CN111197491A - Huge span cavern supporting structure of fractured rock mass and construction method thereof - Google Patents
Huge span cavern supporting structure of fractured rock mass and construction method thereof Download PDFInfo
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- CN111197491A CN111197491A CN202010159480.1A CN202010159480A CN111197491A CN 111197491 A CN111197491 A CN 111197491A CN 202010159480 A CN202010159480 A CN 202010159480A CN 111197491 A CN111197491 A CN 111197491A
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- 239000011435 rock Substances 0.000 title claims abstract description 63
- 238000010276 construction Methods 0.000 title claims abstract description 49
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 30
- 239000010959 steel Substances 0.000 claims abstract description 30
- 230000003014 reinforcing effect Effects 0.000 claims abstract description 25
- 239000004567 concrete Substances 0.000 claims abstract description 22
- 239000000835 fiber Substances 0.000 claims abstract description 22
- 238000009412 basement excavation Methods 0.000 claims abstract description 16
- 239000004570 mortar (masonry) Substances 0.000 claims abstract description 15
- 239000011347 resin Substances 0.000 claims abstract description 12
- 229920005989 resin Polymers 0.000 claims abstract description 12
- 230000035772 mutation Effects 0.000 claims abstract description 7
- 239000002002 slurry Substances 0.000 claims description 9
- 238000005507 spraying Methods 0.000 claims description 8
- 239000010410 layer Substances 0.000 claims description 7
- 239000004568 cement Substances 0.000 claims description 5
- 239000000463 material Substances 0.000 claims description 4
- 238000005452 bending Methods 0.000 claims description 2
- 239000011440 grout Substances 0.000 claims description 2
- 238000007789 sealing Methods 0.000 claims description 2
- 239000002356 single layer Substances 0.000 claims description 2
- 230000008520 organization Effects 0.000 abstract description 7
- 238000009407 construction method and process Methods 0.000 abstract 1
- 238000000034 method Methods 0.000 description 14
- 230000008569 process Effects 0.000 description 12
- 238000010586 diagram Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 239000000725 suspension Substances 0.000 description 4
- 230000002787 reinforcement Effects 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 238000001125 extrusion Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000004873 anchoring Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 239000011210 fiber-reinforced concrete Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 239000002344 surface layer 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
- E21D13/00—Large underground chambers; Methods or apparatus for making them
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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
- E21D11/15—Plate linings; Laggings, i.e. linings designed for holding back formation material or for transmitting the load to main supporting members
- E21D11/152—Laggings made of grids or nettings
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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
-
- 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
-
- 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
- E21D20/025—Grouting with organic components, e.g. resin
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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)
- Underground Structures, Protecting, Testing And Restoring Foundations (AREA)
Abstract
The invention discloses a huge span cavern supporting structure of fractured rock mass and a construction method thereof, wherein the supporting structure comprises: the flexible supporting structure for the surface of the cavern is arranged on an arch part and a side wall of an excavation surface and comprises steel fiber concrete and a steel bar mesh; the self-bearing arch structure of rock mass is arranged on an arch part and a side wall of the cavern and comprises a common mortar anchor rod, an expansion shell type prestressed grouting anchor rod and the rock mass; the locking foot pre-stress anchor cable is arranged at the arch foot part of the chamber; the block body reinforcing prestressed anchor cable is arranged in the range of the unstable block body of the cavern; and the resin anchor rod is arranged in the deformation mutation area after excavation. The support structure has the advantages of rich means, comprehensive range, clear functions, strong bearing capacity, good economical efficiency, simple construction method and process, convenient construction organization, smooth step connection and high safety, and can adjust the self-bearing capacity of the rock mass in multiple levels and reinforce the unstable block so as to ensure that the giant-span cavern reaches a stable state.
Description
Technical Field
The invention relates to the technical field of tunnel and underground engineering design and construction, in particular to a huge span cavern supporting structure of fractured rock mass and a construction method thereof.
