CN108571009B - Construction method for side wall of full-cover excavation top-down subway station - Google Patents
Construction method for side wall of full-cover excavation top-down subway station Download PDFInfo
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- CN108571009B CN108571009B CN201810422126.6A CN201810422126A CN108571009B CN 108571009 B CN108571009 B CN 108571009B CN 201810422126 A CN201810422126 A CN 201810422126A CN 108571009 B CN108571009 B CN 108571009B
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- 238000010276 construction Methods 0.000 title claims abstract description 42
- 238000009412 basement excavation Methods 0.000 title claims abstract description 19
- 239000004567 concrete Substances 0.000 claims abstract description 121
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 56
- 239000010959 steel Substances 0.000 claims abstract description 56
- 229910001294 Reinforcing steel Inorganic materials 0.000 claims abstract description 42
- 238000000034 method Methods 0.000 claims abstract description 18
- 230000008569 process Effects 0.000 claims abstract description 14
- 239000010410 layer Substances 0.000 claims description 49
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 20
- 238000012360 testing method Methods 0.000 claims description 19
- 238000001723 curing Methods 0.000 claims description 18
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 14
- 238000003780 insertion Methods 0.000 claims description 10
- 230000037431 insertion Effects 0.000 claims description 10
- 238000007689 inspection Methods 0.000 claims description 10
- 229910052742 iron Inorganic materials 0.000 claims description 10
- 239000000463 material Substances 0.000 claims description 10
- 239000002689 soil Substances 0.000 claims description 9
- 239000004575 stone Substances 0.000 claims description 9
- 239000002699 waste material Substances 0.000 claims description 9
- 239000004576 sand Substances 0.000 claims description 7
- GNFTZDOKVXKIBK-UHFFFAOYSA-N 3-(2-methoxyethoxy)benzohydrazide Chemical compound COCCOC1=CC=CC(C(=O)NN)=C1 GNFTZDOKVXKIBK-UHFFFAOYSA-N 0.000 claims description 6
- 239000004568 cement Substances 0.000 claims description 6
- 230000000149 penetrating effect Effects 0.000 claims description 6
- 230000002787 reinforcement Effects 0.000 claims description 6
- 241000196324 Embryophyta Species 0.000 claims description 3
- 238000004140 cleaning Methods 0.000 claims description 3
- 238000013461 design Methods 0.000 claims description 3
- 239000003864 humus Substances 0.000 claims description 3
- 238000011900 installation process Methods 0.000 claims description 3
- 239000000203 mixture Substances 0.000 claims description 3
- 230000003020 moisturizing effect Effects 0.000 claims description 3
- 239000004570 mortar (masonry) Substances 0.000 claims description 3
- 230000001681 protective effect Effects 0.000 claims description 3
- 239000011241 protective layer Substances 0.000 claims description 3
- 238000013102 re-test Methods 0.000 claims description 3
- 239000011150 reinforced concrete Substances 0.000 claims description 3
- 238000005204 segregation Methods 0.000 claims description 3
- 238000000926 separation method Methods 0.000 claims description 3
- 238000000638 solvent extraction Methods 0.000 claims description 3
- 238000009864 tensile test Methods 0.000 claims description 3
- 238000005406 washing Methods 0.000 claims description 3
- 238000005056 compaction Methods 0.000 claims description 2
- 238000007788 roughening Methods 0.000 claims description 2
- 239000011435 rock Substances 0.000 claims 1
- 239000002002 slurry Substances 0.000 claims 1
- 238000009434 installation Methods 0.000 abstract description 4
- 238000005516 engineering process Methods 0.000 abstract description 2
- 238000000465 moulding Methods 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 3
- 238000001514 detection method Methods 0.000 description 2
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D29/00—Independent underground or underwater structures; Retaining walls
- E02D29/04—Making large underground spaces, e.g. for underground plants, e.g. stations of underground railways; Construction or layout thereof
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Abstract
The invention discloses a construction method for a side wall of a full-cover excavation top-down subway station, which comprises the following steps: a. excavating to a preset elevation of the beam bottom, surveying the site, and removing ground and overground obstacles; d. and g, connecting the side wall reinforcing steel bars downwards, binding the side wall reinforcing steel bars firstly, then binding the plate reinforcing steel bars, and connecting the side wall reinforcing steel bars in place at one time. Has the advantages that: the construction method optimizes the connection of the steel bars of the side wall of the full-cover excavated inverted main body, adopts one-step mechanical connection molding of the steel bars of the side wall, reduces the steel bar joints, shortens the installation time of the steel bars, ensures the installation work efficiency and quality of the steel bars, adopts the conduit technology, well controls the pressure of the concrete in the downward pouring process, ensures the concrete pouring continuity, and thus effectively improves the concrete pouring work efficiency and the pouring quality.
