CN116378004B - Construction method of integral steel-concrete pedestal of soft soil foundation bridge deck slab - Google Patents
Construction method of integral steel-concrete pedestal of soft soil foundation bridge deck slab Download PDFInfo
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- CN116378004B CN116378004B CN202310437356.0A CN202310437356A CN116378004B CN 116378004 B CN116378004 B CN 116378004B CN 202310437356 A CN202310437356 A CN 202310437356A CN 116378004 B CN116378004 B CN 116378004B
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- NJPPVKZQTLUDBO-UHFFFAOYSA-N novaluron Chemical compound C1=C(Cl)C(OC(F)(F)C(OC(F)(F)F)F)=CC=C1NC(=O)NC(=O)C1=C(F)C=CC=C1F NJPPVKZQTLUDBO-UHFFFAOYSA-N 0.000 title claims abstract description 85
- 238000010276 construction Methods 0.000 title claims abstract description 62
- 239000002689 soil Substances 0.000 title claims abstract description 28
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 88
- 239000010959 steel Substances 0.000 claims abstract description 88
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 34
- 238000005507 spraying Methods 0.000 claims abstract description 25
- 238000013461 design Methods 0.000 claims abstract description 21
- 238000007711 solidification Methods 0.000 claims abstract description 21
- 230000008023 solidification Effects 0.000 claims abstract description 21
- 238000009434 installation Methods 0.000 claims abstract description 16
- 230000036541 health Effects 0.000 claims abstract description 13
- 238000012423 maintenance Methods 0.000 claims abstract description 10
- 229910001294 Reinforcing steel Inorganic materials 0.000 claims abstract description 8
- 238000003756 stirring Methods 0.000 claims description 33
- 239000004575 stone Substances 0.000 claims description 20
- 238000003466 welding Methods 0.000 claims description 19
- 238000000034 method Methods 0.000 claims description 12
- 239000003795 chemical substances by application Substances 0.000 claims description 9
- 238000001514 detection method Methods 0.000 claims description 9
- 239000007921 spray Substances 0.000 claims description 9
- 239000002023 wood Substances 0.000 claims description 9
- 230000008569 process Effects 0.000 claims description 8
- 239000010802 sludge Substances 0.000 claims description 8
- 239000002002 slurry Substances 0.000 claims description 8
- 238000005498 polishing Methods 0.000 claims description 7
- 239000004568 cement Substances 0.000 claims description 6
- 239000000203 mixture Substances 0.000 claims description 6
- 241000251468 Actinopterygii Species 0.000 claims description 5
- 238000011065 in-situ storage Methods 0.000 claims description 4
- 230000002787 reinforcement Effects 0.000 claims description 4
- 230000003014 reinforcing effect Effects 0.000 claims description 4
- 235000017166 Bambusa arundinacea Nutrition 0.000 claims description 3
- 235000017491 Bambusa tulda Nutrition 0.000 claims description 3
- 241001330002 Bambuseae Species 0.000 claims description 3
- 235000015334 Phyllostachys viridis Nutrition 0.000 claims description 3
- 239000011425 bamboo Substances 0.000 claims description 3
- 238000007599 discharging Methods 0.000 claims description 3
- 230000008020 evaporation Effects 0.000 claims description 3
- 238000001704 evaporation Methods 0.000 claims description 3
- 238000002474 experimental method Methods 0.000 claims description 3
- 239000010881 fly ash Substances 0.000 claims description 3
- 238000011900 installation process Methods 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 3
- 239000000463 material Substances 0.000 claims description 3
- 238000002156 mixing Methods 0.000 claims description 3
- 239000011120 plywood Substances 0.000 claims description 3
- 238000009417 prefabrication Methods 0.000 claims description 3
- 238000002360 preparation method Methods 0.000 claims description 3
- 238000005086 pumping Methods 0.000 claims description 3
- 238000003908 quality control method Methods 0.000 claims description 3
- 238000005096 rolling process Methods 0.000 claims description 3
- 238000005070 sampling Methods 0.000 claims description 3
- 239000003381 stabilizer Substances 0.000 claims description 3
- 230000003068 static effect Effects 0.000 claims description 3
- 238000012360 testing method Methods 0.000 claims description 3
- 239000004744 fabric Substances 0.000 claims description 2
- 230000000694 effects Effects 0.000 abstract description 5
- 239000002699 waste material Substances 0.000 abstract description 3
- 238000010586 diagram Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000008439 repair process Effects 0.000 description 2
- 238000005452 bending Methods 0.000 description 1
- 239000004746 geotextile Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D3/00—Improving or preserving soil or rock, e.g. preserving permafrost soil
