Cast-in-place pile casing structure for upper-soft lower-hard stratum
By designing a cast pile guard structure for upper and lower hard formations, the problems of collapse and safety risks in cast pile construction are solved, and the stability of drilling and construction progress are improved.
Patent Information
- Application Number
- CN202420668704.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-02
- Publication Date
- 2025-03-11
- Estimated Expiration
- 2034-04-02
AI Technical Summary
Under the conditions of upper and lower hard formations, hole collapse is prone to the construction of cast-injected piles, resulting in high safety risks and impact on the construction progress.
A cast pile guard structure for upper and lower hard formations is designed, including a rotary drilling rig and guard. The guard is sphericalized by a multi-stage unit barrel. Spherical protrusions are distributed on the outer side of the unit barrel to enhance the grip with the drilling hole wall, and improve the stability of the guard through the connecting plate and the reinforcement ring.
Effectively support drilling, prevent hole collapse risk, improve construction safety and progress, and the adjustable length and flexibility of the guard casing are adapted to different formation conditions.
Smart Images
Figure CN222594796U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of bored pile drilling, in particular to a bored pile casing structure used for upper soft and lower hard strata. Background Art
[0002] The rotary drilling rig is a high-efficiency construction drilling rig suitable for pile foundation hole construction, and is currently being used more and more widely in China. The rotary drilling rig drills holes under the condition of mud wall protection. The turntable or power head on the rotary drilling rig drives the retractable drill rod and the drill bit at the bottom of the drill rod to rotate, and the cutting tools on the bottom and side openings of the drill bucket cut the rock and soil. With the continuous development of land for engineering construction, land reclamation in coastal areas is becoming more and more widespread. The geological conditions for engineering construction in the reclamation area are relatively complex. The upper fill layer is relatively soft, and the rock layer with higher strength and hardness is distributed below the fill layer. On the whole, it is soft on the top and hard on the bottom. When using a rotary drilling rig for drilling operations, due to the soft upper strata and high groundwater level, it is very easy to collapse the hole, which has a high safety risk, and once the hole collapses, it will seriously affect the construction progress. Utility Model Content
[0003] The utility model aims to provide a cast-in-place pile casing structure for use in upper soft and lower hard strata, and aims to solve the technical problems of easy hole collapse and high safety risk during cast-in-place pile construction in upper soft and lower hard strata.
[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:
[0005] The utility model provides a cast-in-place pile casing structure for upper soft and lower hard strata, comprising a rotary drilling rig and a casing, wherein the rotary drilling rig is arranged on the ground, and a drill bit is arranged on the rotary drilling rig for excavating a borehole underground; the strata below the ground are distributed in multiple layers, which are respectively a covering soil layer, a weathered spherical layer, a fully weathered rock layer and a medium-weathered rock layer from top to bottom; the bottom end of the borehole is located in the medium-weathered rock layer, the casing is arranged on the side wall of the borehole, the top surface of the casing is flush with the ground, and the bottom surface exceeds the covering soil layer and is located in the weathered spherical layer; the casing is formed by splicing at least two sections of unit cylinders, the unit cylinders are connected by a connecting plate, and a plurality of spherical protrusions are evenly distributed on the outer side surfaces of the unit cylinders for increasing the gripping force between the casing and the borehole wall.
[0006] Preferably, a connecting plate is provided on the bottom surface of the upper unit cylinder and the top surface of the lower unit cylinder, and the two connecting plates are fixedly connected by connecting bolts.
[0007] Preferably, the top surface of the unit cylinder is provided with a slurry overflow hole.
[0008] Preferably, lifting ears for lifting are symmetrically arranged on the outer side surface of the top of the unit cylinder.
[0009] Preferably, the top surface and the bottom surface of the unit cylinder are both provided with steel reinforcement rings for reinforcement.
[0010] Preferably, the connecting plate, the lifting lugs and the steel reinforcement rings are all welded and fixed to the unit cylinder.
[0011] Preferably, the distance from the bottom end of the borehole to the top surface of the medium-weathered rock layer is twice the diameter of the borehole.
[0012] Preferably, the length of the unit cylinder is not less than 6m.
[0013] Preferably, the borehole diameter is smaller than the diameter of the casing.
