CN117365537A - Construction method for improving stability of tunnel portal easy to collapse - Google Patents
Construction method for improving stability of tunnel portal easy to collapse Download PDFInfo
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- CN117365537A CN117365537A CN202311386331.9A CN202311386331A CN117365537A CN 117365537 A CN117365537 A CN 117365537A CN 202311386331 A CN202311386331 A CN 202311386331A CN 117365537 A CN117365537 A CN 117365537A
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- 238000010276 construction Methods 0.000 title claims abstract description 65
- 238000000034 method Methods 0.000 claims abstract description 28
- 239000002689 soil Substances 0.000 claims abstract description 13
- 238000001514 detection method Methods 0.000 claims abstract description 5
- 238000012544 monitoring process Methods 0.000 claims description 41
- 238000004873 anchoring Methods 0.000 claims description 15
- 230000008569 process Effects 0.000 claims description 15
- 229910000831 Steel Inorganic materials 0.000 claims description 12
- 239000011435 rock Substances 0.000 claims description 12
- 239000010959 steel Substances 0.000 claims description 12
- 239000004575 stone Substances 0.000 claims description 9
- 230000001680 brushing effect Effects 0.000 claims description 8
- 230000008859 change Effects 0.000 claims description 8
- 238000006073 displacement reaction Methods 0.000 claims description 8
- 239000000463 material Substances 0.000 claims description 8
- 238000005516 engineering process Methods 0.000 claims description 5
- 239000011150 reinforced concrete Substances 0.000 claims description 5
- 239000000853 adhesive Substances 0.000 claims description 4
- 238000009412 basement excavation Methods 0.000 claims description 4
- 239000011449 brick Substances 0.000 claims description 4
- 239000004568 cement Substances 0.000 claims description 4
- 239000004927 clay Substances 0.000 claims description 4
- 239000004567 concrete Substances 0.000 claims description 4
- 238000009792 diffusion process Methods 0.000 claims description 4
- 230000000694 effects Effects 0.000 claims description 4
- 239000004570 mortar (masonry) Substances 0.000 claims description 4
- 239000004745 nonwoven fabric Substances 0.000 claims description 4
- 230000003014 reinforcing effect Effects 0.000 claims description 4
- 238000004062 sedimentation Methods 0.000 claims description 4
- 230000035945 sensitivity Effects 0.000 claims description 4
- 230000003068 static effect Effects 0.000 claims description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 4
- 238000005507 spraying Methods 0.000 abstract description 2
- 230000009471 action Effects 0.000 description 3
- 230000002787 reinforcement Effects 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000007774 longterm Effects 0.000 description 2
- 230000004075 alteration Effects 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 239000011378 shotcrete Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Classifications
-
- 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
- E21D9/14—Layout of tunnels or galleries; Constructional features of tunnels or galleries, not otherwise provided for, e.g. portals, day-light attenuation at tunnel openings
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/04—Lining with building materials
- E21D11/10—Lining with building materials with concrete cast in situ; Shuttering also lost shutterings, e.g. made of blocks, of metal plates or other equipment adapted therefor
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/38—Waterproofing; Heat insulating; Soundproofing; Electric insulating
- E21D11/381—Setting apparatus or devices
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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)
- Environmental & Geological Engineering (AREA)
- Devices Affording Protection Of Roads Or Walls For Sound Insulation (AREA)
Abstract
The invention discloses a construction method for improving stability of a tunnel portal easy to collapse, and relates to the technical field of tunnel portal engineering construction. The construction method for improving the stability of the tunnel portal easy to collapse comprises the following specific operations: s1, researching the strength parameters and the stratum distribution of a slope rock-soil body according to survey design data; s2, selecting a typical section of the high steep slope, properly simplifying the slope stratum according to geological data, and establishing a three-dimensional calculation model and natural slope stability detection by adopting FLAC3D software. According to the construction method for improving the stability of the tunnel portal easy to collapse, when the slope of the tunnel portal is stable, the problem can be solved by adopting the traditional anchor spraying support. However, when the tunnel portal is high and steep and extremely unstable, the stratum coverage is complex, the slope collapse and deformation can be well controlled by adopting the method, the range of the slope in a critical state and the instability are greatly reduced, and the stability of the tunnel portal is well protected.
Description
Technical Field
The invention relates to the technical field of tunnel portal engineering construction, in particular to a construction method for improving stability of a tunnel portal easy to collapse.
