CN113803077B - Advanced support construction method for horizontal joint argillaceous shale water-rich tunnel - Google Patents
Advanced support construction method for horizontal joint argillaceous shale water-rich tunnel Download PDFInfo
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- 238000010276 construction Methods 0.000 title claims abstract description 30
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 20
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 63
- 239000010959 steel Substances 0.000 claims abstract description 63
- 239000004570 mortar (masonry) Substances 0.000 claims abstract description 33
- 238000005507 spraying Methods 0.000 claims abstract description 29
- 238000000034 method Methods 0.000 claims abstract description 27
- 238000009412 basement excavation Methods 0.000 claims abstract description 20
- 239000004567 concrete Substances 0.000 claims abstract description 11
- 238000007596 consolidation process Methods 0.000 claims abstract description 7
- 239000011378 shotcrete Substances 0.000 claims abstract description 7
- 238000007789 sealing Methods 0.000 claims abstract description 5
- 238000005553 drilling Methods 0.000 claims description 17
- 239000011435 rock Substances 0.000 claims description 14
- 238000005422 blasting Methods 0.000 claims description 10
- 238000009434 installation Methods 0.000 claims description 7
- 238000006073 displacement reaction Methods 0.000 claims description 6
- 239000000463 material Substances 0.000 claims description 4
- 239000011405 expansive cement Substances 0.000 claims description 3
- 239000004746 geotextile Substances 0.000 claims description 3
- 239000007788 liquid Substances 0.000 claims description 3
- 239000004568 cement Substances 0.000 description 4
- 230000003014 reinforcing effect Effects 0.000 description 3
- 230000005641 tunneling Effects 0.000 description 3
- 238000003466 welding Methods 0.000 description 3
- 230000008901 benefit Effects 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 238000004873 anchoring Methods 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D9/00—Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
- E21D9/001—Improving soil or rock, e.g. by freezing; Injections
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/04—Lining with building materials
- E21D11/10—Lining with building materials with concrete cast in situ; Shuttering also lost shutterings, e.g. made of blocks, of metal plates or other equipment adapted therefor
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/14—Lining predominantly with metal
- E21D11/15—Plate linings; Laggings, i.e. linings designed for holding back formation material or for transmitting the load to main supporting members
- E21D11/152—Laggings made of grids or nettings
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/14—Lining predominantly with metal
- E21D11/18—Arch members ; Network made of arch members ; Ring elements; Polygon elements; Polygon elements inside arches
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D20/00—Setting anchoring-bolts
- E21D20/02—Setting anchoring-bolts with provisions for grouting
- E21D20/021—Grouting with inorganic components, e.g. cement
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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
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Abstract
The invention relates to the technical field of tunnel construction, in particular to a construction method for a horizontal joint argillaceous shale water-rich tunnel advance support, which comprises the following steps: step S1, determining a grouting consolidation outer edge line of the tunnel, performing pre-grouting, and step S2, performing grouting after jacking a support pipe; step S3, pre-grouting the pre-grouting holes, and excavating by a step method after grouting is finished; step S4, arranging mortar anchor rods on the tunnel vault corresponding to the upper step, grouting, and taking down the mold to form a placing groove after the initial setting of the initial sprayed concrete; step S6, installing a grid steel frame in the placing groove, step S7, excavating a lower step of the tunnel, arranging an inverted arch and an arch steel frame after the excavation is finished, correspondingly connecting the arch steel frame with the grid steel frame, and primarily spraying the arch of the tunnel; and step S8, re-spraying after the primary spraying is finished until the inverted arch part is subjected to concrete bottom sealing to finish primary support.
Description
Technical Field
The invention belongs to the technical field of tunnel construction, and particularly relates to a forepoling construction method for a horizontal joint argillaceous shale water-rich tunnel.
Background
At present, in tunnel engineering construction in China, although the whole process is mature and complete, safety accidents of partial tunnel engineering still occur frequently in the construction process, and the main reasons are uncertainty and unpredictability of various reasons such as stratum lithology, geological structure, underground water distribution and the like of the tunnel engineering, so that construction experience of special geology and landform cannot be used for reference in the construction process.
