CN116044418A - Soft rock tunnel excavation reinforcement deformation control construction method - Google Patents
Soft rock tunnel excavation reinforcement deformation control construction method Download PDFInfo
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- CN116044418A CN116044418A CN202310063247.7A CN202310063247A CN116044418A CN 116044418 A CN116044418 A CN 116044418A CN 202310063247 A CN202310063247 A CN 202310063247A CN 116044418 A CN116044418 A CN 116044418A
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- 238000010276 construction Methods 0.000 title claims abstract description 121
- 238000009412 basement excavation Methods 0.000 title claims abstract description 79
- 239000011435 rock Substances 0.000 title claims abstract description 48
- 230000002787 reinforcement Effects 0.000 title claims abstract description 21
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 65
- 239000010959 steel Substances 0.000 claims abstract description 65
- 238000007596 consolidation process Methods 0.000 claims abstract description 7
- 239000011378 shotcrete Substances 0.000 claims abstract description 4
- 239000004567 concrete Substances 0.000 claims description 42
- 238000009434 installation Methods 0.000 claims description 34
- 239000000835 fiber Substances 0.000 claims description 31
- 238000005507 spraying Methods 0.000 claims description 23
- 239000002689 soil Substances 0.000 claims description 10
- 239000007921 spray Substances 0.000 claims description 10
- 238000005553 drilling Methods 0.000 claims description 9
- 239000002002 slurry Substances 0.000 claims description 8
- 239000004568 cement Substances 0.000 claims description 7
- 238000007789 sealing Methods 0.000 claims description 6
- 238000003466 welding Methods 0.000 claims description 3
- 230000000149 penetrating effect Effects 0.000 claims description 2
- 238000000034 method Methods 0.000 abstract description 28
- 239000010410 layer Substances 0.000 description 74
- 229910001294 Reinforcing steel Inorganic materials 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 239000002356 single layer Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 230000005856 abnormality Effects 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 230000009545 invasion Effects 0.000 description 1
- 230000003014 reinforcing 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
- E21D9/04—Driving tunnels or galleries through loose materials; Apparatus therefor not otherwise provided for
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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
- E21D11/006—Lining anchored in the rock
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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
- E21D11/04—Lining with building materials
- E21D11/12—Temporary supports for use during building; Accessories
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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
- 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
- E21D11/28—Longitudinal struts, i.e. longitudinal connections between adjoining 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
- E21D20/00—Setting anchoring-bolts
- E21D20/02—Setting anchoring-bolts with provisions for grouting
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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
-
- 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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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/20—Hydro energy
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- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- Structural Engineering (AREA)
- Architecture (AREA)
- Civil Engineering (AREA)
- Environmental & Geological Engineering (AREA)
- Soil Sciences (AREA)
- Lining And Supports For Tunnels (AREA)
Abstract
The invention discloses a soft rock geological tunnel excavation reinforcement deformation control construction method, which comprises the following steps: grouting and solidifying before excavation, namely dividing a soft rock geological tunnel into four steps from a tunnel top arch to a bottom plate for excavation step by step, and excavating and supporting the next step after each step is excavated and supported; the support system adopts the processes of longitudinally arranging double-layer arches in parallel along the tunnel, connecting and fixing adjacent double-layer arches through longitudinal connecting I-steel and arch connecting ribs, fixedly connecting the wall-hanging net-sprayed concrete of the tunnel, and the like. According to the method, grouting consolidation is carried out on the arch range of the tunnel roof by adopting advanced grouting greenhouse construction and advanced grouting small guide pipes, double-layer arch support is adopted, longitudinal connection I-steel among arches is increased to effectively control primary support deformation of the tunnel, arch locking mode is changed to effectively inhibit tunnel convergence deformation, temporary transverse supports and permanent transverse supports of a bottom plate are increased, a tunnel primary support system is formed into a closed loop, an integral support system is formed to support surrounding rocks, and soft rock deformation is further inhibited.
Description
Technical Field
The invention belongs to the technical field of water conservancy and hydropower construction, in particular to the technical field of excavation construction of water conservancy and hydropower tunnels, and relates to a soft rock tunnel excavation reinforcement deformation control construction method for preventing deformation.
