CN114412509A - Support method suitable for large deformation of mudstone tunnel - Google Patents
Support method suitable for large deformation of mudstone tunnel Download PDFInfo
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- CN114412509A CN114412509A CN202111556878.XA CN202111556878A CN114412509A CN 114412509 A CN114412509 A CN 114412509A CN 202111556878 A CN202111556878 A CN 202111556878A CN 114412509 A CN114412509 A CN 114412509A
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- 238000000034 method Methods 0.000 title claims abstract description 33
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 92
- 239000010959 steel Substances 0.000 claims abstract description 92
- 239000004567 concrete Substances 0.000 claims abstract description 45
- 238000010276 construction Methods 0.000 claims abstract description 36
- 239000011435 rock Substances 0.000 claims abstract description 31
- 238000005507 spraying Methods 0.000 claims abstract description 28
- 238000005553 drilling Methods 0.000 claims abstract description 16
- 230000009545 invasion Effects 0.000 claims abstract description 14
- 230000003014 reinforcing effect Effects 0.000 claims abstract description 9
- 238000002203 pretreatment Methods 0.000 claims abstract description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 8
- 238000009412 basement excavation Methods 0.000 claims description 7
- 230000002787 reinforcement Effects 0.000 claims description 6
- 238000009434 installation Methods 0.000 claims description 4
- 229910052742 iron Inorganic materials 0.000 claims description 4
- 229910001294 Reinforcing steel Inorganic materials 0.000 claims description 3
- 238000005520 cutting process Methods 0.000 claims description 3
- 230000000694 effects Effects 0.000 claims description 3
- 238000004873 anchoring Methods 0.000 claims description 2
- 238000003672 processing method Methods 0.000 claims description 2
- 239000010410 layer Substances 0.000 description 5
- 238000003466 welding Methods 0.000 description 4
- 239000011378 shotcrete Substances 0.000 description 3
- 230000001154 acute effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000002344 surface layer Substances 0.000 description 2
- 230000004075 alteration Effects 0.000 description 1
- 238000005422 blasting Methods 0.000 description 1
- 238000011900 installation process Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012805 post-processing Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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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
- E21D11/105—Transport or application of concrete specially adapted for the lining of tunnels or galleries ; Backfilling the space between main building element and the surrounding rock, e.g. with concrete
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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
- E21D11/18—Arch members ; Network made of arch members ; Ring elements; Polygon elements; Polygon elements inside arches
- E21D11/183—Supporting means for arch members, not provided for in E21D11/22
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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
- E21D20/003—Machines for drilling anchor holes and setting anchor 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
- E21D20/021—Grouting with inorganic components, e.g. cement
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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)
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- Architecture (AREA)
- Civil Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Lining And Supports For Tunnels (AREA)
Abstract
The invention discloses a construction supporting method suitable for large deformation of a mudstone tunnel, which comprises the following specific steps: selecting a corresponding reinforcing and supporting structure according to the tunnel survey data and the deformation condition after primary supporting; step two, excavating a tunnel by adopting a step method, and then sequentially carrying out primary concrete spraying, steel bar mesh laying, arch frame erecting, foot locking anchor rods arranging, radial anchor rod drilling and concrete re-spraying to the designed thickness; respectively carrying out the above construction on the upper step part, the left part of the lower step and the right part of the lower step in sequence; step three, according to different surrounding rock deformation conditions, different arch support structures are arranged in the arch of the primary support structure; fourthly, excavating an inverted arch part; and step five, performing different pretreatments on the tunnel according to different invasion limit degrees, and then completing secondary lining pouring. The scheme improves the capacity of primary support for resisting the deformation of the surrounding rock, and can safely and quickly process the problem to ensure the thickness of the lining.
Description
Technical Field
The invention belongs to the technical field of prevention and control of invasion limit of deformation of surrounding rocks in a carbonaceous mudstone tunnel, and particularly relates to a supporting method suitable for large deformation of the mudstone tunnel.
