Railway subgrade pile cap drilling guide and over-drilling limiting device

Abstract

This application relates to a drilling guide and over-drilling limit device for railway subgrade pile caps, belonging to the technical field of engineering drilling and limiting. It includes a drill rod, with a guide cylinder connected to the bottom of the drill rod when it is vertically positioned. The inner cavity of the guide cylinder is slightly larger than the outer diameter of the pipe pile. Three helical blades are helically fixed on the outer wall of the drill rod. The three helical blades have equal helix angles and the same helical lead. Furthermore, the lower cutting surfaces of the three helical blades are all wedge-shaped structures, which can continuously scrape the bottom during excavation. A horizontally arranged annular baffle is provided inside the guide cylinder to prevent over-drilling. Multiple drainage holes are also provided on the annular baffle to promptly drain accumulated water during excavation. This application effectively solves the problems of difficult positioning and severe deviation during pile cap excavation.

Description

Technical Field

[0001] This application relates to the technical field of drilling and limiting in engineering, and in particular to a drilling guide and over-drilling limiting device for railway subgrade pile caps. Background Technology

[0002] Currently, in the railway construction field, subgrade foundation treatment is a crucial link in ensuring the safe and stable operation of railways. The prestressed concrete pipe pile soil formwork method for pile cap construction is widely used in railway subgrade foundation treatment, playing a significant role in improving foundation bearing capacity and reducing settlement. With the continuous development of railway construction, the requirements for the precision and efficiency of pile cap construction are becoming increasingly stringent. Continuous innovation and improvement of related technologies play a vital role in enhancing the quality and efficiency of railway construction.

[0003] Traditional railway subgrade foundation treatment using the soil mold method for prestressed concrete pipe pile cap construction employs milling drill bits for excavation. These traditional milling drill bits utilize a spiral excavation method, with the drill bit's rotation powered by a hydraulic motor and driven and moved by an excavator. Typically, these drill bits are made by pressing three standard-thickness steel plates together and welding them into a cylinder of a specific inner diameter, with drill teeth welded to the bottom. In practice, operators control the excavator to rotate the drill bit, using the drill teeth to cut the soil and excavate the pile cap. Furthermore, positioning relies primarily on manual observation and experience to roughly determine the drill bit's location.

[0004] However, the existing construction method has significant drawbacks. Positioning the pile cap during molding is extremely difficult, leading to severe misalignment after molding. Even when the position is corrected, the pile cap size becomes unnecessarily larger, resulting in significant concrete waste. Furthermore, the manual leveling and cleaning process is extremely labor-intensive, and the backfill soil between piles after molding is difficult to compact effectively, failing to meet the precision and quality requirements for pile cap construction in railway projects. Utility Model Content

[0005] In order to solve the problems of difficult positioning and serious deviation during the excavation of pile caps, this application provides a drilling guide and over-drilling limit device for railway subgrade pile caps.

[0006] The technical solution for the railway subgrade pile cap drilling guidance and over-drilling limiting device provided in this application is as follows:

[0007] A drilling guide and over-drilling limit device for railway subgrade pile caps includes a drill rod. When the drill rod is set vertically, a guide cylinder is coaxially fixed below the drill rod. The inner cavity size of the guide cylinder is larger than the outer diameter of the pipe pile. Multiple helical blades are provided on the outer wall of the drill rod. The multiple helical blades are helically distributed and fixed along the circumference of the drill rod. An annular baffle is fixed inside the guide cylinder.

[0008] By adopting the above technical solution, the drill rod is connected to a guide cylinder. The inner cavity of the guide cylinder is larger than the outer diameter of the pipe pile, which allows the cavity of the guide cylinder to fit snugly against the pile head, ensuring that the center of the drill bit is aligned with the center of the pipe pile. This achieves centered pile cap formation during drilling, solving the problems of difficult positioning and severe deviation during pile cap excavation. An annular baffle is set inside the guide cylinder to limit the excavation depth of the pile cap and prevent over-drilling. Multiple spiral blades evenly distributed around the circumference of the drill rod assist in the excavation work. In this way, the soil mold can be formed quickly in one go, ensuring the construction accuracy of the pile cap and avoiding quality problems such as non-centered pile position and pile cap, insufficient compaction of crushed stone backfill between the pile cap and pile cap, and damage to the finished pile cap caused by crushed stone backfill in traditional construction. This improves efficiency and quality control.

[0009] Optionally, the number of helical blades is set to three, and the helix angles and helical leads of the three helical blades are equal.

[0010] By adopting the above technical solution, the three helical blades are evenly distributed circumferentially with equal helix angles and the same helical lead, which enables the drill bit to be subjected to more uniform force during excavation, thereby improving the stability and efficiency of excavation.

[0011] Optionally, the lower cutting surfaces of the three helical blades are all wedge-shaped structures, with the tips of the wedge-shaped structures extending toward the bottom of the guide cylinder and integrally formed with the helical blades.

[0012] By adopting the above technical solution, the lower end of the wedge-shaped spiral blade can continuously scrape the bottom during the excavation process, which can effectively avoid manual bottom cleaning and leveling, and make the bottom of the pile cap flatter, while also helping to compact the backfill soil between piles.