- E02D3/02—Improving by compacting
- E02D3/10—Improving by compacting by watering, draining, de-aerating or blasting, e.g. by installing sand or wick drains
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28B23/00—Arrangements specially adapted for the production of shaped articles with elements wholly or partly embedded in the moulding material; Production of reinforced objects
- B28B23/02—Arrangements specially adapted for the production of shaped articles with elements wholly or partly embedded in the moulding material; Production of reinforced objects wherein the elements are reinforcing members
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D1/00—Investigation of foundation soil in situ
- E02D1/08—Investigation of foundation soil in situ after finishing the foundation structure
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D19/00—Keeping dry foundation sites or other areas in the ground
- E02D19/02—Restraining of open water
- E02D19/04—Restraining of open water by coffer-dams, e.g. made of sheet piles
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D3/00—Improving or preserving soil or rock, e.g. preserving permafrost soil
- E02D3/12—Consolidating by placing solidifying or pore-filling substances in the soil
- E02D3/126—Consolidating by placing solidifying or pore-filling substances in the soil and mixing by rotating blades
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A40/00—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production
- Y02A40/80—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production in fisheries management
- Y02A40/81—Aquaculture, e.g. of fish
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- Paleontology (AREA)
- General Engineering & Computer Science (AREA)
- Civil Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Mining & Mineral Resources (AREA)
- Soil Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Agronomy & Crop Science (AREA)
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Abstract
The invention discloses a construction method of an integral steel-concrete pedestal of a soft soil foundation bridge deck, which is applied to the soft foundation construction of the pedestal, realizes the solidification of soft soil such as silt and the like in other temporary engineering construction, has high foundation bearing capacity after solidification treatment, reduces waste soil, changes silt into valuable, and reduces pollution to the environment; the whole rigidity of the construction pedestal is high, deformation caused by uneven settlement possibly occurring on the foundation is avoided, and the flatness requirement of the bridge deck plate bottom is ensured; only a small amount of section steel is used as a positioning framework, the installation engineering quantity of the main structure is small, a plurality of pedestals can be cast and formed once after the reinforcing steel bars and the templates are installed, and the construction period of the pedestals is short; the bottom plate is convenient to model, the model guiding function can be achieved by using a small amount of section steel as a positioning framework sheet, a steel panel is paved after the concrete surface is leveled, and the loss of the section steel is reduced, and meanwhile, the model required by design is achieved; the telescopic intelligent spraying maintenance system with the preformed holes in the pedestal has the advantages of good bridge deck health maintenance effect and water conservation.
Description
Technical Field
The invention particularly relates to a construction method of an integral steel-concrete pedestal of a soft soil foundation bridge deck.
Background
At present, the construction of the prefabricated pedestal of the soft foundation upper bridge deck plate commonly used in China mostly adopts a method of constructing a concrete base after dredging, replacing and filling or polishing and squeezing the soft foundation below the pedestal, and installing a combined steel die on the base. However, the method can lead to the abandonment and replacement of the soil body of the precast slab yard, and as the combined steel mould is a combined welding structure of trusses, steel ribs and steel plates, compared with an integral steel-concrete pedestal, the method has the advantages of low bending resistance and torsional rigidity, high foundation bearing capacity and stability requirements, difficult deformation resistance under the condition that a soft foundation is likely to subside, and higher damage rate of the combined steel mould than that of the integral steel-concrete pedestal under the condition that a large-scale bridge deck is precast.
Disclosure of Invention
In view of the above, the invention aims to provide a construction method of an integral steel-concrete pedestal of a soft soil foundation bridge deck slab.
