A rotary excavating pile drilling assembly type casing and a method of using the same

Abstract

The application discloses a rotary digging pile drilling assembly type casing and a use method thereof, the assembly type casing comprises a main outer casing and an assembly type casing, the assembly type casing is arranged on the upper end of the main outer casing, the inner side of the main outer casing is provided with a main inner casing, the top end of the main inner casing is fixedly connected with the top end of the main outer casing through a top mounting plate, and the bottom end of the main inner casing is fixedly connected with the bottom end of the main outer casing through a bottom mounting plate; a plurality of annular equally-spaced drill bit wear-resistant rollers are rotationally arranged between the top mounting plate and the bottom mounting plate, the inner side of the top mounting plate is fixedly provided with a drill bit guide cylinder, the drill bit of a rotary digging machine is accurately led into the inside of the main inner casing through the drill bit guide cylinder and is in frictional contact with the drill bit wear-resistant rollers, and when the drill bit rotates, the drill bit wear-resistant rollers rotate along with the drill bit, so that the friction between the drill bit and the inside of the main inner casing is reduced, and a better wear-resistant effect is achieved.

Description

Technical Field

[0001] This application relates to the field of prefabricated casing technology, and more specifically, to a prefabricated casing for rotary pile drilling and its application method. Background Technology

[0002] Rotary drilling rigs are comprehensive drilling machines characterized by fast hole-forming speed, low pollution, and high mobility. They use multi-layer telescopic drill rods, which reduces drilling auxiliary time, labor intensity, and the elimination of mud circulation for slag removal, thus saving costs. They are particularly suitable for foundation construction in urban areas. The rotary drilling mechanism of a rotary drilling rig requires the use of prefabricated casings during operation.

[0003] Existing technology publication CN216811604U provides a prefabricated casing for rotary pile drilling. By incorporating splicing rods, mating rings, and threaded caps, it facilitates the assembly and disassembly of two sets of casings. The inclusion of detachable inserts and anti-wear wheels reduces friction between the rotary drilling structure and the casing, thereby improving drilling stability. Although this prefabricated casing achieves assembly through detachable inserts and anti-wear wheels, the large number of anti-wear wheels results in time-consuming installation, and the casing is less likely to penetrate the soil under hammering, leading to lower drilling efficiency for the rotary drilling rig.

[0004] In view of this, we propose a prefabricated casing for rotary pile drilling and its application method. Summary of the Invention

[0005] To overcome a series of shortcomings in existing technologies, the purpose of this patent is to provide a prefabricated casing for rotary pile drilling, comprising:

[0006] Main outer casing 1;

[0007] A main inner casing 101 is provided inside the main outer casing 1. The top end of the main inner casing 101 is fixedly connected to the top end of the main outer casing 1 via a top mounting plate 102, and the bottom end of the main inner casing 101 is fixedly connected to the bottom end of the main outer casing 1 via a bottom mounting plate 104. Multiple drill bit anti-wear rollers 103, arranged in annular and equally spaced configurations, are rotatably disposed between the top mounting plate 102 and the bottom mounting plate 104. A drill bit anti-wear roller is fixedly disposed inside the top mounting plate 102. The drill bit guide cylinder 105 has its sidewall tangential to the inner wall of the drill bit anti-wear roller 103. A protective sleeve lower pressure shell 2 is fixedly installed at the bottom end of the bottom mounting plate 104. The sidewall of the protective sleeve lower pressure shell 2 has multiple annularly spaced mud-sliding grooves 202. A lower pressure part 203 is fixedly installed at the bottom end of the protective sleeve lower pressure shell 2. A lower pressure inner shell 201 is installed on the inner side of the protective sleeve lower pressure shell 2. An assembled protective sleeve 3 is installed at the top end of the top mounting plate 102.

