CN111271080A - Pipe shed construction method for soft surrounding rock section of tunnel portal - Google Patents
Pipe shed construction method for soft surrounding rock section of tunnel portal Download PDFInfo
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- CN111271080A CN111271080A CN202010261851.7A CN202010261851A CN111271080A CN 111271080 A CN111271080 A CN 111271080A CN 202010261851 A CN202010261851 A CN 202010261851A CN 111271080 A CN111271080 A CN 111271080A
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- 238000010276 construction Methods 0.000 title claims abstract description 41
- 239000011435 rock Substances 0.000 title claims abstract description 23
- 238000005553 drilling Methods 0.000 claims abstract description 76
- 238000000034 method Methods 0.000 claims abstract description 44
- 238000007789 sealing Methods 0.000 claims abstract description 12
- 239000002689 soil Substances 0.000 claims abstract description 12
- 238000002360 preparation method Methods 0.000 claims abstract description 5
- 229910000831 Steel Inorganic materials 0.000 claims description 20
- 239000010959 steel Substances 0.000 claims description 20
- 239000004567 concrete Substances 0.000 claims description 13
- 238000013459 approach Methods 0.000 claims description 8
- 238000013461 design Methods 0.000 claims description 7
- 238000003466 welding Methods 0.000 claims description 6
- 238000012545 processing Methods 0.000 claims description 5
- 238000006243 chemical reaction Methods 0.000 claims description 4
- 230000009977 dual effect Effects 0.000 claims description 4
- 230000002787 reinforcement Effects 0.000 claims description 4
- 230000000087 stabilizing effect Effects 0.000 claims description 4
- 239000011378 shotcrete Substances 0.000 claims description 3
- 238000009412 basement excavation Methods 0.000 abstract description 18
- 239000004927 clay Substances 0.000 abstract description 4
- 230000000694 effects Effects 0.000 abstract description 4
- 238000005516 engineering process Methods 0.000 abstract description 4
- 239000004576 sand Substances 0.000 abstract description 3
- 239000002002 slurry Substances 0.000 description 6
- 239000000463 material Substances 0.000 description 4
- 238000002156 mixing Methods 0.000 description 4
- 239000011440 grout Substances 0.000 description 3
- 239000002023 wood Substances 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 229910001294 Reinforcing steel Inorganic materials 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 238000009415 formwork Methods 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000011150 reinforced concrete Substances 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000012360 testing method Methods 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
-
- 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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- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- Excavating Of Shafts Or Tunnels (AREA)
Abstract
The invention discloses a pipe shed construction method for a weak surrounding rock section of a tunnel portal, which comprises the following steps: step one, construction preparation; step two, measuring and paying off; step three, constructing a guide wall; step four, sealing the tunnel face, the side slope surface and the upward slope surface; fifthly, positioning a drilling machine; step six, drilling; step seven, withdrawing the drilling tool; step eight, grouting; and step nine, hole sealing. The precision of pipe shed construction is ensured by adopting a guiding technology, the drilling process provides reference for tunnel excavation to geological records, and effective advance support provides technical support for tunnel excavation. The invention has the advantages of accurate drilling process, no phenomena of deviated holes and hole collapse, high hole forming efficiency, suitability for environments with complex geological conditions and loose soil, such as sand layers, clay layers and the like, and very obvious obtained effect.
Description
Technical Field
The invention relates to a tunnel construction method, in particular to a pipe shed construction method for a weak surrounding rock section at a tunnel portal, and belongs to the technical field of tunnel construction.
Background
In the construction of the tunnel portal of the high-speed railway tunnel engineering in China, the pipe shed is very common as a forepoling for entering the tunnel, the construction method is also very mature, and the common method adopts two construction methods, namely a pilot hole jacking method construction and a pipe following drilling method construction. The pipe shed working principle mainly has two: the beam structure forms a simply supported beam through the portal guide wall and the rock layer in the tunnel; secondly, solidifying surrounding rocks around the steel pipe through grouting, and enabling the steel pipe and the surrounding rocks to jointly form an arching effect; the two form a shell-shaped structure surrounding the contour of the tunnel, thereby effectively inhibiting the surrounding rock from loosening and collapsing. Although the conventional construction process is provided with the hole guide pipe, due to uneven geology, the phenomenon of hole deviation of the pipe shed is frequently generated in the hole leading or drilling process, the inspection means is limited in the construction process, the track of the pipe shed in the drilling process cannot be mastered, the purpose of finally grouting and consolidating the periphery of tunnel excavation cannot be effectively achieved, and the phenomenon that the tail of the pipe shed falls into an excavation contour line is often found after excavation, so that the pipe shed of the conventional construction method is generally controlled within 30-40 m, the construction progress is relatively slow, and the construction precision is relatively low.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the pipe shed construction method for the soft surrounding rock section of the tunnel portal is characterized in that an ultra-long pipe shed follow-up pipe technology is adopted, namely, a pipe shed is formed for 100m at one time, the pipe shed construction precision is ensured by adopting a guiding technology, the drilling process provides reference for tunnel excavation, effective advance support provides technical support for tunnel excavation, and the existing problems are effectively solved.
