CN111963179A - Construction method for replacing shield tail brush through freezing reinforcement - Google Patents

Construction method for replacing shield tail brush through freezing reinforcement Download PDF

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Publication number
CN111963179A
CN111963179A CN202010854679.6A CN202010854679A CN111963179A CN 111963179 A CN111963179 A CN 111963179A CN 202010854679 A CN202010854679 A CN 202010854679A CN 111963179 A CN111963179 A CN 111963179A
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China
Prior art keywords
shield tail
ring
grouting
freezing
tail brush
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CN202010854679.6A
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CN111963179B (en
Inventor
林益剑
王利伟
王建忠
陈细红
林双自
黄春来
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Cccc Third Aviation Bureau Sixth Engineering Xiamen Co Ltd
CCCC Third Harbor Engineering Co Ltd
CCCC Third Harbor Engineering Co Ltd Xiamen Branch
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Cccc Sanya Xiamen Engineering Co ltd
CCCC Third Harbor Engineering Co Ltd
CCCC Third Harbor Engineering Co Ltd Xiamen Branch
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Priority to CN202010854679.6A priority Critical patent/CN111963179B/en
Publication of CN111963179A publication Critical patent/CN111963179A/en
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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
    • E21D9/06—Making by using a driving shield, i.e. advanced by pushing means bearing against the already placed lining
    • E21D9/0635—Tail sealing means, e.g. used as end shuttering
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K9/00—Arc welding or cutting
    • B23K9/16—Arc welding or cutting making use of shielding gas
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K9/00—Arc welding or cutting
    • B23K9/32—Accessories
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING OR HOLDING
    • B25B11/00—Work holders not covered by any preceding group in the subclass, e.g. magnetic work holders, vacuum work holders
    • B25B11/02—Assembly jigs
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING OR HOLDING
    • B25B27/00—Hand tools, specially adapted for fitting together or separating parts or objects whether or not involving some deformation, not otherwise provided for
    • B25B27/02—Hand tools, specially adapted for fitting together or separating parts or objects whether or not involving some deformation, not otherwise provided for for connecting objects by press fit or detaching same
    • B25B27/026—Hand tools, specially adapted for fitting together or separating parts or objects whether or not involving some deformation, not otherwise provided for for connecting objects by press fit or detaching same fluid driven
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • 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
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
    • E21D11/14—Lining predominantly with metal
    • E21D11/18—Arch members ; Network made of arch members ; Ring elements; Polygon elements; Polygon elements inside arches
    • E21D11/20—Special cross- sections, e.g. corrugated
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
    • E21D11/14—Lining predominantly with metal
    • E21D11/18—Arch members ; Network made of arch members ; Ring elements; Polygon elements; Polygon elements inside arches
    • E21D11/22—Clamps or other yieldable means for interconnecting adjacent arch members either rigidly, or allowing arch member parts to slide when subjected to excessive pressure
    • 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
    • E21D11/38—Waterproofing; Heat insulating; Soundproofing; Electric insulating
    • 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
    • E21D11/40—Devices or apparatus specially adapted for handling or placing units of linings or supporting units for tunnels or galleries
    • 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
    • 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
    • E21D9/06—Making by using a driving shield, i.e. advanced by pushing means bearing against the already placed lining
    • E21D9/0607—Making by using a driving shield, i.e. advanced by pushing means bearing against the already placed lining the shield being provided with devices for lining the tunnel, e.g. shuttering
    • 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
    • E21D9/06—Making by using a driving shield, i.e. advanced by pushing means bearing against the already placed lining
    • E21D9/0607—Making by using a driving shield, i.e. advanced by pushing means bearing against the already placed lining the shield being provided with devices for lining the tunnel, e.g. shuttering
    • E21D9/0609—Making by using a driving shield, i.e. advanced by pushing means bearing against the already placed lining the shield being provided with devices for lining the tunnel, e.g. shuttering with means for applying a continuous liner, e.g. sheets of plastics, between the main concrete lining and the rock

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  • Engineering & Computer Science (AREA)
  • Mining & Mineral Resources (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Geology (AREA)
  • Structural Engineering (AREA)
  • Architecture (AREA)
  • Civil Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Environmental & Geological Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Ceramic Engineering (AREA)
  • Soil Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Inorganic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Lining And Supports For Tunnels (AREA)
  • Excavating Of Shafts Or Tunnels (AREA)

Abstract

The invention discloses a construction method for replacing a shield tail brush by freezing reinforcement, which comprises the following steps: before the shield tail brush is replaced, shutdown construction, water stop ring construction, stratum freezing construction, shield tail brush replacement and tunneling recovery are carried out. Before the shield tail brush is replaced and the construction process is stopped, the two ring pipe pieces assembled before the tunneling is stopped are made of steel pipe pieces with freezing compartments; when the stratum freezing construction process is carried out, firstly, the heat insulation plates are laid on the inner surfaces of the two rings of steel pipe sheets, and then, the freezing calandria are laid on the inner surface of each pipe sheet of the two rings of steel pipe sheets respectively; and then connecting a salt water tank in the refrigeration equipment with the refrigeration calandria to form a refrigerating fluid circulation pipeline, and actively freezing the salt water in the refrigerating fluid circulation pipeline through the refrigeration equipment. The construction method can quickly and efficiently form a frozen wall with the average temperature of less than or equal to-8 ℃ and the thickness of more than 0.5m on the soil body after the shield tail, and can effectively prevent muddy water from entering the interior of the shield machine when the shield tail brush is replaced.

Description

Construction method for replacing shield tail brush through freezing reinforcement
Technical Field
The invention relates to a construction method for replacing a tail brush of a shield by freezing reinforcement.
Background
The shield tail brush is located the afterbody of shield structure host computer, with section of jurisdiction in close contact with, is full of the grease in the hoop space that a plurality of rows of shield tail brushes formed, mainly plays to prevent that water, mud etc. from flowing into the inside sealed effect of shield along the section of jurisdiction back, is one sealed measure that prevents that the shield tail from taking place to gush sand, gush mud. In the shield tunnel construction process, inevitable wearing and tearing take place between shield tail brush and the section of jurisdiction. The life of shield tail brush and the gesture relation of notes fat and section of jurisdiction are inseparable, if normal use, and the life-span is 2000m generally, and shield constructs the machine and excavates and surpass this distance, and the tail brush will probably become invalid, causes shield tail water leakage, leaks the thick liquid, and then seriously influences the installation and the slip casting effect of section of jurisdiction. Particularly, in the construction process of the interval shield tunnel with larger length, the shield is positioned in the stratum to replace the shield tail brush. The problem of leakage prevention of the shield tail is solved in the process of disassembling the old shield tail brush and assembling the new shield tail brush. In order to solve the problem of shield tail leakage in the shield tail brush replacement process, the stratum around the shield tail is generally frozen or a waterproof material is adopted to perform grouting reinforcement in the stratum at the tail part of the shield.
Grouting reinforcement: the construction is simple, the construction period is short, and the method is suitable for working conditions of low formation permeability coefficient and low groundwater flow velocity. The grouting reinforcement is easy to wrap the shield body, and the shield tail brush is easy to lose effectiveness and aggravate, so that the reinforcing effect on a water-rich sand layer is poor, and the safety of the shield tail brush during replacement operation is low.
Freezing and reinforcing: the construction is relatively complex, special pipe pieces need to be manufactured, the construction period is long, the method can be applied to various composite stratums, and the requirement on stratum environment is low. The freezing reinforcement can effectively protect the undamaged shield tail brush, and the safety of the shield tail brush during replacement operation is high.
As the stratum where the shield machine is positioned is mucky soil <2-4-2> and fine sand <2-4-6> (containing mud), the underground water content of the stratum is higher, the tunnel burial depth reaches 19.1 meters, the water and soil pressure is high, and the stratum environment is relatively severe. If the plugging effect cannot be guaranteed by adopting a conventional grouting reinforcement mode, the freezing reinforcement mode is adopted for ensuring the construction safety in the shield tail brush replacement process under the influence of the geological conditions.