[0008] The main outer casing 1, the casing lower pressure shell 2, the main inner casing 101, the drill bit guide cylinder 105, the lower pressure inner shell 201, and the lower pressure part 203 are arranged coaxially; the assembled casing 3 is also arranged coaxially with the main outer casing 1; the inner diameters of the main inner casing 101, the lower pressure inner shell 201, and the assembled inner casing 304 are equal; the outer diameters of the main outer casing 1, the casing lower pressure shell 2, and the assembled casing 3 are equal.

[0009] In the above technical solution, the drill bit anti-wear roller 103 does not need to be assembled separately. The drill bit of the rotary drilling rig can enter the interior of the main inner casing 101 more accurately through the drill bit guide tube 105. When the drill bit rotates, the drill bit anti-wear roller 103 will also rotate, thereby reducing the friction between the drill bit and the interior of the main inner casing 101 and achieving a better anti-wear effect.

[0010] As an optional solution to the technical solution of this application, the height of the drill bit anti-wear rollers 103 is the same as the height of the main inner casing 101. A cavity interlayer is provided between the main outer casing 1 and the main inner casing 101. The drill bit anti-wear rollers 103 are located in the cavity interlayer. The side wall of the main inner casing 101 is provided with a plurality of vertical strip holes that match the drill bit anti-wear rollers 103. The side wall of the drill bit anti-wear rollers 103 extends through the corresponding vertical strip holes into the inner cavity of the main inner casing 101.

[0011] In the above technical solution, the height of the drill bit anti-wear roller 103 is the same as the height of the main inner casing 101, which can increase the contact area between the drill bit anti-wear roller 103 and the rotary drilling rig drill bit. The drill bit anti-wear roller 103 is located on the inner side of the cavity interlayer, which ensures that the drill bit anti-wear roller 103 will not affect the use of the drill bit or the protective function of the main outer casing 1 and the main inner casing 101 when it rotates.

[0012] As an optional solution to the technical solution of this application, the lower pressure shell 2 and the lower pressure inner shell 201 of the protective casing are arranged in a hollow structure. A reinforcing circular plate 204 is fixedly arranged on the inner side of the hollow structure. The bottom inner side of the lower pressure part 203 is rounded. The length of the mud sliding groove 202 is the same as the height of the lower pressure shell 2 of the protective casing.

[0013] In the above technical solution, the mud trough 202 can discharge the mud as quickly as possible, reduce the resistance to its descent, and thus allow the lower casing 2 of the casing to descend at a faster speed, thereby improving the effective utilization rate of the hammering force.

[0014] As an optional solution to the technical solution of this application, the inner cavity of the drill bit guide cylinder 105 is configured as an inverted frustum structure, and the inner diameter of the top end of the drill bit guide cylinder 105 is larger than the inner diameter of the bottom end.

[0015] In the above technical solution, the drill bit of the rotary drilling rig can smoothly enter the interior of the main inner casing 101 and be tangent to the drill bit anti-wear roller 103 by being guided by the drill bit guide cylinder 105.

[0016] As an optional solution to the technical solution of this application, the top of the top mounting plate 102 is fixedly provided with a plurality of fixing studs 4 distributed in a ring at equal intervals, and each fixing stud 4 is threadedly connected with a fastening nut 401.

[0017] In the above technical solution, the assembled casing 3 is sleeved on the fixing stud 4 through the guide hole 306 to achieve a fixed connection between the main outer casing 1 and the assembled casing 3. The fastening nut 401 is sleeved on the outside of the fixing stud 4 through the cavity sandwich between the assembled casing 3 and the assembled inner cylinder 304. The fastening nut 401 is rotated until it contacts the inner bottom end of the assembled casing 3, thereby achieving a fixed connection between the main outer casing 1 and the assembled casing 3.

[0018] As an optional solution to the technical solution of this application, the bottom end of the assembled protective sleeve 3 is provided with a plurality of guide holes 306 corresponding one-to-one with the fixing studs 4, and the assembled protective sleeve 3 is slidably disposed on the outside of the fixing studs 4 through the guide holes 306.

[0019] In the above technical solution, the guide hole 306 facilitates the connection between the main outer casing 1 and the assembled casing 3.