Background
With the increasingly perfect transportation system, the intersection of the newly-built railway and the existing road is more and more, and the tunnel is widely used for improving the traffic line type, saving the occupied land and saving the engineering investment. However, in the construction process, how to solve the problem of invasion limit of mudstone tunnel surrounding rock deformation, ensure the safety of tunnel construction and ensure the thickness of a lining becomes a difficult problem in the whole building industry. Especially in the carbonaceous mudstone area, the self-stability is poor, and the mud-rock is easy to soften when meeting water and easy to collapse. How to prevent the problem, ensure the construction safety and reduce the engineering loss becomes a big difficulty in engineering.
Disclosure of Invention
The invention aims to solve the problems in the prior art and provides a supporting method suitable for large deformation of a mudstone tunnel.
In order to achieve the purpose, the invention adopts the following technical scheme: a construction supporting method suitable for large deformation of a mudstone tunnel comprises the following specific steps:
selecting a corresponding reinforcing and supporting structure according to the tunnel survey data and the deformation condition after primary supporting;
step two, excavating a tunnel by adopting a step method, and then sequentially carrying out primary concrete spraying, steel bar mesh laying, arch frame erecting, foot locking anchor rods arranging, radial anchor rod drilling and concrete re-spraying to the designed thickness; respectively carrying out the above construction on the upper step part, the left part of the lower step and the right part of the lower step in sequence; firstly, mechanically excavating an upper step part, establishing a primary supporting structure of the upper step, secondly, mechanically excavating a left side part of a lower step, establishing a primary supporting structure of the left side of the lower step, and spraying concrete again to a designed thickness, and thirdly, mechanically excavating a right side part of the lower step, establishing a primary supporting structure of the right side of the lower step, and spraying concrete again to the designed thickness;
step three, according to different surrounding rock deformation conditions, different arch support structures are arranged in the arch of the primary support structure;
fourthly, performing inverted arch excavation and inverted arch primary support structure construction on the section of tunnel, completing inverted arch concrete spraying and inverted arch reinforcing steel bar application, and then completing inverted arch pouring and filling of the section of tunnel;
and step five, performing different pretreatments on the tunnel according to different invasion limit degrees, and then completing secondary lining pouring.
Preferably, the second step comprises the following steps:
step 21, firstly, mechanically excavating an upper step part, establishing a primary supporting structure at the upper step part, and connecting two rows of first arch frames by using longitudinal steel bars at intervals of 1m along the circumferential direction of the first arch frames in the process of installing the arch frames of the primary supporting structure; arranging double rows of locking anchor pipes 30cm above the arch springs on the two sides of the first arch centering, drilling an angle of 30 degrees, grouting and reinforcing, and finally drilling a radial anchor rod and then spraying concrete again to the designed thickness;
step 22: mechanically excavating the left part of a lower step, establishing a primary supporting structure at the left side of the lower step, supporting and cushioning by using longitudinal 32# channel steel to increase the bearing area of the bottom feet of the arch wall steel frame when the arch wall steel frame is installed, arranging two rows of lower step locking anchor pipes 30cm above the arch feet at two sides of the arch wall steel frame, setting an angle of 30 degrees, grouting by using a grouting small conduit after the arch wall steel frame is stabilized, and spraying concrete again to the designed thickness;
step 23: mechanically excavating the right part of the lower step, establishing a primary supporting structure at the right part of the lower step, supporting and cushioning by using longitudinal 32# channel steel to increase the bearing area of the bottom feet of the arch wall steel frame when the arch wall steel frame is installed, arranging two rows of lower step locking anchor pipes 30cm above the arch feet at two sides of the arch wall steel frame, setting an angle of 30 degrees, grouting by using a grouting small conduit after the arch wall steel frame is stabilized, and spraying concrete again to the designed thickness.
As a preferred scheme, in the fifth step, for the limit-invading part which is 0-8cm away, a pneumatic pick is adopted to remove the surface layer sprayed and protected concrete so as to ensure that the thickness of the second lining meets the requirement, then steel bar installation and concrete pouring are carried out, and finally the second lining pouring is completed; and (3) performing arch changing treatment on the part with 8-25cm of invasion limit, chiseling concrete at the part with the invasion limit through a crushing head, cutting out the I-shaped steel and the connecting steel bar with the invasion limit, installing I20B I-shaped steel, spraying concrete, and finally finishing secondary lining pouring.
