CN113137235B - Construction method of high-ground-stress soft rock extrusion large-deformation tunnel - Google Patents
Construction method of high-ground-stress soft rock extrusion large-deformation tunnel Download PDFInfo
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- 239000011435 rock Substances 0.000 title claims abstract description 56
- 238000010276 construction Methods 0.000 title claims abstract description 54
- 238000001125 extrusion Methods 0.000 title claims abstract description 22
- 238000009412 basement excavation Methods 0.000 claims abstract description 23
- 239000011347 resin Substances 0.000 claims abstract description 12
- 229920005989 resin Polymers 0.000 claims abstract description 12
- 229910000831 Steel Inorganic materials 0.000 claims description 59
- 239000010959 steel Substances 0.000 claims description 59
- 238000005553 drilling Methods 0.000 claims description 27
- 238000000034 method Methods 0.000 claims description 20
- 230000008569 process Effects 0.000 claims description 15
- 239000002002 slurry Substances 0.000 claims description 13
- 238000004873 anchoring Methods 0.000 claims description 11
- 238000005507 spraying Methods 0.000 claims description 10
- 238000003466 welding Methods 0.000 claims description 6
- 239000011440 grout Substances 0.000 claims description 5
- 239000003795 chemical substances by application Substances 0.000 claims description 4
- 238000011161 development Methods 0.000 claims description 4
- 238000003780 insertion Methods 0.000 claims description 4
- 230000037431 insertion Effects 0.000 claims description 4
- 230000007246 mechanism Effects 0.000 claims description 4
- 230000003014 reinforcing effect Effects 0.000 claims description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 4
- 239000004568 cement Substances 0.000 claims description 3
- 238000013461 design Methods 0.000 claims description 3
- 238000006073 displacement reaction Methods 0.000 claims description 3
- 239000007788 liquid Substances 0.000 claims description 3
- 239000000463 material Substances 0.000 claims description 3
- 238000012545 processing Methods 0.000 claims description 2
- 238000010586 diagram Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 239000007921 spray Substances 0.000 description 3
- 238000005422 blasting Methods 0.000 description 2
- 238000007363 ring formation reaction Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000004567 concrete 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
- 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
- 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
- E21D20/025—Grouting with organic components, e.g. resin
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/20—Hydro energy
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- Geology (AREA)
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Abstract
The invention discloses a construction method of a high-ground-stress soft rock extrusion large-deformation tunnel, which mainly comprises the steps of advanced pre-grouting, large-section excavation, large-diameter locking feet, resin prestressed anchor cables, double-control ring forming step pitch, mounting of a sleeve arch and mechanized matched rapid construction. The construction method can improve the intensity and stability of surrounding strata, reduce the disturbance times of excavation to broken surrounding rocks, actively support the surrounding rocks, quickly anchor and early bear, control the expansion of loose circles, strengthen the rigidity of a primary support structure for resisting deformation, compress the unfavorable stress state of the structure to the shortest, improve the working efficiency, obviously improve the operating environment, lighten the labor intensity, save the labor force, effectively solve the construction problems of easy slip and collapse, uncontrollable deformation, unsatisfactory progress and the like of the tunnel face of the high-ground-stress soft rock extrusion large-deformation tunnel, and has the advantages of comprehensively utilizing resources, orderly managing, guaranteeing the safety and quality of engineering and the like.
Description
Technical Field
The invention relates to the technical field of tunnel engineering construction, in particular to a construction method of a high-ground-stress soft rock extrusion large-deformation tunnel.
Background
Along with the rapid development of railways and highway careers in China, growing-up tunnels are more and more, the whole buried depth of the tunnels is also more and more, the geological conditions are more and more complex, and the corresponding geological problems are more and more, particularly, the large deformation tunnels of the extruded surrounding rocks are more and more, the prominent problem of large deformation brings serious challenges to the tunnel construction, and the tunnels with larger deformation and influence in China at present comprise the Zhuban tunnels of the south Kunlun railways, the Wujunling tunnels of the Lanwu-Miao lines, the Moziling tunnels of the Lanyu railways and the like. The tunnels with the problem of large soft rock extrusion deformation are all in high-ground stress and extremely high-ground stress areas, the deformation amount and displacement speed of surrounding rocks are large, the tunnel has high rheological property, the deformation duration is long, the support damage forms are various, the final trend is that clearance in the tunnels is invaded, the support system is seriously damaged, the arch removal and replacement phenomena are frequent, the construction progress is very slow, meanwhile, geological disasters are easily formed, and the life and property safety of personnel is endangered.
