CN115288136A - Anti-floating reinforcement cage and construction method of static pressure immersed tube cast-in-place pile - Google Patents

Abstract

The invention discloses an anti-floating reinforcement cage and a construction method of a static pressure immersed tube cast-in-place pile. The bottom of the cage body is provided with a pocket bottom plate, a plate body in the pocket bottom plate is fixed at the bottom of the cage body through a fixing support, and when concrete is poured, the through holes formed in the plate body can enable the concrete to fall smoothly, so that a gap below the pocket bottom plate can be avoided, and the strength of a pile body is ensured; when the steel sleeve is pulled out, even if friction occurs between the steel sleeve and the cage body, the pressure generated by the concrete on the plate body can also effectively prevent the anti-floating steel reinforcement cage from floating upwards.

Description

Anti-floating reinforcement cage and construction method of static pressure immersed tube cast-in-place pile

Technical Field

The invention relates to the technical field of building construction, in particular to an anti-floating reinforcement cage and a construction method of a static pressure immersed tube cast-in-place pile.

Background

The static pressure immersed tube cast-in-place pile is an important infrastructure in the building engineering, has important influence on the stability of a building structure, has various advantages in the construction stage, is simple and convenient to operate, high in mechanization degree, high in speed, short in construction period and low in manufacturing cost, and is widely applied to the building engineering.

When the static pressure immersed tube cast-in-place pile is constructed, the perpendicularity of the pile body is allowed to be not more than 1 percent of error, so that the outer steel sleeve and the inner steel reinforcement cage are not completely vertically downward, and once the steel sleeve or the steel reinforcement cage is dislocated or inclined, the steel sleeve or the steel reinforcement cage is bound to be tightly attached together; on the other hand, the diameter of the steel reinforcement cage is allowed to have tolerance when the steel reinforcement cage is manufactured, so that the steel reinforcement cage can be further tightly attached to the steel sleeve when the diameter of the steel reinforcement cage is above the tolerance. Due to the two reasons, huge extrusion action is likely to be generated between the steel sleeve and the steel reinforcement cage, so that huge friction force is generated, resultant force borne by the steel sleeve is upward during pipe drawing, the steel reinforcement cage hung on the pile shoe is jointly lifted, the steel reinforcement cage floats upwards, an engineering pile is abandoned, pile supplement is needed, cost is greatly increased, and construction period is delayed.

Taking the static pressure immersed tube bored concrete pile footpath and steel sleeve diameter as an example, the external diameter of steel reinforcement cage is 560mm, steel reinforcement cage protective layer thickness is 70mm, and steel sleeve wall thickness is 30mm, therefore the average distance of the steel reinforcement cage outside distance steel sleeve inner wall is 40mm, the preparation tolerance of steel reinforcement cage diameter is 10mm, if preparation steel reinforcement cage diameter is partial to be +10mm, then the average distance of the steel reinforcement cage outside distance steel sleeve inner wall is only 35mm, can further lead to the steel reinforcement cage to hug closely the steel sleeve. According to the statistics of the data of the pile type site construction in the early stage, the pile type floating cage rate is 3% -6%.

Disclosure of Invention

The invention aims to provide an anti-floating reinforcement cage and a construction method of a static pressure immersed tube cast-in-place pile, which can greatly reduce the floating cage rate, save the construction cost and avoid the delay of the construction period.

The technical problem is solved by the following technical scheme:

the utility model provides an anti steel reinforcement cage that floats, includes cage body and pocket bottom plate, the pocket bottom plate includes plate body and fixed bolster, the fixed bolster set up in the bottom of cage body and with this body coupling of cage, the plate body with the fixed bolster is connected, the through-hole has been seted up at the middle part of plate body.

In one embodiment, the cage body comprises a plurality of main ribs and spiral stirrups surrounding the outer sides of the main ribs, the spiral stirrups are welded with the main ribs, and the fixing supports are welded with the main ribs.

In one embodiment, the fixed support comprises two first fixed ribs, each first fixed rib comprises a first cross rod and two first vertical rods, the two first vertical rods are respectively arranged at two ends of the first cross rod, the first cross rod is welded with the surface of the plate body, and the side surfaces of the first vertical rods are welded with the side surfaces of the main ribs.