The advance support is a common measure for ensuring the construction safety in the tunnel excavation process, and mainly comprises modes of an advance pipe shed, an advance small conduit, an advance anchor rod, advance grouting and the like. Most of the prior advance supports in the tunnel blind hole adopt a mode of a small advanced guide pipe, but for horizontal joint fissure shale geology, the safety and the stability of surrounding rocks on a tunnel face cannot be effectively guaranteed.
Therefore, there is a need to provide an improved solution to the above-mentioned deficiencies of the prior art.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide an excavation method for a horizontal joint argillaceous shale water-rich tunnel.
In order to achieve the above purpose, the invention provides the following technical scheme:
a construction method for a horizontal joint argillaceous shale water-rich tunnel advance support comprises the following steps:
step S1, determining a grouting consolidation outer edge line of the tunnel, performing point location lofting of pre-grouting holes on the cross section of the tunnel, and drilling holes, wherein the pre-grouting holes are arranged in a plurality of circles, each circle of pre-grouting holes are uniformly distributed in the circumferential direction of the cross section of the tunnel, and any circle of pre-grouting holes extend towards the grouting consolidation outer edge line in an umbrella-shaped inclined manner in the excavation direction of the tunnel;
step S2, lofting according to a design drawing, drilling a supporting pipe jacking hole on a lofting coordinate through a drilling machine, jacking the supporting pipe and then grouting;
step S3, pre-grouting the pre-grouting holes, and excavating by a step method after grouting is finished;
step S4, after the excavation of the upper step corresponding to the tunnel is finished, drilling a mortar anchor rod at the vault of the tunnel corresponding to the upper step and grouting, after the grouting is finished, connecting a mould corresponding to the grid steel frame on the mortar anchor rod, and performing primary concrete spraying;
step S5, arranging a mesh between the adjacent dies after the primary spraying is finished; taking down the mould to form a placing groove after the initial setting of the initial sprayed concrete;
step S6, installing a grid steel frame in the placing groove, wherein the grid steel frame is matched with the arch crown part of the tunnel;
step S7, excavating the lower steps of the tunnel, arranging an inverted arch and an arch foot steel frame after the excavation is finished, correspondingly connecting the arch foot steel frame with a grid steel frame, and primarily spraying the arch foot of the tunnel;
and step S8, after the initial spraying at the arch foot of the tunnel is finished, re-spraying the tunnel part corresponding to the upper step and the lower step, applying work from the arch crown of the tunnel to the arch foot in the re-spraying process until the concrete bottom sealing is carried out on the inverted arch part, and finishing the initial supporting.
Preferably, in the initial stage of tunnel excavation, the mountain slope is excavated to form a tunnel section, and a guide wall is arranged at the tunnel section to guide the support pipe, wherein the support pipe is a pipe shed.
Preferably, in step S2, the supporting tube includes a small advance guide tube and advance anchor rods, and the small advance guide tube and the advance anchor rods are arranged in a staggered manner at intervals in the tunnel extending direction.
Preferably, the distance between the upper step and the lower step is controlled within 5 m-10 m, and the distance between the lower step and the inverted arch is controlled within 25 m-30 m.
Preferably, after the primary support of the tunnel is finished, secondary lining construction is carried out when the horizontal deformation rate of the tunnel is less than 0.2mm/d, the sinking rate of the arch part is less than 0.15mm/d or the accumulated displacement value reaches more than 90% of the limit displacement; the distance between the inverted arch and the secondary lining is controlled within 30m-40 m.
Preferably, waterproof boards and geotextiles are laid between the primary support and the secondary lining of the tunnel.
Preferably, the primary support structure is sealed into a ring and then backfilled and grouted, the backfilled and grouted pipe is a PVC grouting flower pipe, the grouting material is micro-expansive cement mortar, and grouting can be finished when the pressure of the backfilled and grouted liquid reaches 0.2 mpa.
Preferably, the backfill grouting pipe is embedded between the outer side of the grid steel frame and the installation groove and between the outer side of the arch foot steel frame and the tunnel surrounding rock.
Preferably, the tunnel is pre-grouted through the orifice pipe, the orifice pipe is pulled out after the tunnel is initially set, and the pre-grouted hole is used as a blasting hole for blasting.