Background
Aiming at the construction of the large deformation tunnel of the soft rock, the existing excavation method adopts four-step excavation, the supporting mode adopts a conventional single-layer arch frame, an advanced grouting small guide pipe, a system anchor rod and a net-hanging sprayed concrete, the excavation collapse and the primary support deformation control effect on the deformation tunnel section of the soft rock are poor, the construction potential safety hazard is great, and accidents such as tunnel collapse, deformation invasion and the like are easy to occur.
In construction, if collapse occurs in the tunnel, collapse treatment is completed according to a field determined treatment method, the tunnel can be restored to be excavated after no abnormality is detected, and meanwhile, the deformation limit part of the tunnel does not meet the lining structure requirement of the tunnel and arch replacement construction is needed. Collapse and deformation treatment can seriously affect the construction progress and the construction safety, so that a construction control method which is safer and higher in efficiency and is used for excavating and reinforcing the soft-rock tunnel and the large deformation possibly occurring in the soft-rock tunnel needs to be designed.
Disclosure of Invention
The invention aims to provide a soft rock tunnel excavation reinforcement deformation control construction method. The invention realizes the integral soft rock deformation control by the construction method of excavation reinforcement and reinforced support control deformation, and provides a construction method combining a four-step reserved core soil excavation method, an advanced big pipe shed and advanced grouting small guide pipe, a double-layer arch frame, a large-scale foot locking anchor pipe, a temporary transverse support and a permanent transverse support on the premise of not changing the existing construction process of a tunnel, thereby realizing the rapid and effective soft rock deformation control.
The invention is realized by the following technical scheme:
a soft rock geological tunnel excavation reinforcement deformation control construction method comprises the following steps:
before excavation, grouting consolidation is carried out on the periphery of the designed outline of the tunnel roof arch by adopting an advanced grouting greenhouse, and then supplementary grouting consolidation is carried out on the inner side range of the designed outline of the tunnel roof arch by adopting an advanced grouting small conduit;
the excavation sequence is that a soft rock geological tunnel is excavated step by dividing a tunnel arch to a bottom plate into four steps, each step is excavated and supported, the next step is excavated and supported after the completion of excavation and supporting of each step, and the first step is excavated by adopting reserved core soil;
the supporting system adopts double-layer arches which are longitudinally arranged in parallel along the tunnel, and adjacent double-layer arches are fixedly connected through longitudinal connection I-steel and arch connecting ribs, so that the wall-hanging net-sprayed concrete of the tunnel is fixedly connected;
each double-layer arch support is formed by two layers of integrated arches which are overlapped and connected and fixed along the radial direction of a tunnel, wherein each double-layer arch support is formed by supporting a top arch to a bottom step to divide the steps and connecting the steps into a whole along with the step excavation; the construction comprises the steps of firstly completing the outer arch support, connecting with adjacent arches, spraying concrete on wall hanging net of adjacent tunnels, arranging grouting lock foot anchor pipes, and then carrying out the same construction steps of the inner arch;
a temporary cross brace is arranged between the footings of each double-layer arch frame of the second-stage step, and the transverse middle part of the tunnel, and is removed before the third-stage step is excavated;
and (3) excavating the bottom steps to the bottom surface of the tunnel, arranging permanent transverse braces between the footings of each double-layer arch frame and below the transverse bottom of the tunnel, and pouring concrete for sealing.
The construction method of the invention comprises the steps of uniformly distributing system anchor rods penetrating into surrounding rocks at intervals in the surrounding rocks of the tunnel.
The construction of the advanced grouting greenhouse comprises the following steps: the cycle length of the advanced grouting greenhouse is 12m, the overlapping is 3m, the hole spacing is 50cm, and the elevation angle is 15 degrees; each advanced grouting greenhouse adopts a seamless steel pipe with phi 108 mm by 6mm, a grouting section is formed by no drilling at the tail part 3m, the grouting hole aperture is phi 15mm, the spacing is 30cm, the quincuncial arrangement is realized, the pipe end is processed into a sharp angle not more than 45 degrees, and the grouting adopts pure cement slurry.
