CN109538216B - Tunnel construction process for crossing mining and subsidence areas - Google Patents
Tunnel construction process for crossing mining and subsidence areas Download PDFInfo
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- CN109538216B CN109538216B CN201811574889.9A CN201811574889A CN109538216B CN 109538216 B CN109538216 B CN 109538216B CN 201811574889 A CN201811574889 A CN 201811574889A CN 109538216 B CN109538216 B CN 109538216B
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- 238000000034 method Methods 0.000 title claims abstract description 54
- 238000010276 construction Methods 0.000 title claims abstract description 44
- 230000008569 process Effects 0.000 title claims abstract description 41
- 238000005065 mining Methods 0.000 title abstract description 4
- 239000004568 cement Substances 0.000 claims abstract description 48
- 239000010881 fly ash Substances 0.000 claims abstract description 32
- 238000005553 drilling Methods 0.000 claims abstract description 30
- 239000011435 rock Substances 0.000 claims abstract description 24
- 239000004570 mortar (masonry) Substances 0.000 claims abstract description 20
- 238000009412 basement excavation Methods 0.000 claims abstract description 17
- 238000005422 blasting Methods 0.000 claims abstract description 15
- 229910000831 Steel Inorganic materials 0.000 claims description 79
- 239000010959 steel Substances 0.000 claims description 79
- 239000002002 slurry Substances 0.000 claims description 20
- 230000002093 peripheral effect Effects 0.000 claims description 16
- 239000011378 shotcrete Substances 0.000 claims description 15
- 238000013461 design Methods 0.000 claims description 14
- 239000004567 concrete Substances 0.000 claims description 13
- 239000011440 grout Substances 0.000 claims description 12
- 239000004576 sand Substances 0.000 claims description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 11
- 230000000694 effects Effects 0.000 claims description 9
- 239000004927 clay Substances 0.000 claims description 7
- 238000005520 cutting process Methods 0.000 claims description 7
- 239000004575 stone Substances 0.000 claims description 7
- 239000011398 Portland cement Substances 0.000 claims description 6
- 230000000903 blocking effect Effects 0.000 claims description 6
- 239000007787 solid Substances 0.000 claims description 6
- 150000001875 compounds Chemical class 0.000 claims description 5
- 239000002360 explosive Substances 0.000 claims description 5
- 239000012535 impurity Substances 0.000 claims description 5
- 239000007788 liquid Substances 0.000 claims description 5
- 239000002689 soil Substances 0.000 claims description 5
- 230000000149 penetrating effect Effects 0.000 claims description 4
- 230000003014 reinforcing effect Effects 0.000 claims description 4
- 238000007789 sealing Methods 0.000 claims description 4
- 238000005452 bending Methods 0.000 claims description 3
- 239000003795 chemical substances by application Substances 0.000 claims description 3
- 238000007596 consolidation process Methods 0.000 claims description 3
- 125000004122 cyclic group Chemical group 0.000 claims description 3
- 238000009792 diffusion process Methods 0.000 claims description 3
- 238000007689 inspection Methods 0.000 claims description 3
- 239000000463 material Substances 0.000 claims description 3
- 238000005259 measurement Methods 0.000 claims description 3
- 235000019353 potassium silicate Nutrition 0.000 claims description 3
- 238000010008 shearing Methods 0.000 claims description 3
- 239000002893 slag Substances 0.000 claims description 3
- 239000010802 sludge Substances 0.000 claims description 3
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical group [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 claims description 3
- 239000000126 substance Substances 0.000 claims description 3
- 230000008719 thickening Effects 0.000 claims description 3
- 238000005406 washing Methods 0.000 claims description 3
- 239000000843 powder Substances 0.000 claims description 2
- 230000000740 bleeding effect Effects 0.000 claims 1
- 238000007664 blowing Methods 0.000 claims 1
- 238000003466 welding Methods 0.000 claims 1
- 238000007569 slipcasting Methods 0.000 description 5
- 239000010883 coal ash Substances 0.000 description 3
- 230000008093 supporting effect Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 230000005641 tunneling Effects 0.000 description 1
Classifications
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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
- E21D9/002—Injection methods characterised by the chemical composition used
-
- 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
-
- 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
-
- 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
-
- 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
- E21D9/006—Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries by making use of blasting methods
-
- 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
- E21D9/12—Devices for removing or hauling away excavated material or spoil; Working or loading platforms
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- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Structural Engineering (AREA)
- Architecture (AREA)
- Environmental & Geological Engineering (AREA)
- Civil Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Soil Sciences (AREA)
- Lining And Supports For Tunnels (AREA)
- Excavating Of Shafts Or Tunnels (AREA)
Abstract
The invention discloses a tunnel construction process for passing through a mining and subsidence area, which relates to the technical field of tunnel construction and solves the problem that the existing mining and subsidence area construction is easy to collapse dangers, and the technical scheme is characterized by comprising the following steps: grouting treatment of a goaf and a collapse area: a. fixing the point; b. drilling to form a hole; c. burying an orifice closing device; d. grouting construction; (II) excavating by a three-step method: a. blasting; b. deslagging; c. primary support; d. advance support; (III) circulating operation; the cement fly ash mortar is solidified and then integrated with the surrounding rock mass, so that the rock mass becomes stable, and the collapse danger is not easy to occur in the process of tunnel excavation construction.
