CN111379580A - Tunnel primary support protection construction method - Google Patents
Tunnel primary support protection construction method Download PDFInfo
- Publication number
- CN111379580A CN111379580A CN202010191777.6A CN202010191777A CN111379580A CN 111379580 A CN111379580 A CN 111379580A CN 202010191777 A CN202010191777 A CN 202010191777A CN 111379580 A CN111379580 A CN 111379580A
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- China
- Prior art keywords
- vault
- channel
- tunnel
- anchor rod
- rock
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Classifications
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D20/00—Setting anchoring-bolts
- E21D20/02—Setting anchoring-bolts with provisions for grouting
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- E—FIXED CONSTRUCTIONS
- E21—EARTH 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 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
Abstract
The invention discloses a tunnel primary support protection construction method, which comprises the following steps: drilling and cleaning holes on the top of the tunnel arch, and then inserting an anchor rod for grouting solidification; the method comprises the following steps that channel steel is additionally arranged at one end, inserted into a vault, of an anchor rod, the end face of the channel steel is tightly attached to the inner rock surface of the vault, and the channel steel is fastened on the inner rock surface of the vault through a nut after one end of the anchor rod is inserted into the channel steel to apply prestress; in the local broken rock area, add the reinforcing bar net piece between channel-section steel and the interior rock face of vault, exert prestressing force on the rock face in the vault through the nut with reinforcing bar net piece, channel-section steel fastening promptly after anchor rod one end inserts reinforcing bar net piece, channel-section steel. According to the tunnel primary support protection construction method, an arch frame does not need to be erected for lower support, and the tunnel primary support protection construction method has good stability; in addition, the reinforcing mesh is arranged in the local broken rock area in a targeted manner, so that the local block falling phenomenon can be effectively prevented, the method is particularly suitable for some emergency projects, and local integral installation can be carried out.
Description
Technical Field
The invention relates to the technical field of tunnel underground excavation,
in particular, the invention relates to a tunnel primary support protection construction method.
Background
Tunnel construction is an important component of traffic construction in China, wherein tunnel safety construction operation is particularly important, primary support is generally carried out in time after excavation, operating personnel are prevented from being injured by falling of broken stones, an arch frame and a reinforcing mesh are erected and anchor-spraying protection is carried out, the construction method is feasible, the construction speed is low, the risk coefficient of workers is high when the workers hang nets, particularly, a steel frame is not considered to be used for spray-anchor support when some low-grade tunnels are designed, but in the actual excavation process, local broken rock masses appear frequently, a good solution is not provided for the problems, only temporary vertical frames can be used for protection, the construction progress is seriously affected, and treatment is complicated, so that a suitable solution is found for the problems, and the tunnel excavation becomes particularly important.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention aims to provide a tunnel primary support protection construction method.
In order to solve the problems, the invention adopts the following technical scheme:
a tunnel primary support protection construction method comprises the following steps:
drilling and cleaning holes on the top of the tunnel arch, and then inserting an anchor rod for grouting solidification;
the method comprises the following steps that a channel steel is additionally arranged at one end, inserted into a vault, of an anchor rod, the end face of the channel steel is tightly attached to the inner rock surface of the vault, and after one end of the anchor rod is inserted into the channel steel, the channel steel is fastened on the inner rock surface of the vault through a nut to apply prestress;
in the local broken rock area, add the reinforcing bar net piece between channel-section steel and the interior rock face of vault, promptly the stock one end insert the reinforcing bar net piece behind the channel-section steel, will through the nut reinforcing bar net piece the channel-section steel fastening is exerted prestressing force on the interior rock face of vault.
Preferably, the method further comprises the following steps: and (4) carrying out guniting to form a tunnel in the local crushed rock area to form a supporting layer.
Preferably, the steel bar meshes are lapped and laid, and the lapping length between the adjacent steel bar meshes is larger than 15 cm.