Disclosure of Invention
Aiming at the technical problems in the prior art, the invention provides a construction method of a high ground stress soft rock extrusion large deformation tunnel, which can overcome the defects in the prior art.
In order to achieve the technical purpose, the technical scheme of the invention is realized as follows:
a construction method of a high-ground-stress soft rock extrusion large-deformation tunnel comprises the following steps:
s1, using the upper step as an operation platform, using a geological horizontal drilling machine to implement middle-distance advanced geological drilling, detecting the geological condition of front surrounding rock, providing geological basis for large deformation sections, and timely adjusting design measures and support parameters;
s2, using the upper steps as an operation platform, constructing an advanced large pipe shed by using a three-arm drill jumbo, firmly welding the tail end of the advanced large pipe shed with a steel frame, and reserving a grout stop section with the tail part not less than 100 cm; after the steel pipe is installed after drilling, a grouting pipeline and equipment are connected, and a circulating grouting process is adopted to form a reinforcing area for surrounding rock in front, so that the stratum strength and stability are improved;
s3, the excavation section in the tunnel arch wall range is divided into an upper step and a lower step, so that the construction process is simplified, the disturbance frequency of excavation on broken surrounding rocks is reduced, the number of steel frame joints is reduced, and excessive stress release is prevented;
s4, after excavating and mucking, the upper step is installed by a steel frame by using an arch assembling machine, the lower step is installed manually, and the connecting ribs are welded firmly with a steel frame;
s5, after all the steel frames are installed, carrying out anchor spraying operation by using a wet spraying manipulator;
s6, reinforcing the deformation resisting rigidity of the primary support structure, adding a prestressed resin anchor rope, applying prestress to actively support the surrounding rock by adopting a length-length combination mode, quickly anchoring, early bearing and controlling the expansion of a loose ring;
s7, additionally arranging foot locking anchor pipes at the wall feet on two side edges of the upper step to limit the displacement of the steel arch frame;
s8, a closed primary support system is formed in time by adopting a double-stack bridge process, the unfavorable stress state of the structure is compressed to the shortest, a double-control mechanism measure is carried out to slow down the deformation rate of the surrounding rock, the closed ring forming distance of the primary support of the inverted arch is not more than 25m from the face, and the closed ring forming time is not more than 20 days;
and S9, in order to enable the primary support structure system to reach a stable state as soon as possible, improving the deformation pressure of the secondary lining for resisting the residual, controlling the deformation potential of the surrounding rock and timely applying the secondary support.
Furthermore, the advanced large pipe shed is made of hot rolled seamless steel pipes with the diameter of 108mm, the wall thickness is 6mm, the arch part in the construction range is 120 degrees, the external insertion angle is controlled to be 1-3 degrees, the annular interval is 40cm, 38 pipes are arranged in each ring, the construction length in each cycle is 9m, the longitudinal lap joint length between two adjacent rings is not less than 3m, and the tail end of the advanced large pipe shed is firmly welded with a steel frame.
Further, the circulating grouting process comprises the following steps: drilling grouting holes on the steel pipe, wherein the hole diameter is 10-16 mm, the longitudinal distance between the holes is 15-20 cm, the grouting holes are arranged in a quincunx shape, and a grout stopping section with the tail part not less than 100cm is reserved; the slurry inlet pipe and the slurry return pipe are connected by a tee joint, the grouting material is cement slurry, the underground water development is adjusted to be cement-water glass double-liquid slurry, the strength grade of the slurry is not less than M20, and the grouting pressure is controlled to be 1.0-2.0 MPa.