Description
Technical Field
The invention relates to the technical field of tunnel construction, in particular to a tunnel construction process for passing through a mined-out and subsided area.
Background
When the tunnel is constructed in the process of passing through a goaf and a subsidence area, the risks of water burst and mud burst and tunnel face collapse are often met, so that great construction difficulty is brought to the construction of the tunnel, the strata of the goaf and the subsidence area are soft and are in an unstable state, although the danger of great collapse is easily caused after the disturbance of tunnel excavation, and the tunnel construction in the process of passing through the goaf and the subsidence area is a great problem in the conventional tunnel construction.
When the tunnel construction is carried out in the process of penetrating through the goaf and the subsidence area in the current stage of engineering, the method of firstly pouring cement paste and then carrying out the tunnel construction is adopted, the cement paste has the problems of low slurry calculus rate and poor water dispersibility, the collapse danger still easily occurs due to the disturbance of tunnel excavation in the later stage of the tunnel construction, and the tunnel construction process which is difficult to collapse danger when the tunnel construction is carried out in the goaf and the subsidence area is urgently needed.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a tunnel construction process for traversing a goaf and subsidence area.
In order to achieve the purpose, the invention provides the following technical scheme: a tunnel construction process for crossing a mined-out and subsidence area is characterized by comprising the following steps: the method comprises the following steps:
grouting treatment of a goaf and a collapse area:
a. fixed point: before drilling, a grouting hole needs to be fixed, a total station is adopted to carry out field measurement lofting during fixing, and the actual position error of the drilling hole is not more than 0.5 m;
b. drilling to form a hole: before drilling, selecting a proper drill bit and a proper drill according to the drilling depth and diameter of a grouting hole and an inspection hole, opening a hole to a specified depth by using a large-diameter drill bit, then putting a wellhead casing into the hole, filling clay between the outer side of the wellhead casing and the wall of the hole, and then replacing the small-diameter drill bit to continuously drill to the designed depth;
c. burying an orifice closing device: after drilling is finished and full hole washing is carried out, embedding an orifice sealing device, wherein the orifice sealing device is an orifice grouting pipe with a flange tray; injecting water cement slurry with a water-solid ratio of 1: 1.5-1: 2.0 into the hole, wherein the height of the slurry in the hole is 4-6 m, adding an accelerator accounting for 2% of the weight of cement into the cement slurry, and then pulling out the orifice sleeve;
d. grouting construction: the grouting liquid is made of cement-coal-powder mortar consisting of water, cement, fly ash, an accelerating agent and sand; the grouting concentration is thin and thick, during grouting, the pressure of a grouting pump is 1.5 times greater than the maximum design pressure of grouting, after the grouting is started, the slurry suction amount and the pump pressure of the pump are observed at regular time, when the pump pressure is gradually increased, the grouting amount is less than 70L/min, the pressure of an orifice pipe is between 1.O and 3.0Mpa, the stability is 10 to 15min, or the grouting phenomenon occurs around a grouting hole, the grouting construction of the hole can be ended;
(II) excavating by a three-step method: the three steps are divided into an upper level, a middle level and a lower level, the upper level is 3m high, the middle level is the part from the upper level to the upper part of the arch camber line, the rest part is the lower level, the step width of each level is 5m, and the left side and the right side are staggered by 2 m; the three-step excavation method comprises the following steps:
a. blasting: firstly, cutting a slot hole, and filling explosive into the slot hole for blasting after the cutting of the slot hole is finished;
b. deslagging: conveying various sludge and broken stones generated in the blasting process to the outer side of the tunnel;
c. primary support: carrying out primary support on surrounding rocks; the support joints are welded firmly, and the surfaces of the steel arches are connected by steel bars; the steel arch frame is erected according to the designed position, and the arch springing is required to be placed on a firm foundation; the steel arch frame is perpendicular to the center line of the tunnel, the allowable deviation of the upper part, the lower part, the left part and the right part is 5cm, the vertical inclination is not more than 2 degrees, and the height of an arch springing is 15-20 cm lower than the bottom line of the upper half section; the gap between the steel arch frame and the surface of the primary sprayed concrete must be filled and compacted by sprayed concrete; when the clearance is too large, the steel template or the concrete wedge block can be used for jacking tightly, and the number of points on one side is not less than 8; the sprayed concrete is symmetrically sprayed upwards from arch springing at two sides, and the steel arch is covered; the arch foot part is easy to generate plastic shearing damage, and