The construction of the advanced grouting small conduit comprises the following steps: the cycle length of the advance grouting small guide pipe is 4.5m, the lap joint is 1.5m, the hole spacing is 30cm, and the elevation angle is 15 degrees; each advanced grouting small guide pipe adopts phi 42 x 3.5mm seamless steel pipes, the tail part of each advanced grouting small guide pipe is 1.5m seamless steel pipes without drilling until the grouting sections are drilled, the grouting hole aperture is phi 10mm, the distance is 15cm, the quincuncial arrangement is realized, the pipe ends are processed into sharp angles not more than 45 degrees, and the grouting adopts pure cement slurry.
The arch step excavation supporting of the invention comprises: step one excavation, 5cm thick concrete spraying and sealing face, system anchor rod construction, steel bar mesh installation, first layer arch frame longitudinal connection I-steel and arch frame connection rib construction, first layer arch frame grouting foot locking anchor pipe construction, first layer 20cm thick coarse fiber concrete spraying and protecting, second layer arch frame installation, second layer arch frame longitudinal connection I-steel and arch frame connection rib construction, second layer arch frame grouting foot locking anchor pipe construction and second layer 20cm thick coarse fiber concrete spraying and protecting.
Step two excavation supporting includes: step two excavation, system anchor rod construction, steel bar mesh installation, first-layer arch frame longitudinal connection I-steel and arch frame connecting rib construction, first-layer arch frame grouting foot locking anchor pipe construction, first-layer 20cm thick coarse fiber concrete spray protection, second-layer arch frame installation, second-layer arch frame longitudinal connection I-steel and arch frame connecting rib construction, second-layer arch frame grouting foot locking anchor pipe construction, second-layer 20cm thick coarse fiber concrete spray protection and middle step temporary cross brace installation.
The three excavation supporting of step includes: the construction method comprises the steps of step two temporary cross brace dismantling, step three excavation, system anchor rod construction, steel bar mesh installation, first-layer arch frame longitudinal connection I-steel and arch frame connection rib construction, first-layer arch frame grouting foot locking anchor pipe construction, first-layer 20cm thick coarse fiber concrete spraying protection, second-layer arch frame installation, second-layer arch frame longitudinal connection I-steel and arch frame connection rib construction, second-layer arch frame grouting foot locking anchor pipe construction and second-layer 20cm thick coarse fiber concrete spraying protection.
The bottom step excavation supporting includes: step four excavation, system anchor rod construction, steel bar mesh installation, first-layer arch frame longitudinal connection I-steel and arch frame connecting rib construction, first-layer arch frame grouting foot locking anchor pipe construction, first-layer 20cm thick coarse fiber concrete spray protection, second-layer arch frame installation, second-layer arch frame longitudinal connection I-steel and arch frame connecting rib construction, second-layer arch frame grouting foot locking anchor pipe construction, second-layer 20cm thick coarse fiber concrete spray protection and four-step permanent cross brace installation.
The grouting foot locking anchor pipe construction comprises drilling, tubing, welding and grouting; the top arch step is provided with a grouting foot locking anchor pipe with the length of phi 42 x 3.5mm and the length of L=4.5 m, and the grouting foot locking anchor pipe and the arch frame are welded and fixed by adopting L-shaped ribs; the other steps are provided with grouting foot locking anchor pipes with the length of phi 76 x 6mm and the length of L=6.0m, and the grouting foot locking anchor pipes are welded and connected with the arch frame by adopting rectangular steel plates with the length of 40cm x 20 cm.
The steel plates with bolt holes are welded at the two ends of the temporary transverse support and are fixedly connected with the arch frame through bolts.
Compared with the prior art, the invention has the following advantages and beneficial effects:
1. according to the method, aiming at the situation of surrounding rock crushing of the soft rock tunnel section, grouting consolidation is carried out on the tunnel roof arch range by adopting advanced grouting greenhouse construction and advanced grouting small guide pipes, frequent block dropping and even collapse in the tunnel surrounding rock crushing and excavating process are avoided, and the tunnel excavating safety is improved.
2. According to the invention, the primary support arch frame is reinforced into a double-layer I20 a arch frame by the original single-layer I20 a arch frame, and meanwhile, the thickness of crude fiber concrete is increased from 20cm to 40cm, so that on one hand, the rigidity of the primary support system is increased, the distortion deformation of the primary support arch frame of the tunnel due to the deformation characteristic of soft rock is avoided, and the safety guarantee rate of the tunnel is increased.
