CN110700247A - Construction method for cast-in-place pile to penetrate through quicksand layer - Google Patents
Construction method for cast-in-place pile to penetrate through quicksand layer Download PDFInfo
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- CN110700247A CN110700247A CN201910925272.5A CN201910925272A CN110700247A CN 110700247 A CN110700247 A CN 110700247A CN 201910925272 A CN201910925272 A CN 201910925272A CN 110700247 A CN110700247 A CN 110700247A
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/22—Piles
- E02D5/34—Concrete or concrete-like piles cast in position ; Apparatus for making same
- E02D5/38—Concrete or concrete-like piles cast in position ; Apparatus for making same making by use of mould-pipes or other moulds
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Abstract
The invention discloses a construction method for a cast-in-place pile to penetrate through a quicksand layer, which comprises the following steps: adopting a full protective cylinder to follow up to form a hole until the full protective cylinder sinks to the bottom surface of a quicksand layer, keeping the position of the full protective cylinder still, and continuously drilling to the bottom end of a pile hole; lifting the full pile casing out of the pile hole; the method comprises the following steps of putting a pipe cage assembly into a pile hole, aligning the bottom end of the pipe cage assembly with the bottom surface of a quicksand layer, and keeping the position unchanged, wherein the pipe cage assembly comprises an inner pipe and a first cage which are coaxially arranged, the first cage is a pipe body with a mesh hole, the first cage is sleeved on the outer side of the inner pipe, and a mortar belt is arranged at the bottom end of the first cage; injecting cement slurry between the outer wall of the inner pipe and the wall of the pile hole, and lifting the inner pipe out of the pile hole after the cement slurry between the outer wall of the inner pipe and the wall of the pile hole is solidified to form a concrete round pipe which is condensed with the quicksand layer into a whole; and installing a second cage body in the pile hole, and pouring concrete to form a pile body. The invention can enable the pile hole to effectively pass through the quicksand layer, and the collapse phenomenon of the pile hole can not be caused.
Description
Technical Field
The invention relates to the field of constructional engineering, in particular to a construction method for a cast-in-place pile to penetrate through a quicksand layer.
Background
The cast-in-situ bored pile is used as the pile foundation for building engineering, highway, railway and bridge engineering and includes the main steps of mechanical or artificial hole forming, hole cleaning, reinforcing cage installation, concrete pouring and other construction processes. The cast-in-place pile comprises an end bearing pile and a friction pile, and in the drilling process, no matter the drill is a percussion drill or a rotary drill, if a thick sand flowing layer is met in the hole forming process and the concrete pouring process, the defects of hole collapse or pile body can be caused, such as the defects of segregation of a honeycomb of the pile body, sand inclusion and pitted surface. Although the full pile casing is adopted for hole forming operation, unqualified pile detection or broken pile detection still occurs, and the engineering quality is seriously influenced.
Disclosure of Invention
In order to solve the problems, the invention provides a construction method for a cast-in-place pile to penetrate through a quicksand layer, which comprises the following steps:
s1, adopting the full pile casing to follow up to form a hole until the full pile casing sinks to the bottom surface of the quicksand layer, keeping the position of the full pile casing still, and continuously drilling to the bottom end of the pile hole;
s2, lifting the full pile casing out of the pile hole;
s3, the pipe cage assembly is lowered into the pile hole, so that the bottom end of the pipe cage assembly is aligned with the bottom surface of the quicksand layer and keeps the position unchanged,
the pipe cage assembly comprises an inner pipe and a first cage which are coaxially arranged, the first cage is a pipe body with meshes, the first cage is sleeved outside the inner pipe, the lower end of the first cage is aligned with the lower end of the inner pipe, a release agent is arranged on the outer wall of the inner pipe, a mortar belt is arranged at the bottom end of the first cage, the mortar belt is annular, and the radial width of the mortar belt is equal to the difference between the outer diameter of the inner pipe and the inner diameter of a pile hole;
s4, injecting cement slurry between the outer wall of the inner pipe and the wall of the pile hole until the cement slurry fills the gap between the inner pipe and the pile hole;
s5, after cement paste between the outer wall of the inner pipe and the wall of the pile hole is solidified to form a concrete circular pipe which is condensed with the quicksand layer into a whole, lifting the inner pipe out of the pile hole;
s6, mounting a second cage in the pile hole, wherein the second cage is a pipe body with meshes;
and S7, pouring concrete to form the pile body.