Preferably, the arch-changing processing method comprises the following steps: and (3) adopting 2 groups of phi 42 grouting small ducts to lock and reinforce I-shaped steel frames of the first arch frame and/or the second arch frame which are not subjected to limit intrusion, and then adopting a mode of dismantling the limit intrusion I-shaped steel frames one by one to process.
Preferably, in the step 21, the periphery of the small grouting pipe phi 42 is radially reinforced by grouting, the single length of the small grouting pipe is 4.5m, the circumferential distance is 1m, the longitudinal distance is 1.2m, the pipe walls are arranged in a quincunx shape by staggered drilling, and the pipe walls are firmly welded with the i-shaped steel frames of the first arch and the second arch to lock and anchor the i-shaped steel frames.
As a preferred scheme, the deviation of the hole position of the drilling hole in the grouting reinforcement construction is not more than 10mm, and the deviation of the hole depth is not more than 50mm, so that the rock surface is vertical to the drilling direction.
As preferred scheme, in step three, when the country rock normal direction warp within 5cm first bow member is inside to establish a first stull and two first sprags, two first sprags symmetry installations, the both ends and the first bow member both sides middle section position fixed connection of first stull, first stull one end is connected with first stull, and the other end slant is upwards connected with first I-steel frame, just the midpoint of first stull is not crossed with the hookup location of first stull to first stull.
Preferably, the first inclined strut and the first cross strut form an included angle of 45 degrees.
Preferably, in the third step, when the surrounding rock deforms 5-10cm in the normal direction, a second arch is placed in the tunnel, a PVC plate with the same shape as the outer edge of the second arch is arranged between the outer ring surface of the second arch and the inner wall of the tunnel, through holes are formed in the PVC plate along the length direction of the PVC plate, the second arch and the PVC plate are connected to the through holes through iron wires, and longitudinal connecting ribs are arranged among the second arches and fixedly connected into a whole.
Preferably, the allowable deviation of the section sizes of the I-steel frames of the first arch and the second arch is +/-20 mm, and the torsion degree is 20 mm.
Advantageous effects
By improving the supporting method, the invention not only improves the safety and stability of the mudstone tunnel construction, but also accelerates the construction progress, and effectively solves the sudden instability condition of the surrounding rock deformation. Through reinforcing the supporting construction, make preliminary bracing resist the ability of country rock deformation and promote, if the limit problem invades appears, can safely, rapidly transacting this problem in order to ensure lining thickness. The supporting structure stability and the mudstone tunnel construction safety are improved, the surrounding rock deformation is effectively prevented from being too large to extrude the arch centering, the secondary consumption of the arch centering is reduced, the second arch centering and the pvc plastic plate can be repeatedly used, and the construction cost is effectively reduced. The construction method can complete the construction of the mudstone tunnel engineering safely, quickly and efficiently, not only improves the safety and stability of the mudstone tunnel construction, but also accelerates the construction progress, and effectively solves the sudden instability condition of the surrounding rock deformation. Avoiding secondary rework and having better social benefit and economic benefit.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the invention, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.
FIG. 1 is a schematic view of a mud-rock large deformation tunnel supporting structure of the invention;
FIG. 2 is a block diagram of a first arch;
FIG. 3 is a block diagram of a second arch;
the labels in the figure are: 11. the structure comprises an upper step foot locking anchor pipe, 12, an upper step outer sprayed concrete layer, 31, a lower step foot locking anchor pipe, 32, a lower step outer sprayed concrete layer, 40, an inverted arch primary support structure, 50, a radial anchor rod, 60, a grouting small guide pipe, 100, a first arch frame, 101, a first cross brace, 102, a first inclined brace, 103, a first I-shaped steel frame, 200, a second arch frame, 201, a PVC plate, 202, a second I-shaped steel frame, 203, a second cross brace, 204, a second inclined brace, 205 and a third inclined brace;
i, an upper step part, II-1, a lower step left part, II-2, a lower step right part, III, an inverted arch III, IV, an inverted arch IV, V and an inverted arch V.
