CN111119910B - Back-blowing sand grouting backfill structure and its construction method for tunnel collapse section - Google Patents
Back-blowing sand grouting backfill structure and its construction method for tunnel collapse section Download PDFInfo
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- CN111119910B CN111119910B CN202010053406.1A CN202010053406A CN111119910B CN 111119910 B CN111119910 B CN 111119910B CN 202010053406 A CN202010053406 A CN 202010053406A CN 111119910 B CN111119910 B CN 111119910B
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- 238000007664 blowing Methods 0.000 title claims abstract description 118
- 239000004576 sand Substances 0.000 title claims abstract description 117
- 238000010276 construction Methods 0.000 title claims abstract description 29
- 239000002689 soil Substances 0.000 claims abstract description 27
- 238000009412 basement excavation Methods 0.000 claims abstract description 16
- 238000005488 sandblasting Methods 0.000 claims description 35
- 239000004568 cement Substances 0.000 claims description 23
- 229910000831 Steel Inorganic materials 0.000 claims description 18
- 239000010959 steel Substances 0.000 claims description 18
- 239000000725 suspension Substances 0.000 claims description 14
- 238000000034 method Methods 0.000 claims description 12
- 238000007789 sealing Methods 0.000 claims description 12
- 239000002002 slurry Substances 0.000 claims description 12
- 238000005507 spraying Methods 0.000 claims description 11
- 239000004570 mortar (masonry) Substances 0.000 claims description 10
- 229910001294 Reinforcing steel Inorganic materials 0.000 claims description 9
- 238000005086 pumping Methods 0.000 claims description 8
- 239000011083 cement mortar Substances 0.000 claims description 5
- 239000002893 slag Substances 0.000 claims description 4
- 230000000903 blocking effect Effects 0.000 claims description 3
- 238000005553 drilling Methods 0.000 claims description 3
- 239000003365 glass fiber Substances 0.000 claims description 3
- 230000002093 peripheral effect Effects 0.000 abstract description 3
- 238000005728 strengthening Methods 0.000 abstract 1
- 239000011435 rock Substances 0.000 description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 9
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000003014 reinforcing effect Effects 0.000 description 2
- 239000004575 stone Substances 0.000 description 2
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 238000004873 anchoring Methods 0.000 description 1
- 238000010009 beating Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000003139 buffering effect Effects 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 235000019353 potassium silicate Nutrition 0.000 description 1
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Classifications
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D9/00—Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
- E21D9/01—Methods or apparatus for enlarging or restoring the cross-section of tunnels, e.g. by restoring the floor to its original level
-
- 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
- E21D11/04—Lining with building materials
- E21D11/05—Lining with building materials using compressible insertions
-
- 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
- E21D11/04—Lining with building materials
- E21D11/10—Lining with building materials with concrete cast in situ; Shuttering also lost shutterings, e.g. made of blocks, of metal plates or other equipment adapted therefor
-
- 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
- E21D11/04—Lining with building materials
- E21D11/10—Lining with building materials with concrete cast in situ; Shuttering also lost shutterings, e.g. made of blocks, of metal plates or other equipment adapted therefor
- E21D11/105—Transport or application of concrete specially adapted for the lining of tunnels or galleries ; Backfilling the space between main building element and the surrounding rock, e.g. with concrete
-
- 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
- E21D11/14—Lining predominantly with metal
-
- 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
- E21D11/14—Lining predominantly with metal
- E21D11/18—Arch members ; Network made of arch members ; Ring elements; Polygon elements; Polygon elements inside arches
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D20/00—Setting anchoring-bolts
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D20/00—Setting anchoring-bolts
- E21D20/02—Setting anchoring-bolts with provisions for grouting
- E21D20/021—Grouting with inorganic components, e.g. cement
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D21/00—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection
- E21D21/0026—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection characterised by constructional features of the bolts
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D21/00—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection
- E21D21/0026—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection characterised by constructional features of the bolts
- E21D21/0033—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection characterised by constructional features of the bolts having a jacket or outer tube
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D21/00—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection
- E21D21/0026—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection characterised by constructional features of the bolts
- E21D21/004—Bolts held in the borehole by friction all along their length, without additional fixing means
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Structural Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- Architecture (AREA)
- Civil Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Mechanical Engineering (AREA)
- Environmental & Geological Engineering (AREA)
- Lining And Supports For Tunnels (AREA)
Abstract
本发明涉及隧道开挖技术领域，提供了一种隧道塌方段反吹砂注浆回填结构及其施工方法。包括用于封闭掌子面上部的缺口的封闭墙，所述掌子面的已开挖侧设有反压回填土，所述反压回填土与已开挖隧道的洞顶之间形成有施工空间；拱部空腔自下而上回填有初次吹砂层、混凝土层及二次吹砂层，所述初次吹砂层处于所述拱部空腔的下部区域，所述混凝土层处于未开挖隧道的拱部轮廓线的外周，所述二次吹砂层处于所述拱部空腔的中部区域；初次吹砂层起到了垫层的作用，混凝土层主要起到加强未开挖隧道的拱部轮廓线的外围结构的作用，二次吹砂层起到了缓冲层的作用；通过上述结构对拱部空腔进行回填，确保了回填结构的稳定性，有效的控制且避免隧道二次塌方。
The present invention relates to the technical field of tunnel excavation, and provides a back-blowing sand grouting backfill structure for a collapsed section of a tunnel and a construction method thereof. The structure comprises a closed wall for closing a gap on the upper portion of a tunnel face, the excavated side of the tunnel face is provided with back-pressure backfill soil, and a construction space is formed between the back-pressure backfill soil and the top of the excavated tunnel; the arch cavity is backfilled from bottom to top with a primary sand blowing layer, a concrete layer and a secondary sand blowing layer, the primary sand blowing layer is located in the lower region of the arch cavity, the concrete layer is located at the periphery of the arch contour line of the unexcavated tunnel, and the secondary sand blowing layer is located in the middle region of the arch cavity; the primary sand blowing layer plays the role of a cushion layer, the concrete layer mainly plays the role of strengthening the peripheral structure of the arch contour line of the unexcavated tunnel, and the secondary sand blowing layer plays the role of a buffer layer; the arch cavity is backfilled by the above structure, the stability of the backfill structure is ensured, and the secondary collapse of the tunnel is effectively controlled and avoided.