Background
For the underground cavern, generally speaking, the excavation span is small span when 5 ~ 8.5m, medium span when 8.5 ~ 12m, large span when 12 ~ 14m, super-large span when 14 ~ 16m, is super-large span when the excavation span is greater than 16 m. At present, the span of the super-large span cavern is mainly concentrated below 30m, and the cavern with the span of 30-40 m can be found at home and abroad. The underground cavern with the span of more than 40 meters can be called as a giant span underground cavern, the risk brought by the increase of the span is also huge, a theoretical building system of an underground structure with the giant span does not exist at present, the engineering examples are fewer, the building risk of the giant span underground cavern is large, and collapse accidents are easily caused, and the method has the following characteristics:
1) the span is increased, so that the loosening ring range of the upper rock body is enlarged, and vault collapse and block falling are easily caused;
2) the span is large, so that the cavern inevitably meets the conditions of cracks, joints and the like, and the risk of unfavorable geology is high;
3) the rock mass above the cavern can form a block after being cut by the cracks, and for the giant span cavern, the stability of the block is a main factor determining the stability of the cavern;
4) the loose load formed after the huge span cavern is excavated is huge, and it is unrealistic to bear the upper loose load by only depending on the supporting structure, and the self-bearing capacity of the rock mass must be considered.
To above-mentioned characteristic, room supporting construction is striden to current super large has following not enough:
1) the existing oversized cross-chamber supporting structure does not consider the supporting of an unstable block, and the safety of the unstable block cannot be ensured;
2) the existing super-large span cavern surface layer supporting structure generally adopts a grid steel frame form, however, for the huge span cavern, the grid steel frame is difficult to erect, the nodes are weak, the stress is limited, and the construction and safety requirements of the huge span underground cavern cannot be met;
3) the existing oversized cross-chamber supporting structure adopts a single anchor rod form and cannot fully transfer the self-bearing capacity of a rock body;
4) the existing construction and support of the oversized span cavern mostly adopts a mode of excavating in parts and erecting temporary supports, and the support mode has complex stress conversion, weak support at nodes and difficult operation and is not suitable for the construction of the oversized span cavern;
5) the existing oversized span cavern secondary lining bears a certain rock mass load, and for the oversized span cavern, if the lining bears, the thickness is huge, so that the problems of difficult pouring, high manufacturing cost and the like can be caused.
For the huge span underground cavern, the conventional huge span supporting structure and concept are infeasible and uneconomical, so that the supporting structure of the huge span cavern needs to utilize various means to adjust the self-bearing capacity of rock mass and strengthen the support of an unstable block, thereby realizing the stability of the cavern in the construction period and the operation period.
Disclosure of Invention
The invention aims to provide a huge span cavern supporting structure of fractured rocks and a construction method thereof, the supporting structure has the advantages of rich means, comprehensive range, clear functions, strong bearing capacity and good economy, the construction method has simple process, convenient construction organization, smooth step connection and high safety, the self-bearing capacity of rocks can be adjusted in multiple levels, and unstable blocks are reinforced so as to enable the huge span cavern to reach a stable state.
In order to achieve the purpose, the specific technical scheme of the giant span cavern supporting structure of the fractured rock mass and the construction method thereof is as follows:
a huge span cavern supporting construction of fissured rock mass includes:
the flexible supporting structure for the surface of the cavern is arranged on an arch part and a side wall of an excavation surface and comprises steel fiber concrete and a steel bar mesh;
the self-bearing arch structure of rock mass is arranged on an arch part and a side wall of the cavern and comprises a common mortar anchor rod, an expansion shell type prestressed grouting anchor rod and the rock mass;
the locking foot pre-stress anchor cable is arranged at the arch foot part of the chamber;
the block body reinforcing prestressed anchor cable is arranged in the range of the unstable block body of the cavern; and
and the resin anchor rod is arranged in the deformation mutation area after excavation.
A construction method of a huge span cavern supporting structure of fractured rock mass comprises the following steps:
firstly, removing surface broken and unstable blocks after cavern excavation, and primarily spraying steel fiber concrete to level and seal an excavation surface;
secondly, setting a common mortar anchor rod and an expansion shell type prestress grouting anchor rod, applying prestress after grout is solidified, and forming a rock self-bearing arch structure with a rock body; applying a resin anchor rod on the deformation mutation area;
step three, symmetrically applying three rows of prestressed anchor cables to arch springing, and applying prestress after the slurry is solidified;
step four, applying a block body to reinforce a prestressed anchor cable in the range of the unstable block body of the cavern, enabling a free section of the anchor cable to penetrate through the unstable block body above the cavern, suspending and reinforcing the unstable block body, and applying prestress after the slurry is solidified;
and fifthly, laying a reinforcing mesh and spraying the steel fiber concrete for the second time to form the flexible supporting structure of the giant-span cavern.