Detailed Description
The invention is described in detail below by way of exemplary embodiments. It should be understood, however, that elements, structures and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.
It should be noted that: unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. The use of the terms "a" and "an" or "the" and similar referents in the description and claims of the present invention are not to be construed as limiting in number, but rather as indicating the presence of at least one. The word "comprise" or "comprises", and the like, indicates that the element or item listed before "comprises" or "comprising" covers the element or item listed after "comprising" or "comprises" and its equivalents, but does not exclude other elements or items having the same function.
The embodiment provides a construction supporting method suitable for large deformation of a mudstone tunnel, which comprises the following specific steps:
selecting a corresponding reinforcing and supporting structure according to the tunnel survey data and the deformation condition after primary supporting; specifically, the geological condition in front of the tunnel face is grasped by an advanced geological forecasting system, and a corresponding reinforcing and supporting structure is adopted after primary supporting according to the deformation condition.
Step two, adopting a step method to excavate a tunnel, and then sequentially carrying out primary concrete spraying, steel bar mesh laying, arch frame erecting, foot locking anchor rods, radial anchor rods 50 drilling and then concrete re-spraying to the designed thickness; erecting a temporary transverse strut at the bottom, and respectively and sequentially carrying out the above construction on the upper step part, the left part of the lower step and the right part of the lower step; firstly, mechanically excavating an upper step part, establishing a primary supporting structure of the upper step, secondly, mechanically excavating a left side part of a lower step, establishing a primary supporting structure of the left side of the lower step, and spraying concrete again to a designed thickness, and thirdly, mechanically excavating a right side part of the lower step, establishing a primary supporting structure of the right side of the lower step, and spraying concrete again to the designed thickness. The tunnel construction should adhere to the principle of 'weak blasting, short footage, strong support, early sealing and frequent measurement', and the next step is excavated when the sprayed concrete of the previous step reaches more than 70% of the design strength.
More specifically, the above specific steps are as follows: step 21, firstly, mechanically excavating an upper step part, establishing a primary supporting structure at the upper step part, and connecting two rows of first arches 100 by longitudinal steel bars at intervals of 1m along the circumferential direction of the first arches 100 in the process of installing the first arches 100; and arranging double rows of locking anchor pipes 30cm above the arch springing at two sides of the first arch centering 100, drilling an angle of 30 degrees, grouting and reinforcing, finally drilling a radial anchor rod 50, and then spraying concrete again to the designed thickness. After the I-steel frame of the first arch 100 is stabilized, grouting reinforcement is performed on the periphery of the phi 42 grouting small guide pipe 60, radial grouting reinforcement is performed on the periphery of the grouting small guide pipe 60, the length of each grouting small guide pipe 60 is 4.5m, the circumferential distance is 1m, the longitudinal distance is 1.2m, holes are drilled in a staggered mode in the pipe wall in a quincunx mode, the pipe wall is firmly welded with the I-steel frame of the first arch 100, and the locking and anchoring effect is achieved on the I-steel frame. And finally, after the radial anchor rods 50 are drilled, concrete is sprayed again to the designed thickness, a bottom temporary cross brace (namely the first cross brace 101) is erected, the deviation of the hole position of the drilled hole in the grouting reinforcement construction is not more than 10mm, and the deviation of the hole depth is not more than 50mm, so that the rock surface is perpendicular to the drilling direction.
Step 22: mechanically excavating the left part of a lower step, establishing a primary supporting structure at the left side of the lower step, when installing an arch wall steel frame, using longitudinal 32# channel steel for supporting and cushioning to increase the bearing area of the bottom feet of the arch wall steel frame, arranging double rows of lower step locking anchor pipes 31 at the positions 30cm above the arch feet at two sides of the arch wall steel frame, setting the driving angle to be 30 degrees, adopting a small grouting guide pipe 60 for grouting after the arch wall steel frame is stabilized, spraying concrete again to the designed thickness, and indicating 32 in the figure as a lower step outer spraying concrete layer.