The technical scheme of the invention is as follows: a pipe shed construction method for a weak surrounding rock section of a tunnel portal comprises the following steps: step one, construction preparation; step two, measuring and paying off; step three, constructing a guide wall; step four, sealing the tunnel face, the side slope surface and the upward slope surface; fifthly, positioning a drilling machine; step six, drilling; step seven, withdrawing the drilling tool; step eight, grouting; and step nine, hole sealing.
In the third step, firstly, installing an inner arch frame of the guide wall; secondly, embedding a guide pipe, wherein the guide pipe is firmly welded with the arch center; and finally, erecting the guide wall and pouring concrete.
And in the fourth step, the concrete is encapsulated by sprayed concrete, and the thickness is more than or equal to 20 cm.
In the sixth step: (1) processing a drill rod: the rod body is 8m in section, an internal screw opening is turned at one end, an external screw opening is turned at the other end, and local welding reinforcement is performed during connection;
(2) the drill rod is connected with a drilling machine: an eccentric drill bit is welded in front of the first section of the drill rod, and the rear part of the rod body is in threaded connection with a drilling tool;
(3) correcting the deviation, namely installing a guide instrument device in the first section rod body, wherein the guide instrument device comprises a positioner for positioning a drill bit, the positioner is placed on a steel plate, two sides of the positioner are fixed by steel pipes, the positioner is connected with a display through a cable, and the display is connected with an external power supply through frequency conversion equipment; in the drilling process, a positioner in a drill steel pipe transmits the drilling condition to a display through a cable, an operator corrects the drilling deviation condition of a rod body fed back by the display in time, and the power is adjusted through manually operating a drilling machine along with the drilling length and the soil layer geological condition to ensure the depth and the position of the drilling machine until the required depth and position are reached;
(4) recording geological conditions: and in the drilling process, the front geological condition is recorded in time according to the rock debris condition.
In the step eight, the grouting sequence of the pipe shed follows the principle of 'first two sides and then middle, and from thin to thick'; the grouting process adopts dual standards of quantity control and pressure control.
The standard of grouting ending is that single-hole grouting can be considered to meet the design requirement and grouting can be ended as long as one of the following three conditions is met: firstly, gradually raising the grouting pressure, and stabilizing for 10min after the designed final pressure is reached; secondly, the grouting amount is not less than 80% of the designed grouting amount; third, the approach velocity is 1/4 of the starting approach velocity.
The invention has the beneficial effects that: compared with the prior art, the invention has the following beneficial effects:
1. the drilling process is accurate, the phenomena of deviated holes and hole collapse are avoided, the hole forming efficiency is high, and the method is suitable for sand layers, clay layers and the like with complex geological conditions and loose soil texture;
2. the power output is uniform in the construction process, and the interference to the geology is less;
3. the water consumption is less in the drilling process, high-pressure air is adopted for forced drilling (dry drilling) in a soil layer by using power, water is controlled in a rock stratum, and the method is particularly suitable for gravel soil, clay layer soil layers and sandy soil layers;
4. the hole forming speed is high, and the work efficiency is high;
5. one end of the long pipe shed enters the bedrock, the other end of the long pipe shed is a tunnel portal guide wall, and the two ends of the long pipe shed are fixed ends, so that the effect of a simply supported beam can be effectively controlled, and the effect of controlling the excavation deformation of a tunnel portal section is obvious;
6. the super-long pipe shed can effectively detect the front stratum condition and provide reference for subsequent tunnel excavation.
Drawings
FIG. 1 is a flow chart of the construction process of the present invention;
FIG. 2 is a schematic view of the working principle of the guide instrument device of the present invention;
FIG. 3 is a schematic view of the guide wall formwork erection of the present invention;
FIG. 4 is a schematic view of the orifice tube construction drilling of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below.
Example 1: a construction method of an ultralong pipe shed at a weak surrounding rock section of a tunnel portal comprises the following steps: step one, construction preparation; step two, measuring and paying off; step three, constructing a guide wall 9; step four, sealing the tunnel face, the side slope surface and the upward slope surface; fifthly, positioning a drilling machine; step six, drilling; step seven, withdrawing the drilling tool; step eight, grouting; and step nine, hole sealing.