In one embodiment, the fixed bolster still includes two second fixed muscle, the second fixed muscle includes second horizontal pole and two second montants, two the second montant set up respectively in the both ends of second horizontal pole, the second horizontal pole with the first horizontal pole deviates from one side welding of board body, the side of second montant with the side welding of main muscle.

In one embodiment, the first cross bar is perpendicular to the second cross bar, the through hole is a rectangular hole, the through hole is located above a rectangular region formed by the first cross bar and the second cross bar in a surrounding mode, and the area of the rectangular hole is smaller than that of the rectangular region.

In one embodiment, each of the main bars is welded to at most one of the first vertical bar or one of the second vertical bar.

In one embodiment, the plate body is located inside the cage body.

In one embodiment, the cage body further comprises a plurality of stiffening stirrups, each stiffening stirrup is annular, the stiffening stirrups are welded to the main reinforcement, and the stiffening stirrups surround the outer side of the main reinforcement or are arranged on the inner side of the main reinforcement.

In one embodiment, the edges of the panel body are rounded and spaced from the main ribs.

The invention also provides a construction method of the static pressure immersed tube bored concrete pile, which comprises the following steps:

leveling the field: the construction site is processed, so that the construction site is flat and solid and has certain hardness, and the drilling machine is prevented from sinking in the drilling process;

pile position measurement: measuring and placing the pile position by using a full drilling instrument, and marking the center of the pile position;

the pile driver is in place: the pile driver is accurately positioned, kept horizontal and stable, the central line of a drill guide rod, the central line of a rotary disc and the central line of a sinking pipe are in the same straight line, and the distance between a machine and a pile position is adjusted, so that the sinking pipe freely and vertically sleeves a pile tip;

pile tip positioning and pile pipe burying: measuring and placing the central position of each engineering pile according to the pile position layout drawing, embedding a prefabricated steel plate pile tip into the central position of each pile position, and taking a water sealing measure for the gap between the pile pipe and the steel pile shoe;

static pressure pipe sinking: the verticality deviation when the steel sleeve is inserted is less than 1%;

manufacturing and hoisting a steel reinforcement cage: the bottom end of the cage body of the steel reinforcement cage is provided with the pocket bottom plate, the use is carried out, and the steel reinforcement cage keeps a vertical state when entering a hole, so that the wall of the hole is prevented from being collided;

pouring concrete: pouring concrete in multiple times;

tube drawing: and (5) after the concrete is measured to reach the calculated elevation, pipe drawing is carried out.

The steel cage has the beneficial effects that in order to resist the friction force possibly existing between the steel sleeve and the steel reinforcement cage and avoid the floating cage phenomenon, the bottom of the cage body is provided with the pocket bottom plate, the plate body in the pocket bottom plate is fixed at the bottom of the cage body through the fixing support, and when concrete is poured, the through hole formed in the plate body can enable the concrete to smoothly fall, so that a gap can be avoided below the pocket bottom plate, and the strength of the pile body is ensured. When the steel sleeve is pulled out, the first bucket of concrete (1.5-1.8 m) ³ ) After falling down, a concrete column with the height of about 3.9-4.7 m is formed, the gravity (about 33 kN) of the concrete column acts on a bottom plate of a steel reinforcement cage pocket, vertical downward force can be applied to the steel reinforcement cage, the steel reinforcement cage can be stably placed on a pile shoe during pipe drawing, and even if friction occurs between a steel sleeve and a cage body, the pressure of concrete on the steel reinforcement cage body can effectively prevent the anti-floating steel reinforcement cage from floating upwards; 642 static pressure immersed tube cast-in-place piles are driven in total in the internal test, only 3 floating cages are driven, the floating cage rate is controlled to be 0.47%, the floating cage rate can be greatly reduced, the construction cost is saved, and the construction period delay is avoided.

Drawings

FIG. 1 is a schematic bottom view of an embodiment of an anti-floating reinforcement cage;

FIG. 2 is a schematic view of an embodiment of a mounting bracket;

FIG. 3 is a schematic structural diagram of a first fixing rib according to an embodiment;

FIG. 4 is a side schematic view of a pocket floor according to one embodiment;

FIG. 5 is a schematic structural view of a cage body according to an embodiment;

FIG. 6 is a schematic illustration of an embodiment of a cage body being received within a steel sleeve;

FIG. 7 is a schematic structural view of an embodiment of poured concrete;

fig. 8 is a flow chart of a method of static pressure driven cast-in-place pile construction.

