CN219825226U

CN219825226U - Prestressed precast pile for foundation pit enclosure

Info

Publication number: CN219825226U
Application number: CN202321073470.1U
Authority: CN
Inventors: 周玉石
Original assignee: Zhongcheng Yanke Shanghai Geotechnical Technology Co ltd
Current assignee: Zhongcheng Yanke Shanghai Geotechnical Technology Co ltd
Priority date: 2023-05-06
Filing date: 2023-05-06
Publication date: 2023-10-13
Anticipated expiration: 2033-05-06

Abstract

The utility model discloses a prestressed precast pile for foundation pit enclosure, which relates to the field of pile foundation construction technology. The utility model has the effect of counteracting the soil pressure by applying the prestress on the pile body, can effectively reduce the deformation of the pile body and ensures the processing quality.

Description

Prestressed precast pile for foundation pit enclosure

Technical Field

The utility model relates to the field of pile foundation construction technology, in particular to a prestressed precast pile for foundation pit support.

Background

The foundation pit enclosure is a reinforcement method for developing and utilizing underground space, constructing various underground buildings such as multi-layer basements, underground railways, underground commercial streets and the like. The foundation pit guard piles are pile foundation structures which are pre-buried around the foundation pit to be excavated and used for reinforcing soil around the foundation pit.

Referring to fig. 1, after the excavation of the foundation pit 1 is completed, the foundation pit guard pile 2 is mainly subjected to extrusion force on one side of the soil body 3, so that the foundation pit guard pile 2 is easy to bend and deform; and bending deformation of the foundation pit guard piles 2 can cause sinking of soil bodies 3 around the foundation pit 1, press structures such as embedded pipelines in the soil bodies 3 and the like, and influence construction quality.

In pile foundation construction, the strength of the pile structure can be enhanced by adopting a mode of arranging two foundation pit guard piles in part of construction, so that deformation of foundation pit guard piles in the foundation pit excavation process is reduced, the influence on construction is reduced, but the construction quantity is increased by adopting the construction mode, and the construction period is prolonged.

In view of the above related art, the inventor designs a prestressed precast pile for foundation pit enclosure.

Disclosure of Invention

In order to improve the supporting effect of the foundation pit enclosure pile, the utility model provides the prestressed precast pile for the foundation pit enclosure, which has the effect of counteracting the soil pressure by applying the prestressing force on the pile body, so that the deformation of the pile body is reduced, and the processing quality is ensured.

The utility model provides a prestressed precast pile for foundation pit support, which adopts the following technical scheme:

the prestress precast pile for the foundation pit support comprises a pile body, wherein a pre-tensioning through hole is formed in the pile body in a penetrating mode along the length direction, a pre-pulling rope is arranged in the pre-tensioning through hole in a penetrating mode, and end fixing pieces for fixing the end portions of the pre-pulling rope and the opposite positions of the pile body are arranged at the two ends of the pile body.

By adopting the technical scheme, after the precast pile is driven into the soil around the foundation pit, pretension force is applied to the pretension rope, and the two ends of the pretension rope are fixed through the end fixing pieces to keep pretension force. When the pile body of the precast pile is pressed by the soil body, the pile body is bent, drawing force is generated on the pretension ropes with the two ends fixed with the pile body, the pretension ropes with the pretension force applied in advance can counteract the drawing force through the pretension force under the condition that the pile body does not deform, and then the pressing force of the soil body is counteracted under the condition that the pile body does not deform, so that the purpose of preventing the deformation of the pile body is achieved, and the construction quality is improved.

Optionally, the pre-tensioning through hole is in clearance fit with the pre-tensioning rope; and a grouting hole is also preset in the pile body, the bottom of the grouting hole is communicated with the bottom of the pre-tensioning through hole, and the upper end of the grouting hole penetrates through the top of the pile body.

