CN109404012B - IV-VI-level surrounding rock overexcavation tunnel primary support method - Google Patents
IV-VI-level surrounding rock overexcavation tunnel primary support method Download PDFInfo
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- CN109404012B CN109404012B CN201811393683.6A CN201811393683A CN109404012B CN 109404012 B CN109404012 B CN 109404012B CN 201811393683 A CN201811393683 A CN 201811393683A CN 109404012 B CN109404012 B CN 109404012B
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- 239000011435 rock Substances 0.000 title claims abstract description 47
- 238000000034 method Methods 0.000 title claims abstract description 33
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 157
- 239000010959 steel Substances 0.000 claims abstract description 157
- 239000004567 concrete Substances 0.000 claims abstract description 81
- 238000005507 spraying Methods 0.000 claims abstract description 51
- 238000009412 basement excavation Methods 0.000 claims abstract description 41
- 239000011800 void material Substances 0.000 claims abstract description 10
- 238000010276 construction Methods 0.000 claims description 14
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 8
- 239000011378 shotcrete Substances 0.000 claims description 8
- 239000002689 soil Substances 0.000 claims description 8
- 239000002002 slurry Substances 0.000 claims description 5
- 238000003466 welding Methods 0.000 claims description 5
- 238000005553 drilling Methods 0.000 claims description 4
- 229910052742 iron Inorganic materials 0.000 claims description 4
- 239000000463 material Substances 0.000 claims description 4
- 239000004568 cement Substances 0.000 claims description 3
- 230000003014 reinforcing effect Effects 0.000 abstract 1
- 230000002787 reinforcement Effects 0.000 description 3
- 239000011150 reinforced concrete Substances 0.000 description 2
- 101150097977 arch-1 gene Proteins 0.000 description 1
- 239000010425 asbestos Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000009415 formwork Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 229910052895 riebeckite Inorganic materials 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000010454 slate Substances 0.000 description 1
- 238000007569 slipcasting Methods 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
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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
- E21D11/04—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
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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
- E21D11/14—Lining predominantly with metal
- E21D11/18—Arch members ; Network made of arch members ; Ring elements; Polygon elements; Polygon elements inside arches
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D20/00—Setting anchoring-bolts
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- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Structural Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- Architecture (AREA)
- Civil Engineering (AREA)
- Lining And Supports For Tunnels (AREA)
Abstract
The invention discloses an IV-VI grade surrounding rock overexcavation tunnel primary support method, relates to the field of civil engineering, and solves the problems of potential safety hazards caused by the phenomena of hollowing and unshelling in the conventional overexcavation tunnel primary support method. The technical scheme adopted by the invention is as follows: the primary support method for the IV-VI grade surrounding rock overexcavation tunnel comprises the following steps: s1, carrying out concrete spraying support on an excavation surface of a tunnel with overexcavation; s2, installing and fixing an arch frame in the tunnel, and installing a reinforcing mesh on the inner side of the arch frame; s3, radially installing steel perforated pipes at the positions of system anchor rods of the tunnel respectively; s4, fixedly connecting an exhaust pipe on the outer side of the steel perforated pipe; s5, installing a steel plate or a steel belt; s6, spraying and filling concrete to the concrete spraying and filling area; s7, spraying concrete to the direct-spraying concrete supporting area, and spraying the concrete by taking the steel plate/belt as an outer template; s8, grouting and/or backfilling concrete in a void area behind the arch frame; and S9, constructing a system anchor rod.
Description
Technical Field
The invention relates to the field of civil engineering, in particular to a tunnel primary support method which is suitable for tunnel excavation in IV-VI grade broken surrounding rocks or loose gravel soil and has a large number of over-excavation conditions.
Background
When a railway, a highway tunnel and an underground cavern project are newly built, the tunnel and the cavern are excavated in IV-VI-level broken surrounding rock or loose gravel soil, and a large amount of over-excavation is easy to happen due to the conditions that the surrounding rock project property becomes poor, the excavation mode is improper, advance support is untimely and the like. The overexcavation means that the actual excavation contour line exceeds the design excavation contour line, namely the actual excavation amount is larger than the design excavation amount. Furthermore, overbreak of tunnel arches in IV-VI level surrounding rock sections is a common phenomenon.