In the figure: 1. a cage body; 11. a main rib; 12. a spiral stirrup; 13. a stiffening stirrup; 2. a pocket bottom plate; 21. a plate body; 22. fixing a bracket; 221. a first fixing rib; 2211. a first cross bar; 2212. a first vertical bar; 222. a second fixing rib; 2221. a second cross bar; 2222. a second vertical bar; 100. a through hole; 3. a first bucket of concrete; 9. a steel sleeve.

Detailed Description

As shown in fig. 1 and 2, the anti-floating reinforcement cage of an embodiment includes a cage body 1 and a pocket bottom plate 2, the pocket bottom plate 2 includes a plate body 21 and a fixing support 22, the fixing support 22 is disposed at the bottom of the cage body 1 and connected with the cage body 1, the plate body 21 is disposed in the cage body 1 and connected with the fixing support 22, and a through hole 100 is opened in the middle of the plate body 21.

Cage body 1's bottom is equipped with pocket bottom plate 2, and the bottom at cage body 1 is fixed through fixed bolster 22 to the edition of books body 21 in pocket bottom plate 2, and during the concreting, the through-hole 100 of seting up on the edition of books body 21 can let the smooth whereabouts of concrete. When the steel sleeve is pulled out, even if friction occurs between the steel sleeve and the cage body 1, the pressure generated by the concrete on the plate body 21 can also effectively prevent the anti-floating steel reinforcement cage from floating upwards. The form of cage body 1 is comparatively special, and it is great directly to stabilize the bottom degree of difficulty of fixing the board body 21 at cage body 1, consequently this implementation at first links together board body 21 and fixed bolster 22 and forms pocket bottom plate 2, and fixed bolster 22 then sets up the form of being connected for with cage body 1, then fixes fixed bolster 22 in the bottom of cage body 1 again, and the construction degree of difficulty is low.

In this embodiment, the plate body 21 is disposed inside the cage body 1, the plate body 21 is welded to the fixing bracket 22, the welding seam is located on the bottom surface of the plate body 21 instead of the top surface, the falling concrete will first contact the plate body 21, no direct impact will be caused to the welding seam, and the welding reliability is high. In addition, since the fixing bracket 22 catches the plate body 21, even if the plate body 21 is loosened, the plate body 21 does not fall out of the cage body 1.

As shown in fig. 1, the cage body 1 includes a plurality of main bars 11 and a spiral stirrup 12 surrounding the main bar 11, the spiral stirrup 12 is welded to the main bar 11, and the fixing bracket 22 is welded to the main bar 11. The spiral stirrups 12 are connected to the main reinforcements 11, so that the cage body 1 can maintain a specific shape. When concreting, pocket bottom plate 2 can produce great pulling force to cage body 1, consequently with the welding of fixed bolster 22 and the great main muscle 11 of tensile strength, avoids cage body 1 to take place obvious deformation.

As shown in fig. 2 and 3, the fixing bracket 22 includes two first fixing ribs 221, each first fixing rib 221 includes a first cross bar 2211 and two first vertical bars 2212, the two first vertical bars 2212 are respectively disposed at two ends of the first cross bar 2211, the first cross bar 2211 is welded to the surface of the plate body 21, and the side surface of the first vertical bar 2212 is welded to the side surface of the main rib 11. The two first cross bars 2211 can provide stable support for the plate body 21 and make the fixing bracket 22 and the plate body 21 firmly combined. The first vertical rod 2212 is provided to weld the side surface of the first vertical rod 2212 to the side surface of the main bar 11, so that the contact area is larger than that of end surface welding, and the welding quality is better.

As shown in fig. 2 and 4, further, the fixing bracket 22 further includes two second fixing ribs 222, each second fixing rib 222 includes a second cross bar 2221 and two second vertical bars 2222, the two second vertical bars 2222 are respectively disposed at two ends of the second cross bar 2221, the second cross bar 2221 and the first cross bar 2211 are welded on one side departing from the board body 21, and the side of each second vertical bar 2222 is welded with the side of the main rib 11. The form of the fixed muscle 222 of second is similar with first fixed muscle 221, and it sets up in one side that first fixed muscle 221 deviates from board body 21, can carry out the bearing to first fixed muscle 221, and second montant 2222 makes more main muscle 11 be connected with fixed bolster 22 through welding with main muscle 11 to the pulling force that receives on making single main muscle 11 reduces, has also improved the stability of pocket bottom plate 2.

