CN112855175A - Construction method suitable for initial support quick arch replacement of fractured rock mass tunnel - Google Patents
Construction method suitable for initial support quick arch replacement of fractured rock mass tunnel Download PDFInfo
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- 238000010276 construction Methods 0.000 title claims abstract description 72
- 239000011435 rock Substances 0.000 title claims abstract description 44
- 230000009545 invasion Effects 0.000 claims abstract description 20
- 238000000034 method Methods 0.000 claims abstract description 17
- 238000012544 monitoring process Methods 0.000 claims abstract description 13
- 230000008569 process Effects 0.000 claims abstract description 8
- 229910000831 Steel Inorganic materials 0.000 claims description 53
- 239000010959 steel Substances 0.000 claims description 53
- 230000003014 reinforcing effect Effects 0.000 claims description 15
- 239000004568 cement Substances 0.000 claims description 9
- 239000004567 concrete Substances 0.000 claims description 9
- 238000013461 design Methods 0.000 claims description 7
- 230000002787 reinforcement Effects 0.000 claims description 7
- 230000000694 effects Effects 0.000 claims description 6
- 238000005259 measurement Methods 0.000 claims description 6
- 238000012360 testing method Methods 0.000 claims description 5
- 229910001294 Reinforcing steel Inorganic materials 0.000 claims description 3
- 238000005422 blasting Methods 0.000 claims description 3
- 230000008859 change Effects 0.000 claims description 3
- 238000007689 inspection Methods 0.000 claims description 3
- 239000000463 material Substances 0.000 claims description 3
- 239000011378 shotcrete Substances 0.000 claims description 3
- 239000002002 slurry Substances 0.000 claims description 3
- 238000005507 spraying Methods 0.000 claims description 3
- 230000008520 organization Effects 0.000 claims description 2
- 238000005553 drilling Methods 0.000 description 4
- 238000009412 basement excavation Methods 0.000 description 2
- 239000004570 mortar (masonry) Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
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- 230000000149 penetrating effect Effects 0.000 description 1
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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
- E21D9/001—Improving soil or rock, e.g. by freezing; Injections
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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
- 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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- 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
- E21D9/001—Improving soil or rock, e.g. by freezing; Injections
- E21D9/002—Injection methods characterised by the chemical composition used
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Abstract
The invention discloses a construction method suitable for primary support quick arch replacement of a fractured rock mass tunnel, which comprises the following steps of: step one, determining an intrusion limit range and an intrusion limit degree; step two, radial grouting of the arch wall of the primary branch limit invasion section; step three, constructing a front arch; step four, dismantling the invasion limit primary support and surrounding rocks around the invasion limit primary support; fifthly, constructing the primary support structure again; step six, dismantling the advanced arch cover; step seven, completing the dismantling and replacing construction; and arranging observation points in the area where the tunnel arch is changed, wherein the steps from the first step to the seventh step are finished, monitoring the settlement and convergence of the arch crown at the characteristic position of the tunnel in the whole process, wherein the monitoring frequency is 2-3 times per day, and feeding back the deformation monitoring result of the initial support of the changed arch to construction technicians in time. The method has the advantages of high safety performance, good economy, strong operability and the like, and is suitable for arch replacement construction of primary support large deformation limit intrusion and overall replacement of the arch wall part of the fractured rock mass tunnel.
Description
Technical Field
The invention relates to the technical field of tunnel engineering, in particular to a construction method suitable for primary support quick arch replacement of a fractured rock mass tunnel.
Background
With the rapid advance of western development strategy, a large number of traffic tunnels are built in western mountainous areas in China. When construction is carried out by penetrating through complex strata, a large amount of tunnels have large deformation of surrounding rocks, so that a primary support structure of the tunnels invades a design limit of the tunnels, the clearance of the tunnels cannot meet the requirement, and arch changing treatment is required. The joint crack of the fractured rock mass is extremely developed, the spacing between structural planes is less than 0.2m and is generally more than 3 groups, the number of separated bodies is large, the overall strength is low, the joint crack is controlled by a weak plane, and compared with general weak surrounding rocks, the joint crack is more easily deformed greatly under the action of construction disturbance and is extremely unfavorable for tunnel construction and structural stress. The cracked rock mass is often the main reason for the large deformation disaster and the initial limit of invasion of the tunnel in the construction period.