In order to solve the technical problems, the technical scheme of the invention is as follows:
a construction method of an integral steel-concrete pedestal of a soft soil foundation bridge deck slab comprises the following steps:
s1, site lofting: measuring and lofting a fish pond area of a site by using a measuring instrument according to the size and site selection position of the precast slab field required by design, and discharging the precast slab field position;
s2, construction preparation, which comprises the following specific steps:
s21, preparing a field: according to the on-site survey, as the water pumping area of the fishpond is large, in order to keep the stability of the fishpond stems, a steel structure and wood structure combined cofferdam is adopted, a plurality of H-shaped steels are arranged between right-angle steel structure corner piles and H-shaped steels, wooden piles are embedded between the right-angle steel structure corner piles and the H-shaped steels in the direction of A, the H-shaped steels and the H-shaped steels are arranged in rows, finally, bamboo plywood is paved on the inner sides of the rows of the wooden piles, the water stop and the reinforcement of the fishpond stems are carried out through the complete cofferdam, and after the reinforcing measures of the fishpond stems are completed, a high-power water pump is adopted to pump the water in the area to be dried, and then the on-site solidification construction is carried out according to construction drawings;
s22, preparing main equipment: conveying a digging machine, stirring equipment and a feeding system to a site for assembly by adopting a flat car, wherein the feeding system is communicated with the stirring equipment through a feeding pipe, a stirring head arm rod of the digging machine is assembled with the stirring equipment, so that the stirring process can be completed, the stirring head arm rod is selected to be suitable for the average solidification depth of a soft foundation under the prefabricated site according to the average solidification depth of about 2.5m, the feeding processes of different solidifying agents are completed by automatic quantitative feeding, meanwhile, the quality control difference is in an allowable range, and the upper end part of a sludge layer serving as a bottom layer is subjected to stirring and feeding treatment by the stirring equipment and the feeding system at the moment, so that a crust layer is gradually formed;
s3, site on-site solidification construction, which comprises the following specific steps:
s31, dividing a construction area: dividing numerous small construction areas of 5m multiplied by 6m in the construction area, setting single-point material conveying quantity and feeding speed, and adopting slurry for construction according to the water content of the sludge on site;
s32, preparing a curing agent: experiments prove that the weight proportion of the solidified mixture is 5 percent of cement, 2 percent of fly ash and 0.02 percent of stabilizer according to the mixing amount of cement, and a mixture metering container is 17kN/m 3 Counting;
s33, in-situ stirring: the stirring lifting or descending speed is controlled to be 10-20s/m, the spraying speed of the curing agent is controlled to be 40-70kg/min, the curing is carried out while the curing is carried out, the overlap width between adjacent blocks is equal to or more than 5cm, the leakage stirring is avoided, and finally the curing is carried out to form an integral uniform crust layer;
s34, leveling a construction area, curing and prepressing: when the solidification area is stirred, the vehicle fetches earth from a sampling site qualified by a detection unit to the site, a soil body with the thickness of about 0.5m is filled to carry out preloading on the stirred soil body, the solidification area is leveled and maintained after the preloading, the integrity of the stirred plate body and the compactness of the surface soil body are ensured, and the maintenance time is preferably more than or equal to 7 days;
s35, bearing capacity detection: after the curing construction of the prefabricated field range is finished, carrying out static sounding on randomly selected points in 28 days by a project department building site laboratory joint detection unit, taking every 200m of the prefabricated field range with the longitudinal length of 396m as a cross section, wherein 3 cross sections are totally arranged at the head end, the middle section and the tail end of the prefabricated field in the range, 3 points are selected for each cross section, 9 points are totally arranged, the single-point bearing capacity is more than 200kPa, and the design requirement that the foundation bearing capacity under a prefabricated field pedestal 36 is more than 150kPa is met;
s4, site cushion layer construction: after the site is solidified on site and the ground is leveled and rolled to reach the foundation bearing capacity required by design, in order to facilitate the drainage of the site, the site is also required to be filled with a soil body with the height of about 1m so as to be higher than surrounding pond ridges, rolling and leveling are carried out after the filling is completed, a portal crane foundation is installed on a portal crane foundation, a construction area is divided, a C20 concrete cushion layer with the thickness of 10cm is constructed in stages, 1% transverse slope drainage is arranged on the cushion layer, a drainage ditch with the width of 30cm multiplied by the depth of 20cm is arranged according to the water collecting quantity, the water on the ground can be discharged in time, and the uneven settlement of the foundation caused by water accumulated on the ground is eliminated;
s5, manufacturing a pedestal positioning framework: the pedestal positioning framework is accurately lofted on the site according to the structural shape of the bottom of the bridge deck plate on the requirement, after the modeling is determined, the section steel which is well blanked is put and integrally welded into frameworks, after the welding forming, supporting positioning steel bars are welded and installed on each framework according to the design height of the pedestal, so that the accurate lofting of the whole positioning framework structure is ensured, the integrity is strong, and the modeling requirement of the top of the pedestal can be met;
