CN110259466B - Large-section shield construction process for water-rich sand layer of subway station - Google Patents
Large-section shield construction process for water-rich sand layer of subway station Download PDFInfo
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- CN110259466B CN110259466B CN201910606986.XA CN201910606986A CN110259466B CN 110259466 B CN110259466 B CN 110259466B CN 201910606986 A CN201910606986 A CN 201910606986A CN 110259466 B CN110259466 B CN 110259466B
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 95
- 238000010276 construction Methods 0.000 title claims abstract description 56
- 239000004576 sand Substances 0.000 title claims abstract description 53
- 238000000034 method Methods 0.000 title claims abstract description 37
- 230000008569 process Effects 0.000 title claims abstract description 29
- 238000012544 monitoring process Methods 0.000 claims abstract description 15
- 230000003014 reinforcing effect Effects 0.000 claims abstract description 10
- 238000002360 preparation method Methods 0.000 claims abstract description 4
- 238000005553 drilling Methods 0.000 claims description 42
- 230000005641 tunneling Effects 0.000 claims description 37
- 239000002002 slurry Substances 0.000 claims description 33
- 239000002689 soil Substances 0.000 claims description 28
- 230000008859 change Effects 0.000 claims description 22
- 230000001360 synchronised effect Effects 0.000 claims description 12
- 239000007788 liquid Substances 0.000 claims description 11
- 239000011440 grout Substances 0.000 claims description 10
- 229910000831 Steel Inorganic materials 0.000 claims description 9
- 229920001971 elastomer Polymers 0.000 claims description 9
- 239000004744 fabric Substances 0.000 claims description 9
- 239000012530 fluid Substances 0.000 claims description 9
- 238000005259 measurement Methods 0.000 claims description 9
- 239000010959 steel Substances 0.000 claims description 9
- 230000000694 effects Effects 0.000 claims description 8
- 238000009434 installation Methods 0.000 claims description 8
- 238000009412 basement excavation Methods 0.000 claims description 6
- 239000013049 sediment Substances 0.000 claims description 6
- 238000013461 design Methods 0.000 claims description 4
- 239000011435 rock Substances 0.000 claims description 4
- 238000004140 cleaning Methods 0.000 claims description 3
- 238000001514 detection method Methods 0.000 claims description 3
- 238000005516 engineering process Methods 0.000 claims description 3
- 230000035929 gnawing Effects 0.000 claims description 3
- 239000004519 grease Substances 0.000 claims description 3
- 238000002347 injection Methods 0.000 claims description 3
- 239000007924 injection Substances 0.000 claims description 3
- 238000007689 inspection Methods 0.000 claims description 3
- 239000000463 material Substances 0.000 claims description 3
- 239000004570 mortar (masonry) Substances 0.000 claims description 3
- 229920002635 polyurethane Polymers 0.000 claims description 3
- 239000004814 polyurethane Substances 0.000 claims description 3
- 235000019353 potassium silicate Nutrition 0.000 claims description 3
- 230000002787 reinforcement Effects 0.000 claims description 3
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 claims description 3
- 239000004568 cement Substances 0.000 claims description 2
- 238000005728 strengthening Methods 0.000 claims description 2
- 230000001502 supplementing effect Effects 0.000 claims description 2
- 239000002893 slag Substances 0.000 claims 1
- 238000013102 re-test Methods 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 238000007596 consolidation process Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 239000003673 groundwater Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000010687 lubricating oil Substances 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000013589 supplement Substances 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
- 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
- E21D11/08—Lining with building materials with preformed concrete slabs
-
- 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
- E21D9/003—Arrangement of measuring or indicating devices for use during driving of tunnels, e.g. for guiding machines
-
- 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
-
- 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
- E21D9/0635—Tail sealing means, e.g. used as end shuttering
Landscapes
- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- Environmental & Geological Engineering (AREA)
- Architecture (AREA)
- Structural Engineering (AREA)
- Civil Engineering (AREA)
- Excavating Of Shafts Or Tunnels (AREA)
Abstract
The invention relates to a large-section shield construction process for a water-rich sand layer of a subway station, which comprises the following steps of: step 1, site preparation, step 2, site hardening, step 3, receiving a bracket, descending a well, placing and reinforcing, step 4, hole door and end reinforcing and coring, step 5, shield machine posture adjustment, step 6, receiving, measuring and monitoring, and step 7, wherein the shield reaches construction. The method has the advantages that the method is suitable for construction when the shield machine reaches the air shaft in the water-rich sand layer large-section geology, and the water gushing, sand gushing or collapse can be avoided.