Has the advantages that: set up the mould and reserve the mounting groove that corresponds the grid steelframe after just spouting, help improving the installation effectiveness, reduce the installation degree of difficulty, the wholeness that the reinforcing tunnel was strutted.
After the lower step is primarily sprayed, secondary spraying can be carried out, secondary spraying and bottom sealing can be completed at one time, the supporting process is simplified, the working efficiency is improved, and the connection strength between primary spraying and secondary spraying is enhanced.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. Wherein:
FIG. 1 is a schematic diagram of pre-grouting hole distribution in an embodiment of the present invention;
FIG. 2 is a schematic view of the pre-grouting hole extending direction in the embodiment of the present invention;
FIG. 3 is a schematic cross-sectional view of a tunnel according to an embodiment of the present invention;
FIG. 4 is a schematic view of a grid steel frame installation according to an embodiment of the present invention;
FIG. 5 is a schematic view of a grid steel frame according to an embodiment of the present invention;
FIG. 6 is a schematic view of the connection between the grid steel frame and the mortar anchor rods according to the embodiment of the present invention;
fig. 7 is a schematic view of the arrangement of the foot-locking anchor rod in the embodiment provided by the invention.
In the figure: 1. grouting and solidifying the outer edge line; 2. a tunnel contour line; 3. pre-grouting holes; 4. primary support; 5. secondary lining; 6. a support tube; 7. a mortar anchor rod; 8. a grid steel frame; 9. reinforcing ribs; 10. pressing a plate; 11. locking the anchor rod; 12. an arch foot steel frame; 13. an inverted arch; 21. an upper step; 22. descending a step; 61. a small advanced catheter; 62. and (5) leading the anchor rod.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments that can be derived by one of ordinary skill in the art from the embodiments given herein are intended to be within the scope of the present invention.
In the description of the present invention, the terms "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are for convenience of description of the present invention only and do not require that the present invention must be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. The terms "connected" and "connected" used herein should be interpreted broadly, and may include, for example, a fixed connection or a detachable connection; they may be directly connected or indirectly connected through intermediate members, and specific meanings of the above terms will be understood by those skilled in the art as appropriate.
The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings. It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
As shown in fig. 1-7, a method for constructing a horizontal joint shale water-rich tunnel advance support comprises the following steps: step S1, determining a tunnel contour line 2 and a grouting consolidation outer edge line 1 of the tunnel, performing point-to-point lofting of pre-grouting holes 3 on the cross section of the tunnel, and drilling holes, wherein the number of the pre-grouting holes is multiple, each circle of the pre-grouting holes are uniformly distributed in the circumferential direction of the cross section of the tunnel, and any circle of the pre-grouting holes obliquely extend towards the grouting consolidation outer edge line 1 in an umbrella shape in the tunnel excavation direction; therefore, the surrounding rock around the tunnel is grouted and reinforced, the stability of the tunnel in the grouting process is improved, and the construction safety is ensured; step S2, lofting according to a design drawing, drilling a supporting pipe 6 jack-in hole on a lofting coordinate through a drilling machine, cleaning the drilled hole after the drilling is finished, and grouting after the supporting pipe 6 is jacked into the drilled hole; the diameter of the drilled hole is slightly larger than that of the supporting pipe 6, the external inserting angle of the inclined angle of the drilled hole is not more than 12 degrees, after the hole is cleaned, the drilled hole is hammered or jacked by a drilling machine, the jacking length is not less than 95 percent of the length of the steel pipe, and sand in the steel pipe is blown out again by high-pressure air. Step S3, pre-grouting the pre-grouting hole 3, and excavating by a step method after grouting is finished; step S4, after the excavation of the upper step 21 corresponding to the tunnel is finished, the excavation footage of each cycle of the upper step 21 is not more than 2 arch frame intervals, and the interval of each arch frame is 0.6 m; timely arranging mortar anchor rods 7 on the excavated upper step 21, and timely grouting, wherein the mortar anchor rods 7 extend along the radial direction of the arch crown and are distributed on the unfolded surface of the arch crown in a plum blossom shape, and the distance between every two adjacent mortar anchor rods 7 is not more than 0.6 m; after grouting, connecting the moulds