s6, mounting a pedestal positioning framework and reinforcing steel bars: setting out the positioning framework of the pedestal according to the position required by the design, installing the positioning framework to the correct position, adopting steel bars as temporary diagonal braces in the installation process, installing the steel bars according to the design requirement after the positioning framework is installed, and ensuring that the steel bars serving as main bars are firmly welded with the steel bars in the foundation of the pedestal after the installation of the steel bars is completed, so that the pedestal forms an integral stable structure;
s7, installing a template and pouring concrete: after the installation of the reinforcing steel bars is completed, checking the installation of the positioning framework, reserving a lifting hole according to the designed position, installing a template and performing concrete pouring, pouring a layer of high concrete with the thickness of about 15cm, paving a first layer of block stones before vibrating, inserting a vibrator into gaps among the block stones to compact the concrete, sinking the block stones into half of the concrete layer and exposing the block stones to half, paving a second layer of concrete, wherein the block stones are hard in texture and clean in surface, the net distance between the block stones and the structural top surfaces of the template and the pedestal is more than 30cm, and covering geotechnical cloth for sprinkling and curing for more than or equal to 7 days after the concrete construction of the pedestal is completed;
s8, mounting a pedestal steel panel: in order to ensure that the flatness of a pedestal steel panel meets the acceptance requirement, firstly, detecting partial uneven top surface of concrete of the pedestal by using a 2m guiding rule, polishing and leveling a convex surface, leveling a concave surface by using slurry, ensuring that the flatness of the top surface of the concrete of the whole pedestal is less than or equal to 1mm, mounting the pedestal steel panel by using a 6mm thick steel plate according to a plurality of blocks of blanking plates of a prefabricated plate bottom angle model, fixing the steel plate blocks and the tops of profile steel in a positioning framework by performing broken welding connection for reducing welding deformation, and finally, integrally connecting a plurality of steel plates by adopting butt welding, polishing and leveling a welding seam after welding, and plugging rubber strips into grooves of profile steel around before prefabrication of a beam plate to ensure that slurry leakage is not generated when the bridge panel performs concrete pouring;
s9, intelligent spraying health preserving system installation: the prefabricated slab yard adopts intelligent spraying health preserving system, the system can set spraying time, automatically stop spraying after the time arrives, turn to the next pedestal, start waiting time after one circle, and confirm the waiting time according to the water evaporation finishing time and the total circulation time of the surface of the test bridge deck.
Further, the intelligent spraying health preserving system in S9 comprises an intelligent spraying control system and spray water pipes arranged above the precast slab yard, and telescopic rotary spray heads are arranged beside each corresponding pedestal position of the spray water pipes.
The technical effects of the invention are mainly as follows:
(1) The steel structure and the wood structure are combined to form the cofferdam for the foundation construction of the pedestal at the fishpond, so that the water stopping and reinforcing effects of the cofferdam are enhanced;
(2) The waste soil is reduced, the sludge soil is changed into valuable by adopting a deep soft foundation on-site solidification construction technology, and the pollution of the traditional soft foundation treatment to the environment is avoided;
(3) The whole rigidity of the construction pedestal is high, deformation caused by uneven settlement possibly occurring on the foundation is avoided, the flatness requirement of the bridge deck slab bottom is ensured, the utilization rate is high, and the repair rate is low;
(4) Only a small amount of section steel is used as a positioning framework, the installation engineering quantity of the main structure is small, after a plurality of pedestals are installed with the reinforcing steel bars and the templates, the steel bars and the templates can be cast and formed once, and the construction period of the pedestals is short;
(5) In the process of pouring the pedestal concrete, the stone blocks accounting for about 30 percent of the whole pedestal volume are buried, so that the concrete is saved, the temperature rise is reduced, the strength is improved, the temperature cracks of the pedestal are reduced, and the workload of dismantling the pedestal in the later stage is reduced;
(6) The bottom plate is convenient to model, the model guiding function can be achieved by using a small amount of section steel as a positioning framework sheet, a steel panel is paved after the concrete surface is leveled, and the loss of the section steel is reduced, and meanwhile, the model required by design is perfectly achieved;
(7) The telescopic intelligent spraying maintenance system with the preformed holes in the pedestal has the advantages of good bridge deck health maintenance effect and water conservation.
Drawings
FIG. 1 is a schematic view of the cofferdam structure in S21 of the present invention;
FIG. 2 is a schematic diagram of the main apparatus in S22 of the present invention;
FIG. 3 is a top view of the pedestal of the present invention S5-S8;
FIG. 4 is a side view of FIG. 3, disassembled;
FIG. 5 is a cross-sectional view of FIG. 3;
fig. 6 is a cross-sectional view of a mounting arrangement of bars;
FIG. 7 is an installation diagram of the intelligent spraying health maintenance system of the invention S9;
FIG. 8 is a flow chart of a method of practicing the present invention.