Description
Technical Field
The invention relates to the technical field of shield machine construction, in particular to a large-section shield construction process for a water-rich sand layer of a subway station.
Background
With the rapid development of urban rail transit construction in China and the gradual improvement of underground space utilization rate, subway construction ranks have been added in various cities, and shield tunnel construction technology is increasingly widely popularized and applied due to the unique characteristics and advantages of intelligence, safety, rapidness, high efficiency and the like.
In subway construction, shield construction is the heaviest of all construction methods; simultaneously, according to construction environment and the construction condition of difference, need constructor to adjust construction process to the construction environment of difference, and in multiple construction environment, the rich water sand bed of section is comparatively special construction environment, because rock breakage in the fracture area, groundwater is abundant, and the shield constructs to take place easily when crossing the fracture area and gushes, the face condition such as cave in, especially lie in: the geological condition of the water-rich sand layer is poor, the shield machine cannot be self-stabilized when arriving, the sand layer is easy to liquefy with water, the sand layer is rich in underground water and has good permeability, the phenomena of water burst and sand burst are easy to occur when arriving at an air shaft, and serious safety accidents such as ground collapse and the like can be caused when the sand layer is serious.
Disclosure of Invention
The invention aims to provide a large-section shield construction process for a water-rich sand layer of a subway station, which is suitable for construction when a shield machine reaches an air shaft in large-section geology of the water-rich sand layer and has the effect of avoiding water gushing, sand gushing or collapse.
The above object of the present invention is achieved by the following technical solutions:
the utility model provides a big section shield of rich water sand bed of subway station constructs construction technology which characterized in that: the method comprises the following steps:
step 1, site preparation: cleaning a construction site, retesting a shield well main body, measuring an actual deviation amount, and providing data support for shield arrival;
step 2, field hardening: lowering the underground water level around the tunnel portal to be below the elevation of the bottom of the tunnel portal, backfilling the site by C30 concrete with the compactness of 2400kg/m3, and paving double-layer mesh concrete with the phi 14 spacing of 20cm multiplied by 20cm and the layer height spacing of 15cm, wherein the thickness is not less than 20 cm;
step 3, receiving the bracket, putting and reinforcing: accurately positioning the right and left positions of the originating station in front of the mounting bracket; the elevation of the starting base of the left and right line brackets of the shield is reduced by 10mm, the shield is prevented from gnawing the brackets, then the brackets are arranged at the preset positions according to requirements, rechecking is carried out, and the brackets are fixed after positioning is finished;
step 4, reinforcing and coring a hole door and an end head: vertical and horizontal drilling and coring are carried out on the tunnel portal before the shield is received, and a geological drilling machine is used for carrying out drilling and coring operation in the vertical coring;
step 5, adjusting the posture of the shield tunneling machine: when the shield is propelled to the shield arrival range, accurately measuring the position of the shield machine, determining the relationship between the central axis of the tunnel to be tunneled and the central axis of the tunnel design, simultaneously rechecking and measuring the positions of the receiving tunnel portal and the bracket, and determining the through attitude of the shield machine and a tunneling deviation correcting plan;
step 6, receiving measurement monitoring: during the shield tunneling period, the shield attitude and the segment attitude must be guaranteed to be measured once per ring, the manual measurement result is fed back to the shield central control room, and the ground monitoring is continuously carried out for 24 hours;
step 7, shield arrival construction:
a. the axial line of the arrival section is a straight line, when a cutter head of the shield tunneling machine contacts a plain concrete wall, the horizontal posture and the vertical posture of the shield tunneling machine are ensured to be coincided with the axial line, and the deviation allowable value is +/-5 mm;
b. when construction is carried out at an arrival section, synchronous grouting amount is required to be ensured to be 12m, synchronous tracking grouting is required for secondary grouting, and double-liquid slurry is adopted as grouting slurry;
c. after the shield tail of the shield tunneling machine passes through the plain concrete wall, a measurer positions the plain concrete wall, and a water stop ring is manufactured at the plain concrete wall to prevent water from coming from the rear;