The current freezing and strengthening methods include the following two methods:
1) freezing calandria are pre-buried in last ring concrete segment and 2 nd from last ring concrete segment, and the freezing calandria interconnect in each segment forms freezing return circuit, carries low temperature refrigerating fluid to freezing calandria through outside refrigerator to with energy transfer to the soil horizon, thereby freeze the soil bin of shield structure machine afterbody department. Because the interval of freezing calandria and section of jurisdiction extrados reaches 13cm, receives the poor influence of the heat conductivity of the reinforcing bar of arranging in the section of jurisdiction and concrete simultaneously for freezing effect is poor.
2) Freezing calandria are pre-buried in the last ring steel pipe piece and the 2 nd ring steel pipe piece, and the freezing calandria in each pipe piece interconnect forms freezing return circuit, carries low temperature refrigerating fluid to freezing calandria through outside refrigerator to transmit the energy to the soil layer, thereby freeze the soil bin of shield structure tail portion department. The freezing and strengthening method has poor freezing effect because the heat transfer is in line contact.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a construction method for freezing, reinforcing and replacing a shield tail brush, which can quickly and efficiently freeze a soil layer at the tail part of a shield tunneling machine, is convenient and fast to operate, has short construction period and has small influence on the stability of a shield tunnel.
The purpose of the invention is realized as follows: a construction method for replacing a shield tail brush by freezing reinforcement is characterized in that a shield machine is provided with three shield tail brushes, and a grease cavity is respectively formed between a first shield tail brush and a second shield tail brush and between the second shield tail brush and a third shield tail brush; the construction method is used for replacing the first shield tail brush and comprises the following procedures: before the shield tail brush is replaced, stopping construction, applying a water stop ring, freezing the stratum, replacing the shield tail brush and recovering tunneling;
the shield tail brush replacement and shutdown construction process comprises the following steps:
selecting the position of the last ring segment of the shield tunneling machine for stopping tunneling according to the stratum characteristics of the position of the shield tunneling machine, and stopping tunneling when a propelling oil cylinder reaches a set stroke when a new ring segment is continuously tunneled after the last ring segment is assembled, so that a first shield tail brush is positioned at the front part of the last ring segment;
step two, injecting sealing grease into a grease cavity between a second shield tail brush and a third shield tail brush in the process from the driving of the penultimate 3-ring segment to the shutdown of the shield machine;
thirdly, assembling the last ring pipe piece and assembling the penultimate ring pipe piece by using steel pipe pieces, and synchronously grouting in four grouting holes of the two ring steel pipe pieces; grouting by adopting bentonite when a new annular duct piece is tunneled to a stop position; filling a synchronous grouting pipe of the shield tail with sealing grease after tunneling to a shutdown position;
each ring of steel pipe pieces is formed by splicing six steel pipe pieces into a whole ring of pipe pieces, and each steel pipe piece comprises a front ring plate, a rear ring plate, a back plate, two end plates and an inner arc plate concentrically positioned at the inner side of the back plate; the inner surface of the back plate is longitudinally connected with a front middle ribbed plate and a rear middle ribbed plate, and the inner end of the front middle ribbed plate and the inner end of the rear middle ribbed plate are respectively welded with a circumferential reinforcing plate; the inner surface of the inner arc plate is connected with a plurality of longitudinal rib plates, the longitudinal rib plates are divided into three sections by the front middle rib plate and the rear middle rib plate, and the inner end of each section of the longitudinal rib plate is also welded with a longitudinal stiffening plate; the inner surfaces of the front ring plate, the rear ring plate, the longitudinal stiffening plate and the annular reinforcing plate form an inner cambered surface of each segment; a hollow wall is formed between the inner arc plate and the back plate, and the hollow wall is divided into a front freezing compartment, an intermediate freezing compartment and a rear freezing compartment by a front intermediate rib plate and a rear intermediate rib plate; the right side of the middle front rib plate is provided with a refrigerating fluid through hole, and the left side of the middle rear rib plate is also provided with a refrigerating fluid through hole; through holes are respectively formed in the two end plates corresponding to the front freezing compartment, the middle freezing compartment and the rear freezing compartment; a pair of refrigerating fluid inlets are formed on the left side of the inner arc plate corresponding to the front cabin, and a pair of refrigerating fluid outlets are formed on the right side of the inner arc plate corresponding to the rear cabin;
fourthly, fastening the bolts between the reinforced pipe pieces before stopping tunneling, and tightly jacking the last ring of pipe pieces by using a propulsion oil cylinder of the shield tunneling machine; simultaneously, four tensioning strips are applied from the last 10 ring pipe piece to the last ring pipe piece and are respectively arranged at the 2-point position, the 6-point position, the 10-point position and the 13-point position;
the water stop ring construction process is carried out after shutdown, and comprises the following steps:
injecting polyurethane into six radial grouting holes of a shield tail, wherein the injection pressure is greater than the underground water pressure, and the injection sequence is from the bottom of a tunnel to the top through two sides;
injecting thick bentonite slurry into a grouting hole of the last 3 ring pipe piece, and filling a space outside the shield tail pipe piece and the last shield tail brush;
thirdly, performing secondary grouting on grouting holes of the 4 th-to-last ring duct piece, the 5 th-to-last ring duct piece, the 6 th-to-last ring duct piece and the 7 th-to-last ring duct piece respectively, wherein the type of the grout of the secondary grouting is cement grout or double-grout grouting;
after the slurry of the secondary grouting is finally solidified, sequentially opening a secondary grouting ball valve of the 4 th last ring pipe piece from bottom to top, punching the pipe piece by using a steel chisel, detecting whether water seeps out and the size of water flow, and determining that the water stopping effect reaches the standard if no water seeps out or the seepage water flow is less than or equal to 1L/h; if the seepage water flow is more than or equal to 1L/h, injecting double-liquid slurry into the reserved holes of the water seepage area; (ii) a
When the stratum freezing construction process is carried out, the method comprises the following steps:
arranging a freezing station and a freezing device on a storage battery flat car in a tunnel, wherein the freezing device comprises two freezers, a plurality of brine tanks, a plurality of brine pumps and a plurality of distribution boxes;
laying an insulation board on the inner surface of the two-ring steel pipe sheet, wherein the laying range of the insulation board is not less than 2m outside the boundary of the designed frozen wall; the heat insulation board is a flame-retardant or flame-retardant plastic foam soft board with the thickness not less than 40 mm; then respectively laying freezing calandria on the inner surface of each pipe piece of the two rings of steel pipe pieces; the freezing calandria on each segment is connected with the freezing calandria interface on the inner arc plate;
connecting a salt water tank in the refrigeration equipment with refrigeration calandria laid on the two ring steel pipe sheets to form a refrigeration liquid circulation pipeline, wherein the refrigeration liquid circulation pipeline comprises a water outlet main pipe and two water return main pipes led out from the salt water tank, and two water outlet branch pipes connected with water outlets of the water outlet main pipes; the freezing calandria on two rings of steel pipe sheets are divided into two groups of freezing calandria respectively, the freezing calandria on each steel pipe sheet is connected in series, the freezing calandria on every three steel pipe sheets are connected in parallel to form a group of freezing calandria, and the two groups of freezing calandria on each ring of steel pipe sheets are connected in series and then are connected with the water outlet of one water outlet branch pipe and the water inlet of one water return header pipe in a one-to-one correspondence manner;
preparing refrigerating fluid, wherein the refrigerating fluid adopts saline water with the specific gravity of 1.26-1.27, a refrigerating fluid circulating pipeline is filled with clear water, a salt water tank with a filtering device is filled with half of the clear water, salt is dissolved in the salt water tank, a salt water pump is started, the salt is dissolved while circulating, and the concentration of the salt water reaches the design requirement;
step five, actively freezing the brine in the refrigerating fluid circulation pipeline through refrigeration equipment, wherein the temperature of the brine is reduced to be below-15 ℃ in 5 days, the temperature of the brine is reduced to be below-25 ℃ in 10 days, and the temperature difference between the brine in the outlet loop and the brine in the return loop is not more than 2 ℃; performing heat exchange with the soil body behind the shield tail by using low-temperature brine circulation to form an effective frozen wall on the soil body behind the shield tail; the thickness of the frozen wall is more than or equal to 0.5m, and the average temperature of the frozen wall is less than or equal to-8 ℃;
after the freezing body is formed preliminarily, namely when the average temperature of the freezing wall is reduced to 0 ℃, respectively injecting polyurethane into 12 grouting holes of the last 3 ring segment and 12 grouting holes of the last 4 ring segment;
the shield tail brush replacing process comprises the following steps: finally, dismantling and installing a ring pipe sheet, dismantling a shield tail brush and installing a new shield tail brush;