At present, primary tunnel supports of IV-VI level surrounding rock areas are generally supported by adopting a grid arch or a section steel arch. The arch frame is made according to the design size in advance, after the tunnel is overedged, the overedged surface is irregular, the overedged size is different, and the actual tunnel excavation contour line is inconsistent with the outline of the arch frame, so that after the arch frame is installed according to the design size, the problems that the arch frame is not closely attached to the actual excavation contour line and the arch frame is not hollow from the tunnel excavation contour line can occur, and the safety technical problems that a system anchor rod cannot be constructed and the like are caused. The prior art does not fully consider the problem of field operability, and does not solve the practical problem on the aspects of tunnel design specification and construction technical specification.
In the prior art, after an arch center is supported in the initial stage of a tunnel, the overexcavation part needs to be densely sprayed and filled by concrete with the same grade. In actual engineering, the tunnel overexcavation is mainly located at the tunnel arch, if the overexcavation thickness of the tunnel arch exceeds 30cm, the tunnel arch is difficult to be densely sprayed and filled with concrete, and finally, the problems of void and unshelling are formed between an arch frame and an excavated rock surface. In addition, after concrete is sprayed, anchor rods of a tunnel arch system cannot be constructed, and grouting cannot be performed. In addition, the tunnel arch cannot be backfilled with debris such as slate, wood, asbestos shingles, or the like, which could create an artificial safety hazard.
The existing tunnel arch part supported by adopting an arch frame has potential safety hazards, the potential safety hazards are different along with the overexcavation and the air escape condition of the tunnel and the primary support condition, and the primary support and the secondary lining are possibly deformed, even the tunnel collapses. The existing primary support technology of the over-excavated tunnel is not actually combined with the site, and the construction operability is poor; the problem of tunnel overexcavation and void treatment is not thoroughly solved, and construction safety risk is high, and the construction progress is slow, and engineering cost is high, and the engineering durability is poor.
Disclosure of Invention
The invention provides an IV-VI grade surrounding rock overexcavation tunnel primary support method, which solves the problem of potential safety hazard caused by the phenomena of void and unshelling in the conventional overexcavation tunnel primary support method.
The technical scheme adopted by the invention for solving the technical problems is as follows: the primary support method for the IV-VI grade surrounding rock overexcavation tunnel comprises the following steps:
s1, spraying concrete to support the tunnel excavation face with the over excavation.
Specifically, the method comprises the following steps: and in the step S1, spraying C20 concrete with the thickness of 4cm along the excavation face of the tunnel for concrete support.
S2, installing an arch frame in the tunnel, and fixing the arch frame in a rock and soil body outside a tunnel excavation contour line; the arch frames are connected through longitudinal connecting steel bars, and steel bar meshes are arranged on the inner sides of the arch frames.
Specifically, the method comprises the following steps: and in the step S2, the arch center is a grid arch center and/or a profile steel arch center, and the arch center is fixed on rock and soil mass outside the tunnel excavation contour line through positioning steel bars and a foot locking anchor rod.
Specifically, the method comprises the following steps: in the step S2, the longitudinal connecting steel bars are made of C22 material and are disposed on the inner side of the arch frame, that is, the longitudinal connecting steel bars are disposed on the side far away from the tunnel excavation contour line.
And S3, respectively installing steel perforated pipes at the positions of system anchor rods of the tunnel, wherein the steel perforated pipes are arranged in the radial direction, the bottoms of the steel perforated pipes tightly push against the rock surface, the exposed ends of the steel perforated pipes are fixedly connected with the arch frame, grouting holes are formed in the pipe walls of the over-cut parts of the steel perforated pipes, and backfill concrete reserved holes are formed in the pipe bottoms of the steel perforated pipes.