Description
Technical Field
The invention belongs to the technical field of tunnel excavation, and particularly relates to a reverse blowing sand grouting backfill structure of a tunnel collapse section and a construction method thereof.
Background
The method has the advantages that the soft rock instability section can be encountered during tunnel excavation, the poor geology of the region is multiple in types, large in scale and complex in geological structure, special rock and soil are widely distributed, and engineering treatment capacity is large. During excavation, karst cave collapse is likely to be encountered, engineering construction is further affected, secondary collapse is likely to be caused if improper treatment is carried out, and overall stability of a tunnel is directly caused.
As shown in figure 1, when a tunnel is excavated, a gap 3 is formed in the upper part of a tunnel face 2 of the excavated tunnel 1, large-area falling blocks are generated, longitudinal cracking towards the rear of the tunnel face 2 is generated along the top of the tunnel, the surrounding rock level at the position is III in the original design, an anchor spraying supporting mode is adopted, and the excavation mode is full section. The arch cavity 4 formed by the large-area collapse is as high as 7-9 m, the lower part of the arch cavity 4 extends to the upper part of the non-excavated tunnel 5, the rock stratum in front of the face is changed into carbonaceous shale which is clamped with carbonaceous phyllite, the carbonaceous phyllite is broken under the influence of an earthquake, the soft strength of the carbonaceous phyllite is extremely low when the carbonaceous phyllite is in contact with water, and the following finding of the rock face has more surrounding rock crack water exudation, so that the whole structure presents a soft rock large deformation trend. For the arch cavity 4, a backfill structure needs to be designed to avoid secondary collapse of the tunnel, and when the tunnel face 2 continues to excavate forwards after backfilling, the non-excavated tunnel 5 below the arch cavity 4 needs to be further protected.
Disclosure of Invention
The invention aims to provide a reverse blowing sand grouting backfill structure for a tunnel collapse section, which is used for backfilling an arch cavity and avoiding secondary collapse of a tunnel.
The tunnel collapse section reverse blowing grouting backfill structure comprises a sealing wall for sealing a gap at the upper part of a tunnel face, wherein a back pressure backfill is arranged on the excavated side of the tunnel face, a construction space is formed between the back pressure backfill and the top of an excavated tunnel, a primary blowing sand layer, a concrete layer and a secondary blowing sand layer are backfilled in an arch cavity from bottom to top, the primary blowing sand layer is positioned in the lower area of the arch cavity, the concrete layer is positioned at the periphery of an arch contour line of an unexcavated tunnel, and the secondary blowing sand layer is positioned in the middle area of the arch cavity.
Optionally, the concrete layer forming device further comprises a first sand blowing pipe and a second sand blowing pipe, wherein the sand outlet end of the first sand blowing pipe extends from the excavated tunnel to the lower area of the arch cavity through the sealing wall, the first sand blowing pipe is used for forming the primary sand blowing layer, the sand outlet end of the second sand blowing pipe extends from the excavated tunnel to the middle area of the arch cavity through the sealing wall, and the second sand blowing pipe is used for forming the concrete layer and the secondary sand blowing layer.
Optionally, the second sand blowing pipe comprises a slant pipe section and a vertical pipe section which are detachably connected, the slant pipe section extends from the excavated tunnel to the lower area of the arch cavity in an inclined mode, and the vertical pipe section extends from the lower area of the arch cavity to the middle area of the arch cavity in a vertical mode.
Optionally, a reinforced steel frame is arranged on the inner wall of the excavated tunnel, and the reinforced steel frame is connected with the existing anchor spraying support of the excavated tunnel.