when the last step of dismantling and installing the ring pipe piece is carried out, the method comprises the following working procedures:
grasping a K segment assembling head of the last ring of segments by using an assembling machine grabbing head, dismantling longitudinal and circumferential bolts of the K segments, loosening a propulsion oil cylinder at a 10-point position, dismantling the K segments, and placing the K segments on a battery flat car in a tunnel; then an erector is used for dismantling L1 pipe pieces and placing the pipe pieces on a storage battery flat car in the tunnel; replacing the worn tail brushes at the positions of the K pipe pieces and the L1 pipe pieces;
grasping an L2 segment assembling head by using an assembling machine grasping head, disassembling longitudinal and circumferential bolts of L2 segments, loosening propulsion oil cylinders at 7-point, 8-point and 9-point positions, rotating the L2 segments to the positions of the original K segments and the original L1 segments, namely assembling at 10-point, 11-point and 12-point positions, and installing circumferential bolts and oil cylinders to tightly prop against the L2 segments; replacing the worn shield tail brush at the original L2 segment position;
grasping the B2 segment assembling heads by using an assembling machine grasping head, dismantling longitudinal and circumferential bolts of B2 segments, loosening the pushing oil cylinders at 4-point, 5-point and 6-point positions, rotating the B2 segments to the positions of the original L2 segments, namely assembling at 7-point, 8-point and 9-point positions, and installing circumferential bolts and jacking the B2 segments by using the oil cylinders; replacing the worn shield tail brush at the original B2 segment position;
grasping the B3 segment assembling heads by using the assembling machine grasping heads, disassembling longitudinal and circumferential bolts of the B3 segments, loosening the pushing oil cylinders at 1-point, 2-point and 3-point positions, rotating the B3 segments to the original B2 segment positions, namely assembling at 4-point, 5-point and 6-point positions, and installing circumferential bolts and tightly jacking the B3 segments by the oil cylinders; replacing the worn shield tail brush at the original B3 segment position;
grasping the B1 segment assembling head by using an assembling machine grasping head, dismantling longitudinal and circumferential bolts of B1 segments, loosening the 14-point, 15-point and 16-point pushing oil cylinders, rotating the B1 segments to the original B3 segment positions, namely assembling at 1-point, 2-point and 3-point positions, and installing circumferential bolts and jacking the B1 segments by using the oil cylinders; replacing the worn shield tail brush at the original B1 segment position;
sequentially assembling the disassembled L1 duct pieces and K duct pieces in place by using an assembling machine, installing longitudinal bolts and circumferential bolts, and tightly jacking the L1 duct pieces and the K duct pieces by using a thrust cylinder;
seventhly, after the K-block pipe pieces are assembled in place, all the longitudinal and circumferential bolts are fastened;
when the shield tail brush is dismantled, the method comprises the following procedures:
firstly, cleaning the exposed first shield tail brush;
cutting off the exposed first shield tail brush by using oxygen and acetylene; after the cutting is finished, polishing the cutting area;
when the new shield tail brush is installed, the method comprises the following procedures:
firstly, the mounting sequence of the new shield tail brushes is sequentially lap-welding and mounting, and the distance between adjacent shield tail brushes is not more than 3 mm; welding is carried out by adopting a welding wire with the diameter of 1.2mm of a secondary welding machine, the front and rear welding beads of the shield tail brush are fully welded, and the height of a welding angle is 8-10 mm;
cleaning or replacing the shield tail brush, and manually smearing sealing grease in the new shield tail brush and a grease cavity between the new shield tail brush and the second shield tail brush; covering a protective film on the coated sealing grease area, and removing the protective film before assembling the segments;
thirdly, after the pipe piece is installed in place, a grease pump is used for pumping sealing grease, and a grease cavity and a new shield tail brush which are artificially smeared and are not compact are filled;
when the tunneling recovery process is carried out, the method comprises the following steps:
firstly, unfreezing frozen soil outside a duct piece at the tail part of a shield tunneling machine, namely introducing hot water into a refrigerating fluid circulating pipeline, providing hot water by adopting an electric heating method, circularly unfreezing the hot water, and grouting a freezing area through reserved holes in a last ring duct piece and a last but 2 ring duct piece to prevent the frozen soil from being thawed; when grouting and tapping, the drill rod penetrates through synchronous grout in depth, and the grouting sequence is as follows: tunnel bottom → tunnel sides → tunnel top; during grouting, temperature measurement of a temperature measuring hole, tunnel deformation and ground settlement monitoring are matched; when the single-day settlement of the tunnel is more than 0.5mm or the accumulated settlement of the tunnel is more than 1.0mm, performing compensation grouting; when the surface of the earth rises to 2.0mm, stopping grouting, namely stopping compensation grouting; completely melting the frozen wall, and stopping compensation grouting when actually measuring the stratum settlement for half a month and no more than 0.1mm per day under the condition of no grouting;
secondly, injecting sealing grease into two grease cavities between the three shield tail brushes in a pressing mode;
and step three, dismantling the freezing calandria laid on the two rings of steel pipe sheets, grouting the freezing cabin of the two rings of steel pipe sheets, and solidifying the slurry and the steel pipe sheets into a whole after final solidification.
The construction method for replacing the shield tail brush by freezing reinforcement comprises the third step of carrying out the construction process before replacing the shield tail brush and stopping the machineIn the process, the slurry mixing ratio of the synchronous grouting is as follows: 250 parts of cement, 300 parts of fly ash, 450 parts of sand, 450 parts of water and 50 parts of bentonite; total grouting amount per ring 4.5m3。
In the construction method for replacing the shield tail brush by freezing reinforcement, the pressure for injecting the polyurethane is 0.3-0.5 MPa, the total injection amount is 300L, and the injection amount per hole is 50L when the step of the water stop ring construction process is performed.
In the construction method for replacing the shield tail brush by freezing reinforcement, when the step two of the water stop ring construction process is carried out, the thick bentonite slurry has the following mixing ratio: 5:1 of water, namely bentonite, and the viscosity is not lower than 60 s; the injection amount is 4m3And the grouting pressure is less than or equal to 0.5 MPa.
In the construction method for replacing the shield tail brush by freezing reinforcement, when the third step of the water stop ring construction process is carried out, the cement paste is prepared from the following components in parts by weight: 1:1 of water and cement; the mixing proportion of the double-liquid slurry is as follows: cement paste, water glass is 0.8:1, and initial setting time is 45 s; the requirements of secondary grouting construction are as follows:
A. performing single-ring grouting in a sequence from bottom to top, and avoiding K blocks in the grouting process; injecting a small amount of cement paste or double-liquid paste into the 4 th last ring pipe piece at the grouting pressure of 0.3MPa, and then injecting the cement paste or double-liquid paste into the 5 th last ring pipe piece, the 6 th last ring pipe piece and the 7 th last ring pipe piece; the grouting sequence is as follows: the penultimate 7 ring segment → the penultimate 6 ring segment → the penultimate 5 ring segment, and the grouting pressure is not more than 5 bar; the grouting amount of each ring of pipe piece is not less than 5m3The grouting amount per hole is not more than 1m3(ii) a After the strength of cement paste or double-liquid paste behind the penultimate 5-ring duct piece, the penultimate 6-ring duct piece and the penultimate 7-ring duct piece is increased, cement paste or double-liquid paste is continuously injected into the penultimate 4-ring duct piece;
B. before punching, installing a ball valve;
C. drilling a drill rod with the length of 1000mm, wherein the opening depth is not less than 10cm after the drill rod penetrates through the synchronous grouting layer, grouting is carried out until cement paste or double-liquid paste emerges from an adjacent ball valve close to the upper side, and then grouting hole sites are injected;
the construction of the shield tail brush of the freezing reinforcement replacementThe method comprises the step I of recovering the tunneling process, wherein the grouting material is mainly cement paste, the water cement ratio is 0.8-1.0, the grouting pressure is less than or equal to 0.5MPa, and the single-ring grouting amount is less than or equal to 4m3。
The construction method for replacing the shield tail brush by freezing reinforcement has the following characteristics:
1) the method comprises the steps that two ring pipe sheets assembled before the shield tunneling machine stops tunneling are made of steel pipe sheets, the pipe walls of the two ring pipe sheets are arranged into a hollow wall, the hollow wall is divided into a front freezing compartment, an intermediate freezing compartment and a rear freezing compartment through two ribbed plates, freezing calandria communicated with the freezing compartment are laid on the inner surface of each steel pipe sheet, low-temperature freezing liquid is conveyed into the freezing compartment cavities of the two ring pipe sheets through the freezing calandria by external freezing equipment, and the low-temperature freezing liquid in the freezing compartment cavities transfers energy to a soil layer around a shield tail, so that the heat transfer area is large, the heat conduction performance is good, the soil bin at the tail of the shield tunneling machine can be rapidly and efficiently frozen, a frozen wall larger than 0.5m is formed, and muddy water can be effectively prevented from entering the interior of the shield tunneling machine when the shield tail is brushed;
2) the invention has convenient operation, short construction period and little influence on the stability of the shield tunnel when the shield tail brush is replaced.