the steel frame at the part is required to be welded on four sides besides bolted connection so as to ensure the rigidity and the strength of the joint; the section height of the steel frame is adapted to the thickness of the sprayed concrete; in order to enhance the overall stability of the steel frame, the steel frame is firmly connected with the longitudinal connecting ribs, the structural anchor rods, the positioning tie bars and the foot locking anchor rods; the foot-locking anchor rods play a decisive role in controlling the settlement of the I-shaped steel, so the foot-locking anchor rods are uniformly distributed at the arch feet of the upper step, the middle step and the lower step, the driving angle of the foot-locking anchor rods is preferably 45 degrees with the surrounding rock, and the foot-locking anchor rods are firmly welded with the I-shaped steel; in the relative broken zone or surrounding rock, the primary support is converged and deformed in a relatively large section, and locking feet at the arch springing of the upper, middle and lower steps are reinforced by a phi 42 grouting small conduit; the length of each small guide pipe is 4m, 2 small guide pipes are arranged at each position, the driving angle of the foot locking guide pipe forms 45 degrees with the surrounding rock, and the foot locking guide pipe is firmly welded with the I-shaped steel;
d. advance support: in order to ensure the excavation safety of the tunnel face, the advanced support adopts a hot-rolled seamless steel tube with the diameter of phi 42 x 4 mm, the front end of the hot-rolled seamless steel tube is in a pointed cone shape, 8 mm grouting holes are drilled on the periphery of the tube wall, the hole interval is 15cm, no grouting hole is arranged at the tail part of the hot-rolled seamless steel tube of 1.2m, the horizontal projection overlapping length of two longitudinally adjacent rows is not less than 100cm, and the external inserting angle is 15 degrees; then, mounting the small guide pipe, wherein the small guide pipe is installed by adopting a drilling and driving method, namely, firstly, drilling according to the design requirement, wherein the diameter of a drilled hole is 3-5 mm larger than that of the steel pipe, then, penetrating the small guide pipe through the steel frame, using a hammering or drilling machine to jack in, wherein the jacking length is not less than 90% of the length of the steel pipe, and using high-pressure air to blow out gravels in the steel pipe; after the small guide pipe is installed, the hole and peripheral cracks are sealed by mud, and concrete is sprayed near the small guide pipe and on the working surface if necessary to prevent the working surface from collapsing; the excavation length of the tunnel is smaller than the grouting length of the small guide pipe, and the reserved part is used as a grout stopping wall of the next cycle; selecting a water-cement ratio of the slurry during grouting to be 1:1, in order to obtain a good consolidation effect, enough grout must be injected to ensure an effective diffusion range, the grouting range is designed according to 0.3-0.5 m outside an excavation contour line, grout uniformly diffuses in a stratum, the grouting pressure is controlled to be 0.5-1 MPa during grouting, and a grout stop plug adopted in the grouting process is sprayed concrete with the thickness of 5-10 cm;
(III) cyclic operation: and blasting, deslagging, primary support and advanced support are carried out in a circulating mode until tunnel construction is completed.
Through adopting above-mentioned technical scheme, adopt cement fly ash mortar to carry out the slip casting operation, and slip casting pressure adopts 1.5 times of the biggest design pressure of slip casting, make cement fly ash mortar can be abundant spread in the middle of the rock mass on every side, and can produce the compaction effect to the rock mass through the ever-increasing of cement fly ash mortar volume in the middle of the pressurization process that lasts, and make the contact between cement fly ash mortar and the rock mass inseparabler, make cement fly ash mortar after the solidification form a whole with peripheral rock mass, the effect of reinforcing and supporting has been played, make in the middle of the follow-up process of excavating the tunnel, be difficult to appear the risk of collapsing.
The invention is further configured to: and step C, when the orifice closing device is buried, a small amount of sandstone is put into the hole for blocking a larger gap after the orifice grouting pipe is installed, and then a small amount of clay is put into the hole for completely blocking the gap.
Through adopting above-mentioned technical scheme, through drill way closing device to adopt grit and clay to block up the gap, make in the middle of the process that carries out cement fly ash mortar and fill, can be better control the pressure of the cement fly ash mortar in the hole of filling, make cement fly ash mortar diffuse under the effect of pressure more easily in the middle of the rock mass on every side.
The invention is further configured to: step d, during grouting construction, preparing the grouting liquid according to the water-solid ratio of 1: 1.0-1: 1.5, and controlling the ratio of cement to fly ash to sand to be 3: 7: 2, adding an accelerator accounting for 2 percent of the weight of the cement into the slurry.
By adopting the technical scheme, the cement fly ash mortar can be accelerated to be solidified within shorter time after being poured into the grouting hole by adding the accelerator.
