) to ensure that the steel casing is closely attached to the wall of the vertical shaft (1); a shaft bottom sealing plate (8) is arranged at the bottom of the shaft (1), and the shaft bottom sealing plate (8) is anchored on a primary support (9); the steel casing is hoisted into the vertical shaft (1) in sections, and adjacent steel casings are connected through threads or welding; all the steel protective cylinders are connected with a protective pipe (2), and the top surface of the protective pipe (2) extends out of the vertical shaft (1);
2) A base (13) is poured outside the vertical shaft (1) by concrete; then, erecting a lock opening joist (6) on a base (13), fixedly connecting the lock opening joist (6) and a protective pipe (2) into a whole, pouring an outer wrapping layer (14) on the base (13) by using concrete, and sealing the parts of the lock opening joist (6) and the protective pipe (2) extending out of the vertical shaft (1) in the outer wrapping layer (14);
3) Arranging a circumferential drainage blind pipe (11) and a longitudinal drainage blind pipe (12) at the back of the secondary lining (10) in the tunnel in an encrypted manner, reinforcing steel bars of the secondary lining (10), and then pouring the secondary lining (10) of the tunnel;
4) Pumping concrete into the protective pipe (2) from the top of the protective pipe (2), vibrating to compact the concrete to form a bottom sealing layer (4), backfilling foamed polyurethane into the protective pipe (2) to form a filling layer (3), then hanging a foldable support (5) into the protective pipe (2), placing the foldable support on the filling layer (3) adjacent to the bottom sealing layer (4), then filling the foamed polyurethane on the foldable support (5) to form a second filling layer (3), then hanging a second foldable support (5) on the second filling layer (3), forming a third filling layer (3) on the second foldable support (5), and so on until the top surface of the filling layer (3) formed by final filling is flush with the top surface of the protective pipe (2), and welding a well top sealing plate (15) on the top surface of the protective pipe (2);
5) And (3) a soil sealing layer (7) is piled on the outer wrapping layer (14), the height of the soil sealing layer (7) higher than the ground surface is not less than 1m, and the construction of the backfill load reduction structure of the top shaft of the large buried deep tunnel is completed.
5. The construction method of the backfill load-reducing structure of the top shaft of the large buried deep tunnel according to claim 4, wherein the encryption in the step 3) is arranged as follows: the distance between the circumferential drainage blind pipes (11) is 2-3 m, and the distance between the longitudinal drainage blind pipes (12) is 2-3 m.
6. The construction method of the backfill load-reducing structure of the top shaft of the large buried deep tunnel according to the claim 4, characterized in that the reinforcing secondary lining (10) steel bars in the step 3) are arranged: the diameter of the stressed main reinforcement of the lining is 25 mm, and the distance is 200mm.
7. The construction method of the backfill load-reducing structure of the top shaft of the large buried deep tunnel according to claim 4, characterized in that the foldable support (5) is lifted in the step 4): before the foldable support (5) is hung, a lifting rope is tied on the two first hanging rings (19) and the two second hanging rings (20) respectively, the foldable support (5) is hung into the protective pipe (2) and falls downwards, in the falling process, the lifting ropes tied on the two first hanging rings (19) are tightened, the lifting ropes tied on the two second hanging rings (20) are loosened, when the foldable support (5) is lowered to a preset design position, the lifting ropes tied on the two second hanging rings (20) are tightened, the foldable support (5) is unfolded, the outer edge of the first support (16) and the outer edge of the second support (22) are closely stuck and clamped with the inner part of the protective pipe (2), and the lifting ropes tied on the first hanging rings (19) cannot be completely loosened before the first support (16) and the second support (22) are clamped and stabilized, so that the component can be adjusted in time in the clamping process of the component.
8. The construction method of the backfill load-reducing structure of the top shaft of the large buried deep tunnel according to claim 4, characterized in that in the step 4), when the foamed polyurethane is backfilled, the actual backfilling work amount is compared with the volume work amount of the protective pipe (2), and the backfilling is compact if the difference is less than 3%.
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| CN205743912U (en) * | 2016-07-07 | 2016-11-30 | 大冶有色设计研究院有限公司 | Compound pit shaft |
| CN207672344U (en) * | 2017-12-12 | 2018-07-31 | 中铁二院工程集团有限责任公司 | Railway bed karez location pin-connected panel foundation stabilization construction |
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