Drawings
FIG. 1 is a diagram showing the positional relationship between a shield tail brush and a duct piece before the shield tail brush is replaced and during the steps of a shutdown construction process in the construction method for replacing the shield tail brush by freezing reinforcement of the invention;
FIG. 2 is a schematic diagram of the shield tail and the segment wall post-reinforcement after the formation freezing construction process is completed in the construction method for replacing the shield tail brush by freezing reinforcement of the invention;
FIG. 3a is an elevation view of a standard steel pipe piece of the steel pipe piece used in the construction method for replacing the shield tail brush by freezing reinforcement according to the present invention;
FIG. 3b is a plan view of a standard steel pipe piece of the steel pipe piece used in the construction method for replacing the shield tail brush by freezing reinforcement according to the present invention;
FIG. 3c is a view from A-A in FIG. 3 a;
FIG. 3d is a view from the B-B direction in FIG. 3 c;
FIG. 4a is a longitudinal sectional view of a frozen wall formed after a formation freezing process is completed in the construction method of freezing, reinforcing and replacing a shield tail brush of the present invention
FIG. 4b is a view from the direction C-C in FIG. 4 a;
FIG. 5 is a state diagram of the construction method for replacing the shield tail brush by freezing reinforcement of the invention before the last ring pipe piece removing and installing step of the shield tail brush replacing process;
FIG. 5a is a state diagram of the first step of dismantling and installing the last ring pipe piece of the shield tail brush replacing process in the construction method for freezing, reinforcing and replacing the shield tail brush of the present invention;
FIG. 5b is a state diagram of the process of the last ring pipe piece removing and installing step of the shield tail brush replacing process of the construction method for freezing, reinforcing and replacing the shield tail brush of the present invention;
FIG. 5c is a state diagram of the third step of removing and installing the last ring pipe piece of the shield tail brush replacing process according to the construction method for freezing, reinforcing and replacing the shield tail brush of the present invention;
FIG. 5d is a diagram showing a state of the last step of removing and installing the ring pipe piece in the shield tail brush replacing process according to the method for replacing the shield tail brush by freezing reinforcement of the present invention;
FIG. 5e is a state diagram of a fifth process step of dismantling and installing the last ring pipe piece of the shield tail brush replacing process according to the construction method for replacing the shield tail brush by freezing reinforcement of the present invention;
fig. 5f is a state diagram of the process of the last annular pipe sheet dismantling and mounting step of the shield tail brush replacing process of the construction method for replacing the shield tail brush by freezing reinforcement of the invention;
fig. 5g is a state diagram of a process of removing and installing the last ring pipe sheet in the shield tail brush replacing process according to the method for constructing the freezing reinforcement replacement shield tail brush of the present invention;
FIG. 6 is a state diagram of a first step of installing a new shield tail brush in a shield tail brush replacement process according to the construction method for replacing a shield tail brush by freezing reinforcement of the present invention;
Detailed Description
The invention will be further explained with reference to the drawings.
Referring to fig. 1 to 6, the method for constructing a freezing strengthening replacement shield tail brush according to the present invention includes three shield tail brushes, wherein a grease chamber is respectively formed between a first shield tail brush 101 and a second shield tail brush 102, and between the second shield tail brush 102 and a third shield tail brush 103.
The construction method is used for replacing the first shield tail brush and comprises the following processes: before the shield tail brush is replaced, stopping construction, applying a water stop ring, freezing the stratum, replacing the shield tail brush and recovering tunneling;
the shield tail brush replacement and shutdown construction process comprises the following steps:
selecting the position of the last ring segment 200 of the shield tunneling machine for stopping tunneling according to the stratum characteristics of the position of the shield tunneling machine, and stopping tunneling when the stroke of a thrust cylinder is 1385mm when a new ring segment is continuously tunneled after the last ring segment 200 is assembled, so that the first shield tail brush 101 is positioned at the front part of the last ring segment 200;
step two, injecting sealing grease into a grease cavity between a second shield tail brush 102 and a third shield tail brush 103 in the process from the driving of the penultimate 3-ring segment 202 to the shutdown of the shield machine, wherein the pressure of the sealing grease during injection is 2.0-3.0 MPa;
step three, assembling the last ring pipe piece 200 and assembling the penultimate ring pipe piece 201 by using steel pipe pieces, and synchronously grouting in four grouting holes of the two ring steel pipe pieces, wherein the slurry mixing ratio of synchronous grouting is as follows: 250 parts of cement, 300 parts of fly ash, 450 parts of sand, 450 parts of water and 50 parts of bentonite; total grouting amount per ring 4.5m3(ii) a When a new ring of pipe segments are tunneled to a stop position, bentonite is adopted for grouting, and the grouting amount is about 4m3(ii) a After the tunnel is tunneled to a shutdown position, the shield tail synchronous grouting pipe is filled with sealing grease, so that pipeline blockage caused by freezing is prevented;
each ring of steel pipe sheets consists of six pipe sheets, namely K steel pipe sheets (capping steel pipe sheets), L1 steel pipe sheets, L2 steel pipe sheets, B1 steel pipe sheets, B2 steel pipe sheets and B3 steel pipe sheets; each steel pipe piece comprises a front ring plate 21, a rear ring plate 22, a back plate 24, an inner arc plate 23 and two end plates 25, wherein the inner surface of the back plate 24 is longitudinally connected with a front middle rib plate 26a and a rear middle rib plate 26b, and the inner end of the front middle rib plate 26a and the inner end of the rear middle rib plate 26b are respectively welded with a middle annular reinforcing plate 260; the inner arc plate 23 is concentrically positioned at the inner side of the back plate, the inner surface of the inner arc plate 23 is connected with a plurality of longitudinal rib plates 27, and the front ends and the rear ends of the plurality of longitudinal rib plates 27 are correspondingly connected with a front annular reinforcing plate 261 and a rear annular reinforcing plate 262 one by one; the plurality of longitudinal rib plates 27 are divided into three sections by the front middle rib plate 26a and the rear middle rib plate 26b, and the inner end of each section of the longitudinal rib plate 27 is also welded with a longitudinal stiffening plate 270; the inner surfaces of the front ring plate 21, the rear ring plate 22, the longitudinal stiffener 270, the middle hoop reinforcement plate 260, the front hoop reinforcement plate 261 and the rear hoop reinforcement plate 262 form an inner cambered surface of each steel pipe sheet; a hollow wall is formed between the inner arc plates 23 and the back plate 24, and the hollow wall is divided into a front freezing compartment, an intermediate freezing compartment and a rear freezing compartment by a front intermediate rib plate 26a and a rear intermediate rib plate 26 b; a refrigerating fluid through hole (not shown) is formed in the right side of the middle front rib plate 26a, and a refrigerating fluid through hole (not shown) is formed in the left side of the middle rear rib plate 26 b; through holes are respectively arranged on the two end plates 25 corresponding to the front freezing compartment, the middle freezing compartment and the rear freezing compartment; a pair of refrigerating fluid inlets 28a is formed on the left side of the inner arc plate 23 corresponding to the front cabin, and a pair of refrigerating fluid outlets 28b is formed on the right side of the inner arc plate 23 corresponding to the rear cabin; one annular rib plate 29 is provided on the apex line of the inner surface of the back plate 24 of each steel pipe piece.