d. the method comprises the following steps of (1) stopping the machine for a short time after a cutter head contacts an enclosure structure, wherein the stopping time is 2-3 hours, observing pressure change in a soil bin, judging the condition of water coming from the rear, if the soil pressure basically keeps unchanged, carrying out the next construction step, if the soil pressure change is large, immediately carrying out secondary grout filling, after grouting is stopped, continuously observing the soil pressure change, if the soil pressure still has obvious change, continuing grouting until the grouting is stopped, the soil pressure does not change, simultaneously checking whether equipment has problems, and preventing the equipment from suddenly stopping working after a wall is broken to cause water gushing and sand gushing;
e. after the receiving condition is met, starting to grind the enclosure structure by a rotary cutter head, and keeping the tunneling speed at 5-10 mm/min;
f. after the cutter head passes through the enclosing structure, if a gap between the excavation surface and the shield body is flooded with water and gushed with sand, the excavation is continued, after the shield body is completely wrapped by the curtain cloth rubber plate, grouting is performed from the grouting holes reserved in the pipe piece, if the water pressure is high and no sand flow phenomenon exists, polyurethane is injected into the holes, and if the water flows and the sand flows, double-liquid slurry is injected; when the shield tunneling machine tunnels until only the last shield tail brush is left in the duct piece, stopping tunneling, binding a circle of steel wire rope outside the cord fabric rubber plate, tensioning the steel wire rope to prevent grout from flowing out from a gap between the cord fabric rubber plate and the shield body due to overlarge grouting pressure, and finally continuously injecting grout from the reserved grouting hole in the duct piece until no water flows out;
g. opening a hole at the position of the grouting hole of the last ring duct piece to check the grouting quality, and if water flows from the hole, continuing tunneling until the shield tail is completely separated from the duct piece;
h. after the shield tail is completely separated from the shield tail, the portal is immediately plugged, so that the portal reinforcement body is prevented from losing efficacy due to overlong exposure time, and water gushing and sand gushing are prevented.
By adopting the technical scheme, the construction of the shield machine can be facilitated when the water-rich sand layer reaches the air shaft in the construction process, and the phenomena of water gushing and sand gushing are avoided.
The invention is further configured to: the step 7 further comprises the installation of the last ring piece, and the installation of the last ring piece comprises the following steps:
a. after the segment is installed, all longitudinal bolts and all transverse bolts are screwed down by a pneumatic wrench, the bolts are fastened again when the next ring is tunneled to about 1.2m, the segment needs to be fastened three times, three ring pipe pieces are connected by channel steel in a grouting hole, no less than six joints are connected among every three rings, the three rings are installed in a staggered mode, and the installation length is no less than 15 rings;
b. the duct pieces are strictly assembled, so that the occurrence of staggered joints and step differences among the duct pieces is prevented; in the assembling process, the gap of the shield tail is ensured, the injection amount of grease of the shield tail is increased, synchronous grouting is kept, and water and sand gushing of the shield tail are prevented;
c. before the segment is installed, the water stop strips are ensured not to be damaged or pre-expanded, and residue soil, mortar and the like on the segment are cleaned in time; the shield tail also needs to be cleaned up, and the assembly quality of the duct pieces is ensured.
The invention is further configured to: step 7 still include entrance to a cave stagnant water, entrance to a cave stagnant water includes following step:
a. water stopping measures are taken during propulsion, double-fluid slurry is injected behind the shield tail in the shield arrival process, double-fluid slurry is repeatedly and additionally injected in each ring, the double-fluid slurry is injected outside the shield body through the radial hole of the shield middle body, the gap between the shield body and the soil body is blocked, and the synchronous grouting amount and the slurry quality are guaranteed;
b. stopping tunneling water stopping measures, injecting double-liquid slurry into the duct piece tunnel at the tunnel portal position after the shield stops, strengthening the water stopping effect, thoroughly plugging the gap between the duct piece and the tunnel portal, and taking the hoisting hole openings on the two sides of each duct piece as inspection holes to inspect the effect.
The invention is further configured to: the double-slurry adopts slurry with the ratio of cement to water being 1:0.8 and slurry with the ratio of water to water glass being 1:1 as secondary slurry supplementing materials.
The invention is further configured to: the grouting pressure value is as follows: 0.1 to 0.3 MPa.