Furthermore, the height of the upper step accounts for 3/5, the length of the upper step is controlled to be 13-15 m, an operation space is created for mechanized matched construction, the height of the lower step accounts for 2/5, the length of the lower step is controlled to be 3-5 m, and the left side and the right side of the lower step are staggered by 2m.
Further, the long and short combination mode is as follows: the length of a short anchor cable in the first period is 5m, the arch part in the construction range is 120 degrees, the early deformation of surrounding rock is controlled, time and space are saved for subsequent anchoring measures, the length of a long anchor cable in the later period is 15m, the side walls on the two sides of the construction range are provided, the tensile strength of the anchor cable is 1860MPa, the longitudinal distance is 1.2m, the circumferential distance is 0.8m, and a rapid resin anchoring agent is fed into the anchor cable, stirred and solidified, and then a matched anchorage device and a backing plate are installed; the prestress is controlled at 500KN.
Furthermore, the drilling angle of the lock pin anchor pipe is controlled to be 20-40 degrees downwards in an inclined mode, the drilling position is controlled to be within 30cm from a steel frame connecting plate, 2 bolts are arranged at each position, and the length of each bolt is 9m; and (3) processing 20mm steel plate auxiliary connecting components in advance, fully welding the lock pin anchor pipes on two sides of a steel frame and the steel frame firmly, and grouting by adopting a quantitative-constant pressure principle.
Furthermore, the locking pin anchor pipe is a phi 89mm large-diameter locking pin anchor pipe.
Further, the double-trestle process comprises the following steps: one group of manually processed steel trestles is placed at the tail side of the lower step to establish a construction channel for the closed loop of the primary support of the inverted arch, and the other group of self-propelled trestles is placed at the end of the lining of the inverted arch to establish a construction channel for the lining of the inverted arch.
Furthermore, the two supports are constructed in principle by constructing a secondary support after one support is constructed into a ring and the deformation of one support reaches 50% of the reserved deformation.
Furthermore, when the deformation of one unclosed ring exceeds 50% of the reserved deformation, the secondary support can be applied in time.
The invention has the beneficial effects that: the construction method of the high-ground-stress soft rock extrusion large-deformation tunnel adopts the three-arm rock drilling trolley to drive the large-advancing pipe shed, carries out pre-grouting on the surrounding rock in front of the tunnel face to manufacture the consolidation ring, and prevents the collapse of the vault part and the loose deformation of the surrounding rock; reasonably dividing the large-section excavation size according to the deformation mechanism and characteristics, reducing the excavation disturbance times and the number of steel frame joints, and preventing excessive stress release; the long and short prestressed resin anchor cables are matched with the lock leg anchor pipes, so that the overall stress of the primary support structure is effectively enhanced; the double-stack bridge process is adopted to realize double control on distance and time so as to realize quick closed cyclization of the primary support and play a bearing role as early as possible; the cover arch is constructed in due time, the primary support structure system is stabilized as soon as possible, the deformation pressure of the secondary lining for resisting the residual is improved, and the deformation potential of the surrounding rock is controlled; the method has the advantages of improving the working efficiency, remarkably improving the working environment, reducing the labor intensity, saving the labor force, effectively solving the construction problems of easy collapse, uncontrollable deformation, unsatisfactory progress and the like of the tunnel face of the high-ground-stress soft rock extrusion large-deformation tunnel, and having the advantages of comprehensively utilizing resources, orderly managing, improving the working efficiency, remarkably improving the working environment, guaranteeing the safety and the quality of engineering and the like.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
FIG. 1 is a schematic diagram of a front layout of a large lead canopy according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of the longitudinal arrangement of a large pipe canopy according to an embodiment of the invention;
FIG. 3 is a schematic cross-sectional view of a large-scale excavation method according to an embodiment of the present invention;
FIG. 4 is a schematic longitudinal section of a large-area excavation method according to an embodiment of the present invention;
FIG. 5 is a schematic illustration of a front view of a lock pin anchor tube and a pre-stressed resin anchor cable in accordance with an embodiment of the invention;
FIG. 6 is a schematic front view of a welded assembly of a foot-locking anchor tube and a steel frame according to an embodiment of the present invention;
FIG. 7 is a schematic view of the welded side arrangement of the lock pin anchor tube and a steel frame according to an embodiment of the present invention;
FIG. 8 is a schematic front view of a support steel frame and two support steel frames according to an embodiment of the present invention;
FIG. 9 is a schematic diagram of an operation flow of a mechanized mating construction technology according to an embodiment of the present invention;
in the figure: 1. a phi 108mm advanced large pipe shed; 2. a steel frame; 3. excavating a section; 4. an upper step; 5. descending a step; 6. a phi 28.6mm prestressed resin anchor cable; 7. a major diameter lockpin anchor pipe with the diameter phi of 89 mm; 8. a double trestle; 9. the primary inverted arch is closed to form a ring; 10. two steel frames; 11. 20mm steel plate; 12. and connecting ribs.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the 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.