Background
In the tunnel construction process, the tunnel portal inevitably presents high-steep side slopes, the reinforcement treatment of the high-steep side slopes is the first problem to be solved, and particularly, the ground surface of part of the high-steep side slopes is covered with complex deposit stratum, so that the tunnel construction and later operation safety are seriously affected. The stability of the high steep slope at the upper part and the reliability of the reinforcement monitoring measure determine the safety of long-term operation of the open cut tunnel and the line to a great extent, and meanwhile, the track of the falling rocks of the slope influences the lengthening length of the open cut tunnel; the size of the falling rock impact force determines the thickness of the open cut tunnel backfill layer and the strength of the open cut tunnel structure;
in railway tunnel engineering construction, water prevention and drainage of open cut tunnel sections are very important construction contents. And most tunnel open cut tunnel sections are waterproof weak areas, so that the requirements on the waterproof and drainage construction quality are high.
Therefore, in order to ensure that the water-proof construction quality of the open cut tunnel section meets the design scheme requirements, the technical key points of each stage of the water-proof construction are required to be analyzed and effective control measures are adopted so as to ensure that the water-proof construction quality meets the national standard and meets the later use requirements.
Disclosure of Invention
(one) solving the technical problems
Aiming at the defects of the prior art, the invention provides a construction method for improving the stability of the tunnel portal which is easy to collapse, and solves the problem that the water-proof and drainage of the open cut tunnel section is very important construction content in the railway tunnel engineering construction. And most tunnel open cut tunnel sections are waterproof weak areas, so that the problem of high requirements on waterproof and drainage construction quality is solved.
(II) technical scheme
In order to achieve the above purpose, the invention is realized by the following technical scheme: the construction method for improving the stability of the tunnel portal easy to collapse comprises the following specific operations:
s1, researching the strength parameters and the stratum distribution of a slope rock-soil body according to survey design data;
s2, selecting a typical section of the high steep slope, properly simplifying the slope stratum according to geological data, and establishing a three-dimensional calculation model by adopting FLAC3D software to perform natural slope stability detection;
s3, adopting brushing side load shedding and slope support design construction;
s4, a deformation monitoring system is established on the high slope surface at the upper part of the whole open cut tunnel, and tunnel slope monitoring construction is carried out;
s5, leading the pipe shed, and carrying out subsequent tunnel excavation supporting and other construction;
s6, lengthening construction is adopted by adopting open cut tunnel to prevent falling rocks;
s7, water-proof and drainage construction of the open cut tunnel.
Preferably, in step S3, the concrete operation of the slope support construction process is as follows:
s31, arranging a pre-reinforcing pile outside a tunnel body, wherein the length of a pile body anchoring tunnel bedrock is not less than 10m, and the pile body adopts a square pile;
s32, arranging a pre-stressed anchor cable at a position 2 meters below the pile top, wherein the anchoring length of the pre-stressed anchor cable is not less than 10m, and the included angle between the anchor cable and the horizontal plane is 20 degrees;
s33, grading and brushing slopes, wherein each 8 meters is one-level, and the grading platform is 1 meter wide;
s34, arranging prestress anchor cable frame beams on the slope, wherein the distance between the prestress anchor cable frame beams is 4*4m, and the frame beams are embedded into the slope by 0.3 m;
s35, arranging a pre-stress anchor cable at the joints of the frame beams, wherein the anchoring length of the pre-stress anchor cable is not less than 10 meters, and the horizontal included angle is 20 degrees.
Preferably, in step S4, the specific operation of the tunnel slope monitoring construction process is as follows:
the deformation monitoring system is built on the slope surface of the high slope at the upper part of the open cut tunnel, 6 monitoring points are arranged on the slope in total, the deformation monitoring system is located at the frame beam nodes, 2 in each layer and 3 in each layer and is used for monitoring deformation displacement conditions of the slope platform and the top of the slope. The monitoring section is provided with an anchor rope meter at a representative position, is buried at the anchor head of the pre-stressed anchor rope and is used for monitoring the change of the pre-stress of the anchor rope, the intelligent multi-string type steel strand is adopted according to the number of the steel strands, the measuring range is 400-600KN according to the anchoring force, and the sensitivity is 0.1KN. To accurately monitor the sedimentation change of the transverse section of the side slope platform, a static level gauge is buried at the side slope platform of the monitoring section. In order to measure the deep sliding of the side slope, 3 displacement meters are arranged along the surface of the side slope, the burying depth is larger than the length of the anchor cable, and the data of each sensor are accessed into an automatic acquisition system.