Preferably, the release agent is a hydrophobic release agent.
Preferably, the mortar belt is a mortar belt added with an accelerator.
Preferably, the gravel is filled between the inner tube and the first cage.
Preferably, the outer diameter of the inner tube is at least 7cm smaller than the pile diameter, and the outer diameter of the first cage is 5cm to 6cm larger than the outer diameter of the inner tube.
Preferably, the cement slurry is doped with an accelerator.
Preferably, in step S4, the grouting pipe is first lowered to the bottom between the outer wall of the inner pipe and the pile hole wall, and the grouting pipe is lifted while grouting.
Preferably, the first cage body and the second cage body are reinforcement cages.
Preferably, the mesh of the first cage is no more than 10mm X10 mm.
Preferably, a plurality of fixing holes are circumferentially provided at the upper end of the inner tube, and the first cage is fixed to the inner tube by fixing ropes passing through the fixing holes and the first cage.
The invention adopts the technical scheme that the steel reinforcement cage is sleeved outside the inner pipe, and the grouting is carried out between the inner pipe and the pile hole, so that the concrete circular pipe for isolating the quicksand layer is quickly formed, and the cement paste and the quicksand are solidified and combined into a whole, so that the pile hole can effectively pass through the quicksand layer, the collapse phenomenon of the pile hole can not be caused, and the excellent quality of the pile body can be ensured.
Drawings
The above features and technical advantages of the present invention will become more apparent and readily appreciated from the following description of the embodiments thereof taken in conjunction with the accompanying drawings.
FIG. 1 is a schematic diagram of a full casing hole forming process illustrating an embodiment of the present invention;
FIG. 2 is a schematic diagram of a tube cage assembly that represents an embodiment of the present invention;
FIG. 3 is a schematic diagram showing a first cage according to an embodiment of the present invention;
FIG. 4 is a schematic illustration of a tube cage assembly being lowered into a pile bore according to an embodiment of the invention;
FIG. 5 is a schematic view showing the setting of cement paste into concrete pipe according to an embodiment of the present invention;
FIG. 6 is a geological stratification diagram illustrating pile holes according to an embodiment of the present invention;
FIG. 7 is a schematic diagram showing the lowering of a second cage in accordance with an embodiment of the present invention;
FIG. 8 is a schematic view of an embodiment of the invention showing cast concrete forming a pile body;
fig. 9 is a step diagram illustrating a construction method of a cast-in-place pile for crossing a quicksand layer according to an embodiment of the present invention.
Detailed Description
An embodiment of a construction method of a cast-in-place pile for crossing a quicksand layer according to the present invention will be described with reference to the accompanying drawings. Those of ordinary skill in the art will recognize that the described embodiments can be modified in various different ways, or combinations thereof, without departing from the spirit and scope of the present invention. Accordingly, the drawings and description are illustrative in nature and not intended to limit the scope of the claims. Furthermore, in the present description, the drawings are not to scale and like reference numerals refer to like parts.
As shown in fig. 9, the construction method of the cast-in-place pile for crossing the quicksand layer includes the following steps:
and S1, as shown in figure 1, adopting a way that the full casing 4 is drilled along with the hole until the full casing 4 sinks to the top surface of the bedrock, keeping the position of the full casing 4 still, and continuously drilling to the bottom end of the pile hole. The following of the full casing 4 means that the full casing 4 is sunk into a bit when the bit is drilled in the drilling process. Of course, the full casing may also be sunk into the bedrock layer as required, and the embodiment is not limited herein.
And S2, lifting the full casing 4 out of the pile hole 100.