Description
Technical Field
The invention relates to the technical field of subway construction, in particular to a construction method for a side wall of a full-cover excavation top-down subway station.
Background
In order to develop economy in the past, trees are cut down and deep forests are damaged, so that water and soil loss is serious at present, when heavy rain occurs, soil on a slope is prone to landslide, the landslide is caused, huge economic loss is caused, and life safety of nearby residents can be threatened, and therefore different forms of measures are adopted for preventing landslide on the slope surface prone to landslide. The miniature pile is a cast-in-place pile with a diameter less than 400mm and a length-to-thickness ratio greater than 30, and is constructed by drilling, reinforcing bars and pressure grouting. Many landslide prevention measures in the prior art are high in cost and can be realized only by a large amount of manpower and material resources, and the landslide prevention capacity is poor, so that maintenance is frequently needed, the financial investment is increased, and the improvement of civil life and the environment is not facilitated.
Disclosure of Invention
The invention aims to solve the problems and provide a construction method for fully excavating and reversely making a side wall of a subway station.
The invention realizes the purpose through the following technical scheme:
a construction method for fully-covered excavation of a side wall of a top-down subway station comprises the following steps:
a. excavating to a preset elevation of the bottom of the beam, surveying the site, removing obstacles on the ground and the ground, excavating the ground by using a large excavator, wherein the excavating depth is the preset elevation, and the excavated soil layer is transported to the outside of the construction site by a transport vehicle;
b. pouring a cushion layer and paving a ground model, tamping the ground after excavation by adopting a vibration type dynamic compactor, manually paving a ground model template, and pouring the cushion layer of the ground model template by adopting concrete, wherein the pouring thickness is 70 mm;
c. installing side wall templates, wherein the middle vibrating openings are reserved in the installation process of the side wall templates, the distance is 2m, and the distance is about 2m according to the height of the side wall;
d. pouring side wall concrete, namely using an extended insertion type vibrator, wherein the tamping thickness is not more than 30cm, when other vibrators are used, the thickness is not more than 15-30 cm, and each layer of concrete is poured and tamped before the initial setting of the previous layer of concrete so as to prevent the damage to the concrete poured in advance and avoid the separation between the surfaces of the two layers of concrete;
e. side wall construction joints are roughened and base surface is plastered, the side wall is divided into an upper horizontal construction joint and a lower horizontal construction joint which are generally arranged at positions 500mm away from a side wall template, and the lower horizontal construction joint is pre-buried with a water stop belt and a water stop steel plate according to requirements; removing cement film, soil on the surface, loose gravel and soft concrete layer from the upper construction joint, roughening to expose clean stones, and washing with water;
f. laying side wall waterproof coiled materials, and covering the surface of the side wall with a water-saving moisturizing film;
g. the side wall steel bars are connected downwards, the side wall steel bars are bound firstly, then the plate steel bars are bound, the side wall steel bars are connected in place at one time, the horizontal positioning bars need to be welded in the binding process of the side wall steel bars, and the up-down connection accuracy and the thickness of the protective layer of the side wall steel bars are guaranteed;
h. binding beam plate reinforcing steel bars, namely penetrating the lower longitudinal stressed reinforcing steel bars and the bent reinforcing steel bars of the main beam, separating the stirrups one by one according to intervals, penetrating the lower longitudinal stressed reinforcing steel bars and the bent reinforcing steel bars of the secondary beam, sleeving the stirrups, placing the erection bars of the main beam and the secondary beam, and firmly binding the erection bars and the stirrups at intervals; adjusting the distance between the stirrups to enable the distance to meet the design requirement, binding the vertical reinforcements, binding the main reinforcements, and simultaneously matching the main beam and the secondary beam;
i. pouring the beam slab reinforced concrete, wherein an elongated inserted vibrator is used for quickly inserting and slowly pulling, inserting points are uniformly arranged and move point by point in sequence without omission to achieve uniform vibration, the moving distance is not more than 1.25 times of the vibration action radius and is generally 300-400mm, a lower layer is inserted for 5-10 cm when an upper layer is vibrated so as to firmly combine two layers of concrete, and a vibrating rod does not touch a reinforcing steel bar and a template during vibration, and a surface vibrator, or the moving distance of a flat vibrator, is used for ensuring that a flat plate of the vibrator covers the edge of a vibrated part;
j. and excavating the next layer of earthwork.