The giant-span cavern supporting structure of the fractured rock mass and the construction method thereof have the advantages that:
1) the supporting structure has the characteristics of rich means, comprehensive range, clear functions, strong bearing capacity, good economy and the like, the construction method is suitable for the giant-span underground cavern with the span of more than 40m, and the supporting structure has the characteristics of simple construction process, convenient construction organization, smooth step connection, high safety and the like;
2) the steel fiber concrete adopted by the invention is simple to operate, can be used as a flexible support of a giant cavern, and can exert the self-bearing function of the surrounding rock to the maximum extent; the form of combining a common mortar anchor rod and an expansion shell type prestressed grouting anchor rod is adopted, the longitudinal and transverse extrusion and suspension effects of the anchor rod on a rock body can be greatly improved, an effective self-bearing arch structure can be ensured to be formed, the suspension effect of the expansion shell type prestressed grouting anchor rod on the self-bearing arch structure can enhance the bearing capacity of the self-bearing arch, and the integral stability of the cavern is ensured;
3) the stability of the arch springing and the side wall is the foundation of the self-bearing arch structure and the stability of the cavern, the supporting structure of the invention adopts high-strength foot-locking anchor cables to prevent the arch springing and the side wall from sliding, and ensure the stability of the arch springing and the side wall;
4) the block body has strong supporting capability of reinforcing the anchor cable, and can play a role in suspending and extruding an unstable block body, so that the safety of the unstable block body is ensured; the resin anchor rod can realize quick tensioning, is timely supported and can provide buffer time for applying a subsequent supporting structure;
5) in order to ensure the safety of the operation period of the cavern, the conventional cavern needs to be provided with a secondary lining, but for the huge span cavern, if the secondary lining is considered for bearing, the lining thickness is very large, and the problems of high manufacturing cost, difficult pouring and the like are caused; the support structure has clear functions and strong operability, fully mobilizes the self-bearing capacity of the surrounding rock, mobilizes the self-bearing capacity of the rock mass in multiple levels, and reinforces the unstable block, so that the giant span cavern reaches a stable state for a long time, the secondary lining does not bear the rock mass load under the action of the system, and the secondary lining can not be applied under the anhydrous condition, thereby greatly reducing the cost and the construction difficulty;
6) the supporting structure of the invention does not need to erect temporary supports, and the stress system does not need to be converted for many times, thereby ensuring the engineering safety. The construction process is simple, the construction sequence is mutually connected, the step sequence is smooth, the construction organization is convenient, and a large amount of time and cost are saved.
Drawings
FIG. 1 is a schematic view of a huge span cavern supporting structure of a fractured rock mass provided by the invention;
FIG. 2 is a schematic diagram of a construction process of primary spraying of steel fiber reinforced concrete in the giant-span chamber supporting structure of fractured rocks provided by the invention;
FIG. 3 is a schematic diagram of the construction process of a common mortar anchor rod, an expanding-shell type prestressed grouting anchor rod and a resin anchor rod of the giant-span cavern supporting structure of fractured rocks provided by the invention;
FIG. 4 is a schematic diagram of a construction process of a foot-locking prestressed anchor cable of the giant-span chamber supporting structure of a fractured rock mass provided by the invention;
FIG. 5 is a schematic view of the construction process of reinforcing a prestressed anchor cable by using a block body of the giant-span chamber supporting structure of fractured rocks provided by the invention;
fig. 6 is a schematic diagram of the construction process of laying a reinforcing mesh and re-spraying steel fiber concrete on the self-supporting structure of the section of the giant span cavern provided by the invention.
In the figure: 1. steel fiber concrete; 2. a reinforcing mesh; 3. a self-supporting arch structure; 4. ordinary mortar anchor rods; 5. an expansion shell type prestress grouting anchor rod; 6. locking a prestressed anchor cable of a leg; 7. reinforcing a prestressed anchor cable by a block; 8. reinforcing a prestressed anchor cable by a block; 9. a resin anchor rod.
Detailed Description
In order to better understand the purpose, structure and function of the present invention, the following describes a huge span cavern supporting structure of fractured rock mass and a construction method thereof in further detail with reference to the attached drawings.