3. According to the invention, the longitudinal connection I-steel among the arches is added, so that the whole primary support system of the tunnel is connected into a whole to form a common stress body, and the primary support deformation of the tunnel is effectively controlled to a certain extent.
4. According to the invention, by changing the arch centering pin locking mode, the large grouting pin locking anchor pipes with phi 42 times of 3.5 mL=4.5 m and phi 76 times of 6 mmL=6.0 m are added, so that the convergence deformation of the tunnel is effectively restrained.
5. According to the invention, the primary support system of the tunnel is closed loop by adding the step two temporary cross braces and the bottom plate permanent cross braces, so that the whole support system is formed to support surrounding rock, and the deformation condition of soft rock is further inhibited.
Drawings
FIG. 1 is a schematic view of a tunnel excavation supporting cross section in accordance with an embodiment of the present invention;
FIG. 2 is a schematic view of an arch longitudinal connection according to an embodiment of the present invention;
FIG. 3 is a schematic view of a grouting foot-locking anchor pipe and arch frame connection according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a grouting foot-locking anchor pipe and arch frame connection according to an embodiment of the present invention;
fig. 5 is a schematic view of a step temporary cross brace connection in an embodiment of the invention.
In the accompanying drawings: the concrete casting device comprises a 1-advanced grouting greenhouse, a 2-advanced grouting small guide pipe, a 3-outer arch frame, a 4-inner arch frame, a 5-grouting foot locking anchor pipe I, a 6-grouting foot locking anchor pipe II, a 7-system anchor rod, an 8-outer layer hanging net spray coarse fiber concrete, a 9-inner layer hanging net spray coarse fiber concrete, a 10-temporary transverse support, an 11-permanent transverse support, a 12-L-shaped connecting rib, a 13-thick steel plate, a 14-longitudinal connecting I-steel, a 15-arch frame connecting rib, a 16-temporary transverse support connecting bolt and a 17-temporary transverse support connecting steel plate; a-step one (top arch step), B-step two, C-step three, D-step four (bottom step).
Detailed Description
The present invention will be further described with reference to the following specific embodiments, which are intended to be illustrative of the principles of the present invention and not in any way limiting, nor will the same or similar techniques be used in connection with the present invention beyond the scope of the present invention.
The invention relates to a soft rock tunnel excavation reinforcement deformation control method, which comprises a four-stage step reserved core soil excavation method, an advanced grouting big pipe shed and advanced grouting small guide pipe, a double-layer arch frame, a large-scale foot locking anchor pipe, a temporary transverse support and a permanent transverse support. Before tunnel excavation, grouting consolidation is carried out on the tunnel roof arch range by adopting advanced grouting greenhouse construction and advanced grouting small guide pipes, so that the integrity of surrounding rocks of the tunnel is improved; and then, tunnel excavation is carried out, a four-stage step core soil method is adopted for tunnel excavation, the reserved core soil can apply a reverse thrust to the tunnel face, surrounding rock of the excavation face is not extruded, meanwhile, the four-stage step excavation has enough operation space and higher construction speed, the stability of the excavation face is facilitated by steps, and especially, after the upper part excavation is supported, the lower part operation is safer. Adopting double-layer arch support, firstly completing construction of a first-layer arch support, adjacent arch connection, net-hanging and concrete spraying and foot locking anchor pipes, and then carrying out construction of a second-layer arch support, adjacent arch connection, net-hanging and concrete spraying and foot locking anchor pipes, wherein a first step adopts a first double-row phi 42 x 3.5 mL = 4.5m grouting foot locking anchor pipe, and a second step, a third step and a fourth step adopt a second double-row phi 76 x 6mmL = 6.0m grouting foot locking anchor pipe; and (5) carrying out permanent transverse bracing construction on the bottom plate after the step four excavation supporting is completed.
According to the technical scheme, construction is organized according to construction procedures, each step is excavated and supported, the next step is excavated, the construction of the previous procedure is completed, and the next procedure is carried out after the construction is checked and accepted.