Detailed Description
The following detailed description of the invention is provided in connection with the accompanying drawings to facilitate understanding and grasping of the technical scheme of the invention.
Examples
A construction method of an integral steel-concrete pedestal of a soft soil foundation bridge deck slab comprises the following steps:
s1, site lofting: measuring and lofting a fish pond area of a site by using a measuring instrument according to the size and site selection position of the precast slab field required by design, and discharging the precast slab field position;
s2, construction preparation, which comprises the following specific steps:
s21, preparing a site, as shown in FIG. 1: according to the field survey, as the water pumping area of the fish pond is large, in order to keep the stability of the pond stems of the fish pond, a steel structure and wood structure combined cofferdam is adopted, a plurality of H-shaped steel 12 are arranged between right-angle steel structure corner piles 11, then wood piles 13 are embedded between the right-angle steel structure corner piles 11 and the H-shaped steel 12 and between the H-shaped steel 12 and the H-shaped steel 12 in the direction of A, and are arranged in rows, finally, bamboo plywood 14 is paved on the inner sides of the rows of the wood piles 13, the water stop and the reinforcement of the pond stems are carried out through the complete cofferdam, and after the reinforcement measures of the pond stems are completed, a high-power water pump is adopted to pump the water in the area, and then the construction is cured in situ according to construction drawings;
s22, preparing main equipment, as shown in FIG. 2: conveying the excavator 21, the stirring equipment 22 and the feeding system 23 to a site for assembly by adopting a flat car, wherein the feeding system 23 is communicated with the stirring equipment 22 through a feeding pipe 231, a stirring head arm rod 211 of the excavator 21 is assembled with the stirring equipment 22, the stirring process can be completed, the stirring head arm rod 211 is selected to be suitable for the average solidification depth of a soft foundation under the prefabricated field according to the average solidification depth of about 2.5m, the feeding processes of different curing agents are completed by automatic quantitative feeding, meanwhile, the quality control is poor in an allowable range, and at the moment, the upper end part of a sludge layer 24 serving as a bottom layer is subjected to stirring and feeding treatment of the stirring equipment 22 and the feeding system 23, so that a crust layer 25 is gradually formed;
s3, site on-site solidification construction, which comprises the following specific steps:
s31, dividing a construction area: dividing numerous small construction areas of 5m multiplied by 6m in the construction area, setting single-point material conveying quantity and feeding speed, and adopting slurry for construction according to the water content of the sludge on site;
s32, preparing a curing agent: experiments prove that the weight proportion of the solidified mixture is 5 percent of cement, 2 percent of fly ash and 0.02 percent of stabilizer according to the mixing amount of cement, and a mixture metering container is 17kN/m 3 Counting;
s33, in-situ stirring: the stirring lifting or descending speed is controlled to be 10-20s/m, the spraying speed of the curing agent is controlled to be 40-70kg/min, the curing is carried out while the curing is carried out, the overlap width between adjacent blocks is equal to or more than 5cm, the leakage stirring is avoided, and finally the curing is carried out to form an integral uniform crust layer;
s34, leveling a construction area, curing and prepressing: when the solidification area is stirred, the vehicle fetches earth from a sampling site qualified by a detection unit to the site, a soil body with the thickness of about 0.5m is filled to carry out preloading on the stirred soil body, the solidification area is leveled and maintained after the preloading, the integrity of the stirred plate body and the compactness of the surface soil body are ensured, and the maintenance time is preferably more than or equal to 7 days;
s35, bearing capacity detection: after the curing construction of the prefabricated field range is finished, carrying out static sounding on randomly selected points in 28 days by a project department building site laboratory joint detection unit, taking every 200m of the prefabricated field range with the longitudinal length of 396m as a cross section, wherein 3 cross sections are totally arranged at the head end, the middle section and the tail end of the prefabricated field in the range, 3 points are selected for each cross section, 9 points are totally arranged, the single-point bearing capacity is more than 200kPa, and the design requirement that the foundation bearing capacity under a prefabricated field pedestal 36 is more than 150kPa is met;