[0020] As an optional solution to the technical solution of this application, the inner side of the assembled casing 3 is provided with an assembled inner cylinder 304, and a reinforcing rib plate 303 is provided between the assembled casing 3 and the assembled inner cylinder 304. The reinforcing rib plate 303 is fixedly disposed between the inner side of the assembled casing 3 and the outer side of the assembled inner cylinder 304. A fixed connecting plate is provided directly above the reinforcing rib plate 303. The fixed connecting plate is fixedly connected to the side wall of the assembled inner cylinder 304. A limiting through hole is provided on the upper side wall of the reinforcing rib plate 303. A threaded mounting hole 301 is provided on the upper side wall of the fixed connecting plate. The axis of the corresponding threaded mounting hole 301 and the limiting through hole coincides. A detachable stud 305 is slidably disposed in the limiting through hole. The lower end of the detachable stud 305 is provided with a thread that matches the threaded mounting hole 301. The top end of the detachable stud 305 is provided with an internal hexagonal groove.

[0021] In the above technical solution, after the main outer casing 1 and the assembled casing 3 are assembled, if it is necessary to connect another assembled casing 3 to the end of the assembled casing 3, the assembled casing 3 to be assembled is placed on the upper side of the assembled casing 3 and the upper and lower threaded mounting holes 301 are aligned. Then, the detachable stud 305 is inserted into the limiting through hole from the upper threaded mounting hole 301. When the detachable stud 305 contacts the lower threaded mounting hole 301, the detachable stud 305 is rotated so that the detachable stud 305 is screwed into the lower threaded mounting hole 301. The threaded mounting hole 301 finally realizes the fixed connection of the two assembled casings 3. The internal hexagonal groove opened at the upper end of the detachable stud 305 makes it easy to install and disassemble, so that the assembled casing 3 can be quickly assembled.

[0022] As an optional solution to the technical solution of this application, both the assembled protective sleeve 3 and the assembled inner sleeve 304 are provided with vent holes 302 on their outer sides.

[0023] In the above technical solution, the vent hole 302 allows the air inside the drill bit to be discharged when it enters the assembled casing 3, thereby further reducing the resistance of the drill bit's descent.

[0024] As an optional solution to the technical solution of this application, the threaded mounting hole 301 and the guide hole 306 are arranged alternately.

[0025] In the above technical solution, any prefabricated casing 3 can be installed on the top of the main outer casing 1 without affecting the assembly between the prefabricated casings 3.

[0026] The present invention also aims to provide a method for using a prefabricated casing for rotary pile drilling, comprising the following steps:

[0027] To assemble a prefabricated sleeve 3 onto the upper end of the main outer sleeve 1, specifically: the prefabricated sleeve 3 is fitted onto the fixing stud 4 through the guide hole 306. At this time, the fastening nut 401 is fitted onto the outside of the fixing stud 4 through the cavity sandwich between the prefabricated sleeve 3 and the prefabricated inner sleeve 304. The fastening nut 401 is rotated until it contacts the inner bottom end of the prefabricated sleeve 3, thereby achieving a fixed connection between the main outer sleeve 1 and the prefabricated sleeve 3.

[0028] If it is necessary to connect another assembled casing 3 to the end of the assembled casing 3, first, place the assembled casing 3 to be assembled on the upper side of the assembled casing 3 and align the threaded mounting holes 301 on the upper and lower sides. Then, insert the detachable stud 305 into the limiting through hole from the upper threaded mounting hole 301. When the detachable stud 305 contacts the lower threaded mounting hole 301, rotate the detachable stud 305 so that the detachable stud 305 is screwed into the lower threaded mounting hole 301, and finally achieve the fixed connection of the two assembled casings 3.

[0029] When the drill bit of the rotary drilling rig enters the main outer casing 1, it enters the main inner casing 101 under the guidance of the drill bit guide cylinder 105 and is tangential to the drill bit anti-wear roller 103. When the drill bit rotates, the drill bit anti-wear roller 103 rotates accordingly, thereby reducing the friction between the drill bit and the inside of the main inner casing 101.