In this embodiment, the first cross bar 2211 is perpendicular to the second cross bar 2221, the through hole 100 is a rectangular hole, the through hole 100 is located above a rectangular area formed by the first cross bar 2211 and the second cross bar 2221, and the area of the rectangular hole is smaller than that of the rectangular area. The through hole 100 is formed according to a rectangular area formed by the first cross bar 2211 and the second cross bar 2221 in a surrounding manner, so that the area of the through hole 100 is large, the fixing support 22 does not obstruct concrete falling from the through hole 100, and smooth falling of the concrete is ensured.

With reference to fig. 1 and 4, each main rib 11 is welded to at most one first vertical bar 2212 or one second vertical bar 2222, so as to ensure that each first vertical bar 2212 or second vertical bar 2222 has enough space to be welded to the main rib 11, so that the tension of the pocket bottom plate 2 on the cage body 1 is distributed more uniformly, and the cage body 1 is not easy to deform obviously.

As shown in fig. 4, the cage body 1 of an embodiment further includes a plurality of stiffening stirrups 13, the stiffening stirrups 13 are annular, the stiffening stirrups 13 are welded to the main reinforcement 11, and the stiffening stirrups 13 are disposed inside the main reinforcement 11. The length of cage body 1 is decided according to actual need, to the longer cage body 1 of length, takes place to warp easily when hoist and mount, and stiffening stirrup 13 can strengthen the rigidity of cage body 1, makes anti steel reinforcement cage that floats difficult emergence of warping when hoist and mount. In other embodiments, the stiffening stirrups 13 are wrapped around the outside of the main bars 11.

Further, the distance between two adjacent stiffening stirrups 13 is 2000mm; establish the protective layer cushion on the cage body 1, every 4000mm a set of, 3 are no less than to every group quantity, and should evenly distributed on the main muscle of same cross-section to guarantee the straightness that hangs down of cage body 1.

As shown in fig. 1, the edge of the plate body 21 is circular, and the edge of the plate body 21 is spaced from the main rib 11, so that the concrete can fall off from the through hole 100 and also from the edge of the plate body 21, the concrete can fall off more smoothly, a gap is prevented from being formed below the pocket bottom plate 2, and the strength of the pile body can be ensured.

The diameter of the plate body 21 should be greater than two-thirds of the internal diameter of the stiffening stirrup 13, and the diameter of the plate body 21 should not be too small, because the middle part of the plate body is provided with the through hole 100 with a large area, if the diameter of the plate body 21 is too small, the concrete cannot generate large pressure on the plate body 21 to resist the floating of the anti-floating reinforcement cage.

As shown in fig. 6, in this embodiment, the diameter of the static pressure immersed tube bored concrete pile and the diameter of the steel sleeve 9 are both 700mm, the wall thickness of the steel sleeve 9 is 30mm, the outer diameter of the cage body 1 is 560mm, the thickness of the steel reinforcement cage protective layer is 70mm, the average distance from the outer side of the steel reinforcement cage to the inner wall of the steel sleeve is 40mm, the diameter of the bottom steel plate is 450mm, the size of the through hole 100 is a 150 × 150mm square opening, and the fixing bracket 22 is made of three-grade steel with a diameter of 14 mm. The reinforcement cage is manufactured in sections, the length of each section can be 12.0-18 m, the diameter of the main reinforcement 11 is smaller than 22mm, welding is adopted, the diameter of the main reinforcement 11 is larger than or equal to 22mm, mechanical connection is adopted, the length of a single-side welding seam is not smaller than 10d (the length of the welding seam is larger than 5d during double-side welding); the width of a welding seam is not less than 0.8d, the thickness is not less than 0.3d, the gap between the end faces of the two main ribs is 2-5 mm, the number of joints of the main ribs 11 with the same section is not more than 50% of the total number of the main ribs 11, the adjacent joints are staggered up and down at intervals, and the staggered distance is not less than 35 times the diameter of the main ribs and is not less than 500mm.