s4, site cushion layer construction: after the site is solidified on site and the ground is leveled and rolled to reach the foundation bearing capacity required by design, in order to facilitate the drainage of the site, the site is also required to be filled with a soil body with the height of about 1m so as to be higher than surrounding pond ridges, rolling and leveling are carried out after the filling is completed, a portal crane foundation is installed on a portal crane foundation, a construction area is divided, a C20 concrete cushion layer with the thickness of 10cm is constructed in stages, 1% transverse slope drainage is arranged on the cushion layer, a drainage ditch with the width of 30cm multiplied by the depth of 20cm is arranged according to the water collecting quantity, the water on the ground can be discharged in time, and the uneven settlement of the foundation caused by water accumulated on the ground is eliminated;
s5, manufacturing a pedestal positioning framework, as shown in fig. 3-6: the pedestal positioning frameworks are accurately lofted on the site according to the structural shape of the bottom of the bridge deck 35 as required, after the modeling is determined, the section steel 31 which is laid with blanking is integrally welded into frameworks, after the welding forming, the supporting positioning steel bars 32 are welded and installed on each framework according to the design height of the pedestal 36, so that the accurate lofting of the whole positioning framework structure is ensured, the integrity is strong, and the modeling requirement of the top of the pedestal 36 can be met;
s6, mounting a pedestal positioning framework and reinforcing steel bars, wherein the mounting is as shown in fig. 3-6: setting out the positioning framework of the pedestal according to the position required by the design, installing the positioning framework to the correct position, adopting the steel bars 37 as temporary diagonal braces in the installation process, installing the steel bars 37 according to the design requirement after the positioning framework is installed, and ensuring that the steel bars 37 as main bars are firmly welded with the steel bars 37 in the foundation of the pedestal 36 after the installation of the steel bars 37, so that the pedestal 36 forms an integral stable structure;
s7, template installation and concrete pouring, as shown in fig. 3-6: after the steel bar 37 is installed, checking the installation of the positioning framework, reserving a lifting hole 33 according to the designed position, installing a template and pouring concrete, pouring a layer of high concrete with the thickness of about 15cm, paving a first layer of stone blocks before vibrating, inserting a vibrator into gaps among the stone blocks to compact the concrete, sinking the stone blocks into half of the concrete layer and exposing the stone blocks to half, paving a second layer of concrete, wherein the stone blocks are hard in texture and clean in surface, the clear distance between the stone blocks and the structural top surface of the template and the pedestal 36 is more than 30cm, and covering geotextile for watering and curing for more than or equal to 7 days after the concrete construction of the pedestal 36 is completed;
s8, mounting a pedestal steel panel 34, as shown in fig. 3-6: in order to ensure that the flatness of the pedestal steel panel 34 meets the acceptance requirement, firstly, detecting partial uneven top surface of concrete of the pedestal 36 by using a 2m guiding rule, polishing and flattening the convex surface, leveling the concave surface by grouting, ensuring that the flatness of the top surface of the concrete of the whole pedestal 36 is less than or equal to 1mm, mounting the pedestal steel panel 34 by adopting a 6mm thick steel plate according to a plurality of blocks of blanking plates of a prefabricated plate bottom bevel model, and fixing the steel plate blocks and the tops of the profile steels 31 in a positioning framework by means of broken welding to reduce the influence of welding deformation, finally, integrally connecting the plurality of steel plates by means of butt welding, polishing and flattening the welding seam after welding, plugging rubber strips into grooves of the profile steels 31 around before prefabrication of the beam plate, and ensuring that slurry leakage is not generated when the bridge panel 35 performs concrete pouring;
s9, intelligent spraying health preserving system installation: the prefabricated slab yard adopts intelligent spraying health preserving system, the system can set spraying time, automatically stop spraying after the time arrives, go to the next pedestal 36, start waiting time after one circle, and the waiting time is confirmed according to the water evaporation finishing time and the total circulation time of the surface of the test bridge deck.
As shown in fig. 7, the intelligent spraying health preserving system in S9 includes an intelligent spraying control system 41, and spray pipes 42 arranged above the prefabricated slab yard, and telescopic rotary spray heads 43 are installed beside each of the spray pipes 42 corresponding to one of the pedestal positions.