The invention is further configured to: step 4, the hole door and the end head are reinforced and cored, and the method comprises the following steps:
(1) vertical and horizontal drilling coring are carried out on the tunnel portal before shield receiving, a geological drilling machine is used for carrying out drilling coring operation in the vertical coring, and the detection number of the reinforcing bodies is not less than 1% and not less than 5;
(2) ensuring that the drill does not incline or shift in the core drilling process, and ensuring that the verticality deviation of the core drilling hole is not more than 0.5 percent;
(3) when the distance between the top surface of the pile and the base of the drilling machine is larger, the orifice pipe is required to be installed, and the orifice pipe is required to be vertical and firm;
(4) in the drilling process, the circulating water flow in the drill hole is not interrupted, and the drilling speed is adjusted according to the sand content and the color of the return water;
(5) when the drill is lifted and the core sample is taken out, the drill bit and the reamer are unscrewed, and the core is strictly forbidden to be knocked and removed;
(6) and controlling the footage within 1.5m every time, drilling sediment and measuring the thickness of the sediment when drilling to the bottom of the pile, and identifying the characteristics of the bearing stratum rock soil at the pile end.
The invention is further configured to: and 5, when the shield machine arrives at the front 50m section, the shield attitude and the tunnel line shape measurement are enhanced, the deviation is corrected in time, and the shield machine is ensured to smoothly enter from the arrival port.
The invention is further configured to: the position of a cutter head of the shield tunneling machine when the tunnel is communicated is adjusted necessarily according to the actually measured position of the station tunnel portal, the allowable deviation value of the plane of the cutter head when the tunnel is communicated is less than or equal to +/-20 mm of the plane, less than or equal to +/-20 mm of the elevation, and the gradient of the shield is slightly greater than the designed gradient by 0.2 percent.
The invention is further configured to: and 6, arranging 3 rows of monitoring points on the ground surface, wherein the distance between the monitoring points and the ground surface is 5m, covering the whole receiving area, measuring the change condition of each measuring point by the reference point, recording the change condition, and comparing the change condition with the original data record which is recorded before engineering construction.
In conclusion, the beneficial technical effects of the invention are as follows:
the construction method has the advantages that the construction method is suitable for the construction of the shield machine reaching the air shaft in the water-rich sand layer large-section geology, and the conditions of water burst, sand burst or collapse are avoided.
Detailed Description
The invention discloses a large-section shield arrival construction process for a water-rich sand layer of a subway station, which comprises the following steps of:
step 1, site preparation:
(1) preparing a construction site, cleaning the construction site, installing water pumps, illuminating lamps and other matched equipment, and preparing for receiving work;
(2) the tunnel portal retest and the axis lofting, item portion should organize the survey crew to carry out the retest to the shield and construct the well main part, determine actual deviation, for the shield arrives provides data support, and main retest project includes: the shield shaft bottom plate elevation, the bottom plate longitudinal slope, the tunnel portal center, the side wall and end wall positions and the inclination, and the bottom longitudinal beam position;
step 2, precipitation at the end and field hardening at the end:
according to hydrogeological conditions and the mouth consolidation condition of the soil body reaching the end, the underground water level around the tunnel portal is reduced to be lower than the elevation of the bottom of the tunnel portal, a large crane used for hoisting the shield machine is used, a hoisting area is backfilled by C30 concrete with the compactness of 2400kg/m3, the thickness of double-layer mesh concrete with the distance of phi 14 being 20cm multiplied by 20cm and the layer height distance being 15cm is not less than 20cm, and the requirement of hoisting the shield machine can be met after 28 days of construction;
step 3, receiving the bracket, putting and reinforcing:
(1) before installing the bracket, fixing two horizontal control points (one is fixed on the central line of a tunnel door, and the other is the central line of a tunnel) on a station bottom plate by a measuring group, and accurately positioning the left and right positions of an originating station according to the pull lines of the two points; the elevation of the starting base of the left and right line brackets of the shield is reduced by 10mm, the shield is prevented from gnawing the brackets, then the brackets are arranged at the preset positions according to requirements and are rechecked by a measuring group, and the brackets are fixed after the positioning is finished;
(2) before the shield machine receives, hard lubricating oil is coated on a track of an originating station to reduce resistance when the shield machine advances on a bracket, and a rail surface on the bracket and a rail surface of a bracket guide rail are in the same plane;
step 4, reinforcing and coring a hole door and an end head:
(1) carry out perpendicularly and horizontal drilling to the portal before the shield is received and get the core, get the core perpendicularly and use the geological drilling rig to carry out the drilling to get the core operation, add solid detection quantity and must not be less than 1%, and must not be less than 5, the core hole number and the drilling position of the stake of receiving to examine should accord with: a, 1 core drilling hole is drilled in each pile, and the hole opening position b is located at the occlusion part of the two piles;
(2) the equipment installation of the drilling machine needs to be circumferential and stable, the base is horizontal, the center of a vertical shaft of the drilling machine, the center of a head sheave (the leading edge tangent point of a crown block) and the center of an orifice of the drilling machine need to be on the same plumb line, the drilling machine is ensured not to incline or shift in the core drilling process, and the verticality deviation of a core drilling hole is not more than 0.5 percent;
(3) when the distance between the top surface of the pile and the base of the drilling machine is larger, the orifice pipe is required to be installed, and the orifice pipe is required to be vertical and firm;
(4) in the drilling process, the circulating water flow in the drill hole is not interrupted, and the drilling speed is adjusted according to the sand content and the color of the return water;
(5) when the drill is lifted and the core sample is taken out, the drill bit and the reamer are unscrewed, and the core is strictly forbidden to be knocked and removed;
(6) controlling the footage within 1.5m every time, drilling sediment and measuring the sediment thickness when drilling to the bottom of the pile, and identifying the characteristics of the bearing stratum rock soil at the pile end;
step 5, adjusting the posture of the shield tunneling machine;
(1) when the shield is pushed to the shield arrival range, accurately measuring the position of the shield machine, and determining the relation between the central axis of the tunnel to be tunneled and the central axis of the tunnel design;
(2) rechecking and measuring the positions of the receiving tunnel portal and the bracket, determining the through attitude and the tunneling attitude of the shield machine and a tunneling deviation rectifying plan, and gradually completing the deviation rectifying;
(3) when the shield machine arrives at the front 50m section, the shield attitude and the tunnel linear measurement are enhanced, and the deviation is corrected in time to ensure that the shield machine smoothly enters from the arrival port;
(4) the position of a cutter head of the shield tunneling machine when a tunnel is communicated is adjusted necessarily according to the actually measured position of a station tunnel portal, the allowable deviation value of the plane of the cutter head when the tunnel is communicated is less than or equal to +/-20 mm of the plane, less than or equal to +/-20 mm of the elevation, and the gradient of the shield is slightly greater than the design gradient by 0.2 percent;
step 6, receiving measurement monitoring:
(1) during the shield tunneling period, the shield attitude and the segment attitude must be guaranteed to be measured once per ring, the results of manual measurement are fed back to a shield responsible person and a central control room in time, the results are reported and monitored in time, ground monitoring needs to be carried out continuously for 24 hours and two shifts, and monitoring data needs to be transmitted in time;
(2) arranging 3 rows of monitoring points on the earth surface, wherein the distance between the monitoring points is 5m, the monitoring points cover the whole receiving area, measuring the change condition of each measuring point by the reference point, making a record, and comparing the record with the original data record made before engineering construction;
step 7, shield arrival construction:
(1) construction measures of an arrival section:
a. the axial line of the arrival section is a straight line, when a cutter head of the shield tunneling machine contacts a plain concrete wall, the horizontal posture and the vertical posture of the shield tunneling machine are ensured to be coincided with the axial line, and the deviation allowable value is +/-5 mm;
b. synchronous grouting amount (12 m) is required to be ensured during construction of the arrival section, synchronous tracking grouting is required for secondary grouting, and double-liquid slurry is adopted for grouting slurry;
c. after the shield tail of the shield tunneling machine passes through the plain concrete wall, a measurer positions the plain concrete wall, and a water stop ring is manufactured at the plain concrete wall to prevent water from coming from the rear;
d. the cutter head is stopped for a short time after contacting the enclosure structure, the stop time is 2-3 hours, the pressure change in the soil bin is mainly observed, the condition of water coming from the rear is judged, and if the soil pressure is basically kept unchanged, the next construction step can be carried out; if the soil pressure change is large, performing secondary slurry supplement immediately, following a small quantity of repeated principles, after stopping grouting, continuously observing the soil pressure change, if the soil pressure still has obvious change, continuously grouting until the soil pressure has no change after stopping grouting, and simultaneously checking whether equipment has problems or not, so as to prevent the equipment from suddenly stopping working after breaking the wall, and further prevent water gushing and sand gushing;