As shown in fig. 1 to 6, the giant-span cavern supporting structure of fractured rock mass and the construction method thereof are suitable for giant-span underground caverns with spans larger than 40 m. As shown in figure 1, the supporting structure comprises a flexible supporting structure for the surface of a cavity, a rock self-bearing arch structure 3, a foot-locking prestressed anchor cable 6, a block-reinforcing prestressed anchor cable 8 and a resin anchor rod 9. The flexible supporting structure for the surface of the cavern is arranged on an arch part and a side wall of an excavation surface and comprises steel fiber concrete 1 and a steel mesh 2; the self-bearing rock arch structure 3 is arranged at an arch part and a side wall of the cavern and comprises a common mortar anchor rod 4, an expansion shell type prestressed grouting anchor rod 5 and a rock body; the locking foot pre-stress anchor cable 6 is arranged at the arch foot part of the chamber; the block body reinforcing pre-stressed anchor cable 8 is arranged in the range of the cavern unstable block body 7; the resin anchor rod is arranged in a deformation and mutation area after excavation and is an emergency reinforcing measure.
Furthermore, the flexible supporting structure on the surface of the cavern comprises three layers, wherein after the cavern is excavated, a layer of steel fiber concrete 1 is sprayed at first, then a reinforcing mesh 2 is laid, and finally a layer of steel fiber concrete 1 is sprayed again. The invention adopts the steel fiber concrete, has simple operation, can be used as the flexible support of the giant cavern, and furthest exerts the self-bearing function of the surrounding rock.
Further, the strength grade of the steel fiber concrete 1 in the flexible supporting structure on the surface of the cavern is not less than C35, the bending strength is not less than 4Mpa, and the thickness is generally 30 cm. The diameter of the mesh reinforcement 2 is 6-12 mm, the mesh reinforcement spacing is 250x250mm or 200x200mm, and the mesh reinforcement can be a single layer or double layers according to geological conditions.
Further, 4 length of ordinary mortar anchor rod in the rock mass self-supporting arch structure 3 set up according to the stable required self-supporting arch thickness in cavern, pass rock mass loose circle, and length is generally 6 ~ 10 meters, and the hoop interval is 1 ~ 1.5 meters, and the longitudinal separation is 1 ~ 1.5 meters. The expansion shell type prestressed grouting anchor rod 5 assists in forming a rock self-bearing arch structure 3 and can suspend and reinforce the rock self-bearing arch structure, the length is generally 1.2-1.8 times (preferably 1.5 times) of the length of a common mortar anchor rod 4, the circumferential distance is 2-3 meters, the longitudinal distance is 2-3 meters, and the prestress is 120-180 KN (preferably 150 kN). The invention adopts the combination of the common mortar anchor rod and the expanding-shell type prestressed grouting anchor rod, can greatly improve the longitudinal and transverse extrusion and suspension effects of the anchor rod on the rock mass, can ensure the formation of an effective self-bearing arch structure, and can strengthen the bearing capacity of the self-bearing arch and ensure the integral stability of the cavern through the suspension effect of the expanding-shell type prestressed grouting anchor rod on the self-bearing arch structure.
Further, in order to ensure stable arrangement of arch springing, the length of the locking leg prestressed anchor cable 6 is generally 3/1-2/1 of the span of the cavern, the arch springing is symmetrically arranged in three rows, the longitudinal distance is 4-6 m, the initial prestress of the locking leg prestressed anchor cable 6 is 1500kN, and then supplementary tensioning is carried out. The stability between the arch springing and the side wall is a foundation for self-bearing arch structure and stable cavern, the supporting structure of the invention adopts high-strength foot-locking anchor cables to prevent the arch springing and the side wall from slipping, and ensure the stability of the arch springing and the side wall.
Further, the block reinforcing prestressed anchor cable 8 is arranged in the range of a cutting surface of the crack, the unstable block 7 above the cavity is extruded and suspended, the free section of the block reinforcing prestressed anchor cable 8 penetrates through the unstable block 7 above the cavity by 3-5 m, the anchoring section of the block reinforcing prestressed anchor cable 8 is fixed in the stable rock body on the upper portion of the cutting surface of the crack, the pre-stress and the arrangement interval of the block reinforcing prestressed anchor cable 8 are set according to the weight of the unstable block 7, and certain safety reserve is considered. Under the condition of large section of the huge span cavern, the fracture and the broken surrounding rock cannot be avoided, and an unstable block is easily formed above the cavern, so that the stability of the block is a main factor for determining the stability of the huge span cavern. The block body provided by the invention has strong supporting capability of reinforcing the anchor cable, and can play a role in suspending and extruding an unstable block body, so that the safety of the unstable block body is ensured.