As shown in FIG. 7, when the first bucket of concrete 3 (1.5-1.8 m) ³ ) After falling down, a concrete column with the height of about 3.9-4.7 m is formed, the gravity (about 33 kN) of the concrete column acts on a bottom plate of a steel reinforcement cage pocket, vertical downward force can be applied to the steel reinforcement cage, the steel reinforcement cage can be stably placed on a pile shoe during pipe drawing, and the cage floating phenomenon is greatly avoided; in the internal test, 642 static pressure immersed tube cast-in-place piles are driven in total, only 3 floating cages are adopted, the floating cage rate is controlled to be 0.47%, the floating cage rate can be greatly reduced, the construction cost is saved, and the delay of the construction period is avoided.

The invention also provides a construction method of the static pressure immersed tube cast-in-place pile, which comprises the following steps:

s1, leveling a field: because the drilling machine is heavy, the construction site must be flat, solid, stable and spacious, and have certain hardness, avoid the drilling machine to sink in the drilling process, when the site condition is not enough, must adopt to set up the steel sheet, fill out the brick sediment or rubble and set up the guadrafts and so on the assurance measure.

S2, pile position measurement: the pile position is measured and placed by a full drilling instrument, a steel bar is inserted into the center of the pile position, and marks are made around the pile position, so that the pile position is convenient to find, and the pile point can be prevented from being damaged when the machine is shifted. After the product is qualified by rechecking, the next procedure is carried out.

S3, placing the pile machine in place: on the basis that the pile position is checked correctly and the floor elevation is measured, the pile driver can be in place, the pile driver needs to be accurately, horizontally, vertically and stably positioned, and the central line of a guide rod of the drilling machine, the central line of a rotary disc and the central line of a immersed tube are kept in the same straight line. Before the pipe sinking construction, the distance between the machine and the pile position is adjusted, the sinking pipe freely verticality sleeves the pile tip, the verticality is corrected at any time in the pipe sinking process, and the verticality error of the pile pipe is ensured not to exceed 1%.

S4, pile tip positioning and pile pipe embedding: (1) according to a planning control point provided by a design unit, according to a pile position arrangement diagram of a design construction diagram, using a theodolite and measuring and placing main axis positions and filling in a measuring and positioning pay-off record, reporting that the related departments check the construction diagram to be correct, measuring and placing the central position of each engineering pile according to the pile position arrangement diagram, and embedding a prefabricated steel plate pile tip in the central position of each pile position. And taking water sealing measures for the gap between the pile pipe and the steel pile shoe;

(2) the steel sleeves are in butt joint by adopting threads. And operating the pile clamping box to clamp the steel sleeve at the bottom, hoisting the steel sleeve at the upper section into a driving sleeve of the hydraulic gyrator by using a crane, and vertically guiding the steel sleeve into the driving sleeve of the hydraulic gyrator.

S5, static pressure pipe sinking: (1) the pile tip is placed on the pile casing pipe head, and the verticality in two mutually orthogonal directions must be checked by a theodolite. The verticality deviation when the steel sleeve is inserted is less than 1 percent, and the pile can be sunk after the requirement is met.

(2) And (4) sinking the pipe, wherein the pipe cannot be eccentric in the static pressure pipe sinking process, and whether the prefabricated steel plate pile tip is damaged or not and whether the pile pipe deviates or inclines or not are checked at any time, and if the situation exists, the situation is corrected immediately. The pile sinking enters the depth of a bearing stratum required by design, and the static pressure pipe sinking pile machine lifts the frame and meets the requirement of load bearing stability.

(3) The final pressure is not less than 7200KN, the pressure is stabilized for not less than 1 minute when the final pressure reaches the design value, and then the pressure is re-pressed for three times according to the final pressure after the pressure is released and stagnated for 5 to 10 minutes (stress release process). The accumulated settling amount of the steel sleeve pressed for three times is not more than 30mm. The pile tip now enters the bearing layer thickness (6)1 layers no less than 3D. And after the final pressure, the pile length and the re-pressing settlement amount reach the final pressure control standard, pile sinking can be stopped. The pressure gauge and other instruments used for observing the pressure should be regularly checked.

(4) After the hole is formed, the hole diameter, the hole depth and the verticality should be checked and accepted in time, and if the hole is not qualified, the hole should be processed in time. Bored concrete pile diameter is the pore-forming diameter promptly, and stake pore-forming deviation: the pile position axis and the vertical axis direction do not exceed 50mm, and the verticality is less than or equal to 0.5 percent. And detecting the pile core by using a plumb aligner, and checking the eccentric distance of the pile core to determine whether the eccentric proportion meets the standard requirement.