The arch changing construction is an important method for solving the problem that primary support deformation is too large to invade a tunnel boundary, surrounding rocks and the primary support within an invasion limit range need to be dismantled, the surrounding rocks are excavated again to a design outline, a certain reserved deformation amount is considered, and then the primary support is constructed again. In general, in order to reduce the construction safety risk of arch replacement, each steel frame is divided into a plurality of units, each construction only carries out local blasting and chiseling on the units to be disassembled and replaced, and then the units are replaced one by one. By adopting the method for arch replacement construction, surrounding rocks cannot be effectively protected, the construction safety is difficult to guarantee, meanwhile, the construction procedure is trivial and complex, the construction efficiency is low, the construction period is prolonged, and the construction cost is increased. Therefore, in the process of tunnel arch-changing construction, how to realize rapid and safe replacement of the invasion-limiting primary support and give consideration to both construction safety and arch-changing efficiency becomes a problem which is closely concerned by the majority of engineering personnel.
Disclosure of Invention
The invention aims to provide a construction method suitable for quick arch replacement of primary support of a fractured rock mass tunnel, which is mainly applied to arch replacement construction of large deformation of a tunnel passing through a fractured rock mass stratum tunnel. Grouting reinforcement is carried out on the arch-changing section arch wall, advanced arch sheathing support is used for assisting, the safe proceeding of the arch-changing construction process is ensured, the whole steel frame is dismantled at one time, the primary support is rapidly constructed again, the support is sealed in time to form a ring, and the arch-changing construction efficiency is greatly improved; the method has the advantages of high safety performance, good economy, strong operability and the like, and is suitable for arch replacement construction of primary support large deformation limit invasion and overall replacement of an arch wall part of the fractured rock mass tunnel.
In order to achieve the purpose, the construction method suitable for the initial support quick arch replacement of the fractured rock mass tunnel provided by the invention comprises the following steps:
firstly, excavating to a water-rich weak surrounding rock section by adopting a step method;
excavating an upper step, quickly applying sprayed concrete, and performing advanced drilling at arch springing positions designed on two sides of an excavation surface by using a drilling machine;
step three, arranging small upper-step guide pipes, conveying the small guide pipes into the drill holes in the step two, performing grouting operation on the small guide pipes, condensing mortar of each small guide pipe and surrounding rock to form a stable structure, and forming first large arch feet on two sides of an excavation surface;
step four, completing upper portion supporting, and erecting a steel frame and a first lock anchor pipe by utilizing the first large arch springing formed in the step three to form a complete upper portion supporting system;
fifthly, excavating a lower step, and utilizing a drilling machine to perform advanced drilling at arch springing positions designed on two sides of the lower step to perform advanced geological forecast;
step six, arranging the small conduits of the lower step, conveying the small conduits into the drill holes in the step five, performing grouting operation on the small conduits, condensing mortar of each small conduit and surrounding rock to form a stable structure, and forming second large arch springing at two sides of the lower step;
step seven, completing lower support, and selecting and erecting a steel frame, a second foot-locking anchor pipe and a reinforcing mesh to construct by utilizing the second large arch foot formed in the step six to form a complete lower support system;
and step eight, excavating an inverted arch part, constructing an inverted arch support by using the second large arch foot formed in the step six, and backfilling the inverted arch.