[0014] The beneficial effects of the utility model are embodied in:
[0015] 1) The utility model provides a cast-in-place pile casing structure for upper soft and lower hard strata. The casing is supported on the side wall of the borehole with a softer covering soil layer on the upper layer, which can effectively support the borehole and prevent the risk of hole collapse caused by soft soil or deep depth. The casing adopts the form of unit cylinder splicing, and its length is adjustable. The overall length of the casing can be adjusted according to the depth of the covering soil layer, and it has strong adaptability, high flexibility and strong turnover.
[0016] 2) The utility model provides a cast-in-place pile casing structure for use in soft upper and hard lower strata. A plurality of spherical protrusions are arranged on the outer side surface of the unit cylinder, which can enhance the grip between the cylinder and the hole wall, making the casing more firmly in the drill hole and increasing stability. A lifting lug is arranged on the top of the unit cylinder for easy installation. Steel reinforcement rings are arranged on the top and bottom surfaces of the unit cylinder to further enhance the strength and stability of the casing.
[0017] Other features and advantages of the utility model will be described in the following description, and partly become apparent from the description, or understood by implementing the utility model. The main purpose and other advantages of the utility model can be realized and obtained by the solutions particularly pointed out in the description. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The utility model is further described in detail below in conjunction with the accompanying drawings.
[0019] Figure 1 It is a structural schematic diagram of the utility model.
[0020] Figure 2 It is a front view of the casing of the utility model.
[0021] Figure 3 It is a horizontal cross-sectional view of the casing 1-1 of the utility model.
[0022] Figure 4 It is a horizontal cross-sectional view of the casing 2-2 of the utility model.
[0023] Figure 5It is a schematic diagram of the steel bar stiffening ring of the utility model.
[0024] Figure numerals: 1-rotary drilling rig, 2-casing, 3-drill bit, 4-borehole, 5-covering soil layer, 6-weathered spherical layer, 7-fully weathered rock layer, 8-moderately weathered rock layer, 9-connecting plate, 10-spherical protrusion, 11-connecting bolt, 12-overflow hole, 13-lifting ear, 14-steel reinforcement ring, 21-unit cylinder. DETAILED DESCRIPTION
[0025] The technical solution of the present invention is described in detail below through embodiments. The following embodiments are merely exemplary and can only be used to explain and illustrate the technical solution of the present invention, but cannot be interpreted as limiting the technical solution of the present invention.
[0026] Reference Figure 1-4 The utility model provides a cast-in-place pile casing structure for upper soft and lower hard strata, comprising a rotary drilling rig 1 and a casing 2, wherein the rotary drilling rig 1 is arranged on the ground, and a drill bit 3 is arranged on the rotary drilling rig 1 for excavating a borehole 4 underground; the strata below the ground are distributed in multiple layers, and from top to bottom are respectively a covering soil layer 5, a weathered spherical layer 6, a fully weathered rock layer 7 and a medium weathered rock layer 8; the bottom end of the borehole 4 is located in the medium weathered rock layer 8, and the distance from the bottom end of the borehole 4 to the top surface of the medium weathered rock layer 8 is twice the diameter of the borehole 4, and the diameter of the borehole 4 is slightly smaller than the diameter of the casing 2; the casing 2 is arranged on the side wall of the borehole 4, the top surface of the casing 2 is flush with the ground, and the bottom surface exceeds the covering soil layer 5 and is located in the weathered spherical layer 6; the casing 2 is composed of at least two sections of unit cylinders 21, which are connected by connecting plates 9, the bottom surface of the upper unit cylinder 21 and the top surface of the lower unit cylinder 21 are both welded with connecting plates 9, and the two connecting plates 9 are fixedly connected by connecting bolts 11; the length of the unit cylinder 21 is not less than 6m, the top surface of the unit cylinder 21 is provided with grouting holes 12, the top outer side surface of the unit cylinder 21 is symmetrically welded with lifting ears 13 for lifting, the top and bottom surfaces of the unit cylinder 21 are both welded with steel reinforcement rings 14 for reinforcement, and the outer side surface of the unit cylinder 21 is evenly distributed with a plurality of spherical protrusions 10 for increasing the gripping force between the casing 2 and the wall of the borehole 4.