Specifically, the method comprises the following steps: in the step S3, the steel perforated pipe is a seamless steel pipe with an outer diameter of phi 70mm and a wall thickness of 5mm, and the length of the steel perforated pipe is equal to the overexcavation amount at the corresponding position + the designed sprayed concrete thickness +10 cm; the pipe wall of the steel perforated pipe positioned at the overexcavation part is provided with three rows of quincunx grouting holes with the diameter of phi 8 mm; the bottom of the steel perforated pipe is cut to form two symmetrically arranged notches with the length of 5cm and the width of 2cm, and the notches are reserved holes for backfilling concrete.
And S4, fixedly connecting an exhaust pipe outside the steel perforated pipe.
Specifically, the method comprises the following steps: and in the step S4, the outer side of the steel perforated pipe is connected with an exhaust pipe through iron wire binding, the length of the exhaust pipe is consistent with that of the steel perforated pipe, and the exhaust pipe is a phi 20mm PVC pipe.
S5, dividing the tunnel arch part and the tunnel side wall into a direct concrete spraying supporting area and an indirect concrete spraying supporting area according to the over-excavated thickness; the method is characterized in that a steel plate or a steel belt is arranged on the outer side of an arch center of a non-direct concrete spraying supporting area, the steel plate/belt is fixedly connected with the arch center, the collision position of the steel plate/belt and a steel perforated pipe is in a mode of avoiding or cutting a hole for the steel perforated pipe to pass through at the steel plate/belt, and the steel plate/belt is connected through the steel bar or a steel bar in a welding mode. Steel plate/strip means steel plate or steel strip.
And S6, dividing the indirect concrete spraying support area into a concrete spraying filling area and a grouting backfilling area according to the thickness of the gap between the steel plate/belt and the rock surface, and densely spraying and filling concrete to the concrete spraying filling area.
Specifically, the method comprises the following steps: and in the step S6, a concrete spraying filling area is formed when the gap between the steel plate/belt and the rock surface is less than 30cm, and a grouting backfilling area is formed when the gap is more than or equal to 30 cm.
And S7, spraying concrete to the direct concrete spraying support area, and spraying concrete by using the steel plate/belt as an outer template.
And S8, in the grouting backfill area, grouting and/or backfilling concrete to the void area behind the arch center through the steel perforated pipes, and stopping grouting or backfilling the concrete after the exhaust pipes of the steel perforated pipes return slurry.
Specifically, the method comprises the following steps: and in the step S8, grouting or backfilling fine aggregate concrete in the grouting and backfilling area according to the void position and the gap thickness between the steel plate/belt and the rock surface.
And S9, constructing the anchor rod of the system by using the steel perforated pipe.
Specifically, the method comprises the following steps: in the step S9, drilling a hole by using a steel floral tube and constructing a system anchor rod by using the construction system anchor rod; after the system anchor rod is grouted, an anchor backing plate is installed at the end part of the system anchor rod, exposed redundant steel flower pipes and exposed redundant steel bars are cut off, and then cement paste is adopted to hook and plug the end head of the system anchor rod and the anchor backing plate.
The invention has the beneficial effects that: the steel perforated pipe is used as temporary and permanent support, grouting and backfilling concrete for the tunnel and a guide pipe of a system anchor rod. The steel perforated pipe plays multiple effective roles in the aspects of ensuring the safety of the construction process, solving the safety problems of collapse possibly occurring in the drilling construction process in the tunnel over-excavation and air-out treatment and the loose and broken surrounding rocks and the anchor rod of the system cannot be constructed after the tunnel over-excavation and air-out.
The steel plate/belt is used as the outer mold, operability of concrete spraying, grouting and backfilling is improved, resilience of the sprayed concrete between an excavation contour line and the outer mold is reduced, safety risks of tunnel deformation and collapse caused by incompact sprayed concrete are reduced, time for spraying the concrete is shortened, and construction cost is saved. Meanwhile, the steel plate/belt and sprayed concrete are used as the bottom die, so that grouting performance and backfill performance of backfilled fine-grained concrete are improved, and the problems of slurry leakage and slurry leakage are effectively prevented. On the basis of early support, surrounding rock deformation is effectively restrained, a tunnel is prevented from falling blocks to hurt people, and the safety of tunnel construction and the safety of permanent support of the tunnel are obviously improved.