(5) The judgment standard of pore-forming is mainly the bearing force value that the static pressure reaches the design requirement, and the pile length and the depth of the pipe pile entering the bearing layer are assisted.

(6) After the hole forming depth meets the design requirement, the displacement of the drilling machine and the final hole acceptance work are carried out as soon as possible; and (5) checking whether the bottom of the pile hole is filled with mud or water or not, and if so, cleaning.

S6, manufacturing and hoisting of a reinforcement cage: (1) the reinforcement cage is manufactured in sections, the length of each section can be 12.0-18 m, and the openings are connected by welding/machinery. If the site conditions allow, the whole body can be lifted and placed.

(2) Before the reinforcement cage is manufactured, the reinforcement is straightened, and dirt, corrosion and the like on the surface of the reinforcement are removed. The through length of the reinforcement cage of the cast-in-place pile is arranged, the blanking length is accurately controlled during the blanking of the reinforcement, and the designed anchoring length of the vertical reinforcement exposed out of the pile top is ensured.

(3) Any steel bar can be replaced after the consent of the design unit in the construction; strictly, the use of modified steel is prohibited.

(4) Welding rods for welding are reasonably selected according to the material of the parent metal, and E50 type welding rods are adopted; the main rib is connected with less than 22 by adopting welding, the main rib is connected with more than or equal to 22 by adopting machinery, the length of a welding seam of single-side welding is not less than 10d (the length of the welding seam is more than 5d when double-side welding is carried out); the width of the welding seam should not be less than 0.8d, the thickness should not be less than 0.3d, and the gap between the two main rib end faces should be 2-5 mm.

(5) The number of the joints on the same section is not more than 50% of the total number of the main ribs, the adjacent joints are arranged in a vertically staggered mode at intervals, and the staggered distance is not less than 35 times of the diameter of the main ribs and is not less than 500mm.

(6) The connection of the annular stirrups and the main reinforcements is formed by adopting electric arc welding spot welding connection; the spiral stirrup and the main reinforcement are connected by adopting iron wire binding and spot welding for fixing at intervals or spot welding for fixing directly. The reinforcement cage cannot deform during installation.

(7) Protective layer cushion blocks are arranged on the reinforcement cage, one group is arranged at intervals of 4.0m, and each group is not less than 3 blocks and is uniformly distributed on the main reinforcement with the same section.

(8) The binding and embedding directions of the reinforcement cage are consistent with the design direction, and the manufacturing deviation of the reinforcement cage conforms to the following regulations:

main rib spacing +/-10 mm stirrup spacing +/-20 mm

Diameter of steel reinforcement cage +/-10 mm and length of steel reinforcement cage +/-100 mm

(9) When the reinforcing cage is inserted into a hole, the reinforcing cage is always kept in a vertical state, is slowly and lightly released in alignment with the hole position, is kept stable, avoids colliding with the hole wall, immediately finds out the reason once being blocked, and prohibits shaking and forced impact releasing.

And (5) welding hanging ribs on the top end of the reinforcement cage at the R part, wherein the hanging ribs are higher than the steel casing. After the reinforcement cage is in place, the hanging ribs are supported on the sleepers at the top of the pile casing and cannot be directly placed on the pile casing.

S7, pouring concrete: the concrete is commercial concrete. The concrete strength grade of the immersed tube cast-in-place pile is C40, and the impermeability grade is not lower than P8. The concrete mixing proportion is determined according to tests, fly ash portland cement is selected, and ground slag is used as an admixture. The mixing amount of the admixture is determined by tests, and the minimum dosage of the cementing material is more than 300kg/m ³ The maximum chloride ion content (percentage of cement dosage) is required to be not less than 0.1 percent, and the maximum water-gel ratio is not more than 0.45.

Natural river sand or machine-made sand, crushed stone or pebbles with hard texture and good gradation should be selected. Using non-alkali active aggregate, the total content of alkali aggregate should be less than 3kg/m ³ . The mixing water is the drinking water which is specified in the current industry standard of concrete water standard JGJ 63.

Pouring concrete in a grading way, wherein the elevation of the bottom of the pile is required to be 2-3 m above the elevation of the pile for the first time, and the steel pipe is pressed for about 2 minutes; and pouring concrete for the second time to the elevation of the pile top, carrying out static pressure for 5-10 seconds, and then starting pipe drawing.