The technical effects of the invention are mainly as follows:
(1) The steel structure and the wood structure are combined to form the cofferdam for the foundation construction of the pedestal at the fishpond, so that the water stopping and reinforcing effects of the cofferdam are enhanced;
(2) The waste soil is reduced, the sludge soil is changed into valuable by adopting a deep soft foundation on-site solidification construction technology, and the pollution of the traditional soft foundation treatment to the environment is avoided;
(3) The whole rigidity of the construction pedestal is high, deformation caused by uneven settlement possibly occurring on the foundation is avoided, the flatness requirement of the bridge deck slab bottom is ensured, the utilization rate is high, and the repair rate is low;
(4) Only a small amount of section steel is used as a positioning framework, the installation engineering quantity of the main structure is small, after a plurality of pedestals are installed with the reinforcing steel bars and the templates, the steel bars and the templates can be cast and formed once, and the construction period of the pedestals is short;
(5) In the process of pouring the pedestal concrete, the stone blocks accounting for about 30 percent of the whole pedestal volume are buried, so that the concrete is saved, the temperature rise is reduced, the strength is improved, the temperature cracks of the pedestal are reduced, and the workload of dismantling the pedestal in the later stage is reduced;
(6) The bottom plate is convenient to model, the model guiding function can be achieved by using a small amount of section steel as a positioning framework sheet, a steel panel is paved after the concrete surface is leveled, and the loss of the section steel is reduced, and meanwhile, the model required by design is perfectly achieved;
(7) The telescopic intelligent spraying maintenance system with the preformed holes in the pedestal has the advantages of good bridge deck health maintenance effect and water conservation.
Of course, the above is only a typical example of the invention, and other embodiments of the invention are also possible, and all technical solutions formed by equivalent substitution or equivalent transformation fall within the scope of the invention claimed.
Claims (2)
1. The construction method of the integral steel-concrete pedestal of the bridge deck of the soft soil foundation is characterized by comprising the following steps of:
s1, site lofting: measuring and lofting a fish pond area of a site by using a measuring instrument according to the size and site selection position of the precast slab field required by design, and discharging the precast slab field position;
s2, construction preparation, which comprises the following specific steps:
s21, preparing a field: according to the field survey, as the water pumping area of the fishpond is large, in order to keep the stability of the fishpond stems, a steel structure and wood structure combined cofferdam is adopted, a plurality of H-shaped steel is arranged between right-angle steel structure corner piles, then wood piles are embedded between the right-angle steel structure corner piles and the H-shaped steel, and the H-shaped steel are arranged in rows, finally, bamboo plywood is paved on the inner sides of the rows of wood piles, the water stop and reinforcement of the fishpond stems are carried out through the complete cofferdam, and after the reinforcing measures of the fishpond stems are completed, a high-power water pump is adopted to pump the water in the region, and then the on-site solidification construction is carried out according to construction drawings;
s22, preparing main equipment: conveying a digging machine, stirring equipment and a feeding system to a site for assembly by adopting a flat car, wherein the feeding system is communicated with the stirring equipment through a feeding pipe, a stirring head arm rod of the digging machine is assembled with the stirring equipment, so that the stirring process can be completed, the stirring head arm rod is selected to be suitable for the average solidification depth of a soft foundation under the prefabricated site according to the average solidification depth of about 2.5m, the feeding processes of different solidifying agents are completed by automatic quantitative feeding, meanwhile, the quality control difference is in an allowable range, and the upper end part of a sludge layer serving as a bottom layer is subjected to stirring and feeding treatment by the stirring equipment and the feeding system at the moment, so that a crust layer is gradually formed;
s3, site on-site solidification construction, which comprises the following specific steps:
s31, dividing a construction area: dividing numerous small construction areas of 5m multiplied by 6m in the construction area, setting single-point material conveying quantity and feeding speed, and adopting slurry for construction according to the water content of the sludge on site;
s32, preparing a curing agent: experiments prove that the weight proportion of the solidified mixture is 5 percent of cement, 2 percent of fly ash and 0.02 percent of stabilizer according to the mixing amount of cement, and a mixture metering container is 17kN/m 3 Counting;
s33, in-situ stirring: the stirring lifting or descending speed is controlled to be 10-20s/m, the spraying speed of the curing agent is controlled to be 40-70kg/min, the curing is carried out while the curing is carried out, the overlap width between adjacent blocks is equal to or more than 5cm, the leakage stirring is avoided, and finally the curing is carried out to form an integral uniform crust layer;
s34, leveling a construction area, curing and prepressing: when the solidification area is stirred, the vehicle fetches earth from a sampling site qualified by a detection unit to the site, a soil body with the thickness of about 0.5m is filled to carry out preloading on the stirred soil body, the solidification area is leveled and maintained after the preloading, the integrity of the stirred plate body and the compactness of the surface soil body are ensured, and the maintenance time is preferably more than or equal to 7 days;