As shown in fig. 1 to 9, according to the construction method of the high ground stress soft rock extrusion large deformation tunnel according to the embodiment of the present invention, the main control measures include advanced pre-grouting, large section excavation, large diameter locking feet, resin pre-stressed anchor cables, double control loop step, mounting of the arch, and mechanized matched rapid construction technology. The mechanized supporting rapid construction technology comprises a geological horizontal drilling rig, a three-arm rock drilling trolley, a roofbolter, an arch frame assembling machine, a wet spraying manipulator, a self-propelled inverted arch trestle, a waterproof plate automatic paving and hanging trolley, a two-lining mold building trolley and a ditch cable trough automatic trolley.
The construction method of the high ground stress soft rock extrusion large deformation tunnel comprises the following steps:
s1, using the upper step 4 as an operation platform, using a geological horizontal drilling machine to implement middle-distance advanced geological drilling, arranging 2 holes in the drilled holes, wherein 1 hole is cored, the detection length is not less than 30m, the lap joint length is not less than 5m, detecting the geological condition of surrounding rock in front, providing geological basis for large deformation sections, adjusting design measures and support parameters in due time, and guiding the smooth implementation of site construction.
S2, taking the upper step 4 as an operation platform, measuring and lofting hole positions of the phi 108mm advanced large pipe shed according to a construction drawing, determining a specific construction range, using a three-arm rock drilling trolley to drill, drilling pipe shed holes on a steel frame along a tunnel excavation section in a longitudinal drilling mode, controlling an external insertion angle in the process, drilling the phi 108mm advanced large pipe shed 1, controlling the arch part of the construction range to be 120 degrees, controlling the external insertion angle to be 1-3 degrees, controlling the circumferential distance to be 40cm, arranging 38 pipes in each ring, preferably setting the length of 9m in each cycle, setting the longitudinal lap joint length between two adjacent rings to be not less than 3m, firmly welding the tail end of the phi 108mm advanced large pipe shed 1 and the steel frame 2, and reserving a grout stop section at the tail part to be not less than 100 cm; after the steel pipe is installed after drilling, a grouting pipeline and equipment are connected, a circulating grouting process is adopted, a grouting material is cement slurry, the underground water development is adjusted to be cement-water glass double-liquid slurry, the strength grade of the slurry is not less than M20, and the grouting pressure is controlled to be 1.0-2.0 MPa.
S3, a large-section excavation method is adopted, the excavation section 3 in the arch wall range is divided into two-step excavation (the excavation section is divided into an upper step and a lower step), the construction process is simplified, the disturbance frequency of excavation on the broken surrounding rock is reduced, the number of steel frame joints is reduced, and excessive stress release is prevented; the height of the upper step 4 is controlled to be 3/5, the length of the upper step is controlled to be 13-15 m, an operation space is created for mechanical matched construction, the height of the lower step 5 is controlled to be 2/5, the length of the lower step is controlled to be 3-5 m, the left side and the right side of the lower step are staggered by 2m, blasting holes are drilled in a hard surrounding rock section through a three-arm rock drilling trolley for weak blasting, mechanical excavation is directly adopted in a poor surrounding rock section, and the loosening range and surrounding rock disturbance damage are reduced.