[0030] Compared with the prior art, the beneficial effects of this application are as follows:

[0031] 1) In this application, the drill bit anti-wear roller does not need to be assembled separately. The drill bit of the rotary drilling rig can enter the interior of the main inner casing more accurately through the drill bit guide tube. When the drill bit rotates, the drill bit anti-wear roller will also rotate, thereby reducing the friction between the drill bit and the interior of the main inner casing and achieving a better anti-wear effect.

[0032] 2) In this application, the mud trough can discharge the mud as quickly as possible, reduce the resistance to its descent, and thus allow the casing to descend at a faster speed, thereby improving the effective utilization rate of the hammering force. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the overall structure of the prefabricated casing for rotary pile drilling disclosed in a preferred embodiment of this application;

[0034] Figure 2 This is a schematic diagram of the upper and lower isometric overall structure of the prefabricated casing for rotary pile drilling disclosed in a preferred embodiment of this application;

[0035] Figure 3 This is a schematic diagram showing the disassembled structure of the prefabricated casing and detachable stud in the prefabricated casing for rotary pile drilling disclosed in the preferred embodiment of this application.

[0036] Figure 4 This is a schematic diagram showing the disassembled structure of the prefabricated casing and fixing stud in the prefabricated casing for rotary pile drilling disclosed in the preferred embodiment of this application;

[0037] Figure 5 This is a schematic diagram showing the internal structure of the main outer casing and the lower pressure shell of the rotary pile drilling prefabricated casing disclosed in the preferred embodiment of this application.

[0038] Figure 6 This is a cross-sectional structural schematic diagram of the main outer casing and the lower pressure shell of the casing in the prefabricated casing for rotary pile drilling disclosed in the preferred embodiment of this application;

[0039] Figure 7 This is a schematic diagram of the upper and lower isometric structure of the prefabricated casing in the rotary pile drilling prefabricated casing disclosed in the preferred embodiment of this application.

[0040] The attached figures are labeled as follows:

[0041] 1. Main outer casing; 2. Lower casing shell; 3. Assembled casing; 4. Fixing studs;

[0042] 101. Main inner casing; 102. Top mounting plate; 103. Drill bit anti-wear roller; 104. Bottom mounting plate; 105. Drill bit guide tube;

[0043] 201. Lowered inner shell; 202. Sliding groove; 203. Lowered section; 204. Reinforcing circular plate; 301. Mounting hole; 302. Vent hole; 303. Reinforcing rib; 304. Assembly inner cylinder; 305. Removable stud; 306. Guide hole;

[0044] 401. Tighten the nuts. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some embodiments of this invention, but not all embodiments.

[0046] Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] The embodiments and directional terms described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0048] In a broad embodiment of the present invention, a prefabricated casing for rotary pile drilling includes a main outer casing 1 and a prefabricated casing 3, characterized in that the prefabricated casing 3 is installed at the upper end of the main outer casing 1, a main inner casing 101 is provided inside the main outer casing 1, the top end of the main inner casing 101 is fixedly connected to the top end of the main outer casing 1 via a top mounting plate 102, and the bottom end of the main inner casing 101 is fixedly connected to the bottom end of the main outer casing 1 via a bottom mounting plate 104; Multiple drill bit anti-wear rollers 103 arranged in an annular pattern and evenly spaced are rotatably disposed between the top mounting plate 102 and the bottom mounting plate 104. A drill bit guide cylinder 105 is fixedly disposed on the inner side of the top mounting plate 102. The drill bit of the rotary drilling rig enters the interior of the main inner casing 101 through the drill bit guide cylinder 105 and comes into frictional contact with the drill bit anti-wear rollers 103. When the drill bit rotates, the drill bit anti-wear rollers 103 rotate with it, thereby reducing the friction between the drill bit and the interior of the main inner casing 101 and achieving a better anti-wear effect.