Through adopting above-mentioned technical scheme, prestretch the through-hole and prestretch rope clearance fit, the wearing of conveniently prestretching the rope is established, reduces simultaneously and prestretches the extra resistance of stay cord when drawing. In order to ensure the strength of the pile body, the gap is required to be filled with high-strength slurry after construction is finished, and as the pile body is vertically inserted into the soil body, the high-strength slurry is directly poured into the gap between the pre-tensioning through hole and the pre-tensioning rope, so that the compactness can be difficult to ensure.

Optionally, the end fixing piece comprises a tensioning end anchor arranged at the top of the pile body, and a grouting communication hole communicated with the pre-tensioning through hole is formed in an anchor backing plate of the tensioning end anchor.

By adopting the technical scheme, the tension end anchorage comprises four parts of the clamping piece, the anchor ring, the anchor backing plate and the spiral rib, the clamping piece is a key component of an anchoring system, the clamping piece is in a two-piece type and is made of high-quality alloy steel, the tension end anchorage does not influence the drawing of the pretension rope, but can limit the rollback of the pretension rope, and is suitable for fixing the end part of the pretension rope. And the grouting communication holes arranged on the anchor backing plate of the tension end anchor device can be directly used as exhaust holes and overflow holes, high-strength slurry is poured from the grouting holes, and when the slurry emerges from the grouting communication holes, the grouting holes and the pre-tensioning through holes are indicated to be filled.

Optionally, the pile further comprises a pointed pile head and an enlarged shell; a first communication hole and a second communication hole are formed in the pointed pile head corresponding to the pre-tensioning through hole and the grouting hole, and a third communication hole communicated with the first communication hole and the second communication hole is formed in the conical side surface of the pointed pile head; the conical head of the pointed pile head is coated with an expansion shell, the expansion shell is a metal shell with good ductility, the expansion shell coats the third communication hole inside, and the edge of the expansion shell is fixed with the pointed pile head.

Through adopting above-mentioned technical scheme, set up in the tip pile head and communicate grout hole and pretension first communication hole, second communication hole and third communication hole of through-hole, when filling high strength thick liquids, utilize the high strength thick liquids of certain pressure, prop open the expansion shell of tip pile head week side, form the expansion head in the bottom of stake, promote the bearing capacity of stake bottom. Construction of precast pile, need install the pointed end pile head at the pile shaft lower extreme to reduce pile resistance, but the setting of pointed end pile head can weaken precast pile bottom's bearing capacity, through setting up the pointed end pile head that takes the enlarged casing, can install the formation enlarged head in place in precast pile bottom of stake, promotes precast pile bottom's bearing capacity.

Optionally, the pile body comprises a steel pipe and a concrete core arranged in the steel pipe, and an inserting cavity formed by unfilled concrete core is reserved at the lower end of the steel pipe; the pointed pile head is close to one end of the pile body and is provided with a plug-in portion, the edge of the expansion shell is coated on the side wall of the plug-in portion, and the plug-in portion of the expansion shell is coated to be in plug-in fit with the plug-in cavity.

Through adopting above-mentioned technical scheme, reserve the grafting chamber in the pile body bottom, set up grafting portion on the tip pile head, made things convenient for the combination of pile body and tip pile head, the grafting portion on the steel pipe cooperation tip pile head can carry out the centre gripping to the border of enlarged shell fixed simultaneously, has saved carrying out special fixed to enlarged shell border.

Optionally, the end fixing piece comprises stretching end anchors arranged at two ends of the pile body, and grouting communication holes communicated with the pre-stretching through holes are formed in anchor backing plates of the stretching end anchors.

By adopting the technical scheme, the two ends of the pre-pulling rope are fixed through the stretching end anchors, so that the material is convenient to use and the process is mature.

Optionally, the pre-stretching through hole is arranged at one side of the pile body close to the foundation pit.