In this embodiment, in the step a, surface weeds, stones, impurities, humus, tree roots and the like in the engineering range are all removed, leveled and compacted, the cleaning thickness is not less than 0.3m, the removed waste residues are not discarded along with the ground, and the waste residues are transported to a waste material yard outside a dump truck.
In this embodiment, after the side wall steel bar end in the step g is processed and qualified through inspection, a special steel bar end protective cap or a special connecting sleeve is used to protect the steel bar end so as to prevent the thread from being damaged or polluted during the steel bar moving or transporting process.
In this embodiment, before the concrete is poured in the steps b, i and d, a tester must be arranged to stop to detect the quality and the water content of the raw concrete material, the mix proportion of the concrete is adjusted according to the actually measured water content, and the detection of the slump (the concrete is controlled to be 180-200 mm when the concrete leaves the station) and the working performance is performed before the concrete leaves the station; the concrete entering field is detected once by one vehicle, the slump is controlled to be 140-160 mm, unqualified concrete is treated by field withdrawal and relevant image records are made, meanwhile, the entering concrete vehicle is randomly weighed to check whether the free blanking height of the concrete is required to be not more than 2m, a method of arranging a tandem tube or lengthening a pump truck hose is added for exceeding the concrete to prevent concrete segregation, a concrete vibrating port is reserved in the middle of the vertical direction of the side wall, and the horizontal interval is 3-4 m; layering, partitioning and symmetrically pouring: the layered thickness is controlled to be about 50cm, high-grade concrete at the longitudinal beam position is preferentially poured, slab concrete is poured in a layered, blocked and symmetrical mode along the two sides of the longitudinal beam when the slab concrete is level with the bottom of the slab, one layer of longitudinal beam concrete is poured when the slab concrete rises for each layer until the concrete is poured to the designed elevation, the layered pouring of the side wall is finished from one end to the other end, and the second pouring is required to be poured according to the original direction; the vibrating rod is operated by adopting the principles of 'quick insertion, slow pulling, no dependence on' and 'no vibration, no vibration and no leakage', namely the vertical insertion speed of the vibrating rod is high, the vibrating time of each insertion is controlled to be about 20 to 30 seconds, the moving distance is 400mm, the lower layer concrete surface is inserted by about 10cm when the upper layer is vibrated, the concrete does not obviously sink any more, and bubbles are not generated. The vibrating time is not too long, and the concrete can generate sand and cement paste to be separated and stones sink to form a sand layer on the surface of the concrete after the vibrating time is too long. The third step is that the vibrating rod does not lean on a template (keeping a distance of 5-15 cm from the template), does not lean on a steel bar, does not lean on an embedded part, and needs a wooden hammer to tap the template when the edge of the template is vibrated; for the part with large density of the reinforcing steel bar, the reinforcing steel bar can be properly pulled open to carry out concrete vibration in the concrete pouring process, but the reinforcing steel bar is required to be restored to the original shape in time after the concrete is poured; in the parts of the side wall and the column which are easy to rot roots, the bottom of the mortar with the same strength as the side wall and the column is made before the concrete is poured; and (3) treating the appearance quality in time after removing the mold, curing the concrete by a watering natural curing method, and curing by a concrete water-saving moisture-preserving curing film when the temperature is lower than 5 ℃, wherein the curing period is not less than 14 days, and the curing film is required to be kept in a wet state in the whole process.