Preferably, the concrete grouting embodiment is as follows:
grouting and reinforcing by adopting steel perforated pipes, wherein the steel perforated pipes are arranged in a staggered manner; the grouting material adopts cement slurry, the concrete grouting pressure is determined according to field tests, and the aggravation of primary support deformation caused by overlarge grouting pressure is avoided; the following principles should be followed during grouting:
the grouting pressure is gradually increased, reaches the designed final pressure value and is stable for more than 10 min; the grouting amount is close to the designed grouting amount, and the grouting amount is below 20-30L/min after grouting is finished; and after grouting reinforcement is completed, 2-3 inspection holes are arranged to inspect the grouting effect, so that the reinforced surrounding rock is basically stable and compact, and grouting should be performed if not.
Furthermore, the steel perforated pipes are arranged in a staggered mode, and the distance between every two steel perforated pipes is 0.8m in the longitudinal direction and 1.0m in the annular direction.
Further, the water cement ratio of the cement paste is 1: 0.8 and the grouting pressure is 0.3-0.5 MPa.
Further, the steel perforated pipe is
The steel flower tube is 4.5m in length.
Preferably, the mode of applying the advanced arching is as follows:
the distance between the front arch and the front end of the invasion limit primary support is a spacing distance, so that the demolition construction is not influenced, and the grouting reinforcement effect can be guaranteed; at least 2 super-front arch sleeves are arranged along the longitudinal direction of the tunnel, and adjacent super-front arch sleeves are longitudinally connected through reinforcing steel bars, so that the overall performance of the super-front arch sleeves is enhanced; the distance is reserved between the front arch sets, and the size of the distance is determined according to the field condition; when the super arch is constructed, the super arch is tightly attached to the intrusion limit primary support, and the bearing capacity of the super arch is fully exerted.
Further, the distance between the front cover arches is 0.5-1.0 m.
Further, the advanced sleeving arch adopts an I18 steel frame.
Further, the reserved deformation amount is 0-20 cm.
Preferably, the new primary support mainly comprises a steel frame, a reinforcing mesh and foot-locking anchor rods, wherein the foot-locking anchor rods are arranged at two ends of the steel frame, and a space is reserved between the steel frames; and the reinforcing mesh is connected with the steel frame, and the new closed primary support is formed by spraying concrete after the reinforcing mesh is arranged.
Compared with the prior art, the invention has the following technical effects:
1. the arch-replacing construction method has the advantages that the arch-replacing section arch wall is reinforced by grouting, and the advanced arch sheathing support is used as an auxiliary means, so that the safe proceeding of the arch-replacing construction process is ensured;
2. the invention demolishs the whole steel frame at one time, rapidly carries out primary support again, and the support is closed into a ring in time, thereby greatly improving the arch-changing construction efficiency;
3. the method is suitable for arch replacement construction of primary support large deformation limit intrusion and overall replacement of the arch wall part of the fractured rock mass tunnel;
4. the invention has the advantages of high safety performance, good economical efficiency, strong operability and the like.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.
FIG. 1 is a schematic view of an arch-changing cross-sectional structure of an embodiment;
FIG. 2 is a schematic structural diagram of an arch-changing longitudinal section of the embodiment;
FIG. 3 is a flow chart of arch replacement construction according to an embodiment;
icon: 1-grouting area, 2-no arch change section, 3-changed arch section, 4-to-be-changed arch section, 5-grouting hole, 6-surrounding rock, 7-steel perforated pipe, 8-advanced arch cover, 9-limited primary support, 10-original primary support and 11-locking anchor rod.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.
In the description of the embodiments of the present application, it should be noted that the indication of orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship which is usually placed when the product of the application is used, or the orientation or positional relationship which is usually understood by those skilled in the art, or the orientation or positional relationship which is usually placed when the product of the application is used, and is only for the convenience of describing the application and simplifying the description, but does not indicate or imply that the indicated device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the application. Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.
In the description of the embodiments of the present application, it should also be noted that, unless otherwise explicitly stated or limited, the terms "disposed," "mounted," and "connected" are to be construed broadly, and may for example be fixedly connected, detachably connected, or integrally connected; may be directly connected or indirectly connected through an intermediate. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.