Step 23: mechanically excavating the right part of a lower step, establishing a primary supporting structure at the right part of the lower step, when installing an arch wall steel frame, using longitudinal 32# channel steel for supporting and cushioning to increase the bearing area of the bottom feet of the arch wall steel frame, arranging two rows of lower step locking anchor pipes 31 at the positions 30cm above the arch feet at two sides of the arch wall steel frame, setting the driving angle to be 30 degrees, adopting a small grouting guide pipe 60 for grouting after the arch wall steel frame is stabilized, spraying concrete again to the designed thickness, and indicating the 32 in the figure as a lower step concrete layer.
As shown in fig. 1, 100 in fig. 1 is a first bracket of an upper step in an upper step part, 101 is a first cross brace, 11 is an anchor pipe of an upper step locking pin, 12 is an outer concrete layer of the upper step, in the figure, the part I is the upper step part, the part II-1 is the left part of a lower step, and the part II-2 is the right part of the lower step.
Step three, arranging different supporting structures in the arch center according to different deformation conditions of the surrounding rock; if the deformation of the surrounding rock is small, namely the normal deformation of the surrounding rock is within 5cm, a temporary cross brace and an inclined brace are arranged in the arch center; specifically, when the normal deformation of the surrounding rock is within 5cm, the first arch 100 comprises a first i-shaped steel frame 103, a first cross brace 101 and two first inclined braces 102 are arranged inside the first i-shaped steel frame 103, the two first inclined braces 102 are symmetrically installed, two ends of the first cross brace 101 are fixedly connected with middle sections of two sides of the first arch 100, one end of each first inclined brace 102 is connected with the corresponding first cross brace 101, the other end of each first inclined brace 102 is obliquely upwards connected with the corresponding first i-shaped steel frame 103, the welding position of the first inclined brace 102 and the welding position of the corresponding first cross brace 101 do not exceed the middle point of the corresponding first cross brace 101, and the first inclined braces 102 and the corresponding first cross braces 101 are firmly welded to form an included angle of 45 degrees.
When the deformation of the surrounding rock is large, namely the normal deformation of the surrounding rock is 5-10cm, a secondary arch (namely a second arch 200) is placed in the tunnel, a temporary cross brace and an inclined brace are arranged in the second arch 200, a longitudinal connecting rib is arranged between the second arches 200, a certain distance is reserved between the longitudinal connecting rib and the inner wall of the tunnel, a PVC plastic plate with the same shape as the outer edge of the second arch 200 is placed on the outer side of the installed second arch 200, the second arch 200 is removed before a second liner, the second arch 200 is placed in the tunnel, a PVC plate 201 with the same shape as the outer edge of the second arch 200 is arranged between the outer ring surface of the second arch 200 and the inner wall of the tunnel, through holes are formed in the PVC plate 201 in the length direction, the second arch 200 and the PVC plate 201 are connected at the through holes through iron wires, and the longitudinal connecting ribs are fixedly connected between the second arches 200 into a whole. The second arch 200 frames and the pvc plastic plates can be reused, so that the secondary consumption of the arch frames is reduced, and the construction cost is effectively reduced.
In this embodiment, the second arch 200 may have the following structure: the second arch 200 comprises a second i-shaped steel frame 202, a second cross brace 203, two second diagonal braces 204 and two third diagonal braces 205, the two second diagonal braces 204 are symmetrically arranged, one end of each second diagonal brace 204 is fixedly connected with the middle point of the corresponding second cross brace 203, the other end of each second diagonal brace extends upwards in an inclined mode and is connected with the corresponding second i-shaped steel frame 202, one end of each third cross brace 205 is connected with the joint of the corresponding second cross brace 203 and the corresponding second i-shaped steel frame 202, the other end of each third cross brace is connected with the joint of the corresponding second cross brace 203 and the corresponding second i-shaped steel frame 202, and the corresponding second cross brace 203, the corresponding second diagonal braces 204 and the corresponding third diagonal braces 205 enclose an acute triangle.