Firstly, constructing an advanced grouting greenhouse, wherein each cycle length of the advanced grouting greenhouse is 12m, the overlapping is 3m, the hole spacing is 50cm, and the elevation angle is 15 degrees; the advanced grouting greenhouse adopts a seamless steel pipe with phi of 108 mm by 6mm, the processed type is that a tail part 3m is not drilled to serve as a grouting section, the aperture of grouting holes is phi 15mm, the spacing is 30cm, the quincuncial arrangement is realized, the pipe ends are processed into sharp angles not more than 45 degrees, and the grouting adopts pure cement slurry; the construction process of the advanced grouting greenhouse comprises the steps of measuring the placement point, drilling, cleaning the hole, installing pipes, grouting and the like.
Secondly, constructing a small advance grouting pipe, wherein the length of each cycle of the small advance grouting pipe is 4.5m, the overlapping is 1.5m, the hole spacing is 30cm, and the elevation angle is 15 degrees; the advanced grouting small guide pipe adopts a phi 42 x 3.5mm seamless steel pipe, the processed type is that a tail 1.5m is not drilled to serve as a slurry section, the grouting hole aperture is phi 10mm, the distance is 15cm, the quincuncial arrangement is realized, the pipe end is processed into a sharp angle not more than 45 degrees, and the grouting adopts pure cement slurry; the construction process of the advanced grouting small guide pipe comprises the steps of measuring the placement point, drilling, cleaning the hole, installing the pipe, grouting and the like.
Thirdly, excavating and supporting the first step, wherein the working procedures are as follows: step one excavation, 5cm thick concrete spraying and sealing face, system anchor rod construction, steel bar mesh installation, first layer arch frame longitudinal connection steel bar construction, first layer arch frame phi 42 x 3.5 mL = 4.5m grouting foot locking anchor pipe one construction, first layer 20cm thick coarse fiber concrete spraying and protecting, second layer arch frame installation, second layer arch frame longitudinal connection steel bar construction, second layer arch frame phi 42 x 3.5 mL = 4.5m grouting foot locking anchor pipe one construction, second layer 20cm thick coarse fiber concrete spraying and protecting.
Fourth, the second step excavates and supports, the process is respectively: step two excavation, system anchor rod construction, steel bar mesh installation, first layer arch frame longitudinal connection steel bar construction, I-steel construction, first layer arch frame phi 76 x 6mmL=6.0m grouting foot locking anchor pipe two construction, first layer 20cm thick coarse fiber concrete spraying protection, second layer arch frame installation, second layer arch frame longitudinal connection steel bar construction, second layer arch frame phi 76 x 6mmL=6.0m grouting foot locking anchor pipe two construction, second layer 20cm thick coarse fiber concrete spraying protection and middle step temporary transverse support installation.
Fifthly, supporting the step three by excavation, wherein the working procedures are as follows: the construction method comprises the steps of step two temporary cross brace dismantling, step three excavation, system anchor rod construction, installation of reinforcing steel meshes, first-layer arch frame installation, first-layer arch frame longitudinal connecting reinforcing steel bar construction, first-layer arch frame phi 76 x 6 mmL=6.0m grouting foot locking anchor pipe two construction, first-layer 20cm thick coarse fiber concrete spraying protection, second-layer arch frame installation, second-layer arch frame longitudinal connecting reinforcing steel bar construction, second-layer arch frame phi 76 x 6 mmL=6.0m grouting foot locking anchor pipe two construction and second-layer 20cm thick coarse fiber concrete spraying protection.
Step six, four excavation supporting steps are respectively carried out, and the working procedures are as follows: step four excavation, system anchor rod construction, steel bar mesh installation, first layer arch frame longitudinal connection steel bar construction, I-steel construction, first layer arch frame phi 76 x 6mmL=6.0m grouting foot locking anchor pipe two construction, first layer 20cm thick coarse fiber concrete spraying protection, second layer arch frame installation, second layer arch frame longitudinal connection steel bar construction, second layer arch frame phi 76 x 6mmL=6.0m grouting foot locking anchor pipe two construction, second layer 20cm thick coarse fiber concrete spraying protection and four-step permanent transverse support installation.
The construction process of each grouting foot locking anchor pipe comprises drilling, tubing, welding and grouting.