In the third step, firstly, the inner arch frame of the guide wall 9 is installed; secondly, embedding a guide pipe, wherein the guide pipe is firmly welded with the arch center; and finally, erecting the guide wall 9 and pouring concrete.
And in the fourth step, the concrete is encapsulated by sprayed concrete, and the thickness is more than or equal to 20 cm.
In the sixth step: (1) processing a drill rod: the rod body is 8m in section, an internal screw opening is turned at one end, an external screw opening is turned at the other end, and local welding reinforcement is performed during connection;
(2) the drill rod is connected with a drilling machine: an eccentric drill bit is welded in front of the first section of the drill rod, and the rear part of the rod body is in threaded connection with a drilling tool;
(3) correcting the deviation, namely installing a guide instrument device in the first section rod body, wherein the guide instrument device comprises a positioner 3 at the position of a drill bit, the positioner 3 is placed on a steel plate 1, two sides of the positioner 3 are fixed by adopting steel pipes 2, the positioner 3 is connected with a display 5 through a cable, and the display 5 is connected with an external power supply 7 through a frequency conversion device 6; in the drilling process, the drilling condition is transmitted to a display 5 by a positioner 3 in a drill steel pipe through a cable, an operator timely corrects the deviation according to the rod body drilling deviation condition fed back by the display 5, and meanwhile, along with the drilling length and the soil layer geological condition, the power is adjusted by manually operating a drilling machine to ensure the depth and the position of the drilling machine until the required depth and position are reached;
(4) recording geological conditions: and in the drilling process, the front geological condition is recorded in time according to the rock debris condition.
In the step eight, the grouting sequence of the pipe shed follows the principle of 'first two sides and then middle, and from thin to thick'; the grouting process adopts dual standards of quantity control and pressure control.
The standard of grouting ending is that single-hole grouting can be considered to meet the design requirement and the grouting can be ended as long as one of the following three conditions is met: firstly, gradually raising the grouting pressure, and stabilizing for 10min after the designed final pressure is reached; secondly, the grouting amount is not less than 80% of the designed grouting amount; third, the approach velocity is 1/4 of the starting approach velocity.
The detailed construction process flow is shown in the attached figure 1:
(1) construction preparation: determining the height and width of an excavation platform according to the height of a drilling machine and the required longitudinal length, excavating steps from top to bottom from the original ground, after the excavation reaches the required height and width, carrying out slope releasing on side slopes and uphill slopes on two sides, and arranging temporary ditches on the two sides; the excavation method adopts mechanical excavation, manual allocation and slag removal by an excavator;
(2) and (3) measurement and paying-off: according to the requirements of design files, adopting a total station instrument to loft out the center line and elevation of the tunnel, and rechecking accurately; according to the correct tunnel center line coordinates and elevations after rechecking, marking the excavation range and elevation of the guide wall on site;
(3) construction of a guide wall 9:
installing an inner arch frame of the guide wall 9: after the position of the guide wall 9 is excavated in place, firstly carrying out bearing capacity test on a guide wall 9 foundation, if the bearing capacity of the guide wall 9 foundation is insufficient, reinforcing treatment is required, after the foundation is qualified, arranging 3I 20b I-shaped steel frames in the guide wall 9, setting each steel frame according to 3 units, and forbidding the arch frame joint to be arranged at the vault position;
embedding a guide pipe: determining the position of the opening of the pipe shed by measuring and setting out, identifying by using a cross mark, adopting a phi 127 multiplied by 6mm steel pipe as a guide pipe, firmly welding the guide pipe with an arch frame, and strictly controlling the angle of the guide pipe according to the design requirement;
and (3) erecting a mold for the guide wall 9, and pouring concrete: the guide wall 9 is connected with the templates through bolts; in order to ensure the roundness of the inner die of the guide wall 9, the end template of the guide wall 9 is installed by adopting a 5cm thick wood board, the connection between the wood boards is reinforced by adopting a back support adding mode, and the wood template and the steel template are firmly connected by adopting a cramp or a steel nail. Coating a release agent on the contact surface of the template and the concrete; after the templates are installed and checked to be qualified, pouring concrete of the guide wall 9, wherein the quality of raw materials and the mixing quality of the reinforced concrete need to be strictly controlled in the pouring process, the concrete is compactly tamped in the pouring process, the concrete is uniformly and intensively supplied by a mixing station, and the pouring sequence is symmetrically poured from two sides of the arch springing to the arch crown; after the concrete pouring is finished, the curing is started, the curing period is 7 days, meanwhile, after the strength reaches 70%, the non-bearing structure and the outer mold are removed, and after the strength reaches 100%, the inner mold and other templates are removed; the orifice tubes are numbered in order. (see attached FIG. 4)