Examples
A construction method suitable for primary support quick arch replacement of a fractured rock mass tunnel comprises the following steps:
firstly, determining an intrusion limit range and an intrusion limit degree, accurately testing vault settlement and convergence monitoring points in a section with larger deformation of a primary support of a tunnel by a construction unit organization field measurement technician through a section scanner or other monitoring and measuring equipment, and determining the intrusion limit range of the primary support according to the analysis of a measurement result to determine the specific intrusion limit degree of each part;
and step two, radial grouting is performed on the arch wall of the primary support limit-invasion section, assuming that the arch section replacement and filling are completely implemented, the tunnel bottom is not limited, and only the arch wall part needs to be disassembled and replaced. After the limit-invading section range and the limit-invading degree of the tunnel are determined and before the limit-invading structure is dismantled, one-time grouting reinforcement is needed to be carried out on surrounding rocks at the arch-changing full-section arch wall, so that the integral stability of a fractured rock mass is improved, and collapse and slip during dismantling construction are prevented. Grouting the arch wall of the radial invasion limit section by using a steel perforated pipe 7;
thirdly, constructing a front arch cover 8, and after the arch wall of the invasion limit section radially grouted by the steel perforated pipe 7 reaches the design strength, locally reinforcing the front arch cover 8 on the arch section 4 to be replaced before beginning to demolish the invasion limit primary support 9, so as to prevent local block falling and collapse caused by demolition construction;
step four, removing the invasion limit primary support 9 and surrounding rocks around the invasion limit primary support, after the step three is completed, comprehensively considering the distance between steel frames of the primary support 10, and performing full-section quick removal construction by matching methods of local weak blasting, breaking hammer removal, manual cutting and the like, removing the invasion limit primary support 9 and the surrounding rocks around the invasion limit primary support, wherein only one steel frame is removed each time, and in the removal construction process, the invasion limit primary support is removed to a design contour through measurement and lofting, and deformation is reserved;
fifthly, constructing the primary support structure again, and performing primary support construction again in time after the step four is completed, and replacing a new primary support;
step six, dismantling the advanced cover arch 8 when the strength of primary sprayed concrete reaches more than 90% of the design strength after the dismantling and replacing construction of the previous trestle of the intrusion structure is completed, eliminating the influence of the advanced cover arch 8 on the dismantling and replacing construction of the next trestle of the arch, and simultaneously constructing the advanced cover arch 8 on the next trestle as required;
step seven, dismantling and replacing construction is completed, the step three to the step six are circulated, roof trusses needing to be replaced are dismantled and replaced one by one until full-section arch replacing construction is completed;
and arranging observation points in the area where the tunnel arch is changed, wherein the steps from the first step to the seventh step are finished, monitoring the settlement and convergence of the arch crown at the characteristic position of the tunnel in the whole process, wherein the monitoring frequency is 2-3 times per day, and feeding back the deformation monitoring result of the initial support of the changed arch to construction technicians in time.
The concrete grouting embodiment is as follows:
grouting and reinforcing by using steel perforated pipes 7, wherein the steel perforated pipes 7 are arranged in a staggered manner; the grouting material adopts cement slurry, the concrete grouting pressure is determined according to field tests, and the aggravation of primary support deformation caused by overlarge grouting pressure is avoided; the following principles should be followed during grouting:
the grouting pressure is gradually increased, reaches the designed final pressure value and is stable for more than 10 min; the grouting amount is close to the designed grouting amount, and the grouting amount is below 20-30L/min after grouting is finished; and after grouting reinforcement is completed, 2-3 inspection holes are arranged to inspect the grouting effect, so that the reinforced surrounding rock is basically stable and compact, and grouting should be performed if not.
The steel perforated pipes 7 are arranged in a staggered mode, and the distance between every two steel perforated pipes 7 is 0.8m in the longitudinal direction and 1.0m in the circumferential direction.
The water-cement ratio of the cement paste is 1: 0.8 and the grouting pressure is 0.3-0.5 MPa.
The steel perforated pipe 7 is
The steel perforated pipe 7 is 4.5m in length.