The embodiment provides a soft rock tunnel excavation reinforcement deformation control method, which adopts the measures of a four-stage step reserved core soil excavation method, an advanced grouting big pipe shed 1, an advanced grouting small pipe 2, an outer arch 3 and an inner arch 4 of a double-layer arch, longitudinal connection and reinforcement of longitudinal connection I-steel 14, a large-scale foot locking anchor pipe, a temporary transverse support 10 and a permanent transverse support 11 as shown in fig. 1 to 5.
The excavation reinforcement advanced measure specifically comprises: the pipe shed advanced grouting device comprises an advanced grouting pipe shed 1 and an advanced grouting small guide pipe 2, wherein the grouting length of the advanced grouting pipe shed 1 is 12m, the diffusion range is changed according to the actual surrounding rock condition, and the pipe shed advanced grouting forms a layer of shell at the top arch part of the pipe shed construction range to stabilize the surrounding rock above the pipe shed due to the adoption of the pipe shed grouting; and after the construction of the advanced grouting greenhouse 1 is finished, an advanced grouting small guide pipe 2 is arranged below the advanced grouting greenhouse, so that surrounding rocks between the excavated contour line and the greenhouse are further consolidated and stabilized, and the falling blocks and even collapse caused by disturbance in the excavation process are prevented.
The four-step reserved core soil excavation method can apply a reverse thrust to the face surface, so that surrounding rock of the excavation surface is not extruded, meanwhile, the four-step excavation has enough operation space and high construction speed, the steps are beneficial to stability of the excavation surface, and particularly, after the upper excavation supporting is carried out, the lower operation is safer. The core soil excavation is reserved, namely, annular excavation is adopted in the step excavation process of the tunnel, and the center position of the step A is reserved without excavation; the length of the core soil is 3-5 m, the cross section is trapezoidal, and the widths of the upper bottom and the lower bottom are 1/3-1/2 of the corresponding tunnel excavation width.
The arch structure comprises an inner arch support and an outer arch support.
The outer arch support structure comprises an outer arch 3, an outer hanging net coarse fiber concrete 8, longitudinal connecting I-steel 14 and longitudinal connecting ribs 15, in practical implementation, the outer arch 3 is installed, the hanging net is completed when the outer arch 3 is installed, the connecting ribs 15 are welded firmly after the outer arch 3 is installed, the longitudinal connecting I-steel 14 is installed and welded firmly, and after the foot locking anchor pipe 5 or the foot locking anchor pipe 6 is completed, the outer hanging net coarse fiber concrete 8 is covered.
The outer arch support construction is accomplished and then the inner arch support installation is carried out, the inner arch support structure comprises an inner arch 4, an inner hanging net coarse fiber concrete 9, longitudinal connecting I-steel 14 and longitudinal connecting ribs 15, in practical implementation, the inner arch 4 is installed first, the connecting ribs 15 are welded firmly after the inner arch 4 is installed, the longitudinal connecting I-steel 14 is installed and welded firmly, and after the foot locking anchor pipe 5 or the foot locking anchor pipe 6 is completed, the inner hanging net coarse fiber concrete 9 is covered.
As shown in fig. 3 and fig. 4, the grouting foot locking anchor pipe comprises a first grouting foot locking anchor pipe with phi 42 x 3.5 ml=4.5m, a second grouting foot locking anchor pipe with phi 76 x 6 mml=6.0m, an 'L' connecting rib 12, a steel plate 13 with the thickness of 40cm x 20cm, and in practical implementation, the first grouting foot locking anchor pipe with phi 42 x 3.5 ml=4.5m and the arch frame are firmly welded by adopting the 'L' connecting rib 12, and the second grouting foot locking anchor pipe with phi 76 x 6 mml=6.0m and the arch frame are fixedly welded by adopting the steel plate 13 with the thickness of 40cm x 20 cm; after the grouting foot locking anchor pipes are welded, the steel pipes are filled with pure cement slurry, surrounding rocks in the range of the grouting foot locking anchor pipes are solidified by pressurized grouting, the foot locking strength of the grouting foot locking anchor pipes to the arch frame is enhanced, and the stability of the arch frame is ensured.