The invention is further configured to: and d, during grouting construction, selecting a grouting material to ensure that water is clean and does not contain harmful substances, wherein the cement is ordinary portland cement or slag portland cement, the accelerator is water glass, the fly ash meets the requirements of class III fly ash of fly ash used in cement and concrete (GB/T1596-2005), the sand is clean, hard, dry, weatherproof and free of impurities, and meets the specified grading, and the content of soil impurities is less than 5%.
Through adopting above-mentioned technical scheme, through selecting suitable cement and accelerator to carry out strict control to the quality of fly ash, water and grit, fixed effect after improvement cement fly ash mortar that can be better solidifies makes the follow-up danger that appears collapsing in the middle of the process of carrying out the tunnel excavation more difficult.
The invention is further configured to: d, when grouting construction is carried out, when the grouting amount exceeds the designed grouting amount of the drill hole and the pressure of the hole opening still does not rise, an intermittent grouting process can be adopted; the intermittent time is controlled to be about 10-12 hours; intermittent post-grouting still adopts a grouting process of firstly thinning and then thickening; and controlling the secondary grouting to be about 25% of the design amount, and if the pressure is not raised, performing intermittent grouting again until the grouting stopping standard meeting the requirement is reached.
Through adopting above-mentioned technical scheme, can surpass the filling hole that drilling relates to the slip casting volume through intermittent type slip casting and play good filling effect to the filling volume for cement fine coal ash mortar also can be in the same place with the good combination of rock stratum around this filling hole.
The invention is further configured to: in the step a, during blasting, the compound straight-hole wedge-shaped undermining mode is adopted to undermine the holes, namely the mode of mutually combining the shallow undermining and the deep undermining; the peripheral eyes are also divided into two stages, the first-stage peripheral eyes are arranged on the outer side, the depth of the first-stage peripheral eyes is half of that of the second-stage peripheral eyes, and meanwhile, the outer inserting eyes are reduced.
Through adopting above-mentioned technical scheme, through adopting compound straight hole wedge undercut's mode to come the underholing hole, can enough reduce the use amount of explosive, can also control the distance of tunnelling more easily.
The invention is further configured to: and c, during primary support, the adopted I-steel is 20A I-steel, the manufacturing of the steel arch frames arranged at the interval of 60cm in each truss is processed according to the specification by a cold bending process, and the size of the steel arch frames meets the design requirement.
Through adopting above-mentioned technical scheme, 20A I-steel's intensity is higher, can reach better supporting effect.
The invention is further configured to: and c, when the primary support is carried out and the arch frame is insufficient in elevation, soil and stones are not required to be used for backfilling, a steel plate is required to be arranged for adjustment, and concrete can be used for reinforcing the base when necessary.
Through adopting above-mentioned technical scheme, consolidate and adjust the basement through setting up steel sheet and concrete, can guarantee the stability of bow member, guarantee the effect of strutting of bow member.
In summary, compared with the prior art, the invention has the following beneficial effects:
1. according to the invention, the cement fly ash mortar is adopted, and the grouting pressure is 1.5 times of the maximum design pressure of grouting, so that the cement fly ash mortar can be fully diffused into the surrounding rock mass, the rock mass can be compacted by increasing the volume of the cement fly ash mortar in the continuous pressurizing process, the contact between the cement fly ash mortar and the rock mass is tighter, the solidified cement fly ash mortar and the surrounding rock mass form a whole, the reinforcing and supporting functions are achieved, and the risk of collapse is not easy to occur in the subsequent tunnel excavation process;
2. the invention adopts the compound straight-hole wedge-shaped cutting mode to cut the holes, thereby not only reducing the use amount of the explosive, but also being easier to control the tunneling distance.