In the welding manufacturing process, the welding point between the upper end of the inclined strut in the second arch centering 200 and the second arch centering 200 is determined according to the larger deformation point of the survey, and the second inclined strut 204, the third inclined strut 205 and the second transverse strut 203 are ensured to form an acute triangle; after the second arch centering 200 is installed, a pvc plastic plate with the same shape is placed on the outer side, holes are formed in the edge of the pvc plastic plate, and iron wires are used for binding with the steel frame. Longitudinal connecting ribs are arranged among the multiple rows of second arch frames 200, a certain distance is reserved between the longitudinal connecting ribs and the inner wall of the tunnel, and the second arch frames 200 are dismantled before two linings. Radial grouting reinforcement is carried out on the periphery of the phi 42 grouting small guide pipe 60, the length of a single grouting small guide pipe 60 is 4.5m, the circumferential distance is 1m, the longitudinal distance is 1.2m, holes are drilled on the pipe wall in a staggered mode (post-processing), the small grouting guide pipe is arranged in a quincunx mode and is firmly welded with a steel frame, and the I-shaped steel frame at the position is locked and anchored.
It should be noted that, the two rows of arch frames are longitudinally connected by steel bars according to the design requirements, the verticality and the distance meet the design requirements, and a longitudinal connection system is formed; after the arch centering is processed, trial splicing is required, the phenomenon of distortion and warping is avoided, and the connection of joints requires that each truss can be interchanged; the allowable deviation of the section size is +/-20 mm, and the torsion degree is 20 mm.
When the deformation of the surrounding rock reaches the convergence range and the dismantling safety is strictly checked, the surrounding rock can be dismantled, and the follow-up of the subsequent operation needs to be paid attention to; if the surrounding rock stability condition meets the design requirement, the temporary support can be dismantled at one time before the inverted arch concrete is poured, and the once dismantling length is determined according to the inverted arch pouring length (generally 2-3 m).
Excavating a III part of the inverted arch, and constructing an inverted arch primary supporting structure 40; pouring an inverted arch IV part and a side wall foundation at a distance from an inverted arch III part excavated later, and pouring inverted arch V part filling concrete to a designed height after the inverted arch concrete is initially set; and laying a waterproof board.
The excavation length of each step of the steps is not too long, the steps can be properly adjusted according to surrounding rock conditions, but the standard requirements are met, the length of the upper step is 3-10m, and the length of the lower step is 15-25m in the step method; after the inverted arch is excavated, the inverted arch is constructed in time and closed to form a ring; and (3) at the initial support closed position of the V-level surrounding rock, the distance between the inverted arch and the tunnel face is not more than 35 m.
And step five, performing different pretreatments on the tunnel according to different invasion limit degrees, and then completing secondary lining pouring. Specifically, for the limit-invading part which occurs at 0-8cm, a pneumatic pick is adopted to remove the surface layer sprayed and protected concrete so as to ensure that the thickness of the secondary lining meets the requirement, then reinforcing steel bar installation and concrete pouring are carried out, and finally secondary lining pouring is completed; and (3) performing arch change treatment on the part with 8-25cm of limit intrusion, wherein the arch change treatment method adopts 2 groups of phi 42 grouting small ducts 60 to lock and reinforce the I-shaped steel frames of the first and second arches 100 and 200 which do not have limit intrusion, and then adopts a mode of dismantling the limit intrusion I-shaped steel frames one by one. The concrete chiseling of the invasion limit part is achieved through the crushing head, the I-shaped steel frame and the connecting steel bars of the invasion limit part are manually cut off, the structural section is cleaned by the manual air pick which is partially under excavated, the I20B I-shaped steel is installed in time, concrete is sprayed, and then secondary lining pouring is completed.
In the scheme, in the installation process of the arch steel frame, two rows of steel frames are connected by longitudinal steel bars with phi 22 at intervals of 1m along the periphery, so that the arch steel frames are integrated and tightly attached to the closed concrete as much as possible. The longitudinal connecting steel bars between the steel frames are required to be constructed and connected firmly in time, the lock pin pipes and the steel frames are required to be welded firmly, and the temporary cross braces are required to be connected with the steel frames so as to be closed into rings in time.
In the scheme, the allowable deviation of the section sizes of the I-shaped steel frames of the first arch 100 and the second arch 200 is +/-20 mm, and the torsion degree is 20 mm.