Optionally, the back pressure backfill is divided into an upper step backfill, a middle step backfill and a lower step backfill from top to bottom, wherein the lengths of the upper step backfill, the middle step backfill and the lower step backfill are gradually increased, and the upper step backfill is only middle core soil.
Optionally, the back section and the front section of the upper step excavation section below the arch cavity are both provided with an upper step arch frame, and the middle section is provided with a hanging arch, wherein the hanging arch comprises a hanging anchor rod connected with the concrete layer and an arch steel template connected with the lower end of the hanging anchor rod.
Optionally, the hanging anchor rod comprises an outer hollow rod and an inner hollow rod which are coaxially matched, a wedge joint type end is arranged at the upper end of the outer hollow rod, a wedge joint type end matched with the inner wall of the wedge joint type end is arranged at the upper end of the inner hollow rod, a fastening nut and a backing plate are arranged at the lower end of the inner hollow rod, glass fibers are arranged at the outer Zhou Du of the outer hollow rod, and a cement mortar roll is further arranged at the periphery of the outer hollow rod.
Optionally, the inner walls of the excavated tunnel and the non-excavated tunnel are provided with drainage pipes.
The invention also aims to provide a construction method of the reverse blowing sand grouting backfill structure of the tunnel collapse section, which is used for backfilling the arch cavity and avoiding secondary collapse of the tunnel.
In order to achieve the purpose, the invention adopts the following technical scheme that the construction method of the back-blowing grouting backfill structure of the tunnel collapse section comprises the following steps:
A. clearing the slag soil collapsed behind the tunnel face, and setting a foot locking anchor rod and a mortar anchor rod on the inner wall of the excavated tunnel, wherein the foot locking anchor rod and the mortar anchor rod are closely adjacent to the existing anchor spraying support construction reinforcing steel frame, and the foot locking anchor rod and the mortar anchor rod are used for fixing the reinforcing steel frame;
B. The back pressure backfill is constructed next to the face, and is divided into upper-step backfill, middle-step backfill and lower-step backfill from top to bottom, the lengths of the upper-step backfill, the middle-step backfill and the lower-step backfill are gradually increased, and the upper-step backfill is only middle core soil;
C. The construction of a sealing wall seals a gap at the upper part of the tunnel face, the first sand blowing pipe is an inclined pipe, the second sand blowing pipe is composed of an inclined pipe section and a vertical pipe section, and when the gap is sealed, the first sand blowing pipe is embedded to extend to the lower area of the arch cavity, and the second sand blowing pipe is embedded to extend to the middle area of the arch cavity;
D. the method comprises the steps of carrying out sand blowing backfilling by a sand blowing pipe I, filling the lower area of an arch cavity to form a primary sand blowing layer, pumping concrete by a sand blowing pipe II, covering the concrete above the primary sand blowing layer to form a concrete layer, setting the concrete layer on the periphery of an arch contour line of an unexcavated tunnel, carrying out sand blowing backfilling by the sand blowing pipe II after initial setting of the concrete, and filling the middle area of the arch cavity to form a secondary sand blowing layer.
E. the method comprises the steps of excavating upper step backfill forwards, firstly breaking a closed wall, then removing inclined pipe sections of a sand blowing pipe I and a sand blowing pipe II, and excavating out flowing sand of a sand blowing layer and upper step soil mass;
F. Firstly drilling a concrete layer, then installing a hanging anchor rod and grouting, then connecting an arch steel template with the hanging anchor rod, reserving a through hole for the lower end of a vertical pipe section of a sand blowing pipe II to extend out, and finally installing a blocking plate to pour concrete to form a hanging arch;
G. The middle step backfill and the lower step backfill are excavated forwards, and permanent primary supports are timely applied to the inner walls of the middle step and the inner walls of the lower step of the unexcavated tunnel in the excavation process;
H. And (3) performing sand-blasting backfilling by the lower end of the vertical pipe section of the sand-blasting pipe II, filling the middle upper region of the arch cavity to form a sand-blasting layer for three times, and finally pumping cement slurry by the lower end of the vertical pipe section of the sand-blasting pipe II, and filling the upper region of the arch cavity to form a cement slurry layer.
Compared with the prior art, when the collapse section is encountered, the back-pressure backfill soil is firstly constructed on the tunnel face to control collapse deformation trend of the tunnel face and the inner wall of the tunnel, the back-pressure backfill soil and the top of the tunnel are arranged at intervals to form a construction space, a person can conveniently construct a closed wall above the back-pressure backfill soil to seal a gap, the lower area of the arch cavity, namely the upper area of the non-excavated tunnel, is filled with the back-pressure backfill soil to form a primary sand blowing layer, the primary sand blowing layer plays a role of a cushion layer to facilitate backfilling of the concrete layer above the primary sand blowing layer, the concrete layer mainly plays a role of reinforcing the peripheral structure of the arch contour line of the non-excavated tunnel, so that the non-excavated tunnel vault is stable, collapse deformation is avoided when the non-excavated tunnel is excavated, the secondary sand blowing layer plays a role of a buffer layer, and the falling stone of the arch cavity is prevented from damaging the concrete layer, and the stability of the backfilling structure is ensured, and the secondary collapse of the tunnel is avoided.