The IV-VI grade surrounding rock overexcavation tunnel primary support method solves the problems of safety risk of back void of an arch center in the existing broken surrounding rock and incapability of constructing a system anchor rod, avoids the problems that the surrounding rock falls, collapses and hurts people and workers are unwilling to construct the system anchor rod in the broken surrounding rock, improves the safety of the construction process, effectively solves the problem of difficult treatment of overexcavation and the safety and the operability of support.
Drawings
FIG. 1 is a schematic diagram of the primary support of IV-VI grade surrounding rock overexcavation tunnel.
Figure 2 is a schematic illustration of a tunnel system bolting.
Fig. 3 is a schematic view of the steel floral tube of fig. 1.
Fig. 4 is a cross-sectional view of the steel flower tube of fig. 3.
Parts, positions and numbers in the drawings: the tunnel excavation construction method comprises the following steps of 1, tunnel excavation contour lines 2, longitudinal connecting steel bars 3, a steel mesh 4, a system anchor rod 5, a steel plate/belt 6, a steel perforated pipe 7, grouting holes 7-1 and cuts 7-2; and (5) building a reinforced concrete lining 8.
Detailed Description
The invention will be further explained with reference to the drawings.
Referring to fig. 1, the invention comprises a primary support method of an IV-VI grade surrounding rock overexcavation tunnel, which comprises the following steps:
s1, spraying concrete to support the tunnel excavation face with the over excavation. The concrete spraying support is used for preliminarily closing the excavation face, for example, C20 concrete with the thickness of 4cm is sprayed along the excavation face of the tunnel.
S2, installing an arch center 1 in the tunnel, and fixing the arch center 1 in a rock and soil body outside a tunnel excavation contour line 2; the arch frames 1 are connected through longitudinal connecting steel bars 3, and steel bar meshes 4 are arranged on the inner sides of the arch frames 1.
The installation of the arch centering 1 is carried out according to design support parameters, the arch centering 1 is installed at a design position, the arch centering 1 is a grating arch centering 1 and/or a section steel arch centering 1, and the arch centering 1 is fixed with a rock-soil body outside a tunnel excavation contour line 2 through positioning steel bars and a locking anchor rod. The arch center 1 is connected through the longitudinal connecting steel bar 3 made of C22 material, the longitudinal connecting steel bar 3 is arranged at the inner side of the arch center 1, namely, at the side far away from the tunnel excavation contour line 2, and the steel bar net 4 is arranged at the inner side of the arch center 1 and clings to the longitudinal connecting steel bar 3 and the arch center 1. In fig. 1, the longitudinal connecting reinforcement 3 and the mesh reinforcement 4 are superposed.
S3, steel perforated pipes 7 are respectively installed at the positions of system anchor rods 5 of the tunnel, the steel perforated pipes 7 are arranged in the radial direction, the bottoms of the steel perforated pipes 7 tightly push the rock surface, the exposed ends of the steel perforated pipes are fixedly connected with the arch center 1, grouting holes 7-1 are formed in the pipe walls of the over-cut portions of the steel perforated pipes 7, and backfill concrete reserved holes are formed in the pipe bottoms of the steel perforated pipes 7.
The annular distance and the longitudinal distance of the system anchor rods 5 are designed corresponding to the tunnel, the steel floral tubes 7 are arranged at the positions of the system anchor rods 5 and close to the arch center 1, and the steel floral tubes 7 are arranged in the radial direction. The arrangement of the system anchor rods 5 is as shown in fig. 2, and the inner side of the arch 1 is the moulded reinforced concrete lining 8.