As shown in fig. 5, the second step B is provided with a temporary cross brace 10, the temporary cross brace 10 and an arch connecting steel plate 17 are connected and supported and fixed with the inner arch 4 through connecting bolts 16, the temporary cross brace 10 is required to be processed in advance before being installed and then transported to the site for installation, the arch connecting steel plates 17 with four bolt holes processed are welded at the two ends of the temporary cross brace 10 and the position of the second step B, where the inner arch 4 is installed, respectively, the temporary cross brace 10 can be quickly installed after being transported to the site, and the cross brace is quickly removed before the third step C is excavated.
The four-D permanent cross brace 11 of the step is used for ensuring that the primary support system of the tunnel continuously supports surrounding rock, further inhibiting the deformation condition of soft rock, and can be directly welded with the four-D primary support arch frame of the step into a whole, and concrete with the thickness of 20cm is required to be poured for sealing after the installation of the permanent cross brace 11 is completed, so that the strength of the permanent cross brace 11 is increased, and the deformation of the tunnel is effectively controlled.
Claims (10)
1. A soft rock geological tunnel excavation reinforcement deformation control construction method is characterized in that:
before excavation, grouting consolidation is carried out on the periphery of the designed outline of the tunnel roof arch by adopting an advanced grouting greenhouse, and then supplementary grouting consolidation is carried out on the inner side range of the designed outline of the tunnel roof arch by adopting an advanced grouting small conduit;
the excavation sequence is that a soft rock geological tunnel is excavated step by dividing a tunnel arch to a bottom plate into four steps, each step is excavated and supported, the next step is excavated and supported after the completion of excavation and supporting of each step, and the first step is excavated by adopting reserved core soil;
the supporting system adopts double-layer arches which are longitudinally arranged in parallel along the tunnel, and adjacent double-layer arches are fixedly connected through longitudinal connection I-steel and arch connecting ribs, so that the wall-hanging net-sprayed concrete of the tunnel is fixedly connected;
each double-layer arch support is formed by two layers of integrated arches which are overlapped and connected and fixed along the radial direction of a tunnel, wherein each double-layer arch support is formed by supporting a top arch to a bottom step to divide the steps and connecting the steps into a whole along with the step excavation; the construction comprises the steps of firstly completing the outer arch support, connecting with adjacent arches, spraying concrete on wall hanging net of adjacent tunnels, arranging grouting lock foot anchor pipes, and then carrying out the same construction steps of the inner arch;
a temporary cross brace is arranged between the footings of each double-layer arch frame of the second-stage step, and the transverse middle part of the tunnel, and is removed before the third-stage step is excavated;
and (3) excavating the bottom steps to the bottom surface of the tunnel, arranging permanent transverse braces between the footings of each double-layer arch frame and below the transverse bottom of the tunnel, and pouring concrete for sealing.
2. The soft-rock geological tunnel excavation reinforcement deformation control construction method according to claim 1, characterized by comprising the following steps: system anchor rods penetrating into surrounding rocks are uniformly distributed in the surrounding rocks of the tunnel at intervals.
3. The soft-rock geological tunnel excavation reinforcement deformation control construction method of claim 2, characterized by comprising the following steps of: the cycle length of the advanced grouting greenhouse is 12m, the overlapping is 3m, the hole spacing is 50cm, and the elevation angle is 15 degrees; each advanced grouting greenhouse adopts a seamless steel pipe with phi 108 mm by 6mm, a grouting section is formed by no drilling at the tail part 3m, the grouting hole aperture is phi 15mm, the spacing is 30cm, the quincuncial arrangement is realized, the pipe end is processed into a sharp angle not more than 45 degrees, and the grouting adopts pure cement slurry.
4. The soft-rock geological tunnel excavation reinforcement deformation control construction method according to claim 2, characterized in that the advanced grouting small pipe construction comprises: the cycle length of the advance grouting small guide pipe is 4.5m, the lap joint is 1.5m, the hole spacing is 30cm, and the elevation angle is 15 degrees; each advanced grouting small guide pipe adopts phi 42 x 3.5mm seamless steel pipes, the tail part of each advanced grouting small guide pipe is 1.5m seamless steel pipes without drilling until the grouting sections are drilled, the grouting hole aperture is phi 10mm, the distance is 15cm, the quincuncial arrangement is realized, the pipe ends are processed into sharp angles not more than 45 degrees, and the grouting adopts pure cement slurry.