Drawings
FIG. 1 is a schematic illustration of arch cavity formation;
FIG. 2 is a schematic view of a back-pressure backfill, a reinforced steel frame, a closed wall, a first sand blowing pipe and a second sand blowing pipe in construction;
FIG. 3 is a schematic diagram of backfilling a primary blow-out layer, a concrete layer, and a secondary blow-out layer;
FIG. 4 is a front view of FIG. 3;
FIG. 5 is a schematic view of an upper step of excavating a tunnel to be excavated;
FIG. 6 is a schematic diagram of backfilling a three-shot sand layer and a cement slurry layer;
FIG. 7 is a front view of FIG. 6;
FIG. 8 is a schematic view of a suspension arch;
Fig. 9 is a schematic view of a hanging anchor.
Reference numerals:
1. The method comprises the following steps of (1) excavating a tunnel, (2) a face, (3) a notch, (4) an arch cavity, (5) an unexcavation tunnel, (6) a closed wall, (7) back pressure backfill, (8) a primary sand blowing layer, (9) a concrete layer, (10) a secondary sand blowing layer, (11) a sand blowing pipe, (12) a sand blowing pipe, (13) a reinforced steel frame, (15) a hanging arch, (16) a hanging anchor rod, (161) an outer hollow rod, (162) a wedge joint end, (163) an inner hollow rod, (164) a wedge end, (165) a fastening nut, (166) a backing plate, (167) a cement mortar roll, (17) an arch steel template, (18) a tertiary sand blowing layer, (19) a cement mortar layer.
Detailed Description
In order that the above-recited objects, features and advantages of the present invention can be more clearly understood, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. It is to be understood that the depicted embodiments are some, but not all, embodiments of the present invention. The specific embodiments described herein are to be considered in an illustrative rather than a restrictive sense. All other embodiments, which are obtained by a person skilled in the art based on the described embodiments of the invention, fall within the scope of protection of the invention.
As shown in fig. 1 to 9, the reverse blowing grouting backfill structure for the tunnel collapse section provided by the invention comprises a sealing wall 6 for sealing a gap 3 at the upper part of a tunnel face 2, wherein the excavated side of the tunnel face 2 is provided with reverse pressure backfill 7, a construction space is formed between the reverse pressure backfill 7 and the top of an excavated tunnel 1, a primary sand blowing layer 8, a concrete layer 9 and a secondary sand blowing layer 10 are backfilled in an arch cavity 4 from bottom to top, the primary sand blowing layer 8 is positioned in the lower area of the arch cavity 4, the concrete layer 9 is positioned at the periphery of an arch contour line of an unexcavated tunnel 5, and the secondary sand blowing layer 10 is positioned in the middle area of the arch cavity 4.
Compared with the prior art, when the collapse section is encountered, the back pressure backfill soil 7 is firstly constructed on the face 2 to control collapse deformation trend of the face 2 and the tunnel inner wall, the back pressure backfill soil 7 and the top of the tunnel 1 are arranged at intervals to form a construction space, personnel can conveniently construct the closed wall 6 above the back pressure backfill soil 7 to seal the gap 3, the lower area of the arch cavity 4, namely the upper area of the non-excavated tunnel 5 is firstly filled to form the primary sand blasting layer 8, the primary sand blasting layer 8 plays a role of a cushion layer to facilitate backfilling the concrete layer 9 above the primary sand blasting layer 8, the concrete layer 9 mainly plays a role of reinforcing the peripheral structure of the arch contour line of the non-excavated tunnel 5, so that the non-excavated tunnel 5 is stable in vault, collapse deformation is avoided when the non-excavated tunnel 5 is excavated, the secondary sand blasting layer 10 plays a role of a buffer layer to avoid damage to the concrete layer 9 caused by dropping stones in the arch cavity 4, the backfilling structure is ensured, and the stability of the backfilling structure is effectively controlled and collapse is avoided.
In some embodiments, as shown in fig. 2 and 3, the device further comprises a first sand blowing pipe 11 and a second sand blowing pipe 12, one or more sand blowing pipes 11 and 12 can be arranged according to actual construction, the sand outlet end of the first sand blowing pipe 11 extends from the excavated tunnel 1 to the lower area of the arch cavity 4 through the closed wall 6, the first sand blowing pipe 11 is used for forming the primary sand blowing layer 8, the sand outlet end of the second sand blowing pipe 12 extends from the excavated tunnel 1 to the middle area of the arch cavity 4 through the closed wall 6, and the second sand blowing pipe 12 is used for forming the concrete layer 9 and the secondary sand blowing layer 10. The first sand-blast pipe 11 is an inclined pipe, the second sand-blast pipe 12 is composed of an inclined pipe section and a vertical pipe section, and when the closed wall 6 is constructed, the first sand-blast pipe 11 is embedded to extend to the lower area of the arch cavity 4, and the second sand-blast pipe 12 is embedded to extend to the middle area of the arch cavity 4.