The type of the steel perforated pipe 7 is determined according to the type of the anchor rod 5 of the tunnel design system, the size of the tunnel excess excavation amount and the design average sprayed concrete thickness, and the steel perforated pipe 7 is recommended to be a seamless steel pipe with the outer diameter phi of 70mm and the wall thickness of 5 mm. The length of the steel perforated pipe 7 is measured according to the over-excavation size of the tunnel, and the steel perforated pipe is blanked after the size is measured on site. The length of the steel perforated pipe 7 should be larger than the sum of the overexcavation amount of the corresponding position and the designed sprayed concrete thickness, for example, the length of the steel perforated pipe 7 is the overexcavation amount + the designed sprayed concrete thickness +10 cm. Three or more quincunx grouting holes (8-1) with the diameter of phi 8mm are drilled in the pipe wall of the steel perforated pipe 7 positioned in the overexcavation part, and the rest part of the steel perforated pipe 7 is not drilled. The end of the steel perforated pipe 7 contacting the rock surface, namely the bottom of the steel perforated pipe 7, is cut to form two symmetrically arranged cuts 7-2 with the length of 5cm and the width of 2cm, and the cuts 7-2 are reserved holes for backfilling concrete, as shown in fig. 3 and 4. The steel flower tube 7 is arranged at the position of an anchor rod of the tunnel design system, is radially arranged, tightly props against the rock surface at the bottom of the tube, and is firmly connected with the arch center 1 through spot welding or iron wire binding. The steel perforated pipe 7 has the following functions: temporary and permanent support surrounding rock, system anchor bolt support pilot hole and tunnel are come to nothing slip casting and are backfilled the concrete pipe.
And S4, fixedly connecting an exhaust pipe outside the steel perforated pipe 7. The exhaust pipes are made of phi 20mmPVC materials and are arranged corresponding to the length of the steel flower pipes 7, the exhaust pipes are connected to the steel flower pipes 7 through iron wire binding, each steel flower pipe 7 is provided with one exhaust pipe, and the exhaust pipes are used for tunnel void grouting and exhaust of backfilled concrete pipes and indicate the grouting and backfilling concrete degrees.
S5, dividing the tunnel arch part and the tunnel side wall into a direct concrete spraying supporting area and an indirect concrete spraying supporting area according to the over-excavated thickness; the tunnel arch and the tunnel side wall are over excavated in a large quantity, the position where the concrete can be sprayed is divided into a direct concrete spraying supporting area, and the position where the concrete is difficult to spray is divided into a non-direct concrete spraying supporting area.
And installing a steel plate or a steel belt at the outer side of the arch center 1 in the non-direct concrete spraying supporting area, wherein the steel plate or the steel belt is abbreviated as the steel plate/belt, the steel plate/belt 6 is fixedly connected with the arch center 1, the specification of the steel plate/belt 6 is determined according to the field requirement, and the steel plate/belt 6 is fixedly connected with the outer edge of the arch center 1 in a spot welding mode. The steel plate/belt 6 and the steel perforated pipe 7 are in collision with each other, and the steel plate/belt 6 is connected with each other by welding through steel bars or steel bars in a mode of avoiding or cutting holes for the steel perforated pipe 7 to pass through on the steel plate/belt 6. The steel plate/strip 6 is a concrete-sprayed formwork and is connected with the arch center 1 and is a part of a permanent support.
And S6, dividing the indirect concrete spraying support area into a concrete spraying filling area and a grouting backfilling area according to the thickness of the gap between the steel plate/belt 6 and the rock surface, and densely spraying and filling concrete to the concrete spraying filling area.
The gap between the steel plate/belt 6 and the rock surface is less than 30cm, and the concrete sprayed filling area can be densely filled by adopting concrete spraying; the gap larger than or equal to 30cm is a grouting backfill area, and a large amount of over-excavation and large separation of the grouting backfill area require subsequent backfill treatment.
And S7, spraying concrete to the direct concrete spraying support area, and spraying concrete by using the steel plate/belt 6 as an outer template. And spraying concrete according to the designed concrete spraying thickness and the concrete spraying position.
And S8, in the grouting backfill area, grouting and/or backfilling concrete to the void area behind the arch frame through the steel perforated pipe 7, and stopping grouting or backfilling the concrete after the exhaust pipe of the steel perforated pipe 7 returns the slurry. Selecting grouting or backfilling concrete by using the constructed steel perforated pipe 7 according to the position of the gap between the steel plate/belt 6 and the rock surface and the thickness of the gap, wherein the grouting is suitable for a small amount of gap and grouting reinforcement; backfilling concrete, such as backfilling fine stone concrete, is suitable for heavy super-excavation.