By adopting the technical scheme, the effect of the pretensioning piece in the pretensioning through hole on resisting the deformation of the pile body is enhanced. When the pile body is subjected to the trend of deformation of the soil pressure, the deformation trend of one side of the pile body, which is close to the foundation pit, is the largest, the action of the drawing force applied by the pre-tensioning rope is more sensitive, and the pre-tensioning rope can better offset the pressure applied by the pile body, so that the pile body is better prevented from deformation or the deformation of the pile body is better reduced.

Optionally, the pile body is a square pile.

Through adopting above-mentioned technical scheme, when square pile used as foundation ditch fender pile, have clear axial direction, the atress direction is clear and easy to distinguish, can be comparatively accurate with the rope setting of stretching in the pile body in be close to one side of foundation ditch, help fully exert the utility of stay cord in advance.

Optionally, the pre-stretching through hole is formed by pre-burying a PVC pipe penetrating through the whole pile body in the pile body.

Through adopting above-mentioned technical scheme, when pouring the steel pipe concrete pile, pre-buried tubular product forms the through-hole structure fast.

In summary, the present utility model includes at least one of the following beneficial technical effects:

1. according to the pre-stressed precast pile for the foundation pit, disclosed by the utility model, the pre-stretching force is applied to the pre-stretching rope which is arranged in the pile body, and the pre-stretching force of the pre-stretching rope is utilized to offset the lateral pressure applied to the pile body, so that the deformation of the pile body can be effectively prevented;

2. the pre-tensioning through holes and the grouting holes are formed by colleagues, so that grouting filling of the pre-tensioning through holes is facilitated, and the compactness of the pile body structure is guaranteed;

3. through set up first communication hole, second intercommunicating pore and third intercommunicating pore in the tip pile head to wrap up the enlarged casing outside the tip pile head, can utilize the pressure that grout was filled to prop up the enlarged casing and open and form the enlarged head that is bigger with soil body area of contact, promote the bearing capacity of fender post.

Drawings

FIG. 1 is a schematic diagram of a foundation pit fender pile stress in the related art;

FIG. 2 is a schematic overall structure of embodiment 1 of the present utility model;

FIG. 3 is a schematic overall structure of embodiment 2 of the present utility model;

FIG. 4 is an enlarged schematic view of area A of FIG. 3;

fig. 5 is a schematic view showing an expanded state of the enlarged case according to embodiment 2 of the present utility model.

Description of the drawings: 1. a foundation pit; 2. foundation pit guard piles; 3. soil mass; 4. pile body; 41. a steel pipe; 411. a plug cavity; 42. a concrete core; 421. prestretching the through hole; 422. grouting holes; 43. a concrete surface layer; 5. a PVC pipe; 6. grouting pipes; 61. a communicating branch pipe; 7. pre-pulling the rope; 71. a limiting plate; 8. stretching an end anchor; 9. a pointed pile head; 91. a first communication hole; 92. a second communication hole; 93. a third communication hole; 94. a plug-in part; 10. enlarging the shell; 11. a multi-way pipe.

Detailed Description

The embodiment of the utility model discloses a prestressed precast pile for foundation pit support.

Example 1:

referring to fig. 2, a pre-stressed precast pile for a foundation pit enclosure comprises a pile body 4 and pre-tensioned ropes 7. The pile body 4 is a steel pipe 41 concrete precast pile and comprises a steel pipe 41, a concrete core 42 cast in the steel pipe 41 and a concrete surface layer 43 cast on the outer side of the steel pipe 41; the pile body 4 is a square pile.

The concrete core 42 is embedded with a PVC pipe 5 penetrating through the whole steel pipe 41 and a grouting pipe 6 made of metal, and two pore canals of a pre-stretching through hole 421 and a grouting hole 422 are respectively formed in the concrete core 42; the PVC pipe 5 is arranged offset from the center of the concrete core 42, and when piling, the pile body 4 is rotated to enable the PVC pipe 5 to be close to the foundation pit side; one side of the grouting pipe 6, which is close to the lower end of the pile body 4, is closed, the grouting pipe 6, which is close to the lower end of the pile body 4, is provided with a communication branch pipe 61 in an extending mode on the side wall, and the communication branch pipe 61 penetrates into the PVC pipe 5 to communicate the lower ends of the PVC pipe 5 and the grouting pipe 6.