And S3, lowering the tube cage assembly 56 into the pile hole, wherein the tube cage assembly 56 comprises the inner tube 6 and the first cage 5 which are coaxially arranged, as shown in figures 2 and 3. The first cage body 5 is a pipe body with meshes, and a plurality of meshes are distributed on the wall of the pipe body. The inner pipe 6 can be made of steel pipe, plastic pipe, etc. The first cage body 5 is sleeved on the outer side of the inner pipe 6, the lower end of the first cage body 5 is aligned with the lower end of the inner pipe 6, and a release agent, preferably a hydrophobic release agent, is coated on the outer wall of the inner pipe 6. And a mortar belt 7 is smeared at the bottom end of the first cage body 5, is in a circular ring shape, and has the radial width equal to the difference between the outer diameter of the inner pipe and the inner diameter of the pile hole so as to seal the bottom of an annular space between the outer wall of the inner pipe 6 of the quicksand layer section and the inner wall of the pile hole. Among them, an epoxy mortar belt is preferable, and the mortar belt is made of quick setting mortar. As shown in fig. 4, tube cage assembly 56 is lowered until its bottom end is aligned with the bottom surface of the quicksand layer and held in place. The inner pipe 6 is at least 7cm smaller than the pile diameter, and the outer diameter of the first cage body 5 is 5-6 cm larger than the outer diameter of the inner pipe 6. Preferably, the gravel is filled between the inner tube and the first cage.
S4, inserting a grouting pipe between the outer wall of the inner pipe 6 and the hole wall for injecting cement paste, wherein the cement paste is doped with an accelerating agent, the grouting pipe is firstly put into the bottom between the outer wall of the inner pipe 6 and the hole wall, the grouting pipe is lifted up while grouting, under a larger grouting pressure, the cement paste extrudes wall protection mud from the pores of quicksand (in the process of forming the hole in the pile hole, the wall protection mud is usually arranged for preventing the hole wall from collapsing), the cement paste permeates into the quicksand layer, and the grouting pressure prevents the quicksand from flowing until the cement paste fills the gaps between the inner pipe 5 and the pile hole 100. As the cement slurry gradually sets, the flow of the quicksand diminishes until it stops.
S5, as shown in figure 5, after cement paste between the outer wall of the inner pipe 6 and the hole wall is solidified, a concrete round pipe 200 which is condensed with a quicksand layer into a whole is formed, the inner pipe can be lifted out of the hole, and the inner pipe and the first cage body 5 can be loosened and separated by rotating the inner pipe 6;
s6, installing a second cage in the hole;
and S7, pouring concrete to form the pile body after hole cleaning.
Wherein, the first cage body is a steel wire with a thin diameter which is not more than 3mm, so as to be beneficial to the extrusion deformation of the first cage body and the mixing of the quicksand and the cement paste into a whole. The second cage body is a reinforcement cage for pouring the conventional cast-in-place pile, and the diameter of the reinforcement of the second cage body needs to meet the design requirement of the cast-in-place pile.
The method is illustrated below by a specific engineering example. FIG. 1 is a geological structure diagram of a certain coastal bridge cast-in-situ bored pile containing a quicksand layer. As shown in fig. 6, the depth of the pile hole of the cast-in-place pile is 50m, and the pile hole comprises a silt layer 1, a quicksand layer 2 and a foundation layer 3 from top to bottom, wherein the thickness of the silt layer 1 is 5 m. The layer thickness of the quicksand layer 2 was 35m and the layer thickness of the bedrock layer 3 was 10 m. Designed as an end-bearing pile.
FIG. 1 is a schematic diagram of a hole formed by punching, grabbing and drilling a full casing, wherein the designed pile diameter is 3m, the outer diameter of the full casing is 3m, the wall thickness is 150mm, and the full casing 4 follows up to the top surface of a bedrock 40m below the ground.
FIG. 3 shows a first cage 5 with a diameter of 2.95m, with a wire diameter of 3mm, a mesh of 10mm by 10mm, a cage length of 40m, and the joints of the wires of the first cage being welded.