Preferably, the grouting solidification adopts early strength cement paste with the strength of above C20, the water cement ratio is 0.7, and the grouting pressure is 0.5-2.0 MPa.
Preferably, the guniting adopts early strength cement paste with the strength of more than C20, the water cement ratio is 0.7, the mixing amount of the accelerator is 4-6% of the weight of the cement, and the anti-permeability grade is not less than S6.
Compared with the prior art, the invention has the technical effects that:
according to the tunnel primary support protection construction method, the channel steel is additionally arranged between the anchor rod and the inner rock surface in the vault, the anchor rod and the rock body are fixed by utilizing the interaction force between the anchor rod and the rock body, an arch center does not need to be erected for lower support, and the tunnel primary support protection construction method has good stability; in addition, the reinforcing mesh is arranged in the local broken rock area in a targeted manner, so that the local block falling phenomenon can be effectively prevented, the required materials are simple to process and easy to operate, the preliminary supporting construction can be quickly carried out, the method is particularly suitable for some emergency projects, and the local integral installation can be carried out.
Drawings
Fig. 1 is a top view of the exterior of a tunnel according to a method for constructing primary support protection of the tunnel provided in an embodiment of the present invention;
fig. 2 is a tunnel front view of a method for implementing tunnel primary support protection according to an embodiment of the present invention.
The steel bar reinforced concrete structure comprises 1 an anchor rod, 2 a nut, 3 a channel steel, 4 a steel bar net piece, 5 and a rock surface.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The embodiment of the invention provides a method for constructing tunnel primary support protection, and the structural schematic diagram of the tunnel primary support protection constructed according to the method of the embodiment of the invention is shown in fig. 1 and fig. 2, and the method comprises the following steps:
(1) drilling and cleaning holes on the top of the tunnel arch, and then inserting an anchor rod 1 for grouting solidification;
(2) the method comprises the following steps that a channel steel 3 is additionally arranged at one end, inserted into a vault, of an anchor rod 1, the end face of the channel steel 3 is tightly attached to a rock surface 5 in the vault, and after one end of the anchor rod 1 is inserted into the channel steel 3, the channel steel 3 is fastened on the rock surface 5 in the vault through a nut 2 to apply prestress;
(3) in the local broken rock area, add reinforcing bar net piece 4 between channel bar 3 and vault inner rock face 5, exert prestressing force on the vault inner rock face 5 through nut 2 with reinforcing bar net piece 4, channel bar 3 fastening through nut 2 behind 1 one end of stock promptly inserted reinforcing bar net piece 4, the channel bar 3.
In the step (1), the hole depth of the drilled hole is not less than the length of the anchor rod 1, the hole site deviation is not more than +/-15 mm, rock debris in the hole is removed through a high-pressure fan after the drilled hole is formed, and then the anchor rod 1 is inserted. After the anchor rod 1 is inserted into a drilled hole, the exposed part of the rod body of the anchor rod 1 is not over 5 percent of the length of the anchor rod 1. In order to enable the anchor rod 1 to be tightly combined with the rock body after being inserted into the rock body and improve the tensile force required by rock body support, impurities such as oil stain, iron rust and the like on the surface of the anchor rod 1 are removed before use.
Preferably, the grouting solidification of the anchor rod 1 adopts early strength cement paste with the weight of above C20, the water cement ratio is 0.7, and the grouting pressure is 0.5-2.0 MPa. So as to ensure that the pulling resistance of the anchor rod 1 is more than 50KN, the anchoring force is more than 50KN, and the pre-tightening torque of the anchor rod is more than 100 N.m.
In addition, the included angle between the anchor rod 1 and the vault contour line during installation should be greater than 80 degrees, and the interval and the row spacing of the anchor rod 1 can be reasonably arranged as required.
Preferably, in the step (3), the steel bar net pieces 4 are lapped and laid, and the lapping length between the adjacent steel bar net pieces 4 is more than 15 cm. The mesh interval can be selected as required, and reinforcing bar net piece 4 is laid along the fluctuation of rock face 5 in the vault, adopts the mode of electric welding to weld together in the junction of reinforcing bar net piece 4 and stock 1 for reinforcing bar net piece 4 is difficult to rock when spraying, and whole supporting construction is more firm.