Fourthly, fastening the bolts between the reinforced pipe pieces before stopping tunneling, and tightly jacking the last ring of pipe pieces 200 by using a propulsion oil cylinder of the shield tunneling machine; and meanwhile, four tensioning strips are applied from the segment with the last 10 rings to the segment with the last ring 200, and the tensioning strips are channel steel with the length of 12m and are respectively arranged at the 2-point position, the 6-point position, the 10-point position and the 13-point position.
The water stop ring construction process is carried out after the shield machine is stopped, and comprises the following steps:
injecting polyurethane into six radial grouting holes of a shield tail to enable the polyurethane to react with underground water around a shield body and wrap the shield body to play a role in blocking muddy water of a soil bin from flowing backwards; the injection pressure is 0.3-0.5 MPa higher than the underground water pressure, the total injection amount is 300L, the injection amount of each hole is 50L, and the injection sequence is from the bottom of the tunnel to the top through two sides;
step two, in order to further seal a channel from a rear grouting space to a shield tail and prevent a grouting body from wrapping the shield tail outer wall of the shield machine or filling a shield tail gap to influence the escaping and the driving of the shield machine, thick bentonite slurry is injected into a grouting hole of a last 3 rd ring segment 202 and is filled in a space between a shield tail segment and a last shield tail brush, so that an original soil body is more compact, on one hand, double-liquid slurry injected from the rear can be effectively prevented from permeating the shield tail brush in front and the shield tail outer wall of the shield machine to play a role in protecting the shield tail brush, on the other hand, the effect of freezing construction can be improved, gaps are prevented from being formed between a frozen wall and the double-liquid slurry after solidification, and a water seepage channel is formed; the thick bentonite slurry comprises the following components in parts by weight: 5:1 of water, namely bentonite, and the viscosity is not lower than 60 s; the injection amount is 4m3The grouting pressure is less than or equal to 0.5 MPa;
and step three, respectively carrying out secondary grouting on grouting holes of the 4 th to last ring duct piece 203, the 5 th to last ring duct piece 304, the 6 th to last ring duct piece 205 and the 7 th to last ring duct piece 206, wherein the type of grout of the secondary grouting is cement grout or double-grout grouting, and the cement grout is in a mixing ratio: 1:1 of water and cement; the mixing ratio of the double-liquid slurry is as follows: cement paste, water glass is 0.8:1, and initial setting time is 45 s; the secondary grouting construction requirements are as follows:
A. single-ring grouting is carried out in the sequence from bottom to top, grouting is symmetrically carried out according to the sequence of 7, 9, 5 and 11. point positions, and the 'small-amount, alternate, cyclic and multiple' grouting is followed, and K blocks are avoided in the grouting process; injecting a small amount of cement paste or double-liquid paste into the 4 th last ring pipe piece at the grouting pressure of 0.3MPa, and then injecting the cement paste or double-liquid paste into the 5 th last ring pipe piece, the 6 th last ring pipe piece and the 7 th last ring pipe piece; the grouting sequence is as follows: the penultimate 7 ring segment → the penultimate 6 ring segment → the penultimate 5 ring segment, and the grouting pressure is not more than 5 bar; the grouting amount of each ring of pipe piece is not less than 5m3, and the grouting amount of each hole is not more than 1m3(ii) a After the strength of cement paste or double-liquid paste behind the penultimate 5-ring pipe piece, the penultimate 6-ring pipe piece and the penultimate 7-ring pipe piece is increased, the penultimate 4-ring pipe piece is subjected to successive treatmentContinuously injecting cement paste or double-liquid paste;
B. before punching, installing a ball valve;
C. drilling a drill rod with the length of 1000mm, wherein the opening depth is not less than 10cm after the drill rod penetrates through the synchronous grouting layer, grouting is carried out until cement paste or double-liquid paste emerges from an adjacent ball valve close to the upper side, and then grouting hole sites are injected;
after the slurry of the secondary grouting is finally solidified, sequentially opening a secondary grouting ball valve of a 4 th last ring duct piece 203 from bottom to top, punching the duct piece by using a steel chisel, detecting whether water seeps out and the size of water flow, and determining that the water stopping effect reaches the standard if no water seeps out or the seepage water flow is less than or equal to 1L/h; and if the seepage water flow is more than or equal to 1L/h, the double-liquid slurry is injected into the reserved holes of the seepage water area, and the stratum freezing construction process can be carried out only when the water stopping effect of all the detection holes reaches the standard.
When the stratum freezing construction process is carried out, the method comprises the following steps:
arranging a freezing station on a storage battery flat car in a tunnel and installing freezing equipment, wherein the freezing equipment comprises two freezers, a plurality of brine tanks, a plurality of brine pumps and a plurality of distribution boxes;
laying insulation boards on the inner surfaces of the two rings of steel pipe sheets 200 and 201, wherein the laying range of the insulation boards is not less than 2m outside the boundary of the designed freezing wall; the heat insulation board is a flame-retardant or flame-retardant plastic foam soft board, the heat conductivity coefficient is not more than 0.04W/m.K, the water absorption rate is not more than 2%, and the heat insulation board cannot be soaked in water; the thickness of the heat insulation plate is not less than 40mm, the heat insulation plate is closely attached to the steel pipe sheet by adopting special glue, and no gap is formed between the heat insulation plates; then, the inner surface of each steel pipe sheet of the two rings of steel pipe sheets 200 and 201 is laid with a freezing calandria 300, the freezing calandria 300 is laid annularly, and the distance is not more than 400 mm; the freezing calandria 300 adopts a seamless soft steel tube with the diameter of 45mm, and the freezing calandria 300 on each segment is connected with the freezing liquid inlet 28a and the freezing liquid outlet 28b on the corresponding inner arc plate 23; each freezing calandria is wrapped with a rubber plastic material heat-insulating layer, the thickness of the heat-insulating layer is 50mm, and the outside of the heat-insulating layer is wrapped by a plastic film;
thirdly, connecting a brine tank in the refrigeration equipment with refrigeration pipes laid on the two rings of steel pipe sheets 200 and 201 to form a refrigeration liquid circulation pipeline, wherein the refrigeration liquid circulation pipeline comprises a main water outlet pipe and two main water return pipes which are led out from the brine tank, and two branch water outlet pipes connected with the water outlets of the main water outlet pipe; the freezing calandria on the two rings of steel pipe sheets 200, 201 are divided into two groups of freezing calandria respectively, the freezing calandria on each steel pipe sheet is connected in series, the freezing calandria on each three steel pipe sheets are connected in parallel to form a group of freezing calandria, the two groups of freezing calandria on each ring of steel pipe sheet are connected in series and then are connected with the water outlet of one water outlet branch pipe and the water inlet of one water return header pipe in a one-to-one correspondence manner; and the low-temperature refrigerating fluid is conveyed to the front freezing compartment, the middle freezing compartment and the rear freezing compartment of the two rings of steel pipe sheets 200 and 201 by a refrigerating fluid circulating pipeline.
Preparing refrigerating fluid, wherein the refrigerating fluid adopts saline water with the specific gravity of 1.26-1.27, a refrigerating fluid circulating pipeline is filled with clear water, a salt water tank with a filtering device is filled with half of the clear water, salt is dissolved in the salt water tank, a salt water pump is started, the salt is dissolved while circulating, and the concentration of the salt water reaches the design requirement;
step five, actively freezing the brine in the refrigerating fluid circulation pipeline through refrigeration equipment, wherein the temperature of the brine is reduced to be below-15 ℃ in 5 days, the temperature of the brine is reduced to be below-25 ℃ in 10 days, and the temperature difference between the brine in the outlet loop and the brine in the return loop is not more than 2 ℃; performing heat exchange with the soil body behind the shield tail by using low-temperature brine circulation to form an effective frozen wall on the soil body behind the shield tail; the thickness of the frozen wall is more than or equal to 0.5m, and the average temperature of the frozen wall is less than or equal to-8 ℃;
and sixthly, after the frozen wall is preliminarily formed, namely when the average temperature of the frozen wall is reduced to 0 ℃, respectively supplementing and injecting polyurethane into the 12 grouting holes of the last 3 ring segment and the 12 grouting holes of the last 4 ring segment, wherein the injection amount is 100L/hole, forming a heat insulation layer for the frozen body in a soil body, and simultaneously reducing the adverse effect of stratum groundwater flow around the frozen wall on the development of the frozen wall.