Further, resin stock 9 sets up in the within range of unstable block 7, can provide pulling force fast, and length is generally 6 ~ 10 meters, and it is regional according to the on-the-spot deformation and decides to set up the interval, and the ring longitudinal spacing is generally 1.5 m. The method has the advantages that tensioning can be carried out only after slurry solidification is needed in supporting structures such as anchor cables, anchor rods and the like, and timely supporting cannot be carried out on sudden deformation occurring on site.
In conclusion, the supporting structure has the characteristics of rich means, comprehensive range, clear functions, strong bearing capacity, good economy and the like, the construction method is suitable for the giant-span underground cavern with the span of more than 40m, and the supporting structure has the characteristics of simple construction process, convenient construction organization, smooth step connection, high safety and the like.
The working process of the construction method of the giant span cavern supporting structure of the fractured rock mass is described in the following with the accompanying drawings:
as shown in fig. 2 to 6, the invention discloses a construction method of a giant span cavern supporting structure of fractured rock mass, which comprises the following steps:
firstly, removing surface broken and unstable blocks after cavern excavation, and primarily spraying a layer of steel fiber concrete 1 for leveling and sealing an excavation surface.
Specifically, the steel fiber concrete 1 is preferably initially sprayed for 8-12 cm (preferably 10 cm).
Sequentially drilling a common mortar anchor rod 4 and an expansion shell type prestress grouting anchor rod 5 according to the designed interval and length, wherein the grouting material is cement paste, and applying prestress after the cement paste is solidified to form a rock self-bearing arch structure 3 with a rock; and applying a resin anchor rod 9 in the deformation mutation area.
And step three, symmetrically applying three rows of prestressed anchor cables 6 to the arch springing, wherein the grouting material is cement slurry, and applying prestress after the slurry is solidified.
And step four, applying a block body reinforcing prestressed anchor cable 8 in the range of the unstable block body 7 of the cavern, enabling the free section of the anchor cable to penetrate through the unstable block body 7 above the cavern to suspend and reinforce the unstable block body, meanwhile, the anchor cable can be used as the safe storage of the whole supporting system, the grouting material is cement slurry, and after the slurry is solidified, applying prestress.
And step five, laying a reinforcing mesh 2 and spraying the steel fiber concrete 1 for the second time to form a flexible supporting structure of the giant-span cavern.
According to the huge span cavern supporting structure of the fractured rock mass and the construction method thereof, the supporting structure has the characteristics of rich means, comprehensive range, clear functions, strong bearing capacity, good economy and the like, the construction method is suitable for the huge span underground cavern with the span of more than 40m, and the huge span cavern supporting structure has the characteristics of simple construction process, convenient construction organization, smooth step connection, high safety and the like; the support structure has clear functions and strong operability, fully mobilizes the self-bearing capacity of the surrounding rock, mobilizes the self-bearing capacity of the rock mass in multiple levels, and reinforces the unstable block, so that the giant span cavern reaches a stable state for a long time, the secondary lining does not bear the rock mass load under the action of the system, and the secondary lining can not be applied under the anhydrous condition, thereby greatly reducing the cost and the construction difficulty; the supporting structure of the invention does not need to erect temporary supports, and the stress system does not need to be converted for many times, thereby ensuring the engineering safety. The construction process is simple, the construction sequence is mutually connected, the step sequence is smooth, the construction organization is convenient, and a large amount of time and cost are saved.
The present invention has been further described with reference to specific embodiments, but it should be understood that the detailed description should not be construed as limiting the spirit and scope of the present invention, and various modifications made to the above-described embodiments by those of ordinary skill in the art after reading this specification are within the scope of the present invention.
Claims (10)
1. The utility model provides a huge span cavern supporting construction of fissured rock mass which characterized in that includes:
the flexible supporting structure for the surface of the cavern is arranged on an arch part and a side wall of an excavation surface and comprises steel fiber concrete (1) and a steel mesh (2);
the self-bearing rock arch structure (3) is arranged at an arch part and a side wall of the cavern and comprises a common mortar anchor rod (4), an expansion shell type prestress grouting anchor rod (5) and a rock body;
the locking foot pre-stress anchor cable (6) is arranged at the arch foot part of the cavern;
the block body reinforcing pre-stressed anchor cable (8) is arranged in the range of the cavern unstable block body (7); and
and the resin anchor rod (9) is arranged in the deformation mutation area after excavation.