In this embodiment, when the v-level surrounding rock section is constructed by a step method, the footage of each circular excavation support of the upper step is not greater than 1 steel frame interval, the footage of each circular excavation support of the side wall is not greater than 2 steel frame intervals, the steel frame locking is required to be completed before the inverted arch excavation, and the footage of each circular excavation support of the inverted arch is not greater than 3 m.
Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (10)
1. A construction supporting method suitable for large deformation of a mudstone tunnel is characterized by comprising the following steps: the method comprises the following specific steps:
selecting a corresponding reinforcing and supporting structure according to the tunnel survey data and the deformation condition after primary supporting;
step two, excavating a tunnel by adopting a step method, and then sequentially carrying out primary concrete spraying, steel bar mesh laying, arch frame erecting, foot locking anchor rods arranging, radial anchor rod drilling and concrete re-spraying to the designed thickness; respectively carrying out the above construction on the upper step part, the left part of the lower step and the right part of the lower step in sequence; firstly, mechanically excavating an upper step part, establishing a primary supporting structure of the upper step, secondly, mechanically excavating a left side part of a lower step, establishing a primary supporting structure of the left side of the lower step, and spraying concrete again to a designed thickness, and thirdly, mechanically excavating a right side part of the lower step, establishing a primary supporting structure of the right side of the lower step, and spraying concrete again to the designed thickness;
step three, according to different surrounding rock deformation conditions, different arch support structures are arranged in the arch of the primary support structure;
fourthly, performing inverted arch excavation and inverted arch primary support structure construction on the section of tunnel, completing inverted arch concrete spraying and inverted arch reinforcing steel bar application, and then completing inverted arch pouring and filling of the section of tunnel;
and step five, performing different pretreatments on the tunnel according to different invasion limit degrees, and then completing secondary lining pouring.
2. The construction supporting method suitable for the large deformation of the mudstone tunnel according to claim 1, which is characterized in that: the second step comprises the following specific steps:
step 21: firstly, mechanically excavating an upper step part, establishing a primary supporting structure at the upper step part, and connecting two rows of first arch frames by using longitudinal steel bars at intervals of 1m along the circumferential direction of the two rows of first arch frames in the process of installing the arch frames of the primary supporting structure; arranging double rows of locking anchor pipes 30cm above the arch springs on the two sides of the first arch centering, drilling an angle of 30 degrees, grouting and reinforcing, and finally drilling a radial anchor rod and then spraying concrete again to the designed thickness;
step 22: mechanically excavating the left part of a lower step, establishing a primary supporting structure at the left side of the lower step, supporting and cushioning by using longitudinal 32# channel steel to increase the bearing area of the bottom feet of the arch wall steel frame when the arch wall steel frame is installed, arranging two rows of lower step locking anchor pipes 30cm above the arch feet at two sides of the arch wall steel frame, setting an angle of 30 degrees, grouting by using a grouting small conduit after the arch wall steel frame is stabilized, and spraying concrete again to the designed thickness;
step 23: mechanically excavating the right part of the lower step, establishing a primary supporting structure at the right part of the lower step, supporting and cushioning by using longitudinal 32# channel steel to increase the bearing area of the bottom feet of the arch wall steel frame when the arch wall steel frame is installed, arranging two rows of lower step locking anchor pipes 30cm above the arch feet at two sides of the arch wall steel frame, setting an angle of 30 degrees, grouting by using a grouting small conduit after the arch wall steel frame is stabilized, and spraying concrete again to the designed thickness.
3. The construction supporting method suitable for the large deformation of the mudstone tunnel as claimed in claim 2, wherein: in the fifth step, removing the surface sprayed and protected concrete by using an air pick on the limit-cutting part of 0-8cm to ensure that the thickness of the second lining meets the requirement, then carrying out steel bar installation and concrete pouring, and finally finishing the pouring of the second lining; and (3) performing arch changing treatment on the part with 8-25cm of invasion limit, chiseling concrete at the part with the invasion limit through a crushing head, cutting out the I-shaped steel and the connecting steel bar with the invasion limit, installing I20B I-shaped steel, spraying concrete, and finally finishing secondary lining pouring.