In this embodiment, when the concrete slab is poured in the steps i and d, the concrete delivery pump pipe needs to be raised by 300mm by using an iron stool, so as to prevent the upper rib of the slab from being collapsed due to the overweight pump pipe. The main channel to the operation surface needs to be provided with an iron stool, a steel springboard is paved on the iron stool, and the iron stool is removed while pouring.
In this embodiment, the formed steel bars in the steps g and h should be placed in the designated places according to the general plane layout, and placed neatly by using the skid, so as to prevent the steel bars from being deformed, corroded and greasy-stained.
In this embodiment, the side wall reinforcing steel bars in the step g need quality acceptance and straight thread joint test, no complete screw thread is exposed when the quality of the joints is checked, and no gap exists between the reinforcing steel bars and the connecting sleeves. If a complete screw thread is exposed, the screw thread is screwed again, then a torque wrench for inspection is used for sampling and inspecting the quality of the joint, a quality inspection torque wrench is used for inspecting the screwing degree of the joint, the straight thread joint experiment adopts the joints with the same grade, the same type and the same specification of the same batch of materials under the same construction condition, 500 joints are used as an acceptance batch for inspection and acceptance, and less than 500 joints are also used as an acceptance batch. And 3 test pieces are taken for one-way tensile test in each batch, and when the tensile strength of the three test pieces is not less than the standard value of the tensile strength of the steel bar at the grade, the acceptance batch is determined to be qualified. If the tensile strength of one test piece does not meet the requirement, six test pieces are taken for rechecking. If one test piece in the retest does not meet the requirement, the acceptance check is judged to be unqualified.
The invention has the beneficial effects that: the construction method optimizes the connection of the steel bars of the side wall of the full-cover excavated inverted main body, adopts one-step mechanical connection molding of the steel bars of the side wall, reduces the steel bar joints, shortens the installation time of the steel bars, ensures the installation work efficiency and quality of the steel bars, adopts the conduit technology, well controls the pressure of the concrete in the downward pouring process, ensures the concrete pouring continuity, and thus effectively improves the concrete pouring work efficiency and the pouring quality.
Drawings
FIG. 1 is a construction sequence diagram of a construction method for a side wall of a full-covered excavation top-down subway station according to the present invention;
FIG. 2 is a pouring schematic diagram of the construction method for the side wall of the full-cover excavation top-down subway station, which is disclosed by the invention;
FIG. 3 is a thread end machining size diagram of the construction method for the side wall of the full-cover excavation top-down subway station.
Detailed Description
The invention will be further described with reference to the accompanying drawings in which:
as shown in fig. 1-3, a construction method for a side wall of a full-cover excavation top-down subway station includes the following steps:
a. excavating to a preset elevation of the bottom of the beam, surveying the site, removing obstacles on the ground and the ground, excavating the ground by using a large excavator, wherein the excavating depth is the preset elevation, and the excavated soil layer is transported to the outside of the construction site by a transport vehicle;
b. pouring a cushion layer and paving a ground model, tamping the ground after excavation by adopting a vibration type dynamic compactor, manually paving a ground model template, and pouring the cushion layer of the ground model template by adopting concrete, wherein the pouring thickness is 70 mm;
c. installing side wall templates, wherein the middle vibrating openings are reserved in the installation process of the side wall templates, the distance is 2m, and the distance is about 2m according to the height of the side wall;
d. and (3) pouring concrete on the side wall, wherein the tamping thickness cannot exceed 30cm by using the lengthened inserted vibrator, and the thickness cannot exceed 15-30 cm by using other vibrators. Each layer of concrete is poured and tamped before the initial setting of the previous layer of concrete so as to prevent the damage of the concrete poured in advance and avoid the separation between the surfaces of the two layers of concrete;
e. the construction joints of the side wall are roughened and the base surface is plastered, and the side wall is divided into an upper horizontal construction joint and a lower horizontal construction joint which are generally arranged at the position 500mm away from the plate. Pre-burying a waterstop and a waterstop steel plate according to requirements at the lower layer of construction joints; removing cement film, soil on the surface, loose sand stone, soft concrete layer, etc. from the upper construction joint, chiseling to expose clean stone, and washing with water;
f. laying side wall waterproof coiled materials, and covering the surface of the side wall with a water-saving moisturizing film;
g. and connecting the side wall reinforcing steel bars downwards, binding the side wall reinforcing steel bars firstly, then binding the plate reinforcing steel bars, and connecting the side wall reinforcing steel bars in place at one time. A horizontal positioning rib needs to be welded in the binding process of the side wall reinforcing steel bars, so that the up-and-down connection accuracy of the side wall reinforcing steel bars and the thickness of a protective layer are ensured;