[0027] Furthermore, the working principle of the utility model is as follows: since the upper covering layer is relatively weak and is very prone to collapse, it is necessary to use casing 2 for wall protection to ensure the stability of the borehole 4; the soil layer is measured in the early stage, and the number of unit cylinders 21 required is determined according to the thickness of the upper covering soil layer 5. The unit cylinders 21 are spliced and installed through the connecting plate 9, and then the spliced casing 2 is hoisted by the hoisting equipment, and the casing 2 is spliced and installed. The rotary drilling rig 1 with a faster hole-forming speed is used for drilling. The diameter of the borehole 4 is slightly smaller than the diameter of the casing 2. After drilling into place, the casing 2 is immediately placed in the hole, and the casing 2 is pressed into the hole by a rotary drilling machine or a vibrating hammer. The casing 2 can continue to be drilled after it is buried in place; if the soft soil layer is thick and the length of the casing 2 is too long, the casing 2 can be pressed while drilling to prevent the collapse of the hole due to excessive drilling depth; after the casing 2 is buried, in order to prevent the frequent lifting of the drill during drilling by the rotary drilling rig 1, which causes the hole wall to become unstable, it is replaced with an impact drill for hole-forming construction.
[0028] The above description is only a preferred specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that a technician familiar with the technical field thinks of within the technical scope disclosed in the present invention should be included in the protection scope of the present invention.
Claims
1. A cast-in-place pile casing structure for soft upper and hard lower strata, characterized in that: The invention comprises a rotary drilling rig (1) and a casing (2), wherein the rotary drilling rig (1) is arranged on the ground, and the rotary drilling rig (1) is provided with a drill bit (3) for excavating a borehole (4) underground; the strata below the ground are distributed in multiple layers, and from top to bottom are respectively a covering soil layer (5), a weathered spherical layer (6), a fully weathered rock layer (7) and a medium weathered rock layer (8); the bottom end of the borehole (4) is located in the medium weathered rock layer (8); the casing (2) is arranged on the side wall of the borehole (4), the top surface of the casing (2) is flush with the ground, and the bottom surface exceeds the covering soil layer (5) and is located in the weathered spherical layer (6); the casing (2) is formed by splicing at least two sections of unit cylinders (21), the unit cylinders (21) are connected by a connecting plate (9), and the outer side surfaces of the unit cylinders (21) are evenly distributed with a plurality of spherical protrusions (10) for increasing the gripping force between the casing (2) and the wall of the borehole (4).
2. A cast-in-place pile casing structure for upper soft and lower hard strata as claimed in claim 1, characterized in that: A connecting plate (9) is provided on the bottom surface of the upper unit cylinder (21) and the top surface of the lower unit cylinder (21), and the two connecting plates (9) are fixedly connected by connecting bolts (11).
3. A cast-in-place pile casing structure for upper soft and lower hard strata as claimed in claim 2, characterized in that: The top surface of the unit cylinder (21) is provided with a slurry overflow hole (12).
4. A cast-in-place pile casing structure for upper soft and lower hard strata as claimed in claim 3, characterized in that: Lifting ears (13) for lifting are symmetrically arranged on the outer side surface of the top of the unit cylinder (21).
5. A cast-in-place pile casing structure for upper soft and lower hard strata as claimed in claim 4, characterized in that: The top surface and the bottom surface of the unit cylinder (21) are both provided with steel reinforcement rings (14) for reinforcement.
6. A cast-in-place pile casing structure for upper soft and lower hard strata as claimed in claim 5, characterized in that: The connecting plate (9), the lifting lug (13), and the steel reinforcement ring (14) are all welded and fixed to the unit cylinder (21).
7. A cast-in-place pile casing structure for upper soft and lower hard strata as claimed in claim 1, characterized in that: The distance from the bottom of the borehole (4) to the top surface of the medium-weathered rock layer (8) is twice the diameter of the borehole (4).
8. The cast-in-place pile casing structure for upper soft and lower hard strata according to claim 1, characterized in that: The length of the unit cylinder (21) is not less than 6 m.
9. A cast-in-place pile casing structure for upper soft and lower hard strata as claimed in claim 1, characterized in that: The diameter of the borehole (4) is smaller than the diameter of the casing (2).