[0049] Preferably, the inner cavity of the drill bit guide cylinder 105 is configured as an inverted frustum structure, the inner diameter of the top end of the drill bit guide cylinder 105 is larger than the inner diameter of its bottom end, and the inner wall of the bottom end of the drill bit guide cylinder 105 is tangent to the outer wall of the drill bit anti-wear roller 103.

[0050] Preferably, a cavity interlayer is provided between the main outer casing 1 and the main inner casing 101, and the drill bit anti-wear roller 103 is located in the cavity interlayer. The side wall of the main inner casing 101 is provided with a plurality of vertical strip holes that match the drill bit anti-wear roller 103. The side wall of the drill bit anti-wear roller 103 extends through the corresponding vertical strip holes into the inner cavity of the main inner casing 101.

[0051] Preferably, a protective sleeve lower pressure shell 2 is fixedly provided at the bottom end of the bottom mounting plate 104, and a plurality of mud-sliding grooves 202 distributed in an annular pattern at equal intervals are provided on the side wall of the protective sleeve lower pressure shell 2. A lower pressure part 203 is fixedly provided at the bottom end of the protective sleeve lower pressure shell 2, and a lower pressure inner shell 201 is provided on the inner side of the protective sleeve lower pressure shell 2.

[0052] Preferably, the lower pressure shell 2 and the lower pressure inner shell 201 of the casing are hollowly arranged, and a reinforcing circular plate 204 is fixedly arranged on the inner side of the hollow structure. The bottom inner side of the lower pressure part 203 is rounded. The height of the drill bit anti-wear roller 103 is the same as the height of the main inner casing 101. The length of the mud groove 202 is the same as the height of the lower pressure shell 2 of the casing.

[0053] Preferably, the top of the top mounting plate 102 is fixedly provided with a plurality of fixed studs 4 distributed in a ring at equal intervals, and each fixed stud 4 is threaded with a fastening nut 401; the bottom of the assembled protective sleeve 3 is provided with a plurality of guide holes 306 corresponding one-to-one with the fixed studs 4, and the assembled protective sleeve 3 is slidably disposed on the outside of the fixed studs 4 through the guide holes 306.

[0054] Preferably, the inner side of the assembled casing 3 is provided with an assembled inner cylinder 304, and a reinforcing rib plate 303 is provided between the assembled casing 3 and the assembled inner cylinder 304. The reinforcing rib plate 303 is fixedly disposed between the inner side of the assembled casing 3 and the outer side of the assembled inner cylinder 304. A fixed connecting plate is provided directly above the reinforcing rib plate 303. The fixed connecting plate is fixedly connected to the side wall of the assembled inner cylinder 304. A limiting through hole is provided on the upper side wall of the reinforcing rib plate 303. A threaded mounting hole 301 is provided on the upper side wall of the fixed connecting plate. The axis of the corresponding threaded mounting hole 301 and the limiting through hole coincides. A detachable stud 305 is slidably disposed in the limiting through hole. The lower end of the detachable stud 305 is provided with a thread that matches the threaded mounting hole 301. The top end of the detachable stud 305 is provided with an internal hexagonal groove.

[0055] Preferably, both the assembled protective sleeve 3 and the assembled inner sleeve 304 have vent holes 302 on their outer sides; the threaded mounting hole 301 and the guide hole 306 are arranged in an alternating structure.

[0056] Preferably, the main outer casing 1, the casing lower pressure shell 2, the main inner casing 101, the drill bit guide cylinder 105, the lower pressure inner shell 201, and the lower pressure part 203 are arranged coaxially; the assembled casing 3 is arranged coaxially with the main outer casing 1; the inner diameters of the main inner casing 101, the lower pressure inner shell 201, and the assembled inner casing 304 are equal; the outer diameters of the main outer casing 1, the casing lower pressure shell 2, and the assembled casing 3 are equal.