In order to monitor the development condition of a frozen wall, 2 temperature measuring holes are arranged in the radial direction of a penultimate ring segment 3 and are respectively positioned at a 4-point position and a 12-point position, and the hole depth is 0.95 m; 4 temperature measuring holes are arranged in the radial direction of the 2 nd-last ring segment and are respectively positioned at 16 point positions, 416 point positions, 816 point positions and 12 point positions, and the hole depth is 0.95 m; every 150mm of temperature measuring holes are provided with one temperature measuring point inwards from the hole opening, and 5 temperature measuring points are arranged in total.
Observing frequency of a temperature measuring hole: the observation is carried out once every 12h during the active freezing period, the observation is carried out once every 8h during the shield tail brush replacement maintenance freezing period, and the observation is carried out once every 24h during the freezing and unfreezing period.
The shield tail brush replacing process comprises the following steps: finally, dismantling and installing a ring pipe sheet, dismantling a shield tail brush and installing a new shield tail brush;
when the last step of dismantling and installing the ring pipe piece is carried out, the method comprises the following working procedures:
grasping a K segment assembling head of the last ring of segments by using an assembling machine grabbing head, dismantling longitudinal and circumferential bolts of the K segments, loosening a propulsion oil cylinder at a 10-point position, dismantling the K segments, and placing the K segments on a battery flat car in a tunnel; then an erector is used for dismantling L1 pipe pieces and placing the pipe pieces on a storage battery flat car in the tunnel; replacing the worn tail brushes at the positions of the K pipe pieces and the L1 pipe pieces;
grasping an L2 segment assembling head by using an assembling machine grasping head, disassembling longitudinal and circumferential bolts of L2 segments, loosening propulsion oil cylinders at 7-point, 8-point and 9-point positions, rotating the L2 segments to the positions of the original K segments and the original L1 segments, namely assembling at 10-point, 11-point and 12-point positions, and installing circumferential bolts and oil cylinders to tightly prop against the L2 segments; replacing the worn shield tail brush at the original L2 segment position;
grasping the B2 segment assembling heads by using an assembling machine grasping head, dismantling longitudinal and circumferential bolts of B2 segments, loosening the pushing oil cylinders at 4-point, 5-point and 6-point positions, rotating the B2 segments to the positions of the original L2 segments, namely assembling at 7-point, 8-point and 9-point positions, and installing circumferential bolts and jacking the B2 segments by using the oil cylinders; replacing the worn shield tail brush at the original B2 segment position;
grasping the B3 segment assembling heads by using the assembling machine grasping heads, disassembling longitudinal and circumferential bolts of the B3 segments, loosening the pushing oil cylinders at 1-point, 2-point and 3-point positions, rotating the B3 segments to the original B2 segment positions, namely assembling at 4-point, 5-point and 6-point positions, and installing circumferential bolts and tightly jacking the B3 segments by the oil cylinders; replacing the worn shield tail brush at the original B3 segment position;
grasping the B1 segment assembling head by using an assembling machine grasping head, dismantling longitudinal and circumferential bolts of B1 segments, loosening the 14-point, 15-point and 16-point pushing oil cylinders, rotating the B1 segments to the original B3 segment positions, namely assembling at 1-point, 2-point and 3-point positions, and installing circumferential bolts and jacking the B1 segments by using the oil cylinders; replacing the worn shield tail brush at the original B1 segment position;
sequentially assembling the disassembled L1 duct pieces and K duct pieces in place by using an assembling machine, installing longitudinal bolts and circumferential bolts, and tightly jacking the L1 duct pieces and the K duct pieces by using a thrust cylinder;
seventhly, after the K-block pipe pieces are assembled in place, all the longitudinal and circumferential bolts are fastened;
all the pipe pieces rotate around the center of the pipe ring by an angle so as to ensure that the K pipe pieces are positioned, the pipe ring rotates clockwise by 67.5 degrees, namely the K pipe pieces are positioned at the 10-point position before replacement, and the K pipe pieces are positioned at the 13-point position after replacement of the shield tail brush;
when the shield tail brush is dismantled, the method comprises the following procedures:
cleaning a first exposed shield tail brush, namely cleaning sundries attached to a shield shell and a grease cavity, and checking whether a grease injection hole is smooth or not while cleaning the sundries;
cutting off the exposed first shield tail brush by using oxygen and acetylene; after the cutting is finished, polishing the cutting area;
when the new shield tail brush is installed, the method comprises the following procedures:
firstly, the mounting sequence of the new shield tail brushes is sequentially lap-welding and mounting, and the distance between adjacent shield tail brushes is not more than 3 mm; welding is carried out by adopting a welding wire with the diameter of 1.2mm of a secondary welding machine, the front and rear welding beads of the shield tail brush are fully welded, and the height of a welding angle is 8-10 mm;
cleaning or replacing the shield tail brush, and manually smearing sealing grease in the new shield tail brush and a grease cavity between the new shield tail brush and the second shield tail brush; covering a protective film on the coated sealing grease area, and removing the protective film before assembling the segments;
thirdly, after the pipe piece is installed in place, a grease pump is used for pumping sealing grease, and a grease cavity and a new shield tail brush which are artificially smeared and are not compact are filled;
when the tunneling recovery process is carried out, the method comprises the following steps:
firstly, unfreezing frozen soil outside a duct piece at the tail part of a shield tunneling machine, namely introducing hot water into a refrigerating fluid circulating pipeline, providing hot water by adopting an electric heating method, circularly unfreezing the hot water, and grouting a freezing area through reserved holes in a last ring duct piece and a last but 2 ring duct piece to prevent the frozen soil from being thawed; when the slip casting trompil, the drilling rod degree of depth will pierce through synchronous thick liquid (take out the drilling rod after, there is the infiltration), and the slip casting order is: tunnel bottom → tunnel sides → tunnel top; the grouting material mainly comprises cement paste, the water cement ratio is 0.8-1.0, the grouting pressure is less than or equal to 0.5MPa, and the single-ring grouting amount is less than or equal to 4m 3; during grouting, temperature measurement of a temperature measuring hole, tunnel deformation and ground settlement monitoring are matched; when the single-day settlement of the tunnel is more than 0.5mm or the accumulated settlement of the tunnel is more than 1.0mm, performing compensation grouting; when the surface of the earth rises to 2.0mm, stopping grouting, namely stopping compensation grouting; completely melting the frozen wall, and stopping compensation grouting when actually measuring the stratum settlement for half a month and no more than 0.1mm per day under the condition of no grouting;
secondly, injecting sealing grease into two grease cavities between the three shield tail brushes in a pressing mode;
and step three, dismantling the freezing calandria laid on the two rings of steel pipe sheets, grouting the freezing cabin of the two rings of steel pipe sheets, and consolidating the slurry and the steel pipe sheets into a whole after final setting so as to increase the rigidity and strength of the two rings of steel pipe sheets.
The above embodiments are provided only for illustrating the present invention and not for limiting the present invention, and those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and therefore all equivalent technical solutions should also fall within the scope of the present invention, and should be defined by the claims.