And S4, after excavating and mucking are finished, the upper step 4 is installed on one steel frame 2 by using an arch truss assembling machine, the lower step 5 is installed manually, the space between the trusses and the verticality are controlled well in the process, and the connecting ribs 12 are welded with one steel frame 2 firmly.
S5, after all the steel support frames 2 are installed, carrying out spray anchor operation by using a wet spraying manipulator, wherein the spray sequence is from bottom to top, the spray anchors in cavities between the steel support frames 2 and the excavation section 3 are compact and full, and the continuous supply of concrete is ensured; in order to meet the welding quality of the follow-up phi 89mm large-diameter lock foot anchor pipe 7 and a steel frame 2, the spraying anchor thickness close to the arch foot is properly reduced, a steel frame 2 wing plate is exposed, and the post-spraying is carried out again.
S6, measuring 6 hole sites of prestressed resin anchor cables with the lofting diameter of 28.6mm, constructing the early-stage short anchor cables synchronously along with the excavation and supporting of each cycle, setting the length of each single anchor cable to be 5m, arranging the single anchor cables in the range of 120 degrees of an arch part, controlling the early deformation of surrounding rocks, gaining time and space for subsequent anchoring measures, setting a drill hole for each 3-5 m concentrated anchor cable in the later stage by using a roofbolter, setting the length of each single anchor cable to be 15m, arranging the single anchor cable on side walls at two sides, setting the longitudinal circumferential interval of the anchor cables to be 1.2 x 0.8m, clearing the hole by high-pressure air after the hole forming is completed, slowly feeding the resin anchoring agent into the hole by using an elongated PVC pipe until the hole bottom, manually penetrating the anchor cable, installing a stirrer at the end, driving the anchor cable to rotate by a drill boom head of the double-arm roofbolter, and keeping the cable body wedged in a centered stable state after stirring the resin anchoring agent at the hole bottom anchoring end for 40 seconds; and after 30 minutes, the forked section of the end of the orifice anchor rope is cut orderly, the cut forked section penetrates into an anchor and a tensioning machine, an oil pump is connected, the prestress is applied to be controlled to be about 500KN, and the cut forked section is locked after being stabilized. The anchor cable penetrates through the plastic zone and is anchored into the original rock, and the bearing arch structure is suspended on the stable rock mass, so that the periphery of the tunnel and surrounding rocks in a remote zone act together to coordinate deformation.
S7, drilling a locking anchor pipe 7 with a major diameter of phi 89mm by using a geological horizontal drilling machine at each 3-5 m of the skirts at the two sides of the upper step 4, controlling the drilling angle to be 20-40 degrees obliquely downwards, controlling the drilling position to be within 30cm from a steel frame 2 connecting plate, controlling 2 bolts at each position, and controlling the length of each bolt to be 9m; the auxiliary connecting component of the 20mm steel plate 11 is processed in advance, the phi 89mm large-diameter locking anchor pipe 7 arranged on two sides of a steel frame 2 is fully welded firmly with the steel frame 2, a grouting pipeline and equipment are connected, and grouting is carried out by adopting a quantitative-constant pressure principle.
S8, a closed primary support system is formed in time by adopting double trestles 8, a group of manually-processed steel trestles are placed on the tail side of a lower step 5 to establish a construction channel for the closed loop 9 of the primary support of the inverted arch, a group of self-propelled trestles are placed at the end of the inverted arch lining to establish a construction channel for the inverted arch lining, and the section between the two groups of trestles is backfilled nearby by utilizing inverted arch excavated cave ballast; the inverted arch primary support closed loop 9 is used for timely following the lower step 5, double control mechanism measures are adopted, the distance from the span to the face is not more than 25m, and the time from excavation to cutting off the inverted arch primary support closed loop is not more than 20 days.