Fig. 2 is a schematic diagram of the first cage body sleeved on the inner tube, the outer diameter of the inner tube 6 is 2.9m, and the wall thickness is 8 mm. Before the first cage body 5 is installed, a hydrophobic release agent is coated on the outer wall of the inner pipe, the first cage body 5 is sleeved on the outer side of the inner pipe 6, and the first cage body 5 is aligned with the lower end of the inner pipe 6. And (3) smearing quick-setting organic mortar smearing belt at the lower end of the first cage body 5, wherein the thickness of the quick-setting organic mortar smearing belt can reach the bottom end of an annular space between the outer wall of the closed inner pipe and the inner wall of the pile hole. The height of the mortar smearing belt is about 5 cm. Preferably, in order to prevent the first cage 5 from slipping off, a plurality of fixing holes 51 are circumferentially provided at the upper end of the inner tube 6, and the first cage 5 is more firmly fixed to the inner tube 6 by fixing strings 52 passing through the fixing holes 51 and the first cage 5. Wherein the fixing rope may be a metal wire.
The tube cage assembly 56 is hoisted into the pile hole by a crane and centered, as shown in fig. 4. Fig. 5 shows a concrete cylinder 200 formed by grouting into the space between the inner pipe 6 and the pile hole wall. And (3) uniformly arranging 6 grouting pipes with the diameter of 20mm along the periphery of the inner pipe wall, inserting the grouting pipes into the bottom of the first cage body, beginning to inject cement slurry, wherein the grouting pressure is 2MPa, and slowly lifting the grouting pipes while grouting until the cement slurry rises to the top end of the pile hole. The initial setting of the cement paste is started after 5 minutes, the final setting is started after 10 minutes, the designed strength of the cement paste is 40MPa, and finally, a concrete cylinder of a steel wire concrete structure integrated with the quicksand on the wall of the pile hole is formed. The inner pipe 6 is rotated to loosen the lower end of the inner pipe from the first cage body, and the inner pipe 6 is pulled out of the pile hole.
As shown in fig. 7 and 8, the second cage 300 is lowered, and concrete 500 is poured into the pile hole, thereby completing the construction of the cast-in-place pile body.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A construction method for a cast-in-place pile to penetrate through a quicksand layer is characterized by comprising the following steps:
s1, adopting the full pile casing to follow up to form a hole until the full pile casing sinks to the bottom surface of the quicksand layer, keeping the position of the full pile casing still, and continuously drilling to the bottom end of the pile hole;
s2, lifting the full pile casing out of the pile hole;
s3, the pipe cage assembly is lowered into the pile hole, so that the bottom end of the pipe cage assembly is aligned with the bottom surface of the quicksand layer and keeps the position unchanged,
the pipe cage assembly comprises an inner pipe and a first cage which are coaxially arranged, the first cage is a pipe body with meshes, the first cage is sleeved outside the inner pipe, the lower end of the first cage is aligned with the lower end of the inner pipe, a release agent is arranged on the outer wall of the inner pipe, a mortar belt is arranged at the bottom end of the first cage, the mortar belt is annular, and the radial width of the mortar belt is equal to the difference between the outer diameter of the inner pipe and the inner diameter of a pile hole;
s4, injecting cement slurry between the outer wall of the inner pipe and the wall of the pile hole until the cement slurry fills the gap between the inner pipe and the pile hole;
s5, after cement paste between the outer wall of the inner pipe and the wall of the pile hole is solidified to form a concrete circular pipe which is condensed with the quicksand layer into a whole, lifting the inner pipe out of the pile hole;
s6, mounting a second cage in the pile hole, wherein the second cage is a pipe body with meshes;
and S7, pouring concrete to form the pile body.
2. The method for constructing the cast-in-place pile to penetrate through the quicksand layer as claimed in claim 1, wherein the release agent is a hydrophobic release agent.
3. The method for constructing a cast-in-place pile through a quicksand layer as claimed in claim 1, wherein the mortar belt is a mortar belt added with an accelerator.