The pre-pulling rope 7 is penetrated in the PVC pipe 5, and the diameter of the pipe hole of the PVC pipe 5 is larger than that of the pre-pulling rope 7 so as to facilitate the penetration and drawing of the pre-pulling rope 7; one end of the pre-pulling rope 7 close to the bottom of the pile body 4 is welded and fixed with a rectangular limiting plate 71, and the limiting plate 71 is clamped at the bottom end of the concrete core 42; the limiting plate 71 may be embedded in the concrete core 42 in advance, or may be fixed to the end of the pretensioning rope 7 when the pretensioning rope 7 is threaded on site.

The upper end of the pre-pulling rope 7 is fixed with the upper end of the pile body 4 by installing a tensioning end anchorage 8; the anchor backing plate of the stretching end anchor device 8 is provided with a grouting opening which is used as a grouting communication hole for communicating the pre-stretching through hole 421; the anchor pad and the helical rib portion of the tension end anchor 8 are first poured into the concrete core 42 of the pile body 4.

The implementation principle of the embodiment 1 is as follows: after the pile body 4 is driven into the soil surrounding the foundation pit, pretension force is applied to the pretension rope 7, and both ends of the pretension rope 7 are fixed through the limiting plates 71 and the tensioning end anchors 8 to maintain the pretension force. When a foundation pit is excavated, the pile body 4 of the precast pile is pressed by soil, a trend of forcing the pile body 4 to bend is generated, the trend of bending the pile body 4 generates drawing force on the pre-pulling rope 7 with the two ends fixed with the pile body 4, the pre-pulling rope 7 with the pre-pulling force is pre-applied, the drawing force can be counteracted by the pre-pulling force under the condition that the pile body 4 does not deform, the pressing force of the soil is counteracted under the condition that the pile body 4 does not deform, the purpose of preventing the pile body 4 from deforming is achieved, and the construction quality is improved.

Example 2:

referring to fig. 3, this embodiment differs from embodiment 1 in that: the pile further comprises a pointed pile head 9 coated with an enlarged shell 10; the lower end of the pre-pulling rope 7 is also fixed by a tensioning end anchorage device 8 with a grouting communication hole; the PVC pipe 5 is not directly connected to the grouting pipe 6.

Referring to fig. 3 and 4, a section of the lower end of the steel pipe 41 is filled with a concrete core 42 to form a socket 411.

The whole pointed pile head 9 is formed by concrete pouring, the main body is in a quadrangular pyramid shape, and one side of the pointed pile head 9, which is close to the pile body 4, is integrally provided with a cuboid-shaped plug-in part 94 formed by concrete pouring; the multi-way pipeline 11 is pre-buried in the pointed pile head 9, a first communication hole 91 communicated with the pre-stretching through hole 421, a second communication hole 92 communicated with the grouting pipe 6 and a third communication hole 93 penetrating through the conical surface side wall of the pointed pile head 9 are formed in the pointed pile head 9, and the first communication hole 91 and the second communication hole 92 are communicated with the third communication hole 93; the first communication hole 91 corresponds to a slurry communication hole on the tensioning end anchor 8 at the lower end of the pile body 4. The enlarged casing 10 is a metal casing with better ductility, and the enlarged casing 10 is coated on the whole rectangular pyramid main body of the pointed pile head 9 and the side wall of the inserting part 94; the plug-in part 94 coated with the expansion shell 10 is in plug-in fit with the plug-in cavity 411 at the lower end of the steel tube 41.