corresponding to the grid steel frames 8 on the mortar anchor rods 7 in a detachable mode, performing concrete primary spraying, and step S5, arranging meshes between the adjacent moulds after the primary spraying is finished, wherein the meshes are correspondingly connected with the mortar anchor rods 7; taking down the mould to form a placing groove after the initial setting of the initial sprayed concrete; step S6, installing grid steel frame 8 in the placing groove, wherein the grid steel frame 8 is matched with the arch crown part of the tunnel, the depth of the placing groove formed after the mold is removed depends on the thickness of the primary sprayed concrete, the grid steel frame 8 is positioned, the problem that the installation difficulty is large due to the fact that the grid steel frame 8 is not accurate enough (especially large) is solved, the construction efficiency is improved, besides, the grid steel frame 8 is arranged between the primary support 4 and the secondary lining 5, the integrity of the lining can be improved, and the supporting strength is improved. Step S7, the lower step 22 of the tunnel is excavated, after the excavation is finished, an inverted arch 13 and an arch foot steel frame 12 are arranged, the arch foot steel frame 12 is correspondingly connected with the grid steel frame 8, the inverted arch 13 is connected with the arch foot steel frame 12, the supporting footage of the lower step 22 is not more than 3 arch frame intervals in each cycle of excavation, and the tunnel arch foot position is primarily sprayed. Step S8, after the initial spraying at the arch foot of the tunnel is finished, re-spraying all the tunnel parts corresponding to the upper step 21 and the lower step 22, applying the re-spraying from the arch crown of the tunnel to the arch foot in the re-spraying process, spraying the part corresponding to the lower step 22 and the inverted arch to the preset thickness of the initial support concrete until the concrete bottom sealing is carried out on the part 13 of the inverted arch to finish the initial support 4; during the spraying process, the concrete is sprayed downwards along the S-shaped horizontal direction in a reciprocating mode, a concave position of a sprayed surface is leveled before spraying, then the spray head is made to move slowly and uniformly in a spiral mode, each circle presses half of the front circle, the diameter of each circle is about 30cm, and the aim that the sprayed concrete layer surface is smooth is achieved. The arch foot steel frames 12 and the inverted arch 13 can be of grid structures or I-steel structures, and reinforcing ribs 9 are arranged between every two adjacent grid steel frames.
In the embodiment, the grouting length of each cycle of pre-grouting is 30 meters, and the pre-grouting is performed once every 22 meters of excavation, so that the excavation is performed forwards in a cycle. And repeating the steps S2-S8, and excavating the tunnel after each cycle of pre-grouting.
In another alternative embodiment, in the initial stage of tunnel excavation, a mountain slope is excavated to form a tunnel section, and pre-grouting is performed on the section; and a guide wall is arranged at the section of the tunnel to guide the support pipe 6, and the support pipe 6 adopted by the guide wall is a pipe shed. The pipe shed adopts phi 108 seamless steel pipes, the number of the inlet parts of the pipe shed is 45, the length of the pipe shed is 40m, the ring distance is 80cm (from the steel pipe to the steel pipe and from the steel pipe to the steel flower pipe is 40 cm), and the front end of each section of hot-rolled seamless steel pipe (the hot-rolled seamless steel pipe with the outer diameter phi 108mm and the wall thickness of 6 mm) with the length of 4-6m is conical; the guide wall is mainly composed of 2I 18 hot-rolled light I-shaped steel frames and C20 concrete. The construction process of the guide wall comprises the following steps: measuring and lofting → erecting a support frame and profile steel → installing a bottom die → erecting positioning steel bars → positioning and welding a guide pipe → installing a side die → pouring and curing concrete → detaching a die.
Before the supporting pipe 6 is jacked into a hole and drilled, the small mileage side of the guide wall construction operation platform is cut downwards, and the cutting depth is 1.5 m; and after cutting, forming a drilling machine construction platform, wherein the distance between the platform and the guide pipe is 2-3 m. The method adopts a process combining large-hole guiding and pipe shed drilling, namely, a guide hole with the diameter larger than that of a shed pipe is drilled firstly, then the shed pipe provided with the working pipe head is drilled along the guide hole by utilizing the impact and the thrust of a modified drilling machine, and the shed pipe is lengthened until the bottom of the hole. And finally, pure cement slurry with the water-cement ratio of 1:1 (weight ratio) is injected into the supporting pipe 6, and the strength grade of the injected cement is 42.5. The initial grouting pressure is 0.5-2.0 MPa, and the final grouting pressure is 2.0 MPa.