[0013] Optionally, a spiral oil guide channel is provided inside the drill pipe.

[0014] By adopting the above technical solution, the spiral oil guide channel can achieve automatic cooling effect, and when connected to an external hydraulic system, it can achieve active cooling.

[0015] Optionally, the guide cylinder includes an inner cylinder and an outer cylinder, which are interference-fitted. The inner cylinder is made of a high-hardness material, and the outer cylinder is made of structural steel.

[0016] By adopting the above technical solutions, the high hardness material of the inner cylinder can effectively improve the service life of the guide cylinder, and the use of structural steel for the outer cylinder can increase the rigidity of the overall structure. The interference fit between the two can effectively eliminate abnormal noise and vibration.

[0017] Optionally, the lower end of the guide cylinder is configured as a tapered guide surface, and the outer surface is coated with a wear-resistant layer.

[0018] By adopting the above technical solution, the conical guide surface design of the guide cylinder can achieve the effect of automatic correction of initial deviation and improve counterweight efficiency.

[0019] Optionally, the annular baffle includes an upper baffle and a lower baffle, a buffer pad is fixed between the upper baffle and the lower baffle, the upper baffle is threadedly fixed to the guide cylinder, and a pressure sensor is fixed to the bottom of the lower baffle.

[0020] By adopting the above technical solution, the buffer pad inside the annular baffle can play a role in buffering and vibration reduction, and the pressure sensor can transmit the corresponding pressure value to the display.

[0021] Optionally, the annular baffle is provided with a plurality of guide holes spaced apart.

[0022] By adopting the above technical solution, the annular baffle has a drainage hole, which can drain water in time during construction, avoid water accumulation from affecting the excavation and forming quality of the pile cap, and at the same time reduce the drilling resistance caused by water accumulation and improve construction efficiency.

[0023] In summary, this application includes at least one of the following beneficial technical effects:

[0024] 1. The drill rod is connected to the guide cylinder, and the inner cavity of the guide cylinder is larger than the outer diameter of the pipe pile. This makes it easier for the guide cylinder to fit with the pile head of the pipe pile, ensuring that the center of the drill bit is consistent with the center of the pipe pile. This effectively solves the problems of difficult positioning during pile cap excavation and serious deviation after forming, and ensures the construction accuracy of the pile cap.

[0025] 2. The cutting surfaces at the lower ends of the three spiral blades on the drill rod are wedge-shaped, which can increase the flatness of the bottom after excavation, reduce the amount of manual leveling work, and effectively solve the problem of the difficulty in compacting the backfill soil between piles after the pile cap is formed.

[0026] 3. The annular baffle inside the guide cylinder can limit the excavation depth of the pile cap, prevent over-drilling, and avoid the pile cap size from becoming too large and the waste of concrete due to over-drilling. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of an embodiment of this application;

[0028] Figure 2 This is a cross-sectional structural diagram of an embodiment of this application.

[0029] In the diagram, 1 is the drill rod; 2 is the guide cylinder; 21 is the inner cylinder; 22 is the outer cylinder; 3 is the helical blade; 31 is the first helical blade; 32 is the second helical blade; 33 is the third helical blade; 4 is the annular baffle; 41 is the upper baffle; 42 is the buffer pad; 43 is the lower baffle; and 5 is the guide hole. Detailed Implementation

[0030] The following is in conjunction with the appendix Figures 1-2 This application will be described in further detail.

[0031] This application discloses a drilling guide and over-drilling limit device for railway subgrade pile caps.

[0032] refer to Figure 1 and Figure 2 A drilling guide and over-drilling limit device for railway subgrade pile caps includes a drill rod 1, a guide cylinder 2, a spiral blade 3, and an annular baffle 4. When the drill rod 1 is vertically set, the bottom of the rotating drill rod 1 is not equipped with drill teeth and is coaxially connected with the guide cylinder 2. There are three spiral blades 3, which are evenly spirally fixed on the outer wall of the drill rod 1 and the guide cylinder 2. The annular baffle 4 is horizontally set inside the guide cylinder 2.

[0033] The top of drill rod 1 is connected to the drive joint via a spline, which drives the drill rod 1 to rotate. The drive joint here is an existing drive rotation structure. A spiral oil guide channel is opened inside the drill rod 1, which is matched with a nozzle and connected to the external hydraulic system to achieve an automatic cooling effect.

[0034] refer to Figure 1 and Figure 2 The inner cavity of the guide cylinder 2 is about 1 cm larger than the outer diameter of the pipe pile. The guide cylinder 2 includes an inner cylinder 21 and an outer cylinder 22. The inner cylinder 21 is made of high-chromium cast iron with high hardness and wear resistance, and the outer cylinder 22 is made of structural steel load-bearing shell. The inner cylinder 21 and the outer cylinder 22 are interference fit.