e. after the receiving condition is met, starting to grind the enclosure structure by a rotary cutter head, and keeping the tunneling speed at 5-10 mm/min;
f. after the cutter head passes through the enclosing structure, if a gap between the excavation surface and the shield body is flooded with water and gushed with sand, the excavation is continued, after the shield body is completely wrapped by the curtain cloth rubber plate, grouting is performed from the grouting holes reserved in the pipe piece, if the water pressure is high and no sand flow phenomenon exists, polyurethane is injected into the holes, and if the water flows and the sand flows, double-liquid slurry is injected; when the shield tunneling machine tunnels until only the last shield tail brush is left in the duct piece, stopping tunneling, binding a circle of steel wire rope outside the cord fabric rubber plate, tensioning the steel wire rope to prevent grout from flowing out from a gap between the cord fabric rubber plate and the shield body due to overlarge grouting pressure, and finally continuously injecting grout from the reserved grouting hole in the duct piece until no water flows out;
g. opening a hole at the position of the grouting hole of the last ring duct piece to check the grouting quality, and if water flows from the hole, continuing tunneling until the shield tail is completely separated from the duct piece;
h. after the shield tail is completely separated from the shield tail, the portal is immediately plugged, so that water gushing and sand gushing caused by failure of a portal reinforcement body due to overlong exposure time are prevented;
(2) and finally, mounting the segment:
a. after the segment is installed, all longitudinal bolts and all transverse bolts are screwed down by a pneumatic wrench, the bolts are fastened again when the next ring is tunneled to about 1.2m, the segment needs to be fastened three times, three ring pipe pieces are connected by channel steel in a grouting hole, no less than six joints are connected among every three rings, the three rings are installed in a staggered mode, and the installation length is no less than 15 rings;
b. assembling the duct pieces strictly according to the operating rules, and preventing the occurrence of staggered joints and step differences among the duct pieces; in the assembling process, the gap between the shield tails is ensured, the injection amount of grease of the shield tails is increased, synchronous grouting is kept, and water and sand gushing of the shield tails are prevented
c. Before the segment is installed, the water stop strips are ensured not to be damaged or pre-expanded, and residue soil, mortar and the like on the segment are cleaned in time; the shield tail also needs to be cleaned up, and the assembly quality of the duct pieces is ensured. (2) sealing the tunnel portal:
a. water stopping measures are taken during propulsion, double-fluid slurry is injected behind the shield tail in the shield arrival process, double-fluid slurry is repeatedly and additionally injected in each ring, the double-fluid slurry is injected outside the shield body through the radial hole of the shield middle body, the gap between the shield body and the soil body is blocked, and the synchronous grouting amount and the slurry quality are guaranteed;
b. stopping tunneling water stopping measures, injecting double-liquid slurry into the duct piece tunnel at the tunnel portal position after the shield stops, enhancing the water stopping effect, thoroughly blocking the gap between the duct piece and the tunnel portal, and taking the hoisting hole openings on the two sides of each ring duct piece as inspection holes to inspect the effect;
c. double-liquid grouting: the grout with the cement-water ratio of 1:0.8 and the grout with the water-glass ratio of 1:1 are adopted as secondary grout-filling materials, and the grouting pressure value is as follows: 0.1-0.3 Mpa;
the process can be suitable for construction when the shield machine reaches the air shaft in the water-rich sand layer large-section geology, and avoids the occurrence of water burst, sand burst or collapse.
The embodiments of the present invention are preferred embodiments of the present invention, and the scope of the present invention is not limited by these embodiments, so: all equivalent changes made according to the structure, shape and principle of the invention are covered by the protection scope of the invention.
Claims (9)
1. The utility model provides a big section shield of rich water sand bed of subway station constructs construction technology which characterized in that: the method comprises the following steps:
step 1, site preparation: cleaning a construction site, retesting a shield well main body, measuring an actual deviation amount, and providing data support for shield arrival;
step 2, field hardening: lowering the underground water level around the tunnel portal to be below the elevation of the bottom of the tunnel portal, backfilling the site by C30 concrete with the compactness of 2400kg/m3, and paving double-layer mesh concrete with the phi 14 spacing of 20cm multiplied by 20cm and the layer height spacing of 15cm, wherein the thickness is not less than 20 cm;
step 3, receiving the bracket, putting and reinforcing: accurately positioning the right and left positions of the originating station in front of the mounting bracket; the elevation of the starting base of the left and right line brackets of the shield is reduced by 10mm, the shield is prevented from gnawing the brackets, then the brackets are arranged at the preset positions according to requirements, rechecking is carried out, and the brackets are fixed after positioning is finished;