Detailed Description
Example (b): a tunnel construction process for crossing a mined-out and subsided area comprises the following steps:
grouting treatment of a goaf and a collapse area:
a. fixed point: before drilling, a grouting hole needs to be fixed, a total station is adopted to carry out field measurement lofting during fixing, and the actual position error of the drilling hole is not more than 0.5 m;
b. drilling to form a hole: before drilling, selecting a proper drill bit and a proper drill according to the drilling depth and diameter of a grouting hole and an inspection hole, opening a hole to a specified depth by using a large-diameter drill bit, then putting a wellhead casing into the hole, filling clay between the outer side of the wellhead casing and the wall of the hole, and then replacing the small-diameter drill bit to continuously drill to the designed depth;
c. burying an orifice closing device: after drilling and full hole washing, burying an orifice closing device, wherein the closing device is an orifice grouting pipe with a flange tray, a small amount of sandstone is put into the orifice for blocking a larger gap, and then a small amount of clay is put into the orifice for completely blocking the gap; injecting water cement slurry with a water-solid ratio of 1: 1.5-1: 2.0 into the hole, wherein the height of the slurry in the hole is 4-6 m, adding an accelerator accounting for 2% of the weight of cement into the cement slurry, and then pulling out the orifice sleeve;
d. grouting construction: the grouting liquid is made of cement-flyash mortar, which is composed of water, cement, coal ash, an accelerating agent and sand, wherein the water-solid ratio is 1: 1.0-1: 1.5, and the ratio of the cement to the coal ash to the sand is controlled to be 3: 7: 2, adding an accelerator accounting for 2 percent of the weight of the cement into the slurry, wherein the accelerator is water glass; the selection of grouting materials is to ensure that water is clean and does not contain harmful substances, the cement adopts ordinary portland cement and slag portland cement, the fly ash meets the requirements of class III fly ash of fly ash used in cement and concrete (GB/T1596-2005), the sand is clean, hard, dry, weatherproof and impurity-free, the sand meets the specified gradation, and the content of soil impurities is less than 5 percent; the grouting concentration is thin and thick, during grouting, the pressure of a grouting pump is 1.5 times greater than the maximum design pressure of grouting, after the grouting is started, the slurry suction amount and the pump pressure of the pump are observed at regular time, when the pump pressure is gradually increased, the grouting amount is less than 70L/min, the pressure of an orifice pipe is between 1.O and 3.0Mpa, the stability is 10 to 15min, or the grouting phenomenon occurs around a grouting hole, the grouting construction of the hole can be ended; when the grouting amount exceeds the designed grouting amount of the drilling hole and the pressure of the hole opening still does not rise, an intermittent grouting process can be adopted; the intermittent time is controlled to be about 10-12 hours; intermittent post-grouting still adopts a grouting process of firstly thinning and then thickening; controlling the secondary grouting to be about 25% of the design amount, and if the pressure is not raised, performing intermittent grouting again until the grouting stopping standard meeting the requirements is reached;
(II) excavating by a three-step method: the three steps are divided into an upper level, a middle level and a lower level, the upper level is 3m high, the middle level is the part from the upper level to the upper part of the arch camber line, the rest part is the lower level, the step width of each level is 5m, and the left side and the right side are staggered by 2 m; the three-step excavation method comprises the following steps:
a. blasting: when the cut holes are cut, a compound straight-hole wedge-shaped cut mode is adopted, namely a mode of mutually combining shallow cut and deep cut; the peripheral eyes are also divided into two stages, the first-stage peripheral eye is arranged on the outer side, the depth of the first-stage peripheral eye is half of that of the second-stage peripheral eye, and meanwhile, the outer inserting eyes are reduced, so that the overexcavation can be reduced as much as possible; after the cutting hole is finished, filling explosive into the cutting hole, and blasting;
b. deslagging: conveying various sludge and broken stones generated in the blasting process to the outer side of the tunnel;
c. primary support: performing primary support on surrounding rocks, wherein the I-steel adopted in the primary support is 20A I-steel, the manufacturing of steel arch frames arranged at the interval of 60cm in each truss is processed according to the specification by a cold bending process, and the size of the steel arch frames meets the design requirement; the support joints are welded firmly, and the surfaces of the steel arches are connected by steel bars; the steel arch frame is erected according to the designed position, and the arch springing is required to be placed on a firm foundation; the steel arch frame is perpendicular to the center line of the tunnel, the allowable deviation of the upper part, the lower part, the left part and the right part is 5cm, the vertical inclination is not more than 2 degrees, when the elevation of the arch frame is insufficient, soil and stones are not required to be used for backfilling, a steel plate is required to be arranged for adjustment, a base can be reinforced by concrete when necessary, and the height of an arch foot is 15-20 cm lower than the bottom line of the upper half section; the gap between the steel arch frame and the surface of the primary sprayed concrete must be filled and compacted by sprayed concrete; when the clearance is too large, the steel template or the concrete wedge block can be used for jacking tightly, and the number of points on one side is not less than 8; the sprayed concrete is symmetrically sprayed upwards from arch springing at two sides, and the steel arch is covered; the arch foot part is easy to generate plastic shearing damage, and the steel frame at the part is required to be welded on four sides