And S9, constructing a system anchor rod 5 by using the steel perforated pipe 7.
When the system anchor rod 5 is constructed, the steel perforated pipe 7 is used for drilling holes, and the system anchor rod 5 is constructed according to design support parameters. After grouting construction of the system anchor rod 5, an anchor backing plate is installed at the end part of the system anchor rod 5, exposed redundant steel perforated pipes 7 and exposed redundant steel bars are cut off, and then cement paste is adopted to hook and block the end head of the system anchor rod 5 and the anchor backing plate.
Claims (9)
1. The primary support method for the IV-VI grade surrounding rock overexcavation tunnel is characterized by comprising the following steps: the method comprises the following steps:
s1, carrying out concrete spraying support on an excavation surface of a tunnel with overexcavation;
s2, installing an arch center (1) in the tunnel, and fixing the arch center (1) in a rock-soil body outside a tunnel excavation contour line (2); the arch frames (1) are connected through longitudinal connecting steel bars (3), and a steel bar mesh (4) is arranged on the inner side of each arch frame (1);
s3, installing steel perforated pipes (7) at the positions of system anchor rods (5) of the tunnel respectively, wherein the steel perforated pipes (7) are arranged in the radial direction, the bottom of each steel perforated pipe (7) is tightly propped against a rock surface, and the exposed end of each steel perforated pipe is fixedly connected with the arch center (1), grouting holes (7-1) are formed in the pipe walls of the steel perforated pipes (7) positioned at the overexcavation parts, and backfill concrete preformed holes are formed in the pipe bottoms of the steel perforated pipes (7);
s4, fixedly connecting an exhaust pipe on the outer side of the steel perforated pipe (7);
s5, dividing the tunnel arch part and the tunnel side wall into a direct concrete spraying supporting area and an indirect concrete spraying supporting area according to the over-excavated thickness; installing steel plates on the outer sides of the arches (1) in the non-direct concrete spraying supporting area, fixedly connecting the steel plates with the arches (1), avoiding or cutting holes for the steel perforated pipes (7) at the collision positions of the steel plates and the steel perforated pipes (7), and welding and connecting the steel plates through steel bars or steel bars;
s6, dividing the indirect concrete spraying support area into a concrete spraying filling area and a grouting backfilling area according to the thickness of a gap between the steel plate and the rock surface, and densely filling the concrete spraying filling area with concrete; wherein, the gap between the steel plate and the rock surface is less than 30cm and is a concrete spraying and filling area, and the gap is more than or equal to 30cm and is a grouting and backfilling area;
s7, spraying concrete to the direct concrete spraying support area, and spraying concrete by taking a steel plate as an outer template;
s8, grouting a void area behind the arch center (1) through the steel perforated pipe (7) in a grouting backfill area, and stopping grouting after the exhaust pipe of the steel perforated pipe (7) returns slurry;
and S9, constructing the anchor rod (5) of the system by using the steel perforated pipe (7).
2. The IV-VI grade surrounding rock overexcavation tunnel primary support method of claim 1, which is characterized in that: the steel plate is a steel strip.
3. The IV-VI grade surrounding rock overexcavation tunnel primary support method of claim 1, which is characterized in that: and in the step S1, spraying C20 concrete with the thickness of 4cm along the excavation face of the tunnel for concrete support.
4. The IV-VI grade surrounding rock overexcavation tunnel primary support method of claim 1, which is characterized in that: in the step S2, the arch centering (1) is a grating arch centering (1) and/or a section steel arch centering (1), and the arch centering (1) is fixed in a rock-soil body outside the tunnel excavation contour line (2) through positioning steel bars and a foot locking anchor rod.
5. The IV-VI grade surrounding rock overexcavation tunnel primary support method of claim 1, which is characterized in that: in the step S2, the longitudinal connecting bars (3) are made of C22 material, and the longitudinal connecting bars (3) are disposed inside the arch frame (1).