The mode of constructing the front arch 8 is as follows:
a spacing distance is reserved between the front end of the advanced sleeve arch 8 and the front end of the invasion limit primary support 9, the spacing distance between the front end of the advanced sleeve arch and the front end of the invasion limit primary support is 0.5-0.8 m, demolition construction is not influenced, and grouting reinforcement effect can be guaranteed; at least 2 super front arch covers 8 are arranged along the longitudinal direction of the tunnel, and the adjacent super front arch covers 8 are longitudinally connected through reinforcing steel bars, so that the overall performance of the super front arch covers 8 is enhanced; the distance is reserved between the front arch 8 and is determined according to the field condition; when the front arch 8 is constructed, the front arch is tightly attached to the intrusion limit primary support 9, and the bearing capacity of the front arch 8 is fully exerted.
The distance between the front cover arches 8 is 0.5-0.8 m.
The forward arch 8 is made of I18 steel frame.
The reserved deformation amount is 0-20 cm.
The new primary support mainly comprises a steel frame, a steel bar mesh and foot-locking anchor rods 11, wherein the foot-locking anchor rods 11 are arranged at two ends of the steel frame, and a space is reserved between the steel frames; the reinforcing mesh is connected with the steel frame, a new primary support is formed by spraying concrete after the reinforcing mesh is arranged, and the new primary support steel frame is an I22b steel frameThe distance is 0.8m, and the reinforcing mesh is adopted
The hot-rolled plain steel bar is made of a locking pin anchor rod pipe
The steel tube had a length of 4.5 m.
The present invention is capable of other embodiments, and various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention.
Claims (10)
1. A construction method suitable for initial support quick arch replacement of a fractured rock mass tunnel is characterized by comprising the following steps:
firstly, determining an intrusion limit range and an intrusion limit degree, accurately testing vault settlement and convergence monitoring points in a section with larger deformation of a primary support of a tunnel by a construction unit organization field measurement technician through a section scanner or other monitoring and measuring equipment, and determining the intrusion limit range of the primary support according to the analysis of a measurement result to determine the specific intrusion limit degree of each part;
step two, radially grouting the arch wall of the primary support limit-invasion section, after determining the tunnel limit-invasion range and the limit-invasion degree, grouting and reinforcing the surrounding rock at the arch-change full-section arch wall, and radially grouting the arch wall of the limit-invasion section by adopting a steel perforated pipe;
constructing a front arch sleeve, after the arch wall of the invasion limit section is grouted radially through a steel perforated pipe to reach the design strength, constructing the front arch sleeve on the arch section to be replaced, and enabling the inner side of the invasion limit primary support of the front arch sleeve to be tightly attached to the invasion limit primary support;
step four, removing the primary support and surrounding rocks around the primary support, after the step three is completed, comprehensively considering the space between the original primary support steel frames, and performing full-section quick removal construction by matching methods of local weak blasting, breaking hammer removal, manual cutting and the like, removing the primary support and the surrounding rocks around the primary support steel frames, wherein only one steel frame is removed each time, and in the removal construction process, the primary support and the surrounding rocks around the primary support steel frames are removed to the designed contour through measurement and lofting, and the deformation is reserved;
fifthly, constructing the primary support structure again, performing primary support construction again in time after the step four is completed, replacing the new primary support, and arranging corresponding observation points;
step six, dismantling the advanced arch when the strength of primary sprayed concrete reaches more than 90% of the design strength after dismantling and replacing the previous truss of intrusion structure, eliminating the influence of the advanced arch on dismantling and replacing construction of the next truss, and simultaneously constructing the advanced arch for the next truss as required;
step seven, dismantling and replacing construction is completed, the step three to the step six are circulated, roof trusses needing to be replaced are dismantled and replaced one by one until full-section arch replacing construction is completed;
and arranging observation points in the area where the tunnel arch is changed, wherein the steps from the first step to the seventh step are finished, monitoring the settlement and convergence of the arch crown at the characteristic position of the tunnel in the whole process, wherein the monitoring frequency is 2-3 times per day, and feeding back the deformation monitoring result of the initial support of the changed arch to construction technicians in time.