According to the tunnel primary support protection construction method, the channel steel 3 is additionally arranged between the anchor rod 1 and the inner rock surface 5 in the vault, the anchor rod 1 and the rock body are fixed by utilizing the interaction force, an arch center does not need to be erected for lower support, and the tunnel primary support protection construction method has good stability; in addition, the reinforcing mesh 4 is arranged in the local broken rock area in a targeted manner, so that the local block falling phenomenon can be effectively prevented, the required materials are simple to process and easy to operate, the preliminary supporting construction can be quickly carried out, the method is particularly suitable for some emergency projects, and the local integral installation can be carried out.
The reinforcing mesh 4 and the channel steel 3 can be processed in advance in a processing field, can be quickly assembled after being transported to a construction site, is particularly suitable for protecting a local broken rock mass under good geological conditions, and belongs to a patch-type quick protection mode. The primary support protection method is different from the traditional method, after the anchor rod 1 is constructed, the reinforcing mesh 4 and the channel steel 3 are fixed, arch frame erection is not needed, and construction progress is greatly accelerated. In addition, by utilizing the unique structure of the channel steel 3, namely the flat end surface of the channel steel 3 can be well attached to the inner edge surface 5 of the vault, and the flat end surface of the channel steel 3 has a larger contact area with the inner edge surface 5 of the vault, so that a better supporting and protecting effect can be achieved; and fastening nut 2 installs in the inslot of channel-section steel 3, can protect nut 2 to avoid the influence of slip casting and environment, makes things convenient for nut 2 to dismantle and install.
After the anchor rods 1, the channel steel 3 and the reinforcing mesh 4 are laid, for the purpose of further strengthening primary support,
preferably, the method further comprises the following steps: (4) and (4) carrying out guniting to form a tunnel in the local crushed rock area to form a supporting layer. In the step (2), the torque of the nut 2 is 100 N.m, and the nut 2 must be fastened again before guniting to form a roadway so as to enhance the supporting effect of the anchor rod 1.
Preferably, the guniting adopts early strength cement paste with the weight of more than C20, the water cement ratio is 0.7, the mixing amount of the accelerator is 4-6% of the weight of the cement, and the anti-permeability grade is not less than S6. Thus, the anchoring effect on broken rock strata and loose soil layers can be enhanced.
According to the embodiment of the invention, the channel steel 3 and the reinforcing mesh 4 are fixed on the rock surface 5 through the anchor rod 1 and the nut 2, then the protection whole is formed by spraying concrete, when the anchor rod 1 is applied, the protection whole is properly expanded outwards for about 2 meters in a protection area, not only the application is carried out in a broken rock body area, but also the anchoring protection is carried out on the periphery, and the falling-off caused by insufficient anchoring force of the anchor rod 1 in the broken area is prevented. And after the anchor rod 1 is completely constructed, the reinforcing mesh 4 and the channel steel 3 are laid, the reinforcing mesh 4 is welded to form an integral mesh, and then the nut 2 is screwed up to tightly attach the reinforcing mesh 4 and the channel steel 3 to the rock surface 5 for fixation.
The present invention is not limited to the above-described specific embodiments, and various modifications and variations are possible. Any modifications, equivalents, improvements and the like made to the above embodiments in accordance with the technical spirit of the present invention should be included in the scope of the present invention.
Claims (5)
1. A tunnel primary support protection construction method is characterized by comprising the following steps:
drilling and cleaning holes on the top of the tunnel arch, and then inserting an anchor rod for grouting solidification;
the method comprises the following steps that a channel steel is additionally arranged at one end, inserted into a vault, of an anchor rod, the end face of the channel steel is tightly attached to the inner rock surface of the vault, and after one end of the anchor rod is inserted into the channel steel, the channel steel is fastened on the inner rock surface of the vault through a nut to apply prestress;
in the local broken rock area, add the reinforcing bar net piece between channel-section steel and the interior rock face of vault, promptly the stock one end insert the reinforcing bar net piece behind the channel-section steel, will through the nut reinforcing bar net piece the channel-section steel fastening is exerted prestressing force on the interior rock face of vault.