h. binding beam plate reinforcing steel bars, namely penetrating the lower longitudinal stressed reinforcing steel bars and the bent reinforcing steel bars of the main beam, separating the stirrups one by one according to intervals, penetrating the lower longitudinal stressed reinforcing steel bars and the bent reinforcing steel bars of the secondary beam, sleeving the stirrups, placing the erection bars of the main beam and the secondary beam, and firmly binding the erection bars and the stirrups at intervals; adjusting the distance between the stirrups to enable the distance to meet the design requirement, binding the vertical reinforcements, binding the main reinforcements, and simultaneously matching the main beam and the secondary beam;
i. the beam slab reinforced concrete is poured, the lengthened plug-in type vibrator is used for fast plugging and slow pulling, plug points are uniformly arranged and move point by point in sequence, omission is avoided, and uniform compaction is achieved. The moving distance is not more than 1.25 times (generally 300-400 mm) of the vibrating radius. And 5-10 cm of the lower layer is inserted when the upper layer is vibrated so as to firmly combine the two layers of concrete. When vibrating, the vibrating rod can not touch the reinforcing steel bar and the template. The moving distance of the surface vibrator (or called a flat vibrator) is to ensure that the flat plate of the vibrator covers the edge of the vibrated part;
j. and excavating the next layer of earthwork.
In this embodiment, in the step a, surface weeds, stones, impurities, humus, tree roots and the like in the engineering range are all removed, leveled and compacted, the cleaning thickness is not less than 0.3m, the removed waste residues are not discarded along with the ground, and the waste residues are transported to a waste material yard outside a dump truck.
In this embodiment, after the side wall steel bar end in the step g is processed and qualified through inspection, a special steel bar end protective cap or a special connecting sleeve is used to protect the steel bar end so as to prevent the thread from being damaged or polluted during the steel bar moving or transporting process.
In this embodiment, before the concrete is poured in the steps b, i and d, a tester must be arranged to stop to detect the quality and the water content of the raw concrete material, the mix proportion of the concrete is adjusted according to the actually measured water content, and the detection of the slump (the concrete is controlled to be 180-200 mm when the concrete leaves the station) and the working performance is performed before the concrete leaves the station; the concrete entering field is detected once by one vehicle, the slump is controlled to be 140-160 mm, unqualified concrete is treated by field withdrawal and relevant image records are made, meanwhile, the entering concrete vehicle is randomly weighed to check whether the free blanking height of the concrete is required to be not more than 2m, a method of arranging a tandem tube or lengthening a pump truck hose is added for exceeding the concrete to prevent concrete segregation, a concrete vibrating port is reserved in the middle of the vertical direction of the side wall, and the horizontal interval is 3-4 m; layering, partitioning and symmetrically pouring: the layered thickness is controlled to be about 50cm, high-grade concrete at the longitudinal beam position is preferentially poured, slab concrete is poured in a layered, blocked and symmetrical mode along the two sides of the longitudinal beam when the slab concrete is level with the bottom of the slab, one layer of longitudinal beam concrete is poured when the slab concrete rises for each layer until the concrete is poured to the designed elevation, the layered pouring of the side wall is finished from one end to the other end, and the second pouring is required to be poured according to the original direction; the vibrating rod is operated by adopting the principles of 'quick insertion, slow pulling, no dependence on' and 'no vibration, no vibration and no leakage', namely the vertical insertion speed of the vibrating rod is high, the vibrating time of each insertion is controlled to be about 20 to 30 seconds, the moving distance is 400mm, the lower layer concrete surface is inserted by about 10cm when the upper layer is vibrated, the concrete does not obviously sink any more, and bubbles are not generated. The vibrating time is not too long, and the concrete can generate sand and cement paste to be separated and stones sink to form a sand layer on the surface of the concrete after the vibrating time is too long. The third step is that the vibrating rod does not lean on a template (keeping a distance of 5-15 cm from the template), does not lean on a steel bar, does not lean on an embedded part, and needs a wooden hammer to tap the template when the edge of the template is vibrated; for the part with large density of the reinforcing steel bar, the reinforcing steel bar can be properly pulled open to carry out concrete vibration in the concrete pouring process, but the reinforcing steel bar is required to be restored to the original shape in time after the concrete is poured; in the parts of the side wall and the column which are easy to rot roots, the bottom of the mortar with the same strength as the side wall and the column is made before the concrete is poured; and (3) treating the appearance quality in time after removing the mold, curing the concrete by a watering natural curing method, and curing by a concrete water-saving moisture-preserving curing film when the temperature is lower than 5 ℃, wherein the curing period is not less than 14 days, and the curing film is required to be kept in a wet state in the whole process.