In some embodiments, as shown in fig. 2,3, 5 and 6, the inner wall of the excavated tunnel 1 is provided with a reinforcing steel frame 13, and the reinforcing steel frame 13 is connected with the existing anchor spraying support of the excavated tunnel 1. When the collapse section is found, the original support type of the excavated tunnel 1 is III-level anchor spraying support, and the existing anchor spraying support construction reinforcing steel frame 13 is also closely adjacent to the construction back-filled soil 7, so that collapse deformation trend of the tunnel face 2 and the inner wall of the tunnel is further ensured and controlled, and a stable support structure is provided for resisting secondary collapse possibly existing subsequently.
In some embodiments, as shown in fig. 2, 3 and 4, the back pressure backfill 7 is divided into an upper step backfill, a middle step backfill and a lower step backfill from top to bottom, the lengths of the upper step backfill, the middle step backfill and the lower step backfill are gradually increased, and the upper step backfill is only the middle core soil. The excavated tunnel 1 is backfilled step by step, so that the construction is convenient for personnel.
In some embodiments, as shown in fig. 5 and 8, the rear section and the front section of the upper step excavation section below the arch cavity 4 are provided with an upper step arch 14, the middle section is provided with a suspension arch 15, and the suspension arch 15 comprises a suspension anchor rod 16 connected with the concrete layer 9 and an arch steel template 17 connected with the lower end of the suspension anchor rod 16. Considering that the excavation of the non-excavated tunnel 5 by adopting multiple steps simultaneously causes large disturbance to surrounding rocks, the long-step method is adopted to excavate the upper step of the non-excavated tunnel 5 first, the rear section and the front section of the excavation section of the upper step are connected with the surrounding rocks, so that the construction of the upper step arch 14 is convenient, the middle section of the excavation section of the upper step is not in an overhead state with the connection of the surrounding rocks, at this time, the suspension arch 15 is required to be constructed below the concrete layer 9 to serve as an initial support of the upper step, specifically, the suspension anchor rod 16 is arranged below the concrete layer 9 in a beating mode, then the arch steel moulding plate 17 is arranged, and finally the suspension arch 15 is cast and formed.
In some embodiments, as shown in fig. 9, the suspension arch 15 needs a sufficient stability for overall construction and thus needs an anchor rod capable of providing a sufficient anchoring force, the suspension anchor rod 16 comprises an outer hollow rod 161 and an inner hollow rod 163 which are coaxially matched, a wedge-shaped end 162 is arranged at the upper end of the outer hollow rod 161, a wedge-shaped end 164 matched with the inner wall of the wedge-shaped end 162 is arranged at the upper end of the inner hollow rod 163, a fastening nut 165 and a backing plate 166 are arranged at the lower end of the inner hollow rod 163, a glass fiber is arranged at the outer Zhou Du of the outer hollow rod 161, and a cement mortar roll 167 is also arranged at the outer periphery of the outer hollow rod 161. Drilling holes in the concrete layer 9, placing the hanging anchor rod 16 into the holes, screwing the fastening nuts 165, keeping the outer hollow rod 161 stationary in the holes, pulling out the lower end of the inner hollow rod 163, sliding the wedge-shaped end head 164 relative to the inner wall of the wedge-shaped end head 162, expanding the wedge-shaped end head 162 and fastening the wedge-shaped end head with the inner wall of the holes, grouting at high pressure through the lower end of the inner hollow rod 163, flowing cement slurry out of the wedge-shaped end head 164 to fill the whole holes, expanding the cement slurry roll 167 by water in the cement slurry and fastening the inner wall of the holes, sealing the holes by matching the backing plate 166 with the slurry stop plug, and finally completing the fixation of the hanging anchor rod 16, and then installing the arch steel template 17.
In some embodiments, the inner walls of the excavated tunnel 1 and the unexcavated tunnel 5 are provided with drainage pipes. The longitudinal, transverse and annular drainage pipes are communicated with the tunnel arch foot longitudinal drainage pipe through a tee joint, the arch foot longitudinal drainage pipe is communicated with the tunnel bottom transverse water diversion pipe through a tee joint, and the transverse water diversion pipe is connected with the tunnel central drainage ditch to timely drain out tunnel seepage.