Preferably, in step S7, the specific operation of the tunnel open cut tunnel water-proof and drainage construction process is as follows:
the method comprises the steps of sequentially constructing a 2mm cement-based permeable crystalline waterproof material, a 3cm thick M10 mortar leveling layer, a self-adhesive waterproof board, geotechnical non-woven fabrics, a 6cm rear brick protection layer, a backfill soil layer and a 50cm thick clay water-resisting layer on a reinforced concrete lining of an open cut tunnel, so that flowing water naturally flows into a roof drainage ditch. The thickness of the backfill buffer soil layer at the upper part of the open cut tunnel should comprehensively consider the safety, the technology and the economical efficiency of nearby available earth and stone materials, and because of the attenuation and diffusion effect of the impact force of falling rocks, the thickness of the backfill buffer layer is not thicker and better, when the general drop distance is 50-100 meters and the wedge body scale is within 1.5 cubic meters, the thickness of the backfill layer of broken stone earth at the upper part of the open cut tunnel is not more than 4 meters, and the thickness can be controlled according to 2-4 meters, so that the load and the deformation of the open cut tunnel structure are prevented from being increased by the excessively thick backfill layer.
(III) beneficial effects
The invention provides a construction method for improving stability of a tunnel portal easy to collapse. The beneficial effects are as follows:
according to the construction method for improving the stability of the tunnel portal easy to collapse, when the slope of the tunnel portal is stable, the problem can be solved by adopting the traditional anchor spraying support. However, when the tunnel portal is high and steep and extremely unstable, the stratum coverage is complex, the slope collapse and deformation can be well controlled by adopting the method, the range of the slope in a critical state and the instability are greatly reduced, and the stability of the tunnel portal is well protected. The method for lengthening the open cut tunnel by adopting the fine falling rocks can play an important role in protecting the safety of road operation, and the method can better prolong the service life of the tunnel by carrying out water-proof treatment on the open cut tunnel of the tunnel, can not easily cause road surface icing in frozen areas, and can well ensure the driving safety.
Drawings
FIG. 1 is a flow chart of the construction method of the present invention;
FIG. 2 is a tunnel portal side slope support design of the present invention;
fig. 3 is a plan view of the tunnel open cut tunnel water-proof construction.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 1-3, the present invention provides a technical solution: the construction method for improving the stability of the tunnel portal easy to collapse comprises the following specific operations:
s1, researching the strength parameters and the stratum distribution of a slope rock-soil body according to survey design data;
s2, selecting a typical section of the high steep slope, properly simplifying the slope stratum according to geological data, and establishing a three-dimensional calculation model by adopting FLAC3D software to perform natural slope stability detection;
s3, adopting brushing load-shedding and slope support design construction, wherein the concrete operation of the slope support construction process is as follows:
s31, arranging a pre-reinforcing pile outside a tunnel body, wherein the length of a pile body anchoring tunnel bedrock is not less than 10m, and the pile body adopts a square pile;
s32, arranging a pre-stressed anchor cable at a position 2 meters below the pile top, wherein the anchoring length of the pre-stressed anchor cable is not less than 10m, and the included angle between the anchor cable and the horizontal plane is 20 degrees;
s33, grading and brushing slopes, wherein each 8 meters is one-level, and the grading platform is 1 meter wide;
s34, arranging prestress anchor cable frame beams on the slope, wherein the distance between the prestress anchor cable frame beams is 4*4m, and the frame beams are embedded into the slope by 0.3 m;
s35, arranging a pre-stress anchor cable at the joints of the frame beams, wherein the anchoring length of the pre-stress anchor cable is not less than 10 meters, and the horizontal included angle is 20 degrees;
s4, a deformation monitoring system is established on the high slope surface at the upper part of the open cut tunnel, and tunnel slope monitoring construction is carried out, wherein the concrete operation of the tunnel slope monitoring construction technology is as follows:
the deformation monitoring system is built on the slope surface of the high slope at the upper part of the open cut tunnel, 6 monitoring points are arranged on the slope in total, the deformation monitoring system is located at the frame beam nodes, 2 in each layer and 3 in each layer and is used for monitoring deformation displacement conditions of the slope platform and the top of the slope. The monitoring section is provided with an anchor rope meter at a representative position, is buried at the anchor head of the pre-stressed anchor rope and is used for monitoring the change of the pre-stress of the anchor rope, the intelligent multi-string type steel strand is adopted according to the number of the steel strands, the measuring range is 400-600KN according to the anchoring force, and the sensitivity is 0.1KN. To accurately monitor the sedimentation change of the transverse section of the side slope platform, a static level gauge is buried at the side slope platform of the monitoring section. In order to measure the deep sliding of the side slope, 3 displacement meters are arranged along the surface of the side slope, the burying depth is larger than the length of the anchor cable, and the data of each sensor are accessed into an automatic acquisition system;
s5, leading the pipe shed, and carrying out subsequent tunnel excavation supporting and other construction;
s6, lengthening construction is adopted by adopting open cut tunnel to prevent falling rocks;
s7, tunnel open cut tunnel water-proof construction, wherein the tunnel open cut tunnel water-proof construction process comprises the following specific operations:
the method comprises the steps of sequentially constructing a 2mm cement-based permeable crystalline waterproof material, a 3cm thick M10 mortar leveling layer, a self-adhesive waterproof board, geotechnical non-woven fabrics, a 6cm rear brick protection layer, a backfill soil layer and a 50cm thick clay water-resisting layer on a reinforced concrete lining of an open cut tunnel, so that flowing water naturally flows into a roof drainage ditch. The thickness of the backfill buffer soil layer at the upper part of the open cut tunnel should comprehensively consider the safety, the technology and the economical efficiency of nearby available earth and stone materials, and because of the attenuation and diffusion effect of the impact force of falling rocks, the thickness of the backfill buffer layer is not thicker and better, when the general drop distance is 50-100 meters and the wedge body scale is within 1.5 cubic meters, the thickness of the backfill layer of broken stone earth at the upper part of the open cut tunnel is not more than 4 meters, and the thickness can be controlled according to 2-4 meters, so that the load and the deformation of the open cut tunnel structure are prevented from being increased by the excessively thick backfill layer.
Examples:
example 1
As shown in fig. 1, is an embodiment of the present invention.
A construction method for improving stability of a tunnel portal easy to collapse comprises the following steps:
step 1, researching the strength parameters and stratum distribution of a slope rock-soil body according to survey design data;
step 2, selecting a typical section of the high steep slope, properly simplifying the slope stratum according to geological data, and establishing a three-dimensional calculation model by adopting FLAC3D software to perform natural slope stability detection;
step 3, adopting a brushing side load-reducing and slope support design and performing construction;
step 4, a deformation monitoring system is established on the slope surface of the high slope at the upper part of the whole open cut tunnel;
step 5, leading pipe shed, subsequent tunnel excavation supporting and other construction;
step 6, lengthening construction by adopting open cut tunnel to prevent falling rocks;
step 7, tunnel open cut tunnel waterproof and drainage construction;
example 2
In a further technical scheme, the slope support construction process comprises the following steps:
and pre-reinforcing piles are arranged at the position 3m outside the open cut tunnel body of the tunnel, the pile spacing is 5m, the pile length is 25.0m, the pile body is anchored into bedrock to be not less than 10m, and the section size of the pile is 1 x 2m. And a prestressed anchor cable is arranged at the position 2.0m below the pile top, the length of the anchor cable is 45m, the length of the anchoring section is 10m, and the included angle between the anchor cable and the horizontal plane is 20 degrees. The anchor cable is made of 8 steel strands with the diameter of 15.2mm and high strength and low relaxation, the strength of the steel strands is 1860MPa, and the locking tension of the anchor cable is 400kN. The slope brushing is carried out on the slope at the upper part of the pre-reinforced pile in a grading manner, and the slope rate of the slope is 1:1, every 8m level; grading a 1m wide platform, arranging a prestress anchor cable frame beam on a slope, wherein the section size of the frame beam is 0.4mX0.4m, and casting C30 reinforced concrete on site; the anchor cable spacing is 4 x 4m, and the embedded side slope is 0.3m. The frame beam node is provided with a prestressed anchor cable, the anchor cable is made of 4 steel strands with the diameter of 15.2mm and high strength and low relaxation, the strength of the steel strands is 1860MPa, the length of the anchor cable is 14.0-22.0 m, the length of an anchoring section is 10m, the length of a free end is 4-12 m, and the included angle between the anchor cable and the horizontal plane is 20 degrees.