step 4, reinforcing and coring a hole door and an end head: vertical and horizontal drilling and coring are carried out on the tunnel portal before the shield is received, and a geological drilling machine is used for carrying out drilling and coring operation in the vertical coring;
step 5, adjusting the posture of the shield tunneling machine: when the shield is propelled to the shield arrival range, accurately measuring the position of the shield machine, determining the relationship between the central axis of the tunnel to be tunneled and the central axis of the tunnel design, simultaneously rechecking and measuring the positions of the receiving tunnel portal and the bracket, and determining the through attitude of the shield machine and a tunneling deviation correcting plan;
step 6, receiving measurement monitoring: during the shield tunneling period, the shield attitude and the segment attitude must be guaranteed to be measured once per ring, the manual measurement result is fed back to the shield central control room, and the ground monitoring is continuously carried out for 24 hours;
step 7, shield arrival construction:
a. the axial line of the arrival section is a straight line, when a cutter head of the shield tunneling machine contacts a plain concrete wall, the horizontal posture and the vertical posture of the shield tunneling machine are ensured to be coincided with the axial line, and the deviation allowable value is +/-5 mm;
b. when construction is carried out at an arrival section, synchronous grouting amount is required to be ensured to be 12m, synchronous tracking grouting is required for secondary grouting, and double-liquid slurry is adopted as grouting slurry;
c. after the shield tail of the shield tunneling machine passes through the plain concrete wall, a measurer positions the plain concrete wall, and a water stop ring is manufactured at the plain concrete wall to prevent water from coming from the rear;
d. the method comprises the following steps of (1) stopping the machine for a short time after a cutter head contacts an enclosure structure, wherein the stopping time is 2-3 hours, observing pressure change in a soil bin, judging the condition of water coming from the rear, if the soil pressure basically keeps unchanged, carrying out the next construction step, if the soil pressure change is large, immediately carrying out secondary grout filling, after grouting is stopped, continuously observing the soil pressure change, if the soil pressure still has obvious change, continuing grouting until the grouting is stopped, the soil pressure does not change, simultaneously checking whether equipment has problems, and preventing the equipment from suddenly stopping working after a wall is broken to cause water gushing and sand gushing;
e. after the receiving condition is met, starting to grind the enclosure structure by a rotary cutter head, and keeping the tunneling speed at 5-10 mm/min;
f. after the cutter head passes through the enclosing structure, if a gap between the excavation surface and the shield body is flooded with water and gushed with sand, the excavation is continued, after the shield body is completely wrapped by the curtain cloth rubber plate, grouting is performed from each grouting hole reserved in the duct piece, if the water pressure is high and no sand flow phenomenon exists, polyurethane is injected into the holes, and if the water flows and the sand flows, double-liquid slurry is injected; when the shield tunneling machine tunnels until only the last shield tail brush is left in the duct piece, stopping tunneling, binding a circle of steel wire rope outside the cord fabric rubber plate, tensioning the steel wire rope to prevent grout from flowing out from a gap between the cord fabric rubber plate and the shield body due to overlarge grouting pressure, and finally continuously injecting grout from the reserved grouting hole in the duct piece until no water flows out;
g. opening a hole at the position of the grouting hole of the last ring duct piece to check the grouting quality, and if water flows from the hole, continuing tunneling until the shield tail is completely separated from the duct piece;
h. after the shield tail is completely separated from the shield tail, the portal is immediately plugged, so that the portal reinforcement body is prevented from losing efficacy due to overlong exposure time, and water gushing and sand gushing are prevented.
2. The large-section shield construction process for the water-rich sand layer of the subway station as claimed in claim 1, wherein: the step 7 further comprises the installation of the last ring piece, and the installation of the last ring piece comprises the following steps:
a. after the segment is installed, all longitudinal bolts and all transverse bolts are screwed down by a pneumatic wrench, the bolts are fastened again when the next ring is tunneled to 1.2m, the segment needs to be fastened three times, three ring pipe pieces are connected by channel steel in a grouting hole, no less than six joints are connected among every three rings, the three rings are installed in a staggered mode, and the installation length is no less than 15 rings;
b. the duct pieces are strictly assembled, so that the occurrence of staggered joints and step differences among the duct pieces is prevented; in the assembling process, the gap of the shield tail is ensured, the injection amount of grease of the shield tail is increased, synchronous grouting is kept, and water and sand gushing of the shield tail are prevented;
c. before the segment is installed, the water stop strips are ensured not to be damaged or pre-expanded, and the slag soil and the mortar on the segment are cleaned in time; the shield tail also needs to be cleaned up, and the assembly quality of the duct pieces is ensured.