(4) Packaging the surfaces of the tunnel face, the side slope and the upward slope: in order to prevent the grouting process, the hole is subjected to grout emission; c25 concrete is sprayed for sealing, and the thickness is 15 cm;
(5) positioning a drilling machine: the drilling machine adopts a crawler-type drilling machine, and the position of the drilling machine is adjusted according to the position of the measured pay-off line; the principle that the holes are odd-numbered first and even-numbered second from high to low is adopted;
(6) drilling:
a, machining a drill rod: the rod bodies are processed by a reinforcing steel bar processing factory in a unified way, the material is a pipe shed material with phi 108 x 6mm, an inner screw opening is machined at one end of the pipe shed material and an outer screw opening is machined at the other end of the pipe shed material according to a section of 6m, the depth of the screw openings is 3mm, the length of the screw openings is 8cm, and local welding reinforcement is carried out during connection;
b, connecting the drill rod with a drilling machine: an eccentric drill bit is welded in front of the first section of the drill rod; the welding is firm, and the drill bit is used for one time; the rear part of the rod body is connected with the drilling tool through threads;
c, correcting, namely installing a guide instrument device in the first section of rod body, wherein the guide instrument device comprises a positioner 3 of a drill bit position, the positioner 3 is placed on a steel plate 1, two sides of the positioner 3 are fixed by steel pipes 2, the positioner 3 is connected with the outside of a hole by a thin steel wire rope, the guide instrument device is connected with an external power supply 7 through a frequency conversion device 6, in the drilling process, the positioner 3 in the steel pipe of the drill bit reflects the drilling condition to a display 5, an operator corrects the deviation in time according to the drilling deviation condition of the rod body fed back by the display 5, meanwhile, power is adjusted along with the drilling length and the soil layer geological condition to ensure the depth and the position of a drilling machine until the required depth and position are reached, a sensor can send out a signal during implementation, the display 5 can display the depth and the height difference of the drill bit from the hole opening and the included angle of a drill rod and a positioning horizontal line after receiving the signal, compares the data received by the guide instrument device with theoretical data, if the height difference h is larger, the included angle α is used for controlling the horizontal direction, if the α value is less than or less than 1, the 3683, the top of the drill bit is pushed in the horizontal direction, and the correction range is allowed.
d recording the geological conditions: and in the drilling process, the front geological condition is recorded in time according to the rock debris condition.
(7) And (3) withdrawing the drilling tool: after drilling to a designed position, loosening the threaded connection between the drill rod and the drilling tool, and installing a grout stop valve on the rod head;
(8) grouting
a grouting sequence
The grouting sequence of the pipe shed follows the principle of 'first two sides and then middle and from thin to thick'. The grouting construction is started from two ends and is propelled towards the arch crown direction of the tunnel, the slurry concentration of grouting is lower at the beginning, and the slurry is gradually thickened to the designed concentration.
b mixing the slurry
The slurry is prepared according to the prepared mixing proportion, and the slurry is uniformly mixed and has good fluidity and viscosity. Stirring work can not be stopped in the grouting process until grouting is finished.
c grouting pressure and grouting amount control
The grouting process adopts dual standards of quantity control and pressure control, the grouting process needs to be slowly pressurized, after the pressure is reached and the pressure is stabilized, the grout can be evenly overflowed from a sealing part sometimes, and can be overflowed from a crack of surrounding rock gaps sometimes to indicate that the grouting process is full. After grouting, the grouting amount should be compared with a theoretical value, when the grouting amount is less than the theoretical value, the pipe is not full, and grouting should be stopped to find the cause and then pressure grouting should be performed.
d, in the grouting process, the single-hole grouting can be considered to meet the design requirement and the grouting can be finished as long as one of the following three conditions is met. Firstly, gradually raising the grouting pressure to reach the design final pressure (generally 1.0-2.0 MPa) and stabilizing for 10 min; secondly, the grouting amount is not less than 80% of the designed grouting amount; third, the approach velocity is 1/4 of the starting approach velocity.
(9) Hole sealing
After grouting is finished, hole sealing is carried out in time, slurry is prevented from flowing outwards, a fixed and stable arch ring (see figure 4) is finally formed, stability in the tunnel excavation process is guaranteed, and deformation risks of the tunnel in the construction process are reduced.