Example 3
In a further technical scheme, the tunnel slope monitoring construction process comprises the following steps:
in order to ensure the long-term safety of construction and operation, a deformation monitoring system is established on the high slope surface at the upper part of the whole open cut tunnel, 6 monitoring points are arranged on the slope in total, the deformation monitoring system is positioned at the nodes of the frame girder, each layer is 2, and the deformation monitoring system is arranged in 3 layers and is used for monitoring deformation displacement conditions of the slope platform and the top of the slope. The monitoring section is provided with an anchor rope meter at a representative position, is buried at the anchor head of the pre-stressed anchor rope and is used for monitoring the change of the pre-stress of the anchor rope, the intelligent multi-string type steel strand is adopted according to the number of the steel strands, the measuring range is 400-600KN according to the anchoring force, and the sensitivity is 0.1KN. To accurately monitor the sedimentation change of the transverse section of the side slope platform, a static level gauge is buried at the side slope platform of the monitoring section. In order to measure the deep sliding of the side slope, 3 displacement meters are arranged along the surface of the side slope, the burying depth is larger than the length of the anchor cable, and the data of each sensor are accessed into an automatic acquisition system.
Example 4
In a further technical scheme, the open cut tunnel waterproof and drainage construction process comprises the following steps:
2mm cement-based permeable crystalline waterproof material, a 3cm thick M10 mortar leveling layer, a self-adhesive waterproof board, geotechnical non-woven fabrics, a 6cm rear brick protection layer, a backfill soil layer and a 50cm thick clay waterproof layer are sequentially constructed on the open cut tunnel reinforced concrete lining. The thickness of the backfill buffer soil layer at the upper part of the open cut tunnel should comprehensively consider the safety, the technology and the economical efficiency of nearby available earth and stone materials, and because of the attenuation and diffusion effect of the impact force of falling rocks, the thickness of the backfill buffer layer is not thicker and better, when the general drop distance is 50-100 meters and the wedge body scale is within 1.5 cubic meters, the thickness of the backfill layer of broken stone earth at the upper part of the open cut tunnel is not more than 4 meters, and the thickness can be controlled according to 2-4 meters, so that the load and the deformation of the open cut tunnel structure are prevented from being increased by the excessively thick backfill layer.
The construction process of the frame anchor cable pre-reinforcement is adopted, the protection of the slope which is easy to collapse can be well processed, the overall control of the slope is achieved, the method of lengthening the open cut tunnel for broken stone rolling is important for protecting the road operation, the water-proof and drainage treatment of the open cut tunnel can be better carried out, the service life of the tunnel can be better prolonged, the road surface is not easy to freeze in frozen areas, and the driving safety can be well ensured.
In summary, according to the construction method for improving the stability of the tunnel portal easy to collapse, when the slope of the tunnel portal is stable, the problem can be solved by adopting the traditional shotcrete support. However, when the tunnel portal is high and steep and extremely unstable, the stratum coverage is complex, the slope collapse and deformation can be well controlled by adopting the method, the range of the slope in a critical state and the instability are greatly reduced, and the stability of the tunnel portal is well protected. The method for lengthening the open cut tunnel by adopting the fine falling rocks can play an important role in protecting the safety of road operation, and the method can better prolong the service life of the tunnel by carrying out water-proof treatment on the open cut tunnel of the tunnel, can not easily cause road surface icing in frozen areas, and can well ensure the driving safety.
It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (4)
1. A construction method for improving stability of a tunnel portal easy to collapse is characterized by comprising the following steps: the specific operation is as follows:
s1, researching the strength parameters and the stratum distribution of a slope rock-soil body according to survey design data;
s2, selecting a typical section of the high steep slope, properly simplifying the slope stratum according to geological data, and establishing a three-dimensional calculation model by adopting FLAC3D software to perform natural slope stability detection;
s3, adopting brushing side load shedding and slope support design construction;
s4, a deformation monitoring system is established on the high slope surface at the upper part of the whole open cut tunnel, and tunnel slope monitoring construction is carried out;
s5, leading the pipe shed, and carrying out subsequent tunnel excavation supporting and other construction;
s6, lengthening construction is adopted by adopting open cut tunnel to prevent falling rocks;
s7, water-proof and drainage construction of the open cut tunnel.