S9, after one branch is subjected to ring formation in principle at the time of two branches, and when the deformation of one branch reaches 50% of the reserved deformation, secondary support is performed; in special cases, when the deformation of an unsealed ring exceeds 50% of the reserved deformation, secondary support can be timely applied. The two steel frames 10 are installed by using an arch installing machine, the installation position is consistent with the overlapping of one steel frame 2, the resistance effect of the double-layer steel frame is effectively exerted, the joint of the connecting plate of the two steel frames is staggered by more than 50cm, the stress concentration of the weak link part is reduced, the parts such as cracking, falling and bulging of sprayed concrete are knocked and cleaned before the spraying anchor of the two steel frames 10, and the spraying anchor construction of the two steel frames 10 is carried out after the primary foundation surface is blown clean by high-pressure air and water.
In conclusion, by means of the technical scheme, the intensity and the stability of the surrounding stratum can be improved, the disturbance frequency of excavation on the broken surrounding rock is reduced, the surrounding rock is actively supported, the anchoring and early bearing are realized, the expansion of the loose ring is controlled, the rigidity of the primary support structure for resisting deformation is enhanced, the unfavorable stress state of the structure is compressed to the shortest, the working efficiency is improved, the working environment is obviously improved, the labor intensity is reduced, the labor force is saved, the construction problems that the tunnel face of the high-ground-stress soft rock extrusion large-deformation tunnel is easy to collapse, the deformation is uncontrollable, the progress is unsatisfactory and the like are effectively solved, and the method has the advantages of comprehensively utilizing resources, managing in an ordered manner, guaranteeing the safety quality of engineering and the like.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (9)
1. A construction method of a high-ground-stress soft rock extrusion large-deformation tunnel is characterized by comprising the following steps of:
s1, using the upper step as an operation platform, using a geological horizontal drilling machine to implement middle-distance advanced geological drilling, detecting the geological condition of surrounding rock in front, providing geological basis for large deformation sections, and adjusting design measures and support parameters in due time;
s2, using the upper steps as an operation platform, constructing an advanced large pipe shed by using a three-arm drill jumbo, firmly welding the tail end of the advanced large pipe shed with a steel frame, and reserving a grout stop section with the tail part not less than 100 cm; after the steel pipe is installed after drilling, a grouting pipeline and equipment are connected, and a circulating grouting process is adopted to form a reinforcing area for the surrounding rock in front, so that the stratum strength and stability are improved;
s3, the excavation section in the tunnel arch wall range is divided into an upper step and a lower step, so that the construction process is simplified, the disturbance frequency of excavation on the broken surrounding rock is reduced, the number of steel frame joints is reduced, and excessive stress release is prevented;
s4, after excavation and mucking are finished, the upper step is installed by a steel frame by using an arch truss assembling machine, the lower step is installed manually, and the connecting ribs are firmly welded with a steel frame;
s5, after all the steel frames are installed, carrying out anchor spraying operation by using a wet spraying manipulator;
s6, reinforcing the rigidity of the primary support structure against deformation, adding a prestressed resin anchor rope, applying prestress to actively support the surrounding rock in a long and short combination mode, quickly anchoring and early bearing, and controlling the expansion of a loose ring;
s7, additionally arranging foot locking anchor pipes at the wall feet on two side edges of the upper step to limit the displacement of the steel arch frame;
s8, a closed primary support system is formed in time by adopting a double-stack bridge process, the unfavorable stress state of the structure is compressed to the shortest, a double-control mechanism measure is carried out to slow down the deformation rate of the surrounding rock, the closed loop forming distance of the primary support of the inverted arch is not more than 25m from the face, the closed loop forming time is not more than 20 days, and the double-stack bridge process comprises the following steps: one group of manually processed steel trestles is arranged at the tail side of the lower step to establish a construction channel for the closed loop of the primary support of the inverted arch, and the other group of self-propelled trestles is arranged at the end of the lining of the inverted arch to establish a construction channel for the lining of the inverted arch;
and S9, in order to enable the primary support structure system to reach a stable state as soon as possible, improve the deformation pressure of the secondary lining for resisting the residual, control the deformation potential of the surrounding rock and apply secondary support at proper time.