In this embodiment, when the concrete slab is poured in the steps i and d, the concrete delivery pump pipe needs to be raised by 300mm by using an iron stool, so as to prevent the upper rib of the slab from being collapsed due to the overweight pump pipe. The main channel to the operation surface needs to be provided with an iron stool, a steel springboard is paved on the iron stool, and the iron stool is removed while pouring.
In this embodiment, the formed steel bars in the steps g and h should be placed in the designated places according to the general plane layout, and placed neatly by using the skid, so as to prevent the steel bars from being deformed, corroded and greasy-stained.
In this embodiment, the side wall reinforcing steel bars in the step g need quality acceptance and straight thread joint test, no complete screw thread is exposed when the quality of the joints is checked, and no gap exists between the reinforcing steel bars and the connecting sleeves. If a complete screw thread is exposed, the screw thread is screwed again, then a torque wrench for inspection is used for sampling and inspecting the quality of the joint, a quality inspection torque wrench is used for inspecting the screwing degree of the joint, the straight thread joint experiment adopts the joints with the same grade, the same type and the same specification of the same batch of materials under the same construction condition, 500 joints are used as an acceptance batch for inspection and acceptance, and less than 500 joints are also used as an acceptance batch. And 3 test pieces are taken for one-way tensile test in each batch, and when the tensile strength of the three test pieces is not less than the standard value of the tensile strength of the steel bar at the grade, the acceptance batch is determined to be qualified. If the tensile strength of one test piece does not meet the requirement, six test pieces are taken for rechecking. If one test piece in the retest does not meet the requirement, the acceptance check is judged as unqualified
The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (7)
1. A construction method for fully-covered excavation of side walls of top-down subway stations is characterized by comprising the following steps: the method comprises the following steps:
a. excavating to a preset elevation of the bottom of the beam, surveying the site, removing obstacles on the ground and the ground, excavating the ground by using a large excavator, wherein the excavating depth is the preset elevation, and the excavated soil layer is transported to the outside of the construction site by a transport vehicle;
b. pouring a cushion layer and paving a ground model, tamping the ground after excavation by adopting a vibration type dynamic compactor, manually paving a ground model template, and pouring the cushion layer of the ground model template by adopting concrete, wherein the pouring thickness is 70 mm;
c. installing side wall templates, wherein the middle vibrating openings are reserved in the installation process of the side wall templates, the distance is 2m, and the distance is about 2m according to the height of the side wall;
d. pouring side wall concrete, namely using an extended insertion type vibrator, wherein the tamping thickness is not more than 30cm, when other vibrators are used, the thickness is not more than 15-30 cm, and each layer of concrete is poured and tamped before the initial setting of the previous layer of concrete so as to prevent the damage to the concrete poured in advance and avoid the separation between the surfaces of the two layers of concrete;
e. the side wall construction joint is roughened and the base surface is plastered, the side wall is divided into an upper horizontal construction joint and a lower horizontal construction joint which are arranged at positions 500mm away from a side wall template, and the lower horizontal construction joint is used for embedding a water stop belt and a water stop steel plate according to requirements; removing cement film, soil on the surface, loose gravel and soft concrete layer from the upper construction joint, roughening to expose clean stones, and washing with water;
f. laying side wall waterproof coiled materials, and covering the surface of the side wall with a water-saving moisturizing film;
g. the side wall steel bars are connected downwards, the side wall steel bars are bound firstly, then the plate steel bars are bound, the side wall steel bars are connected in place at one time, the horizontal positioning bars need to be welded in the binding process of the side wall steel bars, and the up-down connection accuracy and the thickness of the protective layer of the side wall steel bars are guaranteed;