besides bolted connection so as to ensure the rigidity and the strength of the joint; the section height of the steel frame is adapted to the thickness of the sprayed concrete; in order to enhance the overall stability of the steel frame, the steel frame is firmly connected with the longitudinal connecting ribs, the structural anchor rods, the positioning tie bars and the foot locking anchor rods; the foot-locking anchor rods play a decisive role in controlling the settlement of the I-shaped steel, so the foot-locking anchor rods are uniformly distributed at the arch feet of the upper step, the middle step and the lower step, the driving angle of the foot-locking anchor rods is preferably 45 degrees with the surrounding rock, and the foot-locking anchor rods are firmly welded with the I-shaped steel; in the relative broken zone or surrounding rock, the primary support is converged and deformed in a relatively large section, and locking feet at the arch springing of the upper, middle and lower steps are reinforced by a phi 42 grouting small conduit; the length of each small guide pipe is 4m, 2 small guide pipes are arranged at each position, the driving angle of the foot locking guide pipe forms 45 degrees with the surrounding rock, and the foot locking guide pipe is firmly welded with the I-shaped steel;
d. advance support: in order to ensure the excavation safety of the tunnel face, the advanced support adopts a hot-rolled seamless steel tube with the diameter of phi 42 x 4 mm, the front end of the hot-rolled seamless steel tube is in a pointed cone shape, 8 mm grouting holes are drilled on the periphery of the tube wall, the hole interval is 15cm, no grouting hole is arranged at the tail part of the hot-rolled seamless steel tube of 1.2m, the horizontal projection overlapping length of two longitudinally adjacent rows is not less than 100cm, and the external inserting angle is 15 degrees; then, mounting the small guide pipe, wherein the small guide pipe is installed by adopting a drilling and driving method, namely, firstly, drilling according to the design requirement, wherein the diameter of a drilled hole is 3-5 mm larger than that of the steel pipe, then, penetrating the small guide pipe through the steel frame, using a hammering or drilling machine to jack in, wherein the jacking length is not less than 90% of the length of the steel pipe, and using high-pressure air to blow out gravels in the steel pipe; after the small guide pipe is installed, the hole and peripheral cracks are sealed by mud, and concrete is sprayed near the small guide pipe and on the working surface if necessary to prevent the working surface from collapsing; the excavation length of the tunnel is smaller than the grouting length of the small guide pipe, and the reserved part is used as a grout stopping wall of the next cycle; selecting a water-cement ratio of the slurry during grouting to be 1:1, in order to obtain a good consolidation effect, enough grout must be injected to ensure an effective diffusion range, the grouting range is designed according to 0.3-0.5 m outside an excavation contour line, grout uniformly diffuses in a stratum, the grouting pressure is controlled to be 0.5-1 MPa during grouting, and a grout stop plug adopted in the grouting process is sprayed concrete with the thickness of 5-10 cm;
(III) cyclic operation: and blasting, deslagging, primary support and advanced support are carried out in a circulating mode until tunnel construction is completed.
The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may occur to those skilled in the art without departing from the principle of the invention, and are considered to be within the scope of the invention.
Claims (8)
1. A tunnel construction process for crossing a mined-out and subsidence area is characterized by comprising the following steps: the method comprises the following steps:
grouting treatment of a goaf and a collapse area:
a. fixed point: before drilling, a grouting hole needs to be fixed, a total station is adopted to carry out field measurement lofting during fixing, and the actual position error of the drilling hole is not more than 0.5 m;
b. drilling to form a hole: before drilling, selecting a proper drill bit and a proper drill according to the drilling depth and diameter of a grouting hole and an inspection hole, opening a hole to a specified depth by using a large-diameter drill bit, then putting a wellhead casing into the hole, filling clay between the outer side of the wellhead casing and the wall of the hole, and then replacing the small-diameter drill bit to continuously drill to the designed depth;
c. burying an orifice closing device: after drilling is finished and full hole washing is carried out, embedding an orifice sealing device, wherein the orifice sealing device is an orifice grouting pipe with a flange tray; injecting cement slurry with a water-solid ratio of 1: 1.5-1: 2.0 into the hole, wherein the height of the cement slurry in the hole is 4-6 m, adding an accelerator accounting for 2% of the weight of the cement into the cement slurry, and then pulling out the wellhead casing;
d. grouting construction: the grouting liquid is made of cement-coal-powder mortar consisting of water, cement, fly ash, an accelerating agent and sand; the grouting concentration is thin and thick, during grouting, the pressure of a grouting pump is 1.5 times greater than the maximum design pressure of grouting, after the grouting is started, the slurry suction amount and the pump pressure of the pump are observed at regular time, when the pump pressure is gradually increased, the grouting amount is less than 70L/min, the pressure of an orifice grouting pipe is between 1.O and 3.0Mpa, the stability is 10 to 15min, or the phenomenon of slurry bleeding around a grouting hole occurs, the grouting construction of the hole can be finished;
(II) excavating by a three-step method: the three steps are divided into an upper level, a middle level and a lower level, the upper level is 3m high, the middle level is the part from the upper level to the upper part of the arch camber line, the rest part is the lower level, the step width of each level is 5m, and the left side and the right side are staggered by 2 m; the three-step excavation method comprises the following steps:
a. blasting: firstly, cutting a slot hole, and filling explosive into the slot hole for blasting after the cutting of the slot hole is finished;
b. deslagging: conveying various sludge and broken stones generated in the blasting process to the outer side of the tunnel;
c. primary support: carrying out primary support on surrounding rocks; the support joints are welded firmly, and the surfaces of the steel arches are connected by steel bars; the steel arch frame is erected according to the designed position, and the arch springing is required to be placed on a firm foundation; the steel arch frame is perpendicular to the center line of the tunnel, the allowable deviation of the upper part, the lower part, the left part and the right part is 5cm, the vertical inclination is not more than 2 degrees, and the height of an arch springing is 15-20 cm lower than the bottom line of the upper half section; the gap between the steel arch frame and the surface of the primary sprayed concrete must be filled and compacted by sprayed concrete; when the clearance is too large, the steel template or the concrete wedge block can be used for jacking tightly, and the number of points on one side is not less than 8; the sprayed concrete is symmetrically sprayed upwards from arch springing at two sides, and the steel arch is covered; the arch foot part is easy to generate plastic shearing damage, and the steel arch frame at the part needs to be subjected to four-side wall welding besides bolting so as to ensure the rigidity and the strength of the joint; the section height of the steel arch frame is adapted to the thickness of the sprayed concrete; in order to enhance the overall stability of the steel arch, the steel arch is firmly connected with the longitudinal connecting rib, the structural anchor rod, the positioning tie bar and the foot locking anchor rod; the foot-locking anchor rods play a decisive role in controlling the settlement of the I-shaped steel, so the foot-locking anchor rods are uniformly distributed at the arch feet of the upper step, the middle step and the lower step, the driving angle of the foot-locking anchor rods is preferably 45 degrees with the surrounding rock, and the foot-locking anchor rods are firmly welded with the I-shaped steel; in the relative broken zone or surrounding rock, the primary support is converged and deformed in a relatively large section, and locking feet at the arch springing of the upper, middle and lower steps are reinforced by a phi 42 grouting small conduit; the length of each small guide pipe is 4m, 2 small guide pipes are arranged at each position, the driving angle of each small guide pipe is 45 degrees with the surrounding rock, and the small guide pipes are firmly welded with the I-shaped steel;
d. advance support: in order to ensure the excavation safety of the tunnel face, the advanced support adopts a hot-rolled seamless steel tube with the diameter of phi 42 x 4 mm, the front end of the hot-rolled seamless steel tube is in a pointed cone shape, 8 mm grouting holes are drilled on the periphery of the tube wall, the hole interval is 15cm, no grouting hole is arranged at the tail part of the hot-rolled seamless steel tube of 1.2m, the horizontal projection overlapping length of two longitudinally adjacent rows is not less than 100cm, and the external inserting angle is 15 degrees; then, mounting the small guide pipe, wherein the small guide pipe is installed by adopting a drilling and driving method, namely, firstly, drilling according to the design requirement, wherein the diameter of a drilled hole is 3-5 mm larger than that of the steel pipe, then, penetrating the small guide pipe through the steel arch, and then, jacking the small guide pipe by using a hammering or drilling machine, wherein the jacking length is not less than 90% of the length of the steel pipe, and blowing out the sand and stone in the steel pipe by using high-pressure air; after the small guide pipe is installed, the hole and peripheral cracks are sealed by mud, and concrete is sprayed near the small guide pipe and on the working surface if necessary to prevent the working surface from collapsing; the excavation length of the tunnel is smaller than the grouting length of the small guide pipe, and the reserved part is used as a grout stopping wall of the next cycle; selecting a water-cement ratio of the slurry during grouting to be 1:1, in order to obtain a good consolidation effect, enough grout must be injected to ensure an effective diffusion range, the grouting range is designed according to 0.3-0.5 m outside an excavation contour line, grout uniformly diffuses in a stratum, the grouting pressure is controlled to be 0.5-1 MPa during grouting, and a grout stop plug adopted in the grouting process is sprayed concrete with the thickness of 5-10 cm;
(III) cyclic operation: and blasting, deslagging, primary support and advanced support are carried out in a circulating mode until tunnel construction is completed.
2. The tunnel construction process for crossing a mined-out and collapsed area according to claim 1, characterized in that: and step C, when the orifice closing device is buried, a small amount of sandstone is put into the hole for blocking a larger gap after the orifice grouting pipe is installed, and then a small amount of clay is put into the hole for completely blocking the gap.
3. The tunnel construction process for crossing a mined-out and collapsed area according to claim 1, characterized in that: step d, during grouting construction, preparing the grouting liquid according to the water-solid ratio of 1: 1.0-1: 1.5, and controlling the ratio of cement to fly ash to sand to be 3: 7: 2, adding an accelerator accounting for 2 percent of the weight of the cement into the slurry.
4. The tunnel construction process for crossing a mined-out and collapsed area according to claim 1, characterized in that: and d, during grouting construction, selecting a grouting material to ensure that water is clean and does not contain harmful substances, wherein the cement is ordinary portland cement or slag portland cement, the accelerator is water glass, the fly ash meets the requirements of class III fly ash GB/T1596-2005 fly ash of fly ash used in cement and concrete, sand is clean, hard, dry, free of weathering and impurities and meets the specified grading, and the content of soil impurities is less than 5%.