Pouring concrete into the tubular pile as much as possible, and pouring enough concrete once when a long tubular pile is used for driving a short pile; when long piles are driven, the concrete poured into the pile pipe for the first time is filled as much as possible.

The concrete surface after pouring is above 0.5m at the designed pile top elevation, the filling coefficient is not less than 1.15 and not more than 1.3, when the filling coefficient is less than 1.0, the unit is immediately informed of supervision, land survey, design and construction, and the written contact list is reported to the relevant unit to provide a processing scheme.

S8, tube drawing: when the pipe drawing is started, the pipe drawing can be continued only after the concrete reaches the calculated elevation. The pile pipe is pulled up by 0.2-0.3 m after vibrating for about 30s, and the pile pipe is continuously pulled out while vibrating until the concrete surface monitor displays that the concrete at the pile end begins to spread. When pulling up 1 m, the pulling should be stopped and vibrated for 5-10 seconds, and the downward reverse insertion is carried out for 0.3-0.5 m. Repeating the operation until the tubular pile is completely pulled out. The tube drawing speed should be controlled within 1.5 m/min. When the pipe is pulled out within the range of 5.0 meters below the pile top, the pipe is reversely inserted every 1.0 meter or so. The distance between the soil layer and the soft and weak soil layer or the soft and hard mutual layer is not more than 0.8m/min, so that the accidents of reducing diameter, pile breaking and the like easily caused by too high pipe drawing speed are avoided. And (5) filling soil in the holes after the pipes are pulled out, and washing the pipes with water.

S9, on-site inspection requirement: and before construction, an operator should be trained to establish a detection system. Construction personnel should be arranged on the site, a special person is required to take charge of construction, each process of each pile needs to be checked and accepted, and the check and acceptance record of the hidden project is made.

And field inspection content:

1) Pile position, pile top elevation, verticality and hole diameter measurement of the whole pile body from top to bottom by using a hole measuring device after hole forming.

2) The vertical deviation of the tubular pile is ensured to meet the requirements from two mutually perpendicular directions.

3) The tight connection between the pile tip and the pile casing, the slurry entering the pipe pile and the slurry leakage.

4) The pressure condition of the pipe pile, the actual elevation of the pile tip and the rock entering condition.

5) Strength grade, mixing proportion, slump and maximum particle size of aggregate.

6) When concrete is poured, whether the filling coefficient between the actual field pouring quantity and the design quantity calculated according to the pile diameter and the actual hole forming depth meets the design requirement or not should be checked.

7) Manufacturing a steel reinforcement cage, and inspecting the specification of steel reinforcements, the variety and the specification of welding rods, the length and the quality of welding seams.

8) And (3) under the condition of the steel reinforcement cage, the space between the hole walls of the steel reinforcement cage is required to be checked after the steel reinforcement cage is placed in the hole, and the steel reinforcement cage is ensured to have an enough protective layer. Which side of the reinforcement cage faces the foundation pit needs to be marked during manufacturing, so that the reinforcement cage is placed in the hole in a correct direction.

9) Reserving test blocks (with the same mix proportion, not less than one group in the same team and not less than one group in each pile) and testing the strength. The test block is made according to the standard requirement, and the 'eating of a small stove' is strictly forbidden for counterfeiting.

10 Accident recording and processing and post-processing as-built drawings. The cast-in-place piles allow construction deviation and must meet relevant specification requirements.

And S10, well recording construction in the concrete pouring process.

The method for static-pressure immersed tube cast-in-place pile construction can greatly reduce the floating cage rate, 642 static-pressure immersed tube cast-in-place piles are driven in total in internal tests, only 3 floating cages are driven, the floating cage rate is only 0.47 percent, the construction cost can be saved, and the delay of the construction period is avoided

Those of ordinary skill in the art will understand that: the discussion of any embodiment above is meant to be exemplary only, and is not intended to imply that the scope of the application is limited to these examples; within the context of the present application, features from the above embodiments or from different embodiments may also be combined, steps may be implemented in any order, and there are many other variations of different aspects of one or more embodiments in the present application as described above, which are not provided in detail for the sake of brevity.

It is intended that the one or more embodiments of the present application cover all such alternatives, modifications, and variations as fall within the broad scope of the present application. Therefore, any omissions, modifications, substitutions, improvements, and the like that may be made without departing from the spirit and principles of one or more embodiments of the present application are intended to be included within the scope of the present application.