4. The method of constructing a bored pile through a quicksand layer according to claim 1,
macadam is filled between the inner pipe and the first cage body.
5. The method of constructing a bored pile through a quicksand layer according to claim 1,
the outer diameter of the inner pipe is at least 7cm smaller than the pile diameter, and the outer diameter of the first cage is 5cm to 6cm larger than the outer diameter of the inner pipe.
6. The method of constructing a bored pile through a quicksand layer according to claim 1,
the cement slurry is doped with an accelerator.
7. The method of constructing a bored pile through a quicksand layer according to claim 1,
in step S4, the grouting pipe is first lowered to the bottom between the outer wall of the inner pipe and the pile hole wall, and the grouting pipe is lifted while grouting.
8. The method of constructing a bored pile through a quicksand layer according to claim 1,
the first cage body and the second cage body are steel reinforcement cages.
9. The method of constructing a bored pile through a quicksand layer according to claim 8,
the meshes of the first cage body are not more than 10mm X10 mm.
10. The method of constructing a bored pile through a quicksand layer according to claim 1,
a plurality of fixing holes are circumferentially formed in the upper end of the inner pipe, and the first cage body is fixed to the inner pipe through fixing ropes penetrating through the fixing holes and the first cage body.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910925272.5A CN110700247A (en) | 2019-09-27 | 2019-09-27 | Construction method for cast-in-place pile to penetrate through quicksand layer |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910925272.5A CN110700247A (en) | 2019-09-27 | 2019-09-27 | Construction method for cast-in-place pile to penetrate through quicksand layer |
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| CN110700247A true CN110700247A (en) | 2020-01-17 |
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57142035U (en) * | 1981-02-25 | 1982-09-06 | ||
| JPS63284317A (en) * | 1987-05-18 | 1988-11-21 | Mitani Sekisan Kk | Execution of cast-in-place pile |
| CN201473955U (en) * | 2009-06-19 | 2010-05-19 | 中建三局第一建设工程有限责任公司 | Manual hole pile digging device in shifting sand layers |
| CN201574396U (en) * | 2009-11-25 | 2010-09-08 | 甘肃省电力设计院 | Retaining wall device for excavated foundations |
| CN105297757A (en) * | 2015-10-21 | 2016-02-03 | 中铁港航局集团有限公司 | Construction method for quicksand layer pile foundation |
| CN107794919A (en) * | 2017-08-17 | 2018-03-13 | 中铁隧道局集团有限公司 | The method that protective layer is set at the hole wall in major diameter rotary digging hole |
| CN108560545A (en) * | 2018-05-24 | 2018-09-21 | 中国建筑第八工程局有限公司 | The construction method of the anti-collapse hole of rotary digging stake and anti-collapse aperture apparatus |
-
2019
- 2019-09-27 CN CN201910925272.5A patent/CN110700247A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57142035U (en) * | 1981-02-25 | 1982-09-06 | ||
| JPS63284317A (en) * | 1987-05-18 | 1988-11-21 | Mitani Sekisan Kk | Execution of cast-in-place pile |
| CN201473955U (en) * | 2009-06-19 | 2010-05-19 | 中建三局第一建设工程有限责任公司 | Manual hole pile digging device in shifting sand layers |
| CN201574396U (en) * | 2009-11-25 | 2010-09-08 | 甘肃省电力设计院 | Retaining wall device for excavated foundations |
| CN105297757A (en) * | 2015-10-21 | 2016-02-03 | 中铁港航局集团有限公司 | Construction method for quicksand layer pile foundation |
| CN107794919A (en) * | 2017-08-17 | 2018-03-13 | 中铁隧道局集团有限公司 | The method that protective layer is set at the hole wall in major diameter rotary digging hole |
| CN108560545A (en) * | 2018-05-24 | 2018-09-21 | 中国建筑第八工程局有限公司 | The construction method of the anti-collapse hole of rotary digging stake and anti-collapse aperture apparatus |
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