[0035] The inner wall of the inner cylinder 21 is spirally fixed with a ring of elastic self-lubricating guide blocks, which can reduce the wear on the surface of the pipe pile. The lower end of the outer cylinder 22 is set as a tapered guide surface with a taper angle of 15°-25°. The outer surface of the outer cylinder 22 is coated with a wear-resistant layer, which can realize automatic correction of initial deviation and improve the centering efficiency.

[0036] refer to Figure 1 and Figure 2 The spiral blades 3 welded and fixed on the outer wall of the drill rod 1 and the guide cylinder 2 are generally made of wear-resistant steel, such as manganese steel, to improve their service life. The spacing between the three spiral blades 3 is equal along the axial direction of the drill rod 1, and the spiral helix angle and spiral lead are equal. All three spiral blades 3 are circumferentially fixed to the drill rod 1 through slots to prevent the spiral blades 3 from falling off during use.

[0037] The lower cutting surfaces of the three spiral blades 3 are all wedge-shaped structures, with the tips of the wedge-shaped structures extending toward the bottom of the guide cylinder 2 and integrally formed with the spiral blades 3. This wedge-shaped structure is beneficial for continuously scraping the bottom soil during the excavation process.

[0038] refer to Figure 1 and Figure 2The annular baffle 4 includes an upper baffle 41 and a lower baffle 43. A buffer pad 42 is fixed between the upper baffle 41 and the lower baffle 43. The upper baffle 41 is threadedly fixed to the guide cylinder 2. A pressure sensor is fixed at the bottom of the lower baffle 43. The position of the annular baffle 4 in the guide cylinder 2 can be adjusted according to the needs of use to meet the design requirements of the pile cap excavation depth and prevent over-drilling.

[0039] Multiple guide holes 5 are spaced apart on the annular baffle 4, which can drain the water generated during the excavation process in a timely manner and ensure the smooth progress of the excavation work.

[0040] The annular baffle 4 here can also be other shapes, such as square, as long as it can limit the excavation depth.

[0041] The implementation principle of the drilling guidance and over-drilling limiting device for railway subgrade pile caps in this embodiment is as follows: During pile cap excavation, the guide cylinder 2 is fitted onto the pile head of the pipe pile. Since the inner cavity of the guide cylinder 2 is slightly larger than the outer diameter of the pipe pile, the cylinder cavity fits snugly against the pile head, thus ensuring that the center of the drill bit is aligned with the center of the pipe pile, solving the problem of positioning difficulties during pile cap excavation. During the excavation process, the drill rod 1 drives the spiral blade 3 to rotate, and the wedge-shaped structure at the lower end of the spiral blade 3 continuously scrapes and flattens the bottom soil, ensuring that the bottom is flat after excavation. At the same time, the annular baffle 4 limits the excavation depth of the pile cap to prevent over-drilling and avoids problems such as concrete waste caused by over-drilling in traditional construction.

[0042] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A drilling guide and over-drilling limit device for railway subgrade pile caps, characterized in that: The system includes a drill rod (1). When the drill rod (1) is set vertically, a guide cylinder (2) is fixed coaxially below the drill rod (1). The inner cavity size of the guide cylinder (2) is larger than the outer diameter of the pipe pile. Multiple helical blades (3) are provided on the outer wall of the drill rod (1). The multiple helical blades (3) are spirally distributed and fixed along the circumference of the drill rod (1). An annular baffle (4) is fixed inside the guide cylinder (2).

2. The railway subgrade pile cap drilling guide and over-drilling limiting device according to claim 1, characterized in that: The number of the helical blades (3) is set to three, and the helical lift angles of the three helical blades (3) are equal and the helical lead is the same.

3. The railway subgrade pile cap drilling guide and over-drilling limiting device according to claim 2, characterized in that: The lower cutting surfaces of the three spiral blades (3) are all wedge-shaped structures, with the tips of the wedge-shaped structures extending toward the bottom of the guide cylinder (2) and integrally formed with the spiral blades (3).

4. The railway subgrade pile cap drilling guide and over-drilling limiting device according to claim 1, characterized in that: The drill pipe (1) has a spiral oil guiding channel inside.

5. The railway subgrade pile cap drilling guide and over-drilling limiting device according to claim 1, characterized in that: The guide cylinder (2) includes an inner cylinder (21) and an outer cylinder (22), which are interference-fitted. The inner cylinder (21) is made of high-hardness material, and the outer cylinder (22) is made of structural steel.

6. The railway subgrade pile cap drilling guide and over-drilling limiting device according to claim 5, characterized in that: The lower end of the guide cylinder (2) is set as a tapered guide surface, and the outer surface is coated with a wear-resistant layer.

7. The railway subgrade pile cap drilling guide and over-drilling limiting device according to claim 1, characterized in that: The annular baffle (4) includes an upper baffle (41) and a lower baffle (43). A buffer pad (42) is fixed between the upper baffle (41) and the lower baffle (43). The upper baffle (41) and the guide cylinder (2) are threaded together. A pressure sensor is fixed at the bottom of the lower baffle (43).

8. The railway subgrade pile cap drilling guide and over-drilling limiting device according to claim 7, characterized in that: The annular baffle (4) is provided with multiple guide holes (5) spaced apart.

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