2. The construction method of the tunnel with high ground stress soft rock extrusion and large deformation as claimed in claim 1, wherein the advanced large pipe shed is made of a hot rolled seamless steel pipe with a diameter of 108mm, the wall thickness is 6mm, the arch part of the construction range is 120 degrees, the external insertion angle is controlled to be 1-3 degrees, the circumferential distance is 40cm, 38 pipes are arranged in each ring, the construction length per cycle is preferably 9m, the longitudinal lap joint length between two adjacent rings is not less than 3m, and the tail end of the advanced large pipe shed is firmly welded with a steel frame.
3. The construction method of the high-ground-stress soft-rock-extrusion large-deformation tunnel according to claim 1, wherein the circulating grouting process comprises the following steps: drilling grouting holes on the steel pipe, wherein the hole diameter is 10-16 mm, the longitudinal distance between the holes is 15-20 cm, the grouting holes are arranged in a quincunx shape, and a grout stopping section with the tail part not less than 100cm is reserved; the slurry inlet pipe and the slurry return pipe are connected by a tee joint, the grouting material is cement slurry, the underground water development is adjusted to be cement-water glass double-liquid slurry, the strength grade of the slurry is not less than M20, and the grouting pressure is controlled to be 1.0-2.0 MPa.
4. The construction method of the high ground stress soft rock extrusion large deformation tunnel according to claim 1, characterized in that the height of the upper step accounts for 3/5, the length is controlled to be 13-15 m, an operation space is created for mechanized supporting construction, the height of the lower step accounts for 2/5, the length is controlled to be 3-5 m, and the left side and the right side are staggered by 2m.
5. The construction method of the high-ground-stress soft-rock extrusion large-deformation tunnel according to claim 1, wherein the long and short combination mode is adopted as follows: the length of a short anchor cable in the first period is 5m, the arch part in the construction range is 120 degrees, the early deformation of surrounding rock is controlled, time and space are saved for subsequent anchoring measures, the length of a long anchor cable in the later period is 15m, the side walls on the two sides of the construction range are provided, the tensile strength of the anchor cable is 1860MPa, the longitudinal distance is 1.2m, the circumferential distance is 0.8m, and a rapid resin anchoring agent is fed into the anchor cable, stirred and solidified, and then a matched anchorage device and a backing plate are installed; the prestress is controlled at 500KN.
6. The construction method of the high-ground-stress soft-rock-extrusion large-deformation tunnel according to claim 1, wherein the drilling angle of the lock pin anchor pipe is controlled to be 20-40 degrees obliquely downward, the drilling position is controlled to be within 30cm from a steel frame connecting plate, 2 are arranged at each position, and each length is 9m; and (3) processing 20mm steel plate auxiliary connecting components in advance, fully welding the lock pin anchor pipes on two sides of a steel frame with the steel frame firmly, and grouting by adopting a quantitative-constant pressure principle.
7. The construction method of the high ground stress soft rock extrusion large deformation tunnel according to claim 1, wherein the locking pin anchor pipe is a Φ 89mm large diameter locking pin anchor pipe.
8. The construction method of the tunnel with high ground stress soft rock extrusion and large deformation as claimed in claim 1, wherein the two supports are constructed in principle after one support is constructed into a ring and when the deformation of one support reaches 50% of the reserved deformation, the secondary support is constructed.
9. The construction method of the tunnel with high ground stress soft rock extrusion and large deformation as claimed in claim 8, wherein when the deformation of an unsealed ring exceeds 50% of the reserved deformation, secondary support can be timely applied.
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| CN114483129A (en) * | 2022-01-26 | 2022-05-13 | 嵩县山金矿业有限公司 | Full-length anchoring method for prestressed long anchor cable of underground broken surrounding rock large-span chamber |
| CN116357347B (en) * | 2023-03-31 | 2024-02-02 | 重庆建工集团股份有限公司 | Control method for large deformation surrounding rock of tunnel high-ground-stress soft rock |
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