3. The large-section shield construction process for the water-rich sand layer of the subway station as claimed in claim 1, wherein: step 7, still include the entrance to a cave stagnant water, the entrance to a cave stagnant water includes following step:
a. water stopping measures are taken during propulsion, double-fluid slurry is injected behind the shield tail in the shield arrival process, double-fluid slurry is repeatedly and additionally injected in each ring, the double-fluid slurry is injected outside the shield body through the radial hole of the shield middle body, the gap between the shield body and the soil body is blocked, and the synchronous grouting amount and the slurry quality are guaranteed;
b. stopping tunneling water stopping measures, injecting double-liquid slurry into the duct piece tunnel at the tunnel portal position after the shield stops, strengthening the water stopping effect, thoroughly plugging the gap between the duct piece and the tunnel portal, and taking the hoisting hole openings on the two sides of each duct piece as inspection holes to inspect the effect.
4. The large-section shield construction process for the water-rich sand layer of the subway station as claimed in claim 3, wherein: the double-liquid slurry adopts slurry with the ratio of cement to water being 1:0.8 and slurry with the ratio of water to water glass being 1:1 as secondary slurry supplementing materials.
5. The large-section shield construction process for the water-rich sand layer of the subway station as claimed in claim 4, wherein: the grouting pressure value is as follows: 0.1 to 0.3 MPa.
6. The large-section shield construction process for the water-rich sand layer of the subway station as claimed in claim 1, wherein: step 4, the hole door and the end head are reinforced and cored, and the method comprises the following steps:
(1) vertical and horizontal drilling coring are carried out on the tunnel portal before shield receiving, a geological drilling machine is used for carrying out drilling coring operation in the vertical coring, and the detection number of the reinforcing bodies is not less than 1% and not less than 5;
(2) ensuring that the drill does not incline or shift in the core drilling process, and ensuring that the verticality deviation of the core drilling hole is not more than 0.5 percent;
(3) when the distance between the top surface of the pile and the base of the drilling machine is larger, the orifice pipe is required to be installed, and the orifice pipe is required to be vertical and firm;
(4) in the drilling process, the circulating water flow in the drill hole is not interrupted, and the drilling speed is adjusted according to the sand content and the color of the return water;
(5) when the drill is lifted and the core sample is taken out, the drill bit and the reamer are unscrewed, and the core is strictly forbidden to be knocked and removed;
(6) and controlling the footage within 1.5m every time, drilling sediment and measuring the thickness of the sediment when drilling to the bottom of the pile, and identifying the characteristics of the bearing stratum rock soil at the pile end.
7. The large-section shield construction process for the water-rich sand layer of the subway station as claimed in claim 1, wherein: and 5, when the shield machine arrives at the front 50m section, the shield attitude and the tunnel line shape measurement are enhanced, the deviation is corrected in time, and the shield machine is ensured to smoothly enter from the arrival port.
8. The large-section shield construction process for the water-rich sand layer of the subway station as claimed in claim 7, wherein: the position of a cutter head of the shield tunneling machine when the tunnel is communicated is adjusted necessarily according to the actually measured position of the station tunnel portal, the allowable deviation value of the plane of the cutter head when the tunnel is communicated is less than or equal to +/-20 mm of the plane, less than or equal to +/-20 mm of the elevation, and the gradient of the shield is 0.2 percent greater than the designed gradient.
9. The large-section shield construction process for the water-rich sand layer of the subway station as claimed in claim 1, wherein: and 6, arranging 3 rows of monitoring points on the ground surface, wherein the distance between the monitoring points and the ground surface is 5m, covering the whole receiving area, measuring the change condition of each measuring point by the reference point, recording the change condition, and comparing the change condition with the original data record which is recorded before engineering construction.
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| CN111400645B (en) * | 2020-03-20 | 2020-11-13 | 南京坤拓土木工程科技有限公司 | Simplified method for estimating soil pressure distribution condition of water-rich sand layer at opening of cutter head |
| CN112943266B (en) * | 2021-03-15 | 2023-01-13 | 广东工业大学 | High-pressure rotary spraying grouting reinforcement method for high-flow-rate underground water-rich sand layer |
| CN113482632A (en) * | 2021-08-12 | 2021-10-08 | 中铁十二局集团有限公司 | Shield tunneling machine starting construction method with external water-rich silt stratum grouting pipe |
| CN114320321B (en) * | 2021-12-20 | 2023-05-09 | 中国水利水电第十四工程局有限公司 | Construction method for receiving shield machine in composite stratum with sand layer |
| CN115773131A (en) * | 2022-09-22 | 2023-03-10 | 粤水电轨道交通建设有限公司 | Anti-loosening construction method for shield receiving molding segment |
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