The guide technology is adopted to ensure the construction precision of the pipe shed, the drilling process provides reference for tunnel excavation on the geological record, and effective advance support provides technical support for tunnel excavation. Before a tunnel is excavated into a tunnel, after a side-up slope at a tunnel opening is excavated in place, constructing a pipe shed guide wall, embedding guide pipes, simultaneously processing a drill rod, configuring a high-power air compressor, installing a positioner in a drill rod head for positioning after a drilling machine is in place, correcting deviation in time according to drilling deviation of the rod body in the drilling process, simultaneously adjusting power along with the drilling length and the soil layer geological condition to ensure the depth and the position of the drilling machine, separating the drilling machine and the drill rod after drilling is finished, and grouting; the construction of the next pipe shed is started to form a stable arch ring outside the excavation, the drilling process is accurate, the phenomena of deviated holes and collapsed holes are avoided, the hole forming efficiency is high, and the method is suitable for environments such as sand layers and clay layers with complex geological conditions and loose soil texture.
The present invention is not described in detail, but is known to those skilled in the art. Finally, the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all of them should be covered in the claims of the present invention.
Claims (6)
1. A pipe shed construction method for a weak surrounding rock section of a tunnel portal is characterized by comprising the following steps: the method comprises the following steps: step one, construction preparation; step two, measuring and paying off; step three, constructing a guide wall (9); step four, sealing the tunnel face, the side slope surface and the upward slope surface; fifthly, positioning a drilling machine; step six, drilling; step seven, withdrawing the drilling tool; step eight, grouting; and step nine, hole sealing.
2. The pipe shed construction method for the weak surrounding rock section of the tunnel portal according to claim 1, characterized in that: in the third step, firstly, the inner arch frame of the guide wall (9) is installed; secondly, embedding a guide pipe, wherein the guide pipe is firmly welded with the arch center; and finally, erecting the guide wall (9) and pouring concrete.
3. The pipe shed construction method for the weak surrounding rock section of the tunnel portal according to claim 1, characterized in that: and in the fourth step, the concrete is encapsulated by sprayed concrete, and the thickness is more than or equal to 20 cm.
4. The pipe shed construction method for the weak surrounding rock section of the tunnel portal according to claim 1, characterized in that: in the sixth step: (1) processing a drill rod: the rod body is 8m in section, an internal screw opening is turned at one end, an external screw opening is turned at the other end, and local welding reinforcement is performed during connection;
(2) the drill rod is connected with a drilling machine: an eccentric drill bit is welded in front of the first section of the drill rod, and the rear part of the rod body is in threaded connection with a drilling tool;
(3) correcting the deviation, namely installing a guide instrument device in the first section rod body, wherein the guide instrument device comprises a positioner (3) at the position of a drill bit, the positioner (3) is placed on a steel plate (1), two sides of the positioner are fixed by steel pipes (2), the positioner (3) is connected with a display (5) through a cable, and the display (5) is connected with an external power supply (7) through a frequency conversion device (6); in the drilling process, a positioner (3) in a drill steel pipe transmits the drilling condition to a display (5) through a cable, an operator corrects the drilling deviation condition of a rod body fed back by the display (5) in time, and the power is adjusted through manually operating a drilling machine along with the drilling length and the soil layer geological condition to ensure the depth and the position of the drilling machine until the required depth and position are reached;
(4) recording geological conditions: and in the drilling process, the front geological condition is recorded in time according to the rock debris condition.
5. The pipe shed construction method for the weak surrounding rock section of the tunnel portal according to claim 1, characterized in that: in the step eight, the grouting sequence of the pipe shed follows the principle of 'first two sides and then middle, and from thin to thick'; the grouting process adopts dual standards of quantity control and pressure control.
6. The pipe shed construction method for the weak surrounding rock section of the tunnel portal according to claim 1, characterized in that: the standard of grouting ending is that single-hole grouting can be considered to meet the design requirement and grouting can be ended as long as one of the following three conditions is met: firstly, gradually raising the grouting pressure, and stabilizing for 10min after the designed final pressure is reached; secondly, the grouting amount is not less than 80% of the designed grouting amount; third, the approach velocity is 1/4 of the starting approach velocity.
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Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
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CN114961748A (en) * | 2022-06-23 | 2022-08-30 | 中铁九局集团第三建设有限公司 | Construction method of large pipe shed guide wall at tunnel opening of shallow tunnel |
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
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CN114961748A (en) * | 2022-06-23 | 2022-08-30 | 中铁九局集团第三建设有限公司 | Construction method of large pipe shed guide wall at tunnel opening of shallow tunnel |
CN114961748B (en) * | 2022-06-23 | 2023-03-10 | 中铁九局集团第三建设有限公司 | Construction method of large pipe shed guide wall at tunnel opening of shallow tunnel |
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