In another alternative embodiment, in step S2, the supporting tube 6 includes the small advancing guide tube 61 and the advance anchor rods 62, and the small advancing guide tube 61 and the advance anchor rods 62 are arranged in a staggered manner in the extending direction of the tunnel, or the small advancing guide tube 61 and the advance anchor rods 62 are arranged in a staggered manner in the same section of the tunnel.
The small advanced guide pipe 61 is a hot-rolled seamless steel perforated pipe, and is 3.5m long, 42mm in outer diameter and 3.5mm in wall thickness; the advanced anchor rod 62 adopts a cartridge anchor rod or a mortar anchor rod with the diameter of 22mm, and the length of a single anchor rod is 3.5 m; the annular distance between each ring of the advanced small guide pipes 61 is 0.6m, the annular distance between the advanced anchor rods 62 is 0.6m, and the small guide pipes and the anchor rods are arranged in a staggered mode at intervals. The horizontal joint argillaceous shale water-rich tunnel adopts a small conduit and anchor rod combination mode to be used for advance support structure, combines together the rigidity of small conduit and the flexibility of anchor rod, can effectively play the effect of strutting more, greatly increased the security. In the construction process, the horizontal joint surrounding rock fracture layering condition is combined, the angle range of the external inserting angle of the advance support is adjusted to be 10-20 degrees, the horizontal lap joint length of two rows of longitudinally adjacent anchor rods is not less than 100cm, and the anchor rods are welded with a steel frame. Therefore, the integral stability of the surrounding rock of the arch part is better protected, and vault collapse is avoided. Because the horizontal joint argillaceous shale has dense cracks, the grouting amount of the surrounding rock in front of the face is increased by encrypting the small guide pipe grouting holes, the surrounding rock is sealed, and the water stopping effect is achieved.
In another alternative embodiment, the distance between the upper step 21 and the lower step 22 is controlled within 5m to 10m, and the distance between the lower step 22 and the inverted arch 13 is controlled within 25m to 30 m. After the primary support of the tunnel is finished, when the horizontal deformation rate of the tunnel is less than 0.2mm/d, the sinking rate of the arch part is less than 0.15mm/d or the accumulated displacement value reaches more than 90% of the limit displacement, the construction of a secondary lining 5 can be carried out; the distance between the inverted arch 13 and the secondary lining 5 is controlled within 30m-40 m. The working face of the entrance of the secondary lining 5 tunnel main tunnel is provided with one 12 m-long full-face lining trolley and two 9 m-long full-face lining trolleys, the lapping length of the lining trolley and the previous mould lining is more than 10cm, phi 20 galvanized grouting steel pipes are pre-buried at the top of the tunnel when the secondary lining 5 is constructed, the galvanized grouting steel pipes are longitudinally spaced by 3m, and each plate is lined with not less than 2 holes; the grouting material adopts cement paste, and the backfill grouting pressure is 0.2 MPa. And after the slurry is finally set, checking the grouting quality by adopting a geological radar, and if necessary, drilling holes for re-grouting or backfilling and grouting by utilizing a galvanized grouting steel pipe.
In another alternative embodiment, waterproof boards and geotextiles are laid between the tunnel preliminary supports 4 and the secondary lining 5. And in order to improve the waterproof capability of the tunnel, backfilling and grouting are carried out after the primary support 4 structure is sealed into a ring, the backfilling and grouting pipe is a PVC grouting floral tube, the grouting material is micro-expansive cement mortar, and grouting can be finished when the pressure of the backfilling and grouting liquid reaches 0.2 mpa.