5. The soft-rock geological tunnel excavation reinforcement deformation control construction method according to claim 2, characterized in that the top arch step excavation supporting comprises: step one excavation, 5cm thick concrete spraying and sealing face, system anchor rod construction, steel bar mesh installation, first layer arch frame longitudinal connection I-steel and arch frame connection rib construction, first layer arch frame grouting foot locking anchor pipe construction, first layer 20cm thick coarse fiber concrete spraying and protecting, second layer arch frame installation, second layer arch frame longitudinal connection I-steel and arch frame connection rib construction, second layer arch frame grouting foot locking anchor pipe construction and second layer 20cm thick coarse fiber concrete spraying and protecting.
6. The soft-rock geological tunnel excavation reinforcement deformation control construction method of claim 2, characterized in that the step two excavation supporting comprises: step two excavation, system anchor rod construction, steel bar mesh installation, first-layer arch frame longitudinal connection I-steel and arch frame connecting rib construction, first-layer arch frame grouting foot locking anchor pipe construction, first-layer 20cm thick coarse fiber concrete spray protection, second-layer arch frame installation, second-layer arch frame longitudinal connection I-steel and arch frame connecting rib construction, second-layer arch frame grouting foot locking anchor pipe construction, second-layer 20cm thick coarse fiber concrete spray protection and middle step temporary cross brace installation.
7. The soft-rock geological tunnel excavation reinforcement deformation control construction method of claim 2, characterized in that the step three-excavation supporting comprises: the construction method comprises the steps of step two temporary cross brace dismantling, step three excavation, system anchor rod construction, steel bar mesh installation, first-layer arch frame longitudinal connection I-steel and arch frame connection rib construction, first-layer arch frame grouting foot locking anchor pipe construction, first-layer 20cm thick coarse fiber concrete spraying protection, second-layer arch frame installation, second-layer arch frame longitudinal connection I-steel and arch frame connection rib construction, second-layer arch frame grouting foot locking anchor pipe construction and second-layer 20cm thick coarse fiber concrete spraying protection.
8. The soft-rock geological tunnel excavation reinforcement deformation control construction method according to claim 2, characterized in that the bottom step excavation supporting comprises: step four excavation, system anchor rod construction, steel bar mesh installation, first-layer arch frame longitudinal connection I-steel and arch frame connecting rib construction, first-layer arch frame grouting foot locking anchor pipe construction, first-layer 20cm thick coarse fiber concrete spray protection, second-layer arch frame installation, second-layer arch frame longitudinal connection I-steel and arch frame connecting rib construction, second-layer arch frame grouting foot locking anchor pipe construction, second-layer 20cm thick coarse fiber concrete spray protection and four-step permanent cross brace installation.
9. The soft-rock geological tunnel excavation reinforcement deformation control construction method according to claim 2, characterized by comprising the following steps: grouting, foot locking and anchor pipe construction comprises drilling, tubing, welding and grouting; the top arch step is provided with a grouting foot locking anchor pipe with the length of phi 42 x 3.5mm and the length of L=4.5 m, and the grouting foot locking anchor pipe and the arch frame are welded and fixed by adopting L-shaped ribs; the other steps are provided with grouting foot locking anchor pipes with the length of phi 76 x 6mm and the length of L=6.0m, and the grouting foot locking anchor pipes are welded and connected with the arch frame by adopting rectangular steel plates with the length of 40cm x 20 cm.
10. The soft-rock geological tunnel excavation reinforcement deformation control construction method according to claim 2, characterized by comprising the following steps: the steel plates with bolt holes are welded at the two ends of the temporary transverse support and are fixedly connected with the arch frame through bolts.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116446887A (en) * | 2023-06-20 | 2023-07-18 | 湖南省交通规划勘察设计院有限公司 | Tunnel construction method for existing partial collapse position of primary support section |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116446887A (en) * | 2023-06-20 | 2023-07-18 | 湖南省交通规划勘察设计院有限公司 | Tunnel construction method for existing partial collapse position of primary support section |
| CN116446887B (en) * | 2023-06-20 | 2023-09-01 | 湖南省交通规划勘察设计院有限公司 | Tunnel construction method for existing partial collapse position of primary support section |
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