Claims (6)

1. A construction method for replacing a shield tail brush by freezing reinforcement is characterized in that a shield machine is provided with three shield tail brushes, and a grease cavity is respectively formed between a first shield tail brush and a second shield tail brush and between the second shield tail brush and a third shield tail brush; the construction method is characterized in that the construction method is used for replacing the first shield tail brush and comprises the following procedures: before the shield tail brush is replaced, stopping construction, applying a water stop ring, freezing the stratum, replacing the shield tail brush and recovering tunneling;
the shield tail brush replacement and shutdown construction process comprises the following steps:
selecting the position of the last ring segment of the shield tunneling machine for stopping tunneling according to the stratum characteristics of the position of the shield tunneling machine, and stopping tunneling when a propelling oil cylinder reaches a set stroke when a new ring segment is continuously tunneled after the last ring segment is assembled, so that a first shield tail brush is positioned at the front part of the last ring segment;
step two, injecting sealing grease into a grease cavity between a second shield tail brush and a third shield tail brush in the process from the driving of the penultimate 3-ring segment to the shutdown of the shield machine;
thirdly, assembling the last ring pipe piece and assembling the penultimate ring pipe piece by using steel pipe pieces, and synchronously grouting in four grouting holes of the two ring steel pipe pieces; grouting by adopting bentonite when a new annular duct piece is tunneled to a stop position; filling a synchronous grouting pipe of the shield tail with sealing grease after tunneling to a shutdown position;
each ring of steel pipe pieces is formed by splicing six steel pipe pieces into a whole ring of pipe pieces, and each steel pipe piece comprises a front ring plate, a rear ring plate, a back plate, two end plates and an inner arc plate concentrically positioned at the inner side of the back plate; the inner surface of the back plate is longitudinally connected with a front middle ribbed plate and a rear middle ribbed plate, and the inner end of the front middle ribbed plate and the inner end of the rear middle ribbed plate are respectively welded with a circumferential reinforcing plate; the inner surface of the inner arc plate is connected with a plurality of longitudinal rib plates, the longitudinal rib plates are divided into three sections by the front middle rib plate and the rear middle rib plate, and the inner end of each section of the longitudinal rib plate is also welded with a longitudinal stiffening plate; the inner surfaces of the front ring plate, the rear ring plate, the longitudinal stiffening plate and the annular reinforcing plate form an inner cambered surface of each segment; a hollow wall is formed between the inner arc plate and the back plate, and the hollow wall is divided into a front freezing compartment, an intermediate freezing compartment and a rear freezing compartment by a front intermediate rib plate and a rear intermediate rib plate; the right side of the middle front rib plate is provided with a refrigerating fluid through hole, and the left side of the middle rear rib plate is also provided with a refrigerating fluid through hole; through holes are respectively formed in the two end plates corresponding to the front freezing compartment, the middle freezing compartment and the rear freezing compartment; a pair of refrigerating fluid inlets are formed on the left side of the inner arc plate corresponding to the front cabin, and a pair of refrigerating fluid outlets are formed on the right side of the inner arc plate corresponding to the rear cabin;
fourthly, fastening the bolts between the reinforced pipe pieces before stopping tunneling, and tightly jacking the last ring of pipe pieces by using a propulsion oil cylinder of the shield tunneling machine; simultaneously, four tensioning strips are applied from the last 10 ring pipe piece to the last ring pipe piece and are respectively arranged at the 2-point position, the 6-point position, the 10-point position and the 13-point position;
the water stop ring construction process is carried out after shutdown, and comprises the following steps:
injecting polyurethane into six radial grouting holes of a shield tail, wherein the injection pressure is greater than the underground water pressure, and the injection sequence is from the bottom of a tunnel to the top through two sides;
injecting thick bentonite slurry into a grouting hole of the last 3 ring pipe piece, and filling a space outside the shield tail pipe piece and the last shield tail brush;
thirdly, performing secondary grouting on grouting holes of the 4 th-to-last ring duct piece, the 5 th-to-last ring duct piece, the 6 th-to-last ring duct piece and the 7 th-to-last ring duct piece respectively, wherein the type of the grout of the secondary grouting is cement grout or double-grout grouting;
after the slurry of the secondary grouting is finally solidified, sequentially opening a secondary grouting ball valve of the 4 th last ring pipe piece from bottom to top, punching the pipe piece by using a steel chisel, detecting whether water seeps out and the size of water flow, and determining that the water stopping effect reaches the standard if no water seeps out or the seepage water flow is less than or equal to 1L/h; if the seepage water flow is more than or equal to 1L/h, injecting double-liquid slurry into the reserved holes of the water seepage area; (ii) a
When the stratum freezing construction process is carried out, the method comprises the following steps:
arranging a freezing station and a freezing device on a storage battery flat car in a tunnel, wherein the freezing device comprises two freezers, a plurality of brine tanks, a plurality of brine pumps and a plurality of distribution boxes;
laying an insulation board on the inner surface of the two-ring steel pipe sheet, wherein the laying range of the insulation board is not less than 2m outside the boundary of the designed frozen wall; the heat insulation board is a flame-retardant or flame-retardant plastic foam soft board with the thickness not less than 40 mm; then respectively laying freezing calandria on the inner surface of each pipe piece of the two rings of steel pipe pieces; the freezing calandria on each segment is connected with the freezing calandria interface on the inner arc plate;
connecting a salt water tank in the refrigeration equipment with refrigeration calandria laid on the two ring steel pipe sheets to form a refrigeration liquid circulation pipeline, wherein the refrigeration liquid circulation pipeline comprises a water outlet main pipe and two water return main pipes led out from the salt water tank, and two water outlet branch pipes connected with water outlets of the water outlet main pipes; the freezing calandria on two rings of steel pipe sheets are divided into two groups of freezing calandria respectively, the freezing calandria on each steel pipe sheet is connected in series, the freezing calandria on every three steel pipe sheets are connected in parallel to form a group of freezing calandria, and the two groups of freezing calandria on each ring of steel pipe sheets are connected in series and then are connected with the water outlet of one water outlet branch pipe and the water inlet of one water return header pipe in a one-to-one correspondence manner;
preparing refrigerating fluid, wherein the refrigerating fluid adopts saline water with the specific gravity of 1.26-1.27, a refrigerating fluid circulating pipeline is filled with clear water, a salt water tank with a filtering device is filled with half of the clear water, salt is dissolved in the salt water tank, a salt water pump is started, the salt is dissolved while circulating, and the concentration of the salt water reaches the design requirement;
step five, actively freezing the brine in the refrigerating fluid circulation pipeline through refrigeration equipment, wherein the temperature of the brine is reduced to be below-15 ℃ in 5 days, the temperature of the brine is reduced to be below-25 ℃ in 10 days, and the temperature difference between the brine in the outlet loop and the brine in the return loop is not more than 2 ℃; performing heat exchange with the soil body behind the shield tail by using low-temperature brine circulation to form an effective frozen wall on the soil body behind the shield tail; the thickness of the frozen wall is more than or equal to 0.5m, and the average temperature of the frozen wall is less than or equal to-8 ℃;
after the freezing body is formed preliminarily, namely when the average temperature of the freezing wall is reduced to 0 ℃, respectively injecting polyurethane into 12 grouting holes of the last 3 ring segment and 12 grouting holes of the last 4 ring segment;
the shield tail brush replacing process comprises the following steps: finally, dismantling and installing a ring pipe sheet, dismantling a shield tail brush and installing a new shield tail brush;
when the last step of dismantling and installing the ring pipe piece is carried out, the method comprises the following working procedures:
grasping a K segment assembling head of the last ring of segments by using an assembling machine grabbing head, dismantling longitudinal and circumferential bolts of the K segments, loosening a propulsion oil cylinder at a 10-point position, dismantling the K segments, and placing the K segments on a battery flat car in a tunnel; then an erector is used for dismantling L1 pipe pieces and placing the pipe pieces on a storage battery flat car in the tunnel; replacing the worn tail brushes at the positions of the K pipe pieces and the L1 pipe pieces;
grasping an L2 segment assembling head by using an assembling machine grasping head, disassembling longitudinal and circumferential bolts of L2 segments, loosening propulsion oil cylinders at 7-point, 8-point and 9-point positions, rotating the L2 segments to the positions of the original K segments and the original L1 segments, namely assembling at 10-point, 11-point and 12-point positions, and installing circumferential bolts and oil cylinders to tightly prop against the L2 segments; replacing the worn shield tail brush at the original L2 segment position;
