A method of pile foundation construction
By using a pile foundation construction method with elastic spiral metal sheets and guide columns, the problems of low efficiency and poor safety in existing pile foundation construction have been solved, achieving efficient, low-noise, and low-cost pile foundation borehole expansion.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- FANGYUAN CONSTR GRP REAL ESTATE DEVT CO LTD
- Filing Date
- 2023-05-16
- Publication Date
- 2026-05-29
AI Technical Summary
Existing pile foundation construction methods suffer from problems such as slow pile formation speed, low construction safety, high cost, and difficulty in hole enlargement, especially in rock strata where construction is even more difficult and existing hole enlargement methods are inefficient.
A spiral metal sheet with elastic deformation capability is used as a hole-expanding tool. The large-diameter end of the sheet is pressed against the inner wall of the bottom of the pile hole by the pile driver to expand the diameter. The sheet is then removed using its elastic restoring force. Combined with the design of annular bearing pads and guide columns, the hole-expanding efficiency and safety are improved.
It achieves efficient and safe pile foundation borehole enlargement, reduces noise and construction costs, improves borehole enlargement efficiency, and is suitable for construction under various geological conditions.
Smart Images
Figure CN116427405B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of building construction technology and relates to a pile foundation construction method. Background Technology
[0002] To improve the bearing capacity of piles, diameter expansion is often used, creating an enlarged head at the bottom of the pile. A common process involves: first, drilling the pile hole; then, using explosives to expand the diameter at the bottom of the hole; cleaning the hole; lowering the reinforcing cage; and finally, pouring the concrete. However, this method has drawbacks such as slow pile formation, low construction safety, numerous uncertainties, and a high risk of hole collapse in soft soil (leading to extensive hole cleaning). Furthermore, during pile foundation construction, the soil conditions at the ideal pile location often increase construction difficulty. For example, if the bottom of the ideal pile depth is a rock layer, drilling is difficult, but without drilling through the rock layer, the ideal pile depth cannot be achieved. In such cases, diameter expansion is necessary above the rock layer to improve the shear strength of the pile. In short, pile hole diameter expansion is a frequently used method, but current techniques are limited in variety, costly, and inefficient. Summary of the Invention
[0003] The purpose of this invention is to address the aforementioned problems in existing technologies by providing a pile foundation construction method. The technical problem to be solved by this invention is to provide an efficient and simple pile foundation construction process.
[0004] The objective of this invention can be achieved through the following technical solution: A pile foundation construction method, characterized by comprising the following steps: A. Drilling pile holes; B. First-time hole cleaning; C. Placing an annular bearing pad at the bottom of the pile hole, and then lowering a spiral expander into the pile hole, wherein the spiral expander is an elastic spiral metal sheet, which in its natural state is a conical shape with adjacent rings abutting against each other and the small diameter end facing upward, so that the large diameter end of the spiral metal sheet presses against the annular bearing pad, and the outer diameter of the bottom of the spiral metal sheet is smaller than the inner diameter of the pile hole; D. Softly connecting the hammer of the pile driver to the top of the spiral metal sheet through a cable, and using frequent striking of the small diameter end of the spiral metal sheet to squeeze the inner wall surface of the bottom of the pile hole with the large diameter end of the spiral metal sheet, thereby expanding the diameter of the bottom of the pile hole and compacting the soil; E. Removing the spiral metal sheet and cleaning the hole a second time; F. Lowering the steel reinforcement cage and pouring concrete to form the pile foundation.
[0005] Furthermore, the cross-section of the spiral metal sheet includes a vertical guide section and an inclined guide section. The inclined guide section is located below the vertical guide section, and the inclined guide section and the vertical guide section form an inclination angle of 100 to 170°. In the natural state, the inclined guide sections between adjacent turns of the spiral metal sheet have a gap.
[0006] Furthermore, in step D, a guide post is fixed below the hammer of the piling machine, which can be inserted into the inner hole at the top of the spiral metal plate. The bottom of the guide post and the middle of the spiral metal plate are connected by a cable to achieve a flexible connection.
[0007] The core of this solution lies in utilizing a spiral metal sheet structure with elastic deformation capabilities as a tool for hole enlargement. As is well known, the diameter of the elastic spiral structure with adjacent coils abutting each other is smaller under tension than under compression. This means that when compressed, due to the decrease in spiral angle and without a significant increase in the number of coils, its outer diameter increases. Furthermore, under frequent impacts and compression, the outer coil of the spiral metal sheet continuously exerts outward compressive force on the hole wall. After hole enlargement and soil compaction, pulling up the spiral metal sheet causes its spiral angle to increase again due to its own weight, elastic recovery force, and upward pulling force, further reducing its outer diameter and making removal easy. Compared to explosive hole enlargement, this solution is a static pressure construction method, resulting in lower noise, higher efficiency, and direct operation using a pile driver, significantly reducing hole enlargement costs. Attached Figure Description
[0008] Figure 1 This is a schematic diagram showing the state of the spiral metal sheet after it has been lowered into the pile hole and before the hole is enlarged.
[0009] Figure 2 This is a schematic diagram of the state before the spiral metal sheet is removed after the hole enlargement is completed.
[0010] Figure 3 It is a diagram of the completed pile foundation structure.
[0011] Figure 4 It is a cross-sectional view of a spiral metal sheet.
[0012] Figure 5 This is a top-view plan view of the spiral metal sheet.
[0013] Figure 6 yes Figure 1 A magnified view of part A in the middle.
[0014] In the diagram, 1 is a spiral metal sheet; 11 is an inclined guide section; 12 is a vertical guide section; 2 is a hammer; and 3 is a guide post. Detailed Implementation
[0015] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.