A construction method of a reverse blowing sand grouting backfill structure of a tunnel collapse section comprises the following steps:
A. Clearing the slag soil collapsed behind the tunnel face 2, and setting a foot locking anchor rod and a mortar anchor rod on the inner wall of the excavated tunnel 1, wherein the foot locking anchor rod and the mortar anchor rod are closely adjacent to the reinforcing steel frame 13 for the existing anchor spraying support construction, and the foot locking anchor rod and the mortar anchor rod are used for fixing the reinforcing steel frame 13;
B. The back pressure backfill 7 is constructed to the rear side of the face 2, the slag soil collapsed at the rear side of the face 2 can be used as the back pressure backfill 7, the back pressure backfill 7 is divided into upper step backfill, middle step backfill and lower step backfill from top to bottom, the lengths of the upper step backfill, the middle step backfill and the lower step backfill are gradually increased, the upper step backfill is only middle core soil, backfilling is carried out on the upper, middle and lower steps according to a three-step construction method, the lengths of the steps are respectively that the upper step is 1-2m, the middle step is 2-5m and the lower step is 4-8m, the total backfill length is at least 1.5d md=hole diameter, the steps A and B can be constructed simultaneously, and form a support system together to control the collapse deformation trend of the face 2 and the inner wall of a tunnel, and the whole section stress structure behind the face 2 is reconstructed;
C. The construction of a sealing wall 6 seals a gap 3 at the upper part of a tunnel face 2, a sand blowing pipe I11 is an inclined pipe, a sand blowing pipe II 12 is composed of an inclined pipe section and a vertical pipe section, and when the gap 3 is sealed, the sand blowing pipe I11 is embedded to extend to the lower area of an arch cavity 4, and the sand blowing pipe II 12 is embedded to extend to the middle area of the arch cavity 4;
D. The sand blowing pipe I11 is used for performing sand blowing backfilling, the lower area of the arch cavity 4 is filled to form a primary sand blowing layer 8, the tail end of the sand blowing pipe I11 is ensured to extend to the vault position of the upper part of the non-excavated tunnel 5, coarse sand is blown in time by adopting a jet machine, clear water is alternately injected, the coarse sand is driven to flow through the fluidity of water, the lower area of the arch cavity 4, namely the upper area of the non-excavated tunnel 5 can be filled with the coarse sand, and the primary sand blowing layer 8 can be leveled;
Then pumping concrete by the second sand blowing pipe 12, covering the concrete on the primary sand blowing layer 8 to form a concrete layer 9, wherein the concrete layer 9 is positioned on the periphery of the arch outline of the unexcavated tunnel 5, the height of the concrete layer 9 is 2.0-2.5m, and after the concrete pumping is finished, mortar of 2-3 m 3 is pumped immediately, so that the pumping pipe and the second sand blowing pipe 12 are cleaned, and meanwhile, the concrete layer 9 can be leveled;
After the concrete is initially set, sand-blasting is carried out by a second sand-blasting pipe 12, the middle area of the arch cavity 4 is filled up to form a secondary sand-blasting layer 10, meanwhile clear water is alternately injected, coarse sand is driven to flow through the fluidity of the water, the surface of the concrete layer 9 is fully paved with the coarse sand, and the secondary sand-blasting layer 10 can be leveled.
E. The method comprises the steps of excavating upper step backfill soil forwards, firstly breaking a closed wall 6, then disassembling inclined pipe sections of a sand blowing pipe I11 and a sand blowing pipe II 12, and excavating out the sand flowing from a primary sand blowing layer 8 and an upper step soil body, wherein in the excavating process, an upper step arch 14 is timely applied to the rear section and the front section of an upper step excavating section of an unexcavated tunnel 5, and anchor spraying support is also required to be constructed before the upper step arch 14 is applied;
F. the middle section of the upper step excavation section of the non-excavated tunnel 5 is separated from surrounding rock by a certain distance, no foundation is provided with an arch frame as an initial support, so the middle section of the upper step excavation section of the non-excavated tunnel 5 is provided with a hanging arch 15, firstly, a concrete layer 9 is drilled, then a hanging anchor rod 16 is installed and grouting is carried out, an arch steel template 17 is connected with the hanging anchor rod 16, the arch steel template 17 is reserved with a through hole which enables the lower end of the vertical pipe section of a sand blowing pipe II 12 to extend, finally, a blocking plate is installed to cast concrete to form the hanging arch 15, and the hanging arch 15 reinforces a vault support structure of the middle section of the non-excavated tunnel 5;
G. The middle step backfill and the lower step backfill are excavated forwards, permanent primary supports are timely applied to the inner walls of the middle step and the inner walls of the lower step of the non-excavated tunnel 5 in the process of excavation, and the permanent primary supports are formed by anchor spraying supports and steel frames in the prior art, which are conventional technical means of the person skilled in the art and are not repeated herein;
H. The secondary sand-blasting layer 10 can adopt fine sand, the secondary sand-blasting layer 10 only fills the middle area of the arch cavity 4, if the primary sand-blasting layer 10 is backfilled too much, the weight of the secondary sand-blasting layer is still likely to cause a certain pressure influence on the concrete layer 9, so that the secondary sand-blasting layer 10 only plays a certain role in buffering, after the initial support whole is looped and the structure is stable in the non-excavated tunnel 5, the lower end of the vertical pipe section of the sand-blasting pipe 2 is subjected to sand-blasting backfilling, as shown in fig. 6 and 7, the middle upper area of the arch cavity 4 is filled with the cement paste to form a third sand-blasting layer 18, the third sand-blasting layer 18 can be coarse sand, then cement paste is pumped again, and can be slurry matched by phosphoric acid, water glass and cement, and the cement paste is gradually infiltrated into the gaps of the coarse sand of the third sand-blasting layer 18 from the upper area of the arch cavity 4, so that the three sand-blasting layer 18 forms a mortar layer with stable structural performance, and meanwhile the cement paste is infiltrated into the periphery of the arch cavity 4, the integral stability of the arch cavity 4 is further improved, and finally the crack stability of the arch cavity 4 is fully improved, as shown in fig. 6 and 7, the cement paste is prevented from being fully deformed, the cement paste is completely excavated by the upper area of the arch cavity 4, and the cement paste is completely excavated to the tunnel cavity 4, and the cement paste is completely deformed, and the problem of the surrounding the tunnel cavity is completely and completely excavated by the cement-filled by the cement paste layer is avoided, and the cement paste layer is completely and the cement-filled.