6. The primary support method for the IV-VI grade surrounding rock ultra-excavation tunnel according to any one of claims 1 to 5, characterized by comprising the following steps: in the step S3, the steel flower pipe (7) is a seamless steel pipe with an outer diameter of Φ 70mm and a wall thickness of 5mm, and the length of the steel flower pipe (7) is equal to the overexcavation amount at the corresponding position + the designed sprayed concrete thickness +10 cm; the pipe wall of the steel flower pipe (7) positioned at the overexcavation part is provided with three rows of quincunx grouting holes (7-1) with the diameter of phi 8 mm; the steel perforated pipe (7) and the pipe bottom are cut to form two symmetrically arranged notches (7-2) with the length of 5cm and the width of 2cm, and the notches (7-2) are reserved holes for backfilling fine aggregate concrete.
7. The IV-VI grade surrounding rock overexcavation tunnel primary support method of claim 6, which is characterized in that: and in the step S4, the outer side of the steel flower pipe (7) is connected with the exhaust pipe through iron wire binding, the length of the exhaust pipe is consistent with that of the steel flower pipe (7), and the exhaust pipe is a phi 20mm PVC pipe.
8. The primary support method for the IV-VI grade surrounding rock ultra-excavation tunnel according to any one of claims 1 to 5, characterized by comprising the following steps: and in the step S8, grouting is carried out in the grouting backfill area according to the clearance position and the gap thickness between the steel plate and the rock face.
9. The primary support method for the IV-VI grade surrounding rock ultra-excavation tunnel according to any one of claims 1 to 5, characterized by comprising the following steps: in the step S9, drilling a hole by using a steel floral tube (7) and constructing the system anchor rod (5) by using the construction system anchor rod (5); after grouting construction of the system anchor rod (5), an anchor backing plate is installed at the end part of the system anchor rod (5), exposed redundant steel perforated pipes (7) and exposed redundant steel bars are cut off, and then cement paste is adopted to hook and plug the end head of the system anchor rod (5) and the anchor backing plate.
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| CN109707411A (en) * | 2019-03-04 | 2019-05-03 | 中铁十六局集团有限公司 | A kind of technique of tunnel grouting construction |
| CN109764823A (en) * | 2019-03-13 | 2019-05-17 | 中国电建集团成都勘测设计研究院有限公司 | DEFORMATION MONITORING SYSTEM and method for concrete face rockfill dam |
| CN110671125A (en) * | 2019-11-11 | 2020-01-10 | 中铁工程装备集团有限公司 | Anchor-support combined support system and construction method |
| CN111706361A (en) * | 2020-06-04 | 2020-09-25 | 中铁大桥勘测设计院集团有限公司 | Steel frame back filling equipment in tunnel and construction method thereof |
| CN112523790A (en) * | 2020-12-24 | 2021-03-19 | 中铁二十局集团第一工程有限公司 | Anchor box and construction method of primary support anchor rod of tunnel |
| CN114673528B (en) * | 2022-03-28 | 2023-04-28 | 中国电建集团成都勘测设计研究院有限公司 | Tunnel top cavity supporting method |
| CN114837671A (en) * | 2022-03-30 | 2022-08-02 | 中铁第四勘察设计院集团有限公司 | Mechanized supporting tunnel primary support sequential construction method |
| CN115030165B (en) * | 2022-05-13 | 2024-01-19 | 中交一公局第四工程有限公司 | Under-penetration highway structure for ultra-shallow buried tunnel and construction method |
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| EP0472988A3 (en) * | 1990-08-28 | 1992-04-29 | Neuero F+E Forschungs- Und Entwicklungs Gmbh & Co | Lining for underground mine galleries |
| JP2015135040A (en) * | 2013-12-16 | 2015-07-27 | Ｊｆｅシビル株式会社 | Repair and reinforcement structure for reinforced concrete building |
| CN206129286U (en) * | 2016-10-27 | 2017-04-26 | 山东科技大学 | Deep soft rock roadway under high stress high strength support |
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