h. binding beam plate reinforcing steel bars, namely penetrating the lower longitudinal stressed reinforcing steel bars and the bent reinforcing steel bars of the main beam, separating the stirrups one by one according to intervals, penetrating the lower longitudinal stressed reinforcing steel bars and the bent reinforcing steel bars of the secondary beam, sleeving the stirrups, placing the erection bars of the main beam and the secondary beam, and firmly binding the erection bars and the stirrups at intervals; adjusting the distance between the stirrups to enable the distance to meet the design requirement, binding the vertical reinforcements, binding the main reinforcements, and simultaneously matching the main beam and the secondary beam;
i. pouring the beam slab reinforced concrete, wherein an elongated plug-in vibrator is used for quickly plugging and slowly pulling, plug points are uniformly arranged and move point by point in sequence without omission to achieve uniform compaction, the moving distance is 300-400mm, a lower layer is inserted for 5-10 cm when an upper layer is vibrated so as to firmly combine two layers of concrete, and a vibrating rod does not contact with a reinforcing steel bar and a template during vibration, the moving distance of a surface vibrator, or called a flat vibrator, is used for ensuring that a flat plate of the vibrator covers the edge of a vibrated part;
j. and excavating the next layer of earthwork.
2. The construction method of the side wall of the full-cover excavation top-down subway station as claimed in claim 1, wherein: in the step a, surface weeds, rock blocks, sundries, humus soil and tree roots in the engineering range are all cleaned, leveled and compacted, the cleaning thickness is not less than 0.3m, the cleaned waste residues cannot be discarded along with the ground, and the waste residues are transported to a waste stock dump outside a dump truck.
3. The construction method of the side wall of the full-cover excavation top-down subway station as claimed in claim 1, wherein: and g, after the side wall steel bar thread head in the step g is processed and qualified through inspection, protecting the steel bar thread head by using a special steel bar thread head protective cap or a special connecting sleeve to prevent the thread from being damaged or polluted in the process of moving or transporting the steel bar.
4. The construction method of the side wall of the full-cover excavation top-down subway station as claimed in claim 1, wherein: b, arranging testers to stop for detecting the quality and the water content of the raw concrete materials before pouring the concrete in the steps b, i and d, adjusting the mix proportion of the concrete according to the actually measured water content, and controlling the slump to be out of the station before the concrete is out of the station and detecting the working performance of the slump at 180-200 mm; the concrete entering field is detected once by one vehicle, the slump is controlled to be 140-160 mm, unqualified concrete is treated by field withdrawal and relevant image records are made, meanwhile, the entering concrete vehicle is randomly weighed to check whether the free blanking height of the concrete is required to be not more than 2m, a method of arranging a tandem tube or lengthening a pump truck hose is added for exceeding the concrete to prevent concrete segregation, a concrete vibrating port is reserved in the middle of the vertical direction of the side wall, and the horizontal interval is 3-4 m; layering, partitioning and symmetrically pouring: the layered thickness is controlled to be about 50cm, high-grade concrete at the position of the longitudinal beam is poured preferentially, plate concrete is poured in a layered, blocked and symmetrical mode along the two sides of the longitudinal beam when the bottom of the side wall template is flush, one layer of longitudinal beam concrete is poured when the plate concrete rises for each layer until the concrete is poured to the designed elevation, the layered pouring of the side wall is finished from one end to the other end, and the second pouring is carried out according to the original direction; the operation of the vibrating rod adopts the principles of 'quick insertion, slow pulling, no dependence on' and 'no vibration, no vibration and no leakage', namely the speed of vertically inserting the vibrating rod is high, the vibration time of each insertion is controlled to be about 20 to 30 seconds, the movement distance is 300-400mm, the lower layer concrete surface is inserted by about 10cm when the upper layer is vibrated, the