Claims (10)

1. The utility model provides an anti steel reinforcement cage that floats, its characterized in that includes cage body (1) and pocket bottom plate (2), pocket bottom plate (2) are including the plate body (21) and fixed bolster (22), fixed bolster (22) set up in the bottom of cage body (1) and with cage body (1) are connected, plate body (21) with fixed bolster (22) are connected, through-hole (100) have been seted up at the middle part of plate body (21).

2. The anti-floating reinforcement cage according to claim 1, characterized in that the cage body (1) comprises a plurality of main reinforcements (11) and spiral stirrups (12) surrounding the main reinforcements (11), the spiral stirrups (12) are welded with the main reinforcements (11), and the fixed brackets (22) are welded with the main reinforcements (11).

3. The anti-floating reinforcement cage according to claim 2, wherein the fixing bracket (22) comprises two first fixing ribs (221), the first fixing ribs (221) comprise a first cross bar (2211) and two first vertical bars (2212), the two first vertical bars (2212) are respectively disposed at two ends of the first cross bar (2211), the first cross bar (2211) is welded to the surface of the plate body (21), and the side surface of the first vertical bar (2212) is welded to the side surface of the main rib (11).

4. The anti-floating reinforcement cage according to claim 3, wherein the fixing bracket (22) further comprises two second fixing ribs (222), the second fixing ribs (222) comprise a second cross bar (2221) and two second vertical bars (2222), the two second vertical bars (2222) are respectively disposed at two ends of the second cross bar (2221), the second cross bar (2221) is welded to a side of the first cross bar (2211) facing away from the plate body (21), and a side of the second vertical bar (2222) is welded to a side of the main rib (11).

5. The anti-floating reinforcement cage according to claim 4, wherein the first cross bar (2211) is perpendicular to the second cross bar (2221), and the through hole (100) is a rectangular hole, and the through hole (100) is located above a rectangular area formed by the first cross bar (2211) and the second cross bar (2221) in a surrounding manner, and the area of the rectangular hole is smaller than that of the rectangular area.

6. Anti-floating reinforcement cage according to claim 4, characterized in that each of said main reinforcements (11) is welded to at most one of said first vertical bars (2212) or one of said second vertical bars (2222).

7. Anti-floating reinforcement cage according to claim 2, characterized in that the plate body (21) is located inside the cage body (1).

8. The anti-floating reinforcement cage according to claim 2, characterized in that the cage body (1) further comprises a plurality of stiffening stirrups (13), the stiffening stirrups (13) are annular, the stiffening stirrups (13) are welded to the main reinforcement (11), and the stiffening stirrups (13) surround the outside of the main reinforcement (11) or are arranged inside the main reinforcement (11).

9. An anti-floating reinforcement cage according to claim 8, characterized in that the edges of the plate body (21) are rounded, the edges of the plate body (21) being spaced from the main reinforcement (11).

10. A construction method of a static pressure immersed tube filling pile is characterized by comprising the following steps:

leveling the field: the construction site is processed, so that the construction site is flat and solid and has certain hardness, and the drilling machine is prevented from sinking in the drilling process;

pile position measurement: measuring and placing the pile position by using a full drilling instrument, and marking the center of the pile position;

the pile driver is in place: the pile driver is accurately positioned, kept horizontal and stable, the central line of a drill guide rod, the central line of a rotary disc and the central line of a sinking pipe are in the same straight line, and the distance between a machine and a pile position is adjusted, so that the sinking pipe freely and vertically sleeves a pile tip;

pile tip positioning and pile pipe embedding: measuring and placing the central position of each engineering pile according to the pile position layout drawing, embedding a prefabricated steel plate pile tip into the central position of each pile position, and taking a water sealing measure for the gap between the pile pipe and the steel pile shoe;

static pressure pipe sinking: the verticality deviation when the steel sleeve is inserted is less than 1%;

manufacturing and hoisting a steel reinforcement cage: the bottom end of the cage body of the steel reinforcement cage is provided with a pocket bottom plate which is arranged when the steel reinforcement cage is used, and the steel reinforcement cage is kept in a vertical state when entering a hole, so that the wall of the hole is prevented from being collided;

pouring concrete: pouring concrete in multiple times;

tube drawing: and (5) after the concrete is measured to reach the calculated elevation, pipe drawing is carried out.

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