2. The support structure according to claim 1, characterized in that the flexible support structure of the cavern surface comprises three layers, which are steel fiber concrete (1), a steel mesh (2) and steel fiber concrete (1) in sequence.
3. The support structure according to claim 1 or 2, characterized in that the steel fiber concrete (1) in the flexible support structure of the cavern surface has a strength grade not less than C35, a bending strength not less than 4MPa and a thickness of generally 30 cm.
4. The supporting structure according to claim 1 or 2, wherein the diameter of the reinforcing mesh (2) in the flexible supporting structure on the surface of the cavern is 6-12 mm, the spacing between reinforcing meshes is 250x250mm or 200x200mm, and the supporting structure is arranged in a single layer or a double layer.
5. The supporting structure according to claim 1, characterized in that ordinary mortar anchor rods (4) in the self-bearing arch structure (3) of the rock body are arranged through the rock body loosening ring, the length is 6-10 m, the circumferential spacing is 1-1.5 m, and the longitudinal spacing is 1-1.5 m.
6. The supporting structure according to claim 1 or 5, wherein the length of the expanding-shell type prestressed grouting anchor rod (5) is 1.2-1.8 times of the length of the common mortar anchor rod (4), the circumferential distance is 2-3 m, and the longitudinal distance is 2-3 m, so that the supporting structure is used for assisting in forming and suspending and reinforcing the self-bearing arch structure (3) of the rock mass.
7. The supporting structure of claim 1, wherein the length of the locking leg prestressed anchor cable (6) is 3/1-2/1 of the span of the cavern, the arch legs are symmetrically arranged in three rows, and the longitudinal distance is 4-6 m.
8. A construction method of a huge span cavern supporting structure of fractured rock mass is characterized by comprising the following steps:
firstly, removing surface broken and unstable blocks after cavern excavation, and primarily spraying steel fiber concrete (1) for leveling and sealing an excavation surface;
secondly, setting a common mortar anchor rod (4) and an expansion shell type prestress grouting anchor rod (5), applying prestress after grout is solidified, and forming a rock self-bearing arch structure (3) with a rock body; applying a resin anchor rod (9) in the deformation mutation area;
step three, symmetrically applying three rows of prestressed anchor cables (6) on arch legs, and applying prestress after the slurry is solidified;
step four, applying a block body to reinforce a prestressed anchor cable (8) in the range of the unstable block body (7) of the cavern, enabling a free section of the anchor cable to penetrate through the unstable block body (7) above the cavern to suspend and reinforce the unstable block body, and applying prestress after the slurry is solidified;
and fifthly, laying a reinforcing mesh (2) and spraying the steel fiber concrete (1) for the second time to form a flexible supporting structure of the giant-span cavern.
9. The construction method according to claim 8, wherein in the step one, the steel fiber concrete (1) of 8-12 cm is initially sprayed.
10. The construction method according to claim 8, wherein in the second, third and fourth steps, the grouting material is cement paste.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010159480.1A CN111197491A (en) | 2020-03-10 | 2020-03-10 | Huge span cavern supporting structure of fractured rock mass and construction method thereof |
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| CN202010159480.1A CN111197491A (en) | 2020-03-10 | 2020-03-10 | Huge span cavern supporting structure of fractured rock mass and construction method thereof |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111502715A (en) * | 2020-05-29 | 2020-08-07 | 中铁第六勘察设计院集团有限公司 | Method for comprehensively constructing fractured rock mass in oversized underground cavern crossing stage |
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2020
- 2020-03-10 CN CN202010159480.1A patent/CN111197491A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111502715A (en) * | 2020-05-29 | 2020-08-07 | 中铁第六勘察设计院集团有限公司 | Method for comprehensively constructing fractured rock mass in oversized underground cavern crossing stage |
| CN111502715B (en) * | 2020-05-29 | 2021-07-20 | 中铁第六勘察设计院集团有限公司 | Method for comprehensively constructing fractured rock mass in oversized underground cavern crossing stage |
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