Backfill grouting pipes are at least pre-buried between the outer side of the grid steel frame 8 and the mounting groove, between the outer side of the arch foot steel frame 12 and the tunnel surrounding rock, and between the arch crown of the primary support 4 and the tunnel surrounding rock. After the primary support back is reinforced, disturbed surrounding rocks are excavated and possible gaps of sprayed concrete are filled, so that the looseness of the surrounding rocks, surface subsidence and structural water seepage are reduced to the maximum extent, gaps in the outer sides of the grid steel frames 8 or the arch foot steel frames 12 can be effectively avoided, and the support quality is improved.
In another alternative embodiment, the tunnel is pre-grouted through the orifice pipe, the orifice pipe is pulled out after the tunnel is initially set, and 3 holes of the pre-grouted hole are used as blasting holes for blasting. In the tunneling process, the excavation section can be broken by adopting a micro-blasting mode, the construction difficulty can be reduced by adopting the blasting mode, the argillaceous shale is soft in texture, a blast hole does not need to be drilled again, only blasting is carried out in 3 holes of a pre-grouting hole, after a surface rock layer is broken, the tunnel is continuously tunneled by a step method, the method is used when a whole rock is encountered in the tunneling process of the tunnel, the tunneling difficulty of the excavator is reduced after blasting, and the construction speed is increased.
When the section of the side slope is excavated, the side slope is excavated step by step from top to bottom, and greening protection is carried out on the upward slope and the side slope at the entrance of the tunnel.
In another alternative embodiment, a locking bolt 11 is arranged at the arch foot steel frame 12 to improve the supporting strength. After the grid steel frame 8 is arranged, connecting the net sheet with the grid steel frame 8 into a whole in a welding mode; and laying the mesh after the initial spraying is carried out on the arch springing of the tunnel, and welding the mesh with the mesh at the arch top or overlapping the mesh to a certain extent.
The mould is for corresponding 8 profile's of grid steelframe PVC spare or aluminum alloy spare, can be I shape or channel-section steel column structure, when carrying out mortar anchor 7 and beat and establish, the both sides that same grid steelframe corresponds the position will correspond three group's mortar anchor 7 at least, three mortar anchor 7 corresponds grid steelframe both ends and middle part respectively, every group mortar anchor 7 has two, be equipped with clamp plate 10 between two mortar anchor 7, clamp plate 10 both ends are fixed through the anchor nut of mortar anchor 7 respectively, fix grid steelframe or mould with this, after the installation of grid steelframe, between clamp plate 10 and mortar anchor 7, weld between clamp plate 10 and the grid steelframe.
Or, three mortar anchor 7 should be corresponded to at least of same grid steelframe correspondence position, three mortar anchor 7 corresponds grid steelframe both ends and middle part respectively, erect the back at the grid steelframe, treat the mortar initial set, mortar anchor 7 passes or stretches into the grid steelframe, it fixes the grid steelframe to do benefit to the anchor board, it is corresponding with it, be provided with on the mould along its length direction extension, the bar perforation of corresponding mortar anchor 7, so that the mould is installed, mortar anchor 7 passes behind the mortar anchor 7 and fixes through the anchor board, and the part that corresponds mortar anchor 7 at the mould sets up the apron, avoid the big problem of the later stage post-guniting dismantlement degree of difficulty. In the process of installing the die, if the corresponding mortar anchor rod 7 is arranged at the non-strip-shaped perforation position, the part of the mortar anchor rod 7, which protrudes out of the corresponding anchoring plate, is cut off. It should be understood that the above description is only exemplary, and the embodiments of the present application do not limit the present invention.
The above description is only exemplary of the invention and should not be taken as limiting the invention, as any modification, equivalent replacement, or improvement made within the spirit and principle of the invention is intended to be covered by the appended claims.