It should be noted that, when the sand-blowing layer 18 and the cement slurry layer 19 are backfilled three times, the vertical pipe section of the second sand-blowing pipe 12 only extends to the middle part of the arch cavity 4, so that the lower end of the vertical pipe section of the second sand-blowing pipe 12 can be additionally driven into the inner pipe upwards to extend to the upper part of the arch cavity 4 for blowing sand and pumping cement slurry.
It should be noted that the above-mentioned embodiments are merely for illustrating the technical solution of the present invention, and not for limiting the same, and although the present invention has been described in detail with reference to the above-mentioned embodiments, it should be understood by those skilled in the art that the technical solution described in the above-mentioned embodiments may be modified or some technical features may be equivalently replaced, and these modifications or substitutions do not make the essence of the corresponding technical solution deviate from the spirit and scope of the technical solution of the embodiments of the present invention.
Claims (7)
1. The back-blowing sand grouting backfill structure for the tunnel collapse section is characterized by comprising a sealing wall (6) for sealing a gap (3) at the upper part of a tunnel face (2), wherein the excavated side of the tunnel face (2) is provided with back-pressure backfill soil (7), a construction space is formed between the back-pressure backfill soil (7) and the top of an excavated tunnel (1), an arch cavity (4) is backfilled with a primary sand blowing layer (8), a concrete layer (9) and a secondary sand blowing layer (10) from bottom to top, the primary sand blowing layer (8) is positioned in the lower area of the arch cavity (4), the concrete layer (9) is positioned at the periphery of the arch contour line of an unexcavated tunnel (5), and the secondary sand blowing layer (10) is positioned in the middle area of the arch cavity (4);
The back pressure backfill (7) is divided into upper-step backfill, middle-step backfill and lower-step backfill from top to bottom, the lengths of the upper-step backfill, the middle-step backfill and the lower-step backfill are gradually increased, and the upper-step backfill is only middle core soil;
An upper step arch (14) is arranged at the rear section and the front section of the upper step excavation section below the arch cavity (4), a suspension arch (15) is arranged at the middle section, and the suspension arch (15) comprises a suspension anchor rod (16) connected with the concrete layer (9) and an arch steel template (17) connected with the lower end of the suspension anchor rod (16);
the hanging anchor rod (16) comprises an outer hollow rod (161) and an inner hollow rod (163) which are coaxially matched, a wedge joint type end head (162) is arranged at the upper end of the outer hollow rod (161), a wedge joint type end head (164) matched with the inner wall of the wedge joint type end head (162) is arranged at the upper end of the inner hollow rod (163), a fastening nut (165) and a backing plate (166) are arranged at the lower end of the inner hollow rod (163), glass fibers are arranged at the outer Zhou Du of the outer hollow rod (161), and a cement mortar roll (167) is further arranged at the periphery of the outer hollow rod (161).
2. The reverse blowing grouting backfill structure for a tunnel collapse section according to claim 1, further comprising a first blowing pipe (11) and a second blowing pipe (12), wherein a sand outlet end of the first blowing pipe (11) extends from the excavated tunnel (1) to a lower region of the arch cavity (4) through the closed wall (6), the first blowing pipe (11) is used for forming the primary blowing layer (8), and a sand outlet end of the second blowing pipe (12) extends from the excavated tunnel (1) to a middle region of the arch cavity (4) through the closed wall (6), and the second blowing pipe (12) is used for forming the concrete layer (9) and the secondary blowing layer (10).
3. The reverse-blowing grouting backfill structure for tunnel collapse section according to claim 2, wherein the second sand blowing pipe (12) comprises a detachably connected inclined pipe section and a vertical pipe section, the inclined pipe section extends obliquely from the excavated tunnel (1) to the lower region of the arch cavity (4), and the vertical pipe section extends vertically from the lower region of the arch cavity (4) to the middle region of the arch cavity (4).