4. The construction supporting method suitable for the large deformation of the mudstone tunnel according to claim 3, characterized in that: the arch-changing processing method comprises the following specific steps: and (3) adopting 2 groups of phi 42 grouting small ducts to lock and reinforce I-shaped steel frames of the first arch frame and/or the second arch frame which are not subjected to limit intrusion, and then adopting a mode of dismantling the limit intrusion I-shaped steel frames one by one to process.
5. The construction supporting method suitable for the large deformation of the mudstone tunnel as claimed in claim 2, wherein: in the step 21, the periphery of the small grouting pipe phi 42 is radially grouted and reinforced, the single length of each small grouting pipe is 4.5m, the circumferential distance is 1m, the longitudinal distance is 1.2m, holes are drilled on the pipe wall in a staggered mode and are arranged in a quincunx mode, the pipe wall is firmly welded with the I-shaped steel frames of the first arch frame and the second arch frame, and the locking and anchoring effects are achieved for the I-shaped steel frames.
6. The construction supporting method suitable for the large deformation of the mudstone tunnel according to claim 5, characterized in that: the deviation of the hole position of the drilling hole in the grouting reinforcement construction is not more than 10mm, and the deviation of the hole depth is not more than 50mm, so that the rock surface is vertical to the drilling direction.
7. The construction supporting method suitable for the large deformation of the mudstone tunnel according to claim 1, which is characterized in that: in the third step, when the country rock normal direction warp when within 5cm first bow member includes first I-steel frame, establishes a first stull and two first bracing inside first I-steel frame, and two first bracing symmetries are installed, the both ends and the first bow member both sides middle section position fixed connection of first stull, first bracing one end is connected with first stull, and the other end slant is upwards connected with first I-steel frame, just the midpoint of first stull is not crossed with the hookup location of first stull to first bracing.
8. The construction supporting method suitable for the large deformation of the mudstone tunnel according to claim 7, characterized in that: the first inclined strut and the first cross strut form an included angle of 45 degrees.
9. A construction supporting method suitable for large deformation of a mudstone tunnel according to claim 7 or 8, wherein: and in the third step, when the surrounding rock deforms 5-10cm in the normal direction, placing a second arch frame in the tunnel, arranging a PVC plate which has the same shape as the outer edge of the second arch frame between the outer ring surface of the second arch frame and the inner wall of the tunnel, forming a through hole on the PVC plate along the length direction of the PVC plate, connecting the second arch frame and the PVC plate at the through hole through iron wires, and arranging longitudinal connecting ribs among the second arch frames and fixedly connecting the second arch frames into a whole.
10. The construction supporting method suitable for the large deformation of the mudstone tunnel according to claim 9, which is characterized in that: the allowable deviation of the section sizes of the I-shaped steel frames of the first arch frame and the second arch frame is +/-20 mm, and the torsion degree is 20 mm.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115012997A (en) * | 2022-06-23 | 2022-09-06 | 中铁十二局集团有限公司 | Rapid low-disturbance cross intermediate partition wall tunnel secondary lining construction method |
| CN115110966A (en) * | 2022-08-30 | 2022-09-27 | 中铁十六局集团地铁工程有限公司 | Tunnel supporting structure and construction method |
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2021
- 2021-12-18 CN CN202111556878.XA patent/CN114412509A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115012997A (en) * | 2022-06-23 | 2022-09-06 | 中铁十二局集团有限公司 | Rapid low-disturbance cross intermediate partition wall tunnel secondary lining construction method |
| CN115012997B (en) * | 2022-06-23 | 2023-05-16 | 中铁十二局集团有限公司 | Quick low-disturbance cross middle partition wall method tunnel two-lining construction method |
| CN115110966A (en) * | 2022-08-30 | 2022-09-27 | 中铁十六局集团地铁工程有限公司 | Tunnel supporting structure and construction method |
| CN115110966B (en) * | 2022-08-30 | 2022-11-08 | 中铁十六局集团地铁工程有限公司 | Tunnel supporting structure and construction method |
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