2. The method for constructing tunnel primary support protection according to claim 1, further comprising the steps of: and (4) carrying out guniting to form a tunnel in the local crushed rock area to form a supporting layer.
3. The construction method of the primary tunnel support protection as claimed in claim 1 or 2, wherein the steel mesh sheets are laid in an overlapping manner, and the overlapping length between adjacent steel mesh sheets is greater than 15 cm.
4. The construction method for the primary tunnel support protection according to claim 1 or 2, wherein the grouting solidification is performed by using early strength cement paste with the cement-cement ratio of 0.7 and the grouting pressure of 0.5-2.0 MPa, wherein the early strength cement paste is above C20.
5. The construction method for tunnel primary support protection as claimed in claim 2, wherein the shotcrete is early strength cement paste with a C20 or more, a water cement ratio is 0.7, an admixture amount of an accelerator is 4-6% of the cement weight, and an impermeability grade is not less than S6.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010191777.6A CN111379580A (en) | 2020-03-18 | 2020-03-18 | Tunnel primary support protection construction method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010191777.6A CN111379580A (en) | 2020-03-18 | 2020-03-18 | Tunnel primary support protection construction method |
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| CN111379580A true CN111379580A (en) | 2020-07-07 |
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| CN202010191777.6A Pending CN111379580A (en) | 2020-03-18 | 2020-03-18 | Tunnel primary support protection construction method |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19828503A1 (en) * | 1998-06-26 | 1999-12-30 | Seiz Tunnelausbau Systeme Gmbh | New design of support frame for air placed concrete shell to be used in mining or tunnel construction |
| CN201218105Y (en) * | 2008-05-28 | 2009-04-08 | 山西焦煤集团有限责任公司 | Mine tunnel digging support component |
| CN202500580U (en) * | 2012-03-21 | 2012-10-24 | 叶长青 | Spraying anchorage structure |
| CN103850688A (en) * | 2014-03-24 | 2014-06-11 | 昆明理工大学 | Method for dynamically superimposing coupling support on large-section roadway in complicated fault fracture zone |
| CN105134264A (en) * | 2015-06-29 | 2015-12-09 | 上海大屯能源股份有限公司 | Bolting and shotcrete net propping construction process |
| CN208252137U (en) * | 2018-05-08 | 2018-12-18 | 西安科技大学 | Based on the bump coal mine rectangle crossheading composite support system for unloading strong branch theory by force |
-
2020
- 2020-03-18 CN CN202010191777.6A patent/CN111379580A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19828503A1 (en) * | 1998-06-26 | 1999-12-30 | Seiz Tunnelausbau Systeme Gmbh | New design of support frame for air placed concrete shell to be used in mining or tunnel construction |
| CN201218105Y (en) * | 2008-05-28 | 2009-04-08 | 山西焦煤集团有限责任公司 | Mine tunnel digging support component |
| CN202500580U (en) * | 2012-03-21 | 2012-10-24 | 叶长青 | Spraying anchorage structure |
| CN103850688A (en) * | 2014-03-24 | 2014-06-11 | 昆明理工大学 | Method for dynamically superimposing coupling support on large-section roadway in complicated fault fracture zone |
| CN105134264A (en) * | 2015-06-29 | 2015-12-09 | 上海大屯能源股份有限公司 | Bolting and shotcrete net propping construction process |
| CN208252137U (en) * | 2018-05-08 | 2018-12-18 | 西安科技大学 | Based on the bump coal mine rectangle crossheading composite support system for unloading strong branch theory by force |
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Application publication date: 20200707 |