s35, bearing capacity detection: after the curing construction of the prefabricated field range is finished, carrying out static sounding on randomly selected points in 28 days by a project department building site laboratory joint detection unit, taking every 200m of the prefabricated field range with the longitudinal length of 396m as a cross section, wherein 3 cross sections are totally arranged at the head end, the middle section and the tail end of the prefabricated field in the range, 3 points are selected for each cross section, 9 points are totally arranged, the single-point bearing capacity is more than 200kPa, and the design requirement that the foundation bearing capacity under a prefabricated field pedestal is more than 150kPa is met;
s4, site cushion layer construction: after the site is solidified on site and the ground is leveled and rolled to reach the foundation bearing capacity required by design, in order to facilitate the drainage of the site, the site is also required to be filled with a soil body with the height of about 1m so as to be higher than surrounding pond ridges, rolling and leveling are carried out after the filling is completed, a portal crane foundation is installed on a portal crane foundation, a construction area is divided, a C20 concrete cushion layer with the thickness of 10cm is constructed in stages, 1% transverse slope drainage is arranged on the cushion layer, a drainage ditch with the width of 30cm multiplied by the depth of 20cm is arranged according to the water collecting quantity, the water on the ground can be discharged in time, and the uneven settlement of the foundation caused by water accumulated on the ground is eliminated;
s5, manufacturing a pedestal positioning framework: the pedestal positioning framework is accurately lofted on the site according to the structural shape of the bottom of the bridge deck plate on the requirement, after the modeling is determined, the section steel which is well blanked is put and integrally welded into frameworks, after the welding forming, supporting positioning steel bars are welded and installed on each framework according to the design height of the pedestal, so that the accurate lofting of the whole positioning framework structure is ensured, the integrity is strong, and the modeling requirement of the top of the pedestal can be met;
s6, mounting a pedestal positioning framework and reinforcing steel bars: setting out the positioning framework of the pedestal according to the position required by the design, installing the positioning framework to the correct position, adopting steel bars as temporary diagonal braces in the installation process, installing the steel bars according to the design requirement after the positioning framework is installed, and ensuring that the steel bars serving as main bars are firmly welded with the steel bars in the foundation of the pedestal after the installation of the steel bars is completed, so that the pedestal forms an integral stable structure;
s7, installing a template and pouring concrete: after the installation of the reinforcing steel bars is completed, checking the installation of the positioning framework, reserving a lifting hole according to the designed position, installing a template and performing concrete pouring, pouring a layer of high concrete with the thickness of about 15cm, paving a first layer of block stones before vibrating, inserting a vibrator into gaps among the block stones to compact the concrete, sinking the block stones into half of the concrete layer and exposing the block stones to half, paving a second layer of concrete, wherein the block stones are hard in texture and clean in surface, the net distance between the block stones and the structural top surfaces of the template and the pedestal is more than 30cm, and covering geotechnical cloth for sprinkling and curing for more than or equal to 7 days after the concrete construction of the pedestal is completed;
s8, mounting a pedestal steel panel: in order to ensure that the flatness of a pedestal steel panel meets the acceptance requirement, firstly, detecting partial uneven top surface of concrete of the pedestal by using a 2m guiding rule, polishing and leveling a convex surface, leveling a concave surface by using slurry, ensuring that the flatness of the top surface of the concrete of the whole pedestal is less than or equal to 1mm, mounting the pedestal steel panel by using a 6mm thick steel plate according to a plurality of blocks of blanking plates of a prefabricated plate bottom angle model, fixing the steel plate blocks and the tops of profile steel in a positioning framework by performing broken welding connection for reducing welding deformation, and finally, integrally connecting a plurality of steel plates by adopting butt welding, polishing and leveling a welding seam after welding, and plugging rubber strips into grooves of profile steel around before prefabrication of a beam plate to ensure that slurry leakage is not generated when the bridge panel performs concrete pouring;
s9, intelligent spraying health preserving system installation: the prefabricated slab yard adopts intelligent spraying health preserving system, the system can set spraying time, automatically stop spraying after the time arrives, turn to the next pedestal, start waiting time after one circle, and confirm the waiting time according to the water evaporation finishing time and the total circulation time of the surface of the test bridge deck.
2. The construction method of the integral steel-concrete pedestal of the soft soil foundation bridge deck slab of claim 1, wherein the construction method comprises the following steps: the intelligent spraying health preserving system in S9 comprises an intelligent spraying control system and spray pipes arranged above the precast slab yard, wherein each spray pipe is provided with a telescopic rotary spray head corresponding to one pedestal.
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