2. The construction method suitable for the initial support quick arch replacement of the fractured rock mass tunnel according to claim 1 is characterized in that the concrete grouting implementation mode is as follows:
grouting and reinforcing by adopting steel perforated pipes, wherein the steel perforated pipes are arranged in a staggered manner; the grouting material adopts cement slurry, the concrete grouting pressure is determined according to field tests, and the aggravation of primary support deformation caused by overlarge grouting pressure is avoided; the following principles should be followed during grouting:
the grouting pressure is gradually increased, reaches the designed final pressure value and is stable for more than 10 min; the grouting amount is close to the designed grouting amount, and the grouting amount is below 20-30L/min after grouting is finished; and after grouting reinforcement is completed, 2-3 inspection holes are arranged to inspect the grouting effect, so that the reinforced surrounding rock is basically stable and compact, and grouting should be performed if not.
3. The construction method suitable for the initial support quick arch replacement of the fractured rock mass tunnel according to claim 2, wherein the construction method comprises the following steps: the steel perforated pipe has a plurality of, and the interval between a plurality of steel perforated pipes is according to vertical 0.8m, and the hoop is 1.0m staggered arrangement.
4. The construction method suitable for the initial support quick arch replacement of the fractured rock mass tunnel according to claim 2, wherein the construction method comprises the following steps: the water-cement ratio of the cement paste is 1: 0.8 and the grouting pressure is 0.3-0.5 MPa.
5. The construction method suitable for the initial support quick arch change of the fractured rock mass tunnel according to claim 1, 2 or 3, wherein the construction method comprises the following steps: the steel perforated pipe is
The steel flower tube is 4.5m in length.
6. The construction method suitable for the initial support quick arch replacement of the fractured rock mass tunnel according to claim 1, wherein the mode of constructing the advanced arch is as follows:
a spacing distance is reserved between the front arch and the front end of the intrusion limit primary support; at least 2 super front arch brackets are arranged along the longitudinal direction of the tunnel, and adjacent super front arch brackets are longitudinally connected through reinforcing steel bars; the distance is reserved between the front arch sets, and the size of the distance is determined according to the field condition; when the front arch is constructed, the front arch is tightly attached to the intrusion limit primary support.
7. The construction method suitable for the initial support quick arch replacement of the fractured rock mass tunnel according to claim 6, wherein the construction method comprises the following steps: the distance between the front cover arches is 0.5-1.0 m.
8. The construction method suitable for the initial support quick arch change of the fractured rock mass tunnel according to claim 1, 6 or 7, wherein the construction method comprises the following steps: the advanced cover arch adopts an I18 steel frame.
9. The construction method suitable for the initial support quick arch replacement of the fractured rock mass tunnel according to claim 1, wherein the construction method comprises the following steps: the reserved deformation amount is 0-20 cm.
10. The construction method suitable for the initial support quick arch replacement of the fractured rock mass tunnel according to claim 1, wherein the construction method comprises the following steps: the new primary support mainly comprises a steel frame, a reinforcing mesh and foot locking anchor rods, wherein the foot locking anchor rods are arranged at two ends of the steel frame, and a space is reserved between the steel frames; and the reinforcing mesh is connected with the steel frame, and the new closed primary support is formed by spraying concrete after the reinforcing mesh is arranged.
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| CN106869960A (en) * | 2017-03-09 | 2017-06-20 | 洛阳理工学院 | The movement that a kind of tunnel initial support invades limit section is changed arch device and its changes arch method |
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| CN110656959A (en) * | 2019-10-31 | 2020-01-07 | 中铁二十局集团有限公司 | Large-section loess tunnel primary support limit-invasion arch-changing construction method |
| CN110700860A (en) * | 2019-11-20 | 2020-01-17 | 中铁二十局集团有限公司 | Construction method of soil-stone boundary tunnel crossing loess valley |
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