grasping the B2 segment assembling heads by using an assembling machine grasping head, dismantling longitudinal and circumferential bolts of B2 segments, loosening the pushing oil cylinders at 4-point, 5-point and 6-point positions, rotating the B2 segments to the positions of the original L2 segments, namely assembling at 7-point, 8-point and 9-point positions, and installing circumferential bolts and jacking the B2 segments by using the oil cylinders; replacing the worn shield tail brush at the original B2 segment position;
grasping the B3 segment assembling heads by using the assembling machine grasping heads, disassembling longitudinal and circumferential bolts of the B3 segments, loosening the pushing oil cylinders at 1-point, 2-point and 3-point positions, rotating the B3 segments to the original B2 segment positions, namely assembling at 4-point, 5-point and 6-point positions, and installing circumferential bolts and tightly jacking the B3 segments by the oil cylinders; replacing the worn shield tail brush at the original B3 segment position;
grasping the B1 segment assembling head by using an assembling machine grasping head, dismantling longitudinal and circumferential bolts of B1 segments, loosening the 14-point, 15-point and 16-point pushing oil cylinders, rotating the B1 segments to the original B3 segment positions, namely assembling at 1-point, 2-point and 3-point positions, and installing circumferential bolts and jacking the B1 segments by using the oil cylinders; replacing the worn shield tail brush at the original B1 segment position;
sequentially assembling the disassembled L1 duct pieces and K duct pieces in place by using an assembling machine, installing longitudinal bolts and circumferential bolts, and tightly jacking the L1 duct pieces and the K duct pieces by using a thrust cylinder;
seventhly, after the K-block pipe pieces are assembled in place, all the longitudinal and circumferential bolts are fastened;
when the shield tail brush is dismantled, the method comprises the following procedures:
firstly, cleaning the exposed first shield tail brush;
cutting off the exposed first shield tail brush by using oxygen and acetylene; after the cutting is finished, polishing the cutting area;
when the new shield tail brush is installed, the method comprises the following procedures:
firstly, the mounting sequence of the new shield tail brushes is sequentially lap-welding and mounting, and the distance between adjacent shield tail brushes is not more than 3 mm; welding is carried out by adopting a welding wire with the diameter of 1.2mm of a secondary welding machine, the front and rear welding beads of the shield tail brush are fully welded, and the height of a welding angle is 8-10 mm;
cleaning or replacing the shield tail brush, and manually smearing sealing grease in the new shield tail brush and a grease cavity between the new shield tail brush and the second shield tail brush; covering a protective film on the coated sealing grease area, and removing the protective film before assembling the segments;
thirdly, after the pipe piece is installed in place, a grease pump is used for pumping sealing grease, and a grease cavity and a new shield tail brush which are artificially smeared and are not compact are filled;
when the tunneling recovery process is carried out, the method comprises the following steps:
firstly, unfreezing frozen soil outside a duct piece at the tail part of a shield tunneling machine, namely introducing hot water into a refrigerating fluid circulating pipeline, providing hot water by adopting an electric heating method, circularly unfreezing the hot water, and grouting a freezing area through reserved holes in a last ring duct piece and a last but 2 ring duct piece to prevent the frozen soil from being thawed; when grouting and tapping, the drill rod penetrates through synchronous grout in depth, and the grouting sequence is as follows: tunnel bottom → tunnel sides → tunnel top; during grouting, temperature measurement of a temperature measuring hole, tunnel deformation and ground settlement monitoring are matched; when the single-day settlement of the tunnel is more than 0.5mm or the accumulated settlement of the tunnel is more than 1.0mm, performing compensation grouting; when the surface of the earth rises to 2.0mm, stopping grouting, namely stopping compensation grouting; completely melting the frozen wall, and stopping compensation grouting when actually measuring the stratum settlement for half a month and no more than 0.1mm per day under the condition of no grouting;
secondly, injecting sealing grease into two grease cavities between the three shield tail brushes in a pressing mode;
and step three, dismantling the freezing calandria laid on the two rings of steel pipe sheets, grouting the freezing cabin of the two rings of steel pipe sheets, and solidifying the slurry and the steel pipe sheets into a whole after final solidification.
2. The construction method for replacing the shield tail brush by freezing reinforcement as claimed in claim 1, wherein before the shield tail brush is replaced and when the step three of the shutdown construction process is carried out, the slurry mixing ratio of the synchronous grouting is as follows: 250 parts of cement, 300 parts of fly ash, 450 parts of sand, 450 parts of water and 50 parts of bentonite; total grouting amount per ring 4.5m3。
3. The construction method for freezing, reinforcing and replacing the tail brush of the shield according to claim 1, wherein in the step I of the water stop ring construction process, the pressure for injecting the polyurethane is 0.3-0.5 MPa, the total injection amount is 300L, and the injection amount per hole is 50L.
4. The construction method for replacing the shield tail brush by freezing reinforcement according to claim 1, wherein in the second step of the water stop ring construction process, the thick bentonite slurry is prepared from the following components in percentage by weight: 5:1 of water, namely bentonite, and the viscosity is not lower than 60 s; the injection amount is 4m3And the grouting pressure is less than or equal to 0.5 MPa.
5. The construction method for freezing, reinforcing and replacing the tail brush of the shield according to claim 1, wherein in the third step of the water stop ring construction process, the cement slurry is prepared by the following components in parts by weight: 1:1 of water and cement; the mixing proportion of the double-liquid slurry is as follows: cement paste, water glass is 0.8:1, and initial setting time is 45 s; the requirements of secondary grouting construction are as follows:
A. performing single-ring grouting in a sequence from bottom to top, and avoiding K blocks in the grouting process; injecting a small amount of cement paste or double-liquid paste into the 4 th last ring pipe piece at the grouting pressure of 0.3MPa, and then injecting the cement paste or double-liquid paste into the 5 th last ring pipe piece, the 6 th last ring pipe piece and the 7 th last ring pipe piece; the grouting sequence is as follows: the penultimate 7 ring segment → the penultimate 6 ring segment → the penultimate 5 ring segment, and the grouting pressure is not more than 5 bar; the grouting amount of each ring of pipe piece is not less than 5m3The grouting amount per hole is not more than 1m3(ii) a After the strength of cement paste or double-liquid paste behind the penultimate 5-ring duct piece, the penultimate 6-ring duct piece and the penultimate 7-ring duct piece is increased, cement paste or double-liquid paste is continuously injected into the penultimate 4-ring duct piece;
B. before punching, installing a ball valve;
C. and drilling by adopting a drill rod with the length of 1000mm, wherein the opening depth is not less than 10cm after the drill rod penetrates through the synchronous grouting layer, grouting is carried out until cement paste or double-liquid paste emerges from the adjacent ball valve close to the upper side, and then grouting hole sites are injected.
6. The construction method for replacing the tail brush of the shield by freezing reinforcement as claimed in claim 1, wherein in the step of recovering the tunneling process, the grouting material is mainly cement paste, the water cement ratio is 0.8-1.0, the grouting pressure is less than or equal to 0.5MPa, and the single-ring grouting amount is less than or equal to 4m3。
CN202010854679.6A 2020-08-24 2020-08-24 Construction method for replacing shield tail brush through freezing reinforcement Active CN111963179B (en)

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Publication number Priority date Publication date Assignee Title
CN114165263A (en) * 2021-11-05 2022-03-11 中交(南京)建设有限公司 Steel pipe ring piece for realizing rapid freezing of stratum and processing method thereof

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CN102242633A (en) * 2011-07-23 2011-11-16 中铁十二局集团有限公司 Method for replacing tail brush in extra large diameter shield driving under high water pressure condition
CN102720506A (en) * 2012-05-31 2012-10-10 中铁隧道股份有限公司 Method for replacing tail brush in shield tunnel through liquid nitrogen freezing
CN105840202A (en) * 2016-03-29 2016-08-10 中铁时代建筑设计院有限公司 Shield tail brush replacement annular freezing reinforcing water seal structure and construction method thereof
CN109707386A (en) * 2018-12-18 2019-05-03 上海隧道工程有限公司 The method of disposable replacement first of shield tail brush of shield machine

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CN101251015A (en) * 2008-04-02 2008-08-27 上海隧道工程股份有限公司 Construction method for exchanging shield ventral brush
CN102242633A (en) * 2011-07-23 2011-11-16 中铁十二局集团有限公司 Method for replacing tail brush in extra large diameter shield driving under high water pressure condition
CN102720506A (en) * 2012-05-31 2012-10-10 中铁隧道股份有限公司 Method for replacing tail brush in shield tunnel through liquid nitrogen freezing
CN105840202A (en) * 2016-03-29 2016-08-10 中铁时代建筑设计院有限公司 Shield tail brush replacement annular freezing reinforcing water seal structure and construction method thereof
CN109707386A (en) * 2018-12-18 2019-05-03 上海隧道工程有限公司 The method of disposable replacement first of shield tail brush of shield machine

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114165263A (en) * 2021-11-05 2022-03-11 中交(南京)建设有限公司 Steel pipe ring piece for realizing rapid freezing of stratum and processing method thereof
CN114165263B (en) * 2021-11-05 2023-10-27 中交(南京)建设有限公司 Steel pipe ring piece for realizing stratum quick freezing and processing method thereof

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