[0016] First, use a pile driver to drill the pile hole, followed by a hole cleaning. Depending on the soil conditions, determine whether wall protection is needed. Place an annular bearing pad at the bottom of the pile hole. This annular bearing pad is a metal sheet and can be removed after hole reaming by using a rope, or it can remain in place. The function of the annular bearing pad is to support the large-diameter end of the spiral metal sheet 1, preventing it from sinking into the soil and rock under impact and becoming trapped, thus preventing the spiral metal sheet 1 from expanding outwards. Then, lower a spiral reamer into the pile hole. The structure of the spiral metal sheet can be referenced... Figure 1 , Figure 2 , Figure 5 and Figure 6 The spiral expander is a flexible spiral metal sheet 1. In its natural state, the spiral metal sheet 1 is a conical shape with adjacent coils abutting against each other and the smaller diameter end facing upwards. This allows the larger diameter end of the spiral metal sheet 1 to press against an annular bearing pad. The outer diameter of the bottom of the spiral metal sheet 1 is smaller than the inner diameter of the pile hole. The pile driver's hammer 2 is flexibly connected to the top of the spiral metal sheet 1 via a cable. Figure 1 As shown, by frequently striking the small-diameter end of the spiral metal sheet 1, the large-diameter end of the spiral metal sheet 1 is forced to compress the inner wall surface at the bottom of the pile hole, thereby expanding the diameter of the pile hole and compacting the soil. After the diameter expansion is completed, as shown... Figure 2 As shown, specifically, a guide post 3 is fixed below the hammer 2 of the piling machine, which can be inserted into the inner hole at the top of the spiral metal sheet 1. The bottom of the guide post 3 is flexibly connected to the middle of the spiral metal sheet 1 by a cable. The setting of the guide post 3 can limit the shrinkage of the small diameter end of the spiral metal sheet 1, further improving the outward expansion efficiency of the large diameter end of the spiral metal sheet 1 under the impact force. Finally, the spiral metal sheet 1 is removed, and the hole is cleaned a second time. The steel reinforcement cage is lowered and poured to form a shape as shown. Figure 3 The pile foundation shown.
[0017] As a preferred option, such as Figure 4 As shown, the cross-section of the spiral metal sheet 1 includes a vertical guide section 12 and an inclined guide section 11. The inclined guide section 11 is located below the vertical guide section 12, and the inclined guide section 11 and the vertical guide section 12 form an inclination angle of 100 to 170°. In its natural state, the spiral metal sheet 1 has a gap between the inclined guide sections 11 between adjacent rings. When the adjacent rings of the spiral metal sheet 1 interact with each other until the inclined guide sections come into contact, the original close contact between the adjacent rings is changed, so that there is a gap between the vertical guide sections 12 between the adjacent rings of the spiral metal sheet 1, thereby improving the diameter expansion capability. At the same time, the presence of the inclined guide section can also reduce the resistance when the large diameter end moves relative to the annular bearing plate.
[0018] This method utilizes a spiral metal sheet 1 with elastic deformation capabilities as a tool for hole enlargement. As is well known, the diameter of the sheet-like elastic spiral structure with adjacent coils abutting each other is smaller under tension than under compression. This means that when compressed, due to the decrease in spiral angle and without a significant increase in the number of coils, its outer diameter increases. Consequently, under frequent impacts and compression, the outer coil of the spiral metal sheet 1 continuously exerts outward compressive force on the hole wall. After hole enlargement and soil compaction, pulling up the spiral metal sheet 1 causes its spiral angle to increase again due to its own weight, elastic recovery force, and upward pulling force, resulting in a further reduction in its outer diameter, making removal easy. Compared to explosive hole enlargement, this method employs static pressure construction, resulting in lower noise, higher efficiency, and direct operation using a pile driver, significantly reducing hole enlargement costs.
[0019] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.
Claims
1. A pile foundation construction method, characterized in that, The process includes the following steps: A. Opening the pile hole; B. Cleaning the hole once; C. Placing an annular bearing pad at the bottom of the pile hole, and then placing a spiral expander into the pile hole. The spiral expander is an elastic spiral metal sheet (1). In its natural state, the spiral metal sheet (1) is a cone-shaped structure with adjacent rings abutting against each other and the small diameter end facing upwards, so that the large diameter end of the spiral metal sheet (1) presses against the annular bearing pad. The outer diameter of the bottom of the spiral metal sheet (1) is smaller than the inner diameter of the pile hole. D. Connect the top of the pile driver hammer (2) and the spiral metal plate (1) with a cable. By frequently striking the small diameter end of the spiral metal plate (1), the large diameter end of the spiral metal plate (1) is squeezed against the inner wall of the bottom of the pile hole, thereby expanding the diameter of the pile hole and ramming the soil. E. Remove the spiral metal plate (1) and clean the hole a second time. F. Lower the steel reinforcement cage and pour the concrete to form the pile foundation.
2. The pile foundation construction method according to claim 1, characterized in that, The cross-section of the spiral metal sheet (1) includes a vertical guide section (12) and an inclined guide section (11). The inclined guide section (11) is located below the vertical guide section (12), and the inclined guide section (11) and the vertical guide section (12) form an inclination angle of 100 to 170°. In its natural state, the spiral metal sheet (1) has a gap between the inclined guide sections (11) of adjacent turns.
3. A pile foundation construction method according to claim 1 or 2, characterized in that, In step D, a guide post (3) is fixed below the hammer (2) of the pile driver, which can be inserted into the inner hole at the top of the spiral metal plate (1). The bottom of the guide post (3) and the middle part of the spiral metal plate (1) are connected by a cable to achieve a soft connection.