Claims (9)
1. A construction method for advanced support of a horizontal joint argillaceous shale water-rich tunnel is characterized by comprising the following steps:
step S1, determining a grouting consolidation outer edge line of the tunnel, performing point location lofting of pre-grouting holes on the cross section of the tunnel, and drilling holes, wherein the pre-grouting holes are arranged in a plurality of circles, each circle of pre-grouting holes are uniformly distributed in the circumferential direction of the cross section of the tunnel, and any circle of pre-grouting holes extend towards the grouting consolidation outer edge line in an umbrella-shaped inclined manner in the excavation direction of the tunnel;
step S2, lofting according to a design drawing, drilling a supporting pipe jacking hole on a lofting coordinate through a drilling machine, jacking the supporting pipe and then grouting;
step S3, pre-grouting the pre-grouting holes, and excavating by a step method after grouting is finished;
step S4, after the excavation of the upper step corresponding to the tunnel is finished, drilling a mortar anchor rod at the vault of the tunnel corresponding to the upper step and grouting, connecting a mould corresponding to the grid steel frame on the mortar anchor rod in a detachable mode after the grouting is finished, and performing initial concrete spraying;
step S5, arranging a mesh between the adjacent dies after the primary spraying is finished; taking down the mould to form a placing groove after the initial setting of the initial sprayed concrete;
step S6, installing a grid steel frame in the placing groove, wherein the grid steel frame is matched with the arch crown part of the tunnel;
step S7, excavating the lower steps of the tunnel, arranging an inverted arch and an arch foot steel frame after the excavation is finished, correspondingly connecting the arch foot steel frame with a grid steel frame, and primarily spraying the arch foot of the tunnel;
and step S8, after the initial spraying at the arch foot of the tunnel is finished, re-spraying the tunnel part corresponding to the upper step and the lower step, applying work from the arch crown of the tunnel to the arch foot in the re-spraying process until the concrete bottom sealing is carried out on the inverted arch part, and finishing the initial supporting.
2. The method for constructing the advanced support of the horizontal joint argillaceous shale water-rich tunnel according to claim 1, wherein in the initial stage of tunnel excavation, a mountain slope is excavated to form a tunnel section, and a guide wall is arranged at the tunnel section to guide a support pipe, wherein the support pipe is a pipe shed.
3. The method for constructing the advanced support of the horizontal joint shale water-rich tunnel according to claim 1, wherein in the step S2, the support pipe comprises small advanced guide pipes and advanced anchor rods, and the small advanced guide pipes and the advanced anchor rods are arranged in a staggered mode at intervals in the tunnel extending direction.
4. The construction method for the advanced support of the horizontal joint argillaceous shale water-rich tunnel according to claim 1, wherein a distance between an upper step and a lower step is controlled within 5 m-10 m, and a distance between the lower step and an inverted arch is controlled within 25 m-30 m.
5. The construction method for the advanced support of the horizontal joint argillaceous shale water-rich tunnel according to claim 4, wherein after the initial support of the tunnel is completed, secondary lining construction is performed until the horizontal deformation rate of the tunnel is less than 0.2mm/d, the sinking rate of the arch part is less than 0.15mm/d or the accumulated displacement value reaches more than 90% of the limit displacement; the distance between the inverted arch and the secondary lining is controlled within 30m-40 m.
6. The construction method for the advanced support of the horizontal joint argillaceous shale water-rich tunnel according to claim 5, wherein a waterproof board and geotextile are laid between the primary support and the secondary lining of the tunnel.
7. The construction method for the advanced support of the horizontally jointed shale water-rich tunnel according to claim 1, wherein the primary support structure is sealed into a ring and then backfilled and grouted, the backfilled and grouted pipe is a PVC grouting flower pipe, the grouting material is micro-expansive cement mortar, and grouting can be finished when the pressure of the backfilled and grouted liquid reaches 0.2 mpa.
8. The construction method for the advanced support of the horizontal joint argillaceous shale water-rich tunnel according to claim 7, wherein backfill grouting pipes are pre-buried between the outer side of the grid steel frame and the installation groove and between the outer side of the arch foot steel frame and tunnel surrounding rocks.
9. The construction method for the advanced support of the horizontal joint argillaceous shale water-rich tunnel according to claim 1, wherein the tunnel is pre-grouted through the orifice pipe, the orifice pipe is pulled out after the tunnel is initially set, and the pre-grouted hole is used as a blasting hole for blasting.
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| CN109184742B (en) * | 2018-09-19 | 2020-04-07 | 中国水利水电第四工程局有限公司 | Advanced pre-grouting method for high-pressure water-rich soft surrounding rock mountain tunnel |
| CN111042823B (en) * | 2019-12-30 | 2021-12-28 | 中国铁建投资集团有限公司 | Non-blasting through method for tunnel in complex environment |
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