The embodiment of example 2 is: before piling, penetrating the pre-pulling rope 7 into the pre-pulling through hole 421, and installing anchor rings and clamping pieces of the stretching end anchor 8 at two ends of the pre-pulling rope 7 to fix the end part of the pre-pulling rope 7; the pointed pile head 9 and the pile body 4 coated with the enlarged casing 10 are assembled again, and the inserting part 94 is inserted into the inserting cavity 411 and Kong Yukong correspondingly. The pile body 4 and the pinnacle rotary structure drawing pin are nailed into the soil body, and the upper end of the pre-pulling rope 7 is pulled by a hollow jack; after the pile body is driven into the ground, high-strength slurry, such as epoxy resin slurry, is poured through the grouting pipe 6, when the slurry overflows from the slurry communication hole of the tensioning end anchor 8 at the upper end of the pile body 4, the slurry communication hole is plugged by using a plug, grouting pressure is increased step by 1-40 mpa, the grouting is continued, 1-5T high-strength slurry is poured, and the enlarged casing 10 is propped open with reference to FIG. 5.

The above embodiments are not intended to limit the scope of the present utility model, so: all equivalent changes in structure, shape and principle of the utility model should be covered in the scope of protection of the utility model.

Claims

1. The utility model provides a prestressing force precast pile for foundation ditch enclosure, includes pile body (4), its characterized in that: a pre-pulling rope (7) is arranged in the pre-pulling through hole (421), and end fixing pieces for fixing the end parts of the pre-pulling rope (7) and the opposite positions of the pile body (4) are arranged at two ends of the pile body (4); the pre-tensioning through hole (421) is in clearance fit with the pre-tensioning rope (7); grouting holes (422) are further preset in the pile body (4), the bottoms of the grouting holes (422) are communicated with the bottoms of the pre-tensioning through holes (421), and the upper ends of the grouting holes (422) penetrate through the top of the pile body (4).

2. A pre-stressed precast pile for foundation pit bracing according to claim 1, wherein: the end fixing piece comprises a tensioning end anchor (8) arranged at the top of the pile body (4), and a grouting communication hole communicated with the pre-tensioning through hole (421) is formed in an anchor backing plate of the tensioning end anchor (8).

3. A pre-stressed precast pile for foundation pit bracing according to claim 1, wherein: the pile further comprises a pointed pile head (9) and an enlarged shell (10); a first communication hole (91) and a second communication hole (92) are formed in the pointed pile head (9) corresponding to the pre-stretching through hole (421) and the grouting hole (422), and a third communication hole (93) communicated with the first communication hole (91) and the second communication hole (92) is formed in the conical side surface of the pointed pile head (9); the conical head of the pointed pile head (9) is coated with an expansion shell (10), the expansion shell (10) coats the third communication hole (93) inside, and the edge of the expansion shell (10) is fixed with the pointed pile head (9).

4. A pre-stressed precast pile for foundation pit bracing according to claim 3, wherein: the pile body (4) comprises a steel pipe (41) and a concrete core (42) arranged in the steel pipe (41), and an inserting cavity (411) which is formed by unfilling the concrete core (42) is reserved at the lower end of the steel pipe (41); the pointed pile head (9) is provided with a plug-in part (94) near one end of the pile body (4), the edge of the expansion shell (10) is coated on the side wall of the plug-in part (94), and the plug-in part (94) of the expansion shell (10) is coated to be in plug-in fit with the plug-in cavity (411).

5. A pre-stressed precast pile for foundation pit bracing according to claim 3 or 4, wherein: the end fixing piece comprises tensioning end anchors (8) arranged at two ends of the pile body (4), and grouting communication holes communicated with the pre-tensioning through holes (421) are formed in anchor backing plates of the tensioning end anchors (8).

6. A pre-stressed precast pile for foundation pit bracing according to claim 1, wherein: the pre-tensioning through hole (421) is arranged on one side, close to the foundation pit, of the pile body (4).

7. The pre-stressed precast pile for foundation pit bracing of claim 6, wherein: the pile body (4) is a square pile.

8. A pre-stressed precast pile for foundation pit bracing according to claim 1, wherein: and a PVC pipe (5) penetrating through the whole pile body (4) is pre-buried in the pile body (4) to form the pre-stretching through hole (421).