2. The construction method for improving the stability of the tunnel portal easy to collapse according to claim 1, which is characterized by comprising the following steps: in step S3, the concrete operation of the slope support construction process is as follows:
s31, arranging a pre-reinforcing pile outside a tunnel body, wherein the length of a pile body anchoring tunnel bedrock is not less than 10m, and the pile body adopts a square pile;
s32, arranging a pre-stressed anchor cable at a position 2 meters below the pile top, wherein the anchoring length of the pre-stressed anchor cable is not less than 10m, and the included angle between the anchor cable and the horizontal plane is 20 degrees;
s33, grading and brushing slopes, wherein each 8 meters is one-level, and the grading platform is 1 meter wide;
s34, arranging prestress anchor cable frame beams on the slope, wherein the distance between the prestress anchor cable frame beams is 4*4m, and the frame beams are embedded into the slope by 0.3 m;
s35, arranging a pre-stress anchor cable at the joints of the frame beams, wherein the anchoring length of the pre-stress anchor cable is not less than 10 meters, and the horizontal included angle is 20 degrees.
3. The construction method for improving the stability of the tunnel portal easy to collapse according to claim 1, which is characterized by comprising the following steps: in step S4, the specific operation of the tunnel slope monitoring construction process is as follows:
the deformation monitoring system is built on the slope surface of the high slope at the upper part of the open cut tunnel, 6 monitoring points are arranged on the slope in total, the deformation monitoring system is located at the frame beam nodes, 2 in each layer and 3 in each layer and is used for monitoring deformation displacement conditions of the slope platform and the top of the slope. The monitoring section is provided with an anchor rope meter at a representative position, is buried at the anchor head of the pre-stressed anchor rope and is used for monitoring the change of the pre-stress of the anchor rope, the intelligent multi-string type steel strand is adopted according to the number of the steel strands, the measuring range is 400-600KN according to the anchoring force, and the sensitivity is 0.1KN. To accurately monitor the sedimentation change of the transverse section of the side slope platform, a static level gauge is buried at the side slope platform of the monitoring section. In order to measure the deep sliding of the side slope, 3 displacement meters are arranged along the surface of the side slope, the burying depth is larger than the length of the anchor cable, and the data of each sensor are accessed into an automatic acquisition system.
4. The construction method for improving the stability of the tunnel portal easy to collapse according to claim 1, which is characterized by comprising the following steps: in step S7, the specific operation of the tunnel open cut tunnel waterproof and drainage construction process is as follows:
the method comprises the steps of sequentially constructing a 2mm cement-based permeable crystalline waterproof material, a 3cm thick M10 mortar leveling layer, a self-adhesive waterproof board, geotechnical non-woven fabrics, a 6cm rear brick protection layer, a backfill soil layer and a 50cm thick clay water-resisting layer on a reinforced concrete lining of an open cut tunnel, so that flowing water naturally flows into a roof drainage ditch. The thickness of the backfill buffer soil layer at the upper part of the open cut tunnel should comprehensively consider the safety, the technology and the economical efficiency of nearby available earth and stone materials, and because of the attenuation and diffusion effect of the impact force of falling rocks, the thickness of the backfill buffer layer is not thicker and better, when the general drop distance is 50-100 meters and the wedge body scale is within 1.5 cubic meters, the thickness of the backfill layer of broken stone earth at the upper part of the open cut tunnel is not more than 4 meters, and the thickness can be controlled according to 2-4 meters, so that the load and the deformation of the open cut tunnel structure are prevented from being increased by the excessively thick backfill layer.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311386331.9A CN117365537A (en) | 2023-10-25 | 2023-10-25 | Construction method for improving stability of tunnel portal easy to collapse |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202311386331.9A CN117365537A (en) | 2023-10-25 | 2023-10-25 | Construction method for improving stability of tunnel portal easy to collapse |
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| CN117365537A true CN117365537A (en) | 2024-01-09 |
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| CN202311386331.9A Pending CN117365537A (en) | 2023-10-25 | 2023-10-25 | Construction method for improving stability of tunnel portal easy to collapse |
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- 2023-10-25 CN CN202311386331.9A patent/CN117365537A/en active Pending
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