4. The reverse blowing grouting backfill structure of the tunnel collapse section according to claim 1, wherein a reinforced steel frame (13) is arranged on the inner wall of the excavated tunnel (1), and the reinforced steel frame (13) is connected with the existing anchor spraying support of the excavated tunnel (1).
5. The reverse blowing grouting backfill structure for tunnel collapse sections according to claim 1, wherein drain pipes are arranged on the inner walls of the excavated tunnel (1) and the unexcavated tunnel (5).
6. The construction method of the reverse blowing sand grouting backfill structure of the tunnel collapse section is applied to the reverse blowing sand grouting backfill structure of the tunnel collapse section as claimed in claim 3, and is characterized by comprising the following steps:
A. Clearing the slag soil collapsed behind the tunnel face (2), and arranging a foot locking anchor rod and a mortar anchor rod on the inner wall of the excavated tunnel (1) to be closely adjacent to the existing anchor spraying support construction reinforcing steel frame (13), and fixing the reinforcing steel frame (13) by utilizing the foot locking anchor rod and the mortar anchor rod;
B. The back pressure backfill (7) is constructed towards the rear of the face (2), the back pressure backfill (7) is divided into upper-step backfill, middle-step backfill and lower-step backfill from top to bottom, the lengths of the upper-step backfill, the middle-step backfill and the lower-step backfill are gradually increased, and the upper-step backfill is only middle core soil;
C. Constructing a sealing wall (6) to seal a gap (3) at the upper part of the tunnel face (2), wherein a sand blowing pipe I (11) is an inclined pipe, a sand blowing pipe II (12) is formed by an inclined pipe section and a vertical pipe section, when the gap (3) is sealed, the sand blowing pipe I (11) is embedded to extend to the lower part area of the arch cavity (4), and the sand blowing pipe II (12) is embedded to extend to the middle part area of the arch cavity (4);
D. The method comprises the steps of carrying out sand blasting backfilling by a sand blasting pipe I (11), filling the lower area of an arch cavity (4) to form a primary sand blasting layer (8), pumping concrete by a sand blasting pipe II (12), covering the concrete above the primary sand blasting layer (8) to form a concrete layer (9), enabling the concrete layer (9) to be positioned on the periphery of an arch outline of an unexcavated tunnel (5), carrying out sand blasting backfilling by the sand blasting pipe II (12) after initial setting of the concrete, and filling the middle area of the arch cavity (4) to form a secondary sand blasting layer (10).
7. The construction method of the reverse blowing grouting backfill structure for tunnel collapse section according to claim 6, further comprising the following steps after the step D:
E. The method comprises the steps of excavating upper step backfill forwards, firstly breaking a closed wall (6), then disassembling inclined pipe sections of a first sand blowing pipe (11) and a second sand blowing pipe (12), and excavating out the sand flow of a first sand blowing layer (8) and an upper step soil body;
F. Firstly, drilling a concrete layer (9), then installing a hanging anchor rod (16) and grouting, then connecting an arch steel template (17) with the hanging anchor rod (16), reserving a through hole for extending out of the lower end of the vertical pipe section of a sand blowing pipe II (12) by the arch steel template (17), and finally installing a blocking plate to cast concrete to form the hanging arch (15);
G. the middle step backfill and the lower step backfill are excavated forwards, and permanent primary supports are timely applied to the inner walls of the middle step and the inner walls of the lower step of the unexcavated tunnel (5) in the excavation process;
H. And (3) performing sand-blasting backfilling by the lower end of the vertical pipe section of the sand-blasting pipe II (12), filling the middle upper region of the arch cavity (4) to form a third sand-blasting layer (18), and finally pumping cement slurry by the lower end of the vertical pipe section of the sand-blasting pipe II (12), and filling the upper region of the arch cavity (4) to form a cement slurry layer (19).
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| CN112901207B (en) * | 2021-04-23 | 2023-04-07 | 中交路桥南方工程有限公司 | Treatment method for collapse in tunnel during arch change of secondary lining in sulfate corrosion section of operation tunnel |
| CN113944481A (en) * | 2021-11-05 | 2022-01-18 | 广西路桥工程集团有限公司 | A kind of treatment method of tunnel vault filled karst cave in karst karst area |
| CN113944486A (en) * | 2021-11-05 | 2022-01-18 | 广西路桥工程集团有限公司 | Tunnel hall type karst cave treatment construction method |
| CN115614047B (en) * | 2022-10-09 | 2025-04-18 | 武汉大学 | A method for dealing with collapse of a large-span tunnel excavated by step method |
| CN116556997A (en) * | 2023-05-17 | 2023-08-08 | 西安建筑科技大学 | An anti-collapse disposal device and construction method for an unstable collapse cavity cavity at the top of a tunnel |
| CN116677417B (en) * | 2023-08-03 | 2023-09-22 | 中铁十六局集团有限公司 | Treatment device and treatment method for tunnel collapse cavity |
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