concrete does not obviously sink any more, bubbles do not appear preferably, the vibration time is not too long, the concrete can generate sand and cement slurry to be separated after the time is too long, stones sink to form a sand layer on the concrete surface, the dependence means that the vibrating rod does not depend on a template and the template to keep a distance of 5-15 cm, does not depend on a reinforcing steel bar, does not depend on an embedded part, and needs a wooden hammer to slightly knock the template when the edge of the template is vibrated; for the part with large density of the reinforcing steel bar, the reinforcing steel bar is properly pulled open to carry out concrete vibration in the concrete pouring process, but the reinforcing steel bar is timely restored to the original shape after the concrete is poured; in the parts of the side wall and the column which are easy to rot roots, the bottom of the mortar with the same strength as the side wall and the column is made before the concrete is poured; and (3) treating the appearance quality in time after removing the mold, curing the concrete by a watering natural curing method, and curing by a concrete water-saving moisture-preserving curing film when the temperature is lower than 5 ℃, wherein the curing period is not less than 14 days, and the curing film is required to be kept in a wet state in the whole process.
5. The construction method of the side wall of the full-cover excavation top-down subway station as claimed in claim 1, wherein: and (e) when the concrete is poured in the steps i and d, erecting the concrete conveying pump pipe by 300mm by using an iron stool, preventing the upper rib of the plate from collapsing due to the overweight pump pipe, arranging the iron stool for a main channel going to an operation surface, paving a steel gangway on the steel gangway, and removing the concrete while pouring.
6. The construction method of the side wall of the full-cover excavation top-down subway station as claimed in claim 1, wherein: and g, placing the formed steel bars in the steps g and h according to the designated place of the general plane layout, and using a skid for neatly placing the formed steel bars to prevent the steel bars from deforming, rusting and oil stain.
7. The construction method of the side wall of the full-cover excavation top-down subway station as claimed in claim 1, wherein: the side wall steel bars in the step g need quality acceptance and straight thread joint test, the appearance quality of the joint is checked to have no complete screw thread exposed when the quality is accepted, no gap exists between the steel bars and the connecting sleeve, if a complete screw thread is found to be exposed, the steel bars and the connecting sleeve need to be screwed again, then the joint quality is checked by using a torque wrench for checking, the screwing degree of the joint is checked by using a quality inspection torque wrench, the straight thread joint test adopts joints of the same material batch with the same grade, the same type and the same specification under the same construction condition, 500 are used as one acceptance batch for checking, less than 500 are used as one acceptance batch, 3 test pieces are taken as one-way tensile test in each batch, when the tensile strength of three test pieces is not less than the standard value of the tensile strength of the steel bars at the grade, the acceptance batch is determined to be qualified, if the tensile strength of one test piece does not meet the requirement, six test pieces are taken for rechecking, if one test piece in the retest does not meet the requirement, the acceptance check is judged to be unqualified.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201221079Y (en) * | 2008-05-16 | 2009-04-15 | 中冶天工建设有限公司 | Supporting structure for deep foundation pit structure wall |
| CN104060629A (en) * | 2014-07-02 | 2014-09-24 | 中铁十二局集团第七工程有限公司 | Covered top-down excavation subway station overlapped wall construction method and movable side wall formwork jumbo |
| JP2015021290A (en) * | 2013-07-19 | 2015-02-02 | 株式会社フジタ | Method for reinforcing concrete structures |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201221079Y (en) * | 2008-05-16 | 2009-04-15 | 中冶天工建设有限公司 | Supporting structure for deep foundation pit structure wall |
| JP2015021290A (en) * | 2013-07-19 | 2015-02-02 | 株式会社フジタ | Method for reinforcing concrete structures |
| CN104060629A (en) * | 2014-07-02 | 2014-09-24 | 中铁十二局集团第七工程有限公司 | Covered top-down excavation subway station overlapped wall construction method and movable side wall formwork jumbo |
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