5. The tunnel construction process for crossing a mined-out and collapsed area according to claim 1, characterized in that: d, when grouting construction is carried out, when the grouting amount exceeds the designed grouting amount of the drill hole and the pressure of the hole opening still does not rise, an intermittent grouting process can be adopted; the intermittent time is controlled to be about 10-12 hours; after intermittent grouting, adopting a grouting process of firstly thinning and then thickening; and controlling the secondary grouting to be about 25% of the design amount, and if the pressure is not raised, performing intermittent grouting again until the grouting stopping standard meeting the requirement is reached.
6. The tunnel construction process for crossing a mined-out and collapsed area according to claim 1, characterized in that: in the step a, during blasting, the compound straight-hole wedge-shaped undermining mode is adopted to undermine the holes, namely the mode of mutually combining the shallow undermining and the deep undermining; the peripheral eyes are also divided into two stages, the first-stage peripheral eyes are arranged on the outer side, the depth of the first-stage peripheral eyes is half of that of the second-stage peripheral eyes, and meanwhile, the outer inserting eyes are reduced.
7. The tunnel construction process for crossing a mined-out and collapsed area according to claim 1, characterized in that: and c, during primary support, 20A I-beams are adopted, the distance between every two beams is 60cm, the steel arch is manufactured by a cold bending process according to the specification, and the size of the steel arch meets the design requirement.
8. The tunnel construction process for crossing a mined-out and collapsed area according to claim 1, characterized in that: and c, when the primary support is carried out and the steel arch frame is insufficient in elevation, earth and stones are not required to be used for backfilling, a steel plate is required to be arranged for adjustment, and concrete can be used for reinforcing the base when necessary.
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| CN110005435B (en) * | 2019-05-05 | 2020-07-07 | 中交第三航务工程局有限公司 | Construction process for primary support of tunnel body |
| CN110130317A (en) * | 2019-05-07 | 2019-08-16 | 中铁十六局集团第一工程有限公司 | Goaf Treatment Methods are lied prostrate on a kind of freeway tunnel |
| CN111236884A (en) * | 2020-03-10 | 2020-06-05 | 华北有色工程勘察院有限公司 | Grouting stopping device for grouting broken rock mass and grouting method |
| CN113982597B (en) * | 2021-09-29 | 2023-06-23 | 中铁七局集团有限公司 | Tunneling construction method suitable for karst subsidence area strong water permeability unconsolidated formation tunnel |
| CN114233378B (en) * | 2021-12-17 | 2023-11-10 | 中国十七冶集团有限公司 | Goaf self-walking drilling grouting integrated equipment and installation and use method |
| CN116677417B (en) * | 2023-08-03 | 2023-09-22 | 中铁十六局集团有限公司 | Treatment device and treatment method for tunnel collapse cavity |
| CN116971788B (en) * | 2023-09-22 | 2023-12-01 | 中铁十六局集团有限公司 | Method for hydraulic filling of karst cave of underwater tunnel |
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| KR101041301B1 (en) * | 2010-07-29 | 2011-06-14 | 이평우 | Method for digging tunnel |
| CN102383806B (en) * | 2011-07-18 | 2013-09-18 | 广东华盟路桥工程有限公司 | Construction technology for allowing tunnel to pass through ultra-large karst cave |
| CN102720508B (en) * | 2012-04-28 | 2015-03-04 | 中铁二局股份有限公司 | Shield construction method for continuously under-passing dense buildings in silty-soil and silty-sand formation |
| KR101437882B1 (en) * | 2013-10-25 | 2014-09-04 | 최진원 | Tunnel excavating method having various cross sectional shapes |
| CN104100272A (en) * | 2014-07-11 | 2014-10-15 | 中国路桥工程有限责任公司 | Quick construction method of tunnels traversing unfavorable geology |
| CN104481548B (en) * | 2014-11-01 | 2016-05-11 | 中铁一局集团有限公司 | A kind of shield tunnel construction face void handling method |
| CN104806256B (en) * | 2015-04-16 | 2017-03-15 | 粤水电轨道交通建设有限公司 | A kind of shield is prominent to meet processing method in molten chamber hole |
| CN106522981B (en) * | 2016-10-25 | 2018-08-21 | 招商局重庆交通科研设计院有限公司 | Pass through the method for protecting support in goaf tunnel |
| CN106401600B (en) * | 2016-10-28 | 2018-04-13 | 招商局重庆交通科研设计院有限公司 | Strengthen Treatment Methods and supporting construction in tunnel based on molten chamber position |
| CN106593467A (en) * | 2016-11-09 | 2017-04-26 | 大唐陇东能源有限公司 | Supporting method for underground soft rock roadway of coal mine |
| CN106968676B (en) * | 2017-03-27 | 2019-12-17 | 山西潞安环保能源开发股份有限公司 | Method for tunneling through cavity |
| CN106988758B (en) * | 2017-05-08 | 2023-09-01 | 中铁五局集团第五工程有限责任公司 | Construction method for crossing large-scale vertical karst cave group tunnel |
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