[0057] The present invention also aims to provide a method for using a prefabricated casing for rotary pile drilling, comprising the following steps:

[0058] To assemble a prefabricated sleeve 3 onto the upper end of the main outer sleeve 1, specifically: the prefabricated sleeve 3 is fitted onto the fixing stud 4 through the guide hole 306. At this time, the fastening nut 401 is fitted onto the outside of the fixing stud 4 from the cavity between the prefabricated sleeve 3 and the prefabricated inner sleeve 304. The fastening nut 401 is rotated sequentially until it contacts the inner bottom end of the prefabricated sleeve 3, thereby achieving a fixed connection between the main outer sleeve 1 and the prefabricated sleeve 3.

[0059] If it is necessary to connect another assembled casing 3 to the end of the assembled casing 3, first, place the assembled casing 3 to be assembled on the upper side of the assembled casing 3 and align the threaded mounting holes 301 on the upper and lower sides. Then, insert the detachable studs 305 into the limiting through holes from the upper threaded mounting holes 301. When the detachable studs 305 contact the lower threaded mounting holes 301, rotate the detachable studs 305 so that the detachable studs 305 are screwed into the lower threaded mounting holes 301, and finally achieve the fixed connection of the two assembled casings 3.

[0060] When the drill bit of the rotary drilling rig enters the main outer casing 1, it is guided by the drill bit guide cylinder 105 into the main inner casing 101 and tangential to the drill bit anti-wear roller 103. As the drill bit rotates, the drill bit anti-wear roller 103 rotates accordingly, thereby reducing friction between the drill bit and the inside of the main inner casing 101. The preferred embodiments of the present invention are described below with reference to the accompanying drawings for further detailed explanation.

[0061] Reference Figure 1 and Figure 5 This application discloses an assembled casing for rotary pile drilling, including...

[0062] A main outer casing 1, with a main inner casing 101 disposed inside the main outer casing 1. The top end of the main inner casing 101 is fixedly connected to the top end of the main outer casing 1 via a top mounting plate 102, and the bottom end of the main inner casing 101 is fixedly connected to the bottom end of the main outer casing 1 via a bottom mounting plate 104. Multiple drill bit anti-wear rollers 103, arranged in a ring and evenly spaced, are rotatably disposed between the top mounting plate 102 and the bottom mounting plate 104. The inner side of the top mounting plate 102 is fixedly equipped with... A drill bit guide cylinder 105 is provided, and the side wall of the drill bit anti-wear roller 103 is tangentially arranged with the inner wall of the drill bit guide cylinder 105. A protective sleeve lower pressure shell 2 is fixedly provided at the bottom end of the bottom mounting plate 104. The side wall of the protective sleeve lower pressure shell 2 is provided with a plurality of annularly distributed mud grooves 202. A lower pressure part 203 is fixedly provided at the bottom end of the protective sleeve lower pressure shell 2. A lower pressure inner shell 201 is provided on the inner side of the protective sleeve lower pressure shell 2. An assembled protective sleeve 3 is provided at the top end of the top mounting plate 102.

[0063] The main outer casing 1, the casing lower pressure shell 2, the main inner casing 101, the drill bit guide cylinder 105, the lower pressure inner shell 201, and the lower pressure part 203 are arranged coaxially; the assembled casing 3 is also arranged coaxially with the main outer casing 1; the inner diameters of the main inner casing 101, the lower pressure inner shell 201, and the assembled inner casing 304 are equal; the outer diameters of the main outer casing 1, the casing lower pressure shell 2, and the assembled casing 3 are equal.

[0064] The drill bit anti-wear roller 103 does not need to be assembled separately. The drill bit of the rotary drilling rig can enter the interior of the main inner casing 101 more accurately through the drill bit guide tube 105. When the drill bit rotates, the drill bit anti-wear roller 103 will also rotate, thereby reducing the friction between the drill bit and the interior of the main inner casing 101 and achieving a better anti-wear effect.

[0065] Reference Figure 5 and Figure 6 The height of the drill bit anti-wear roller 103 is the same as the height of the main inner casing 101. A cavity interlayer is provided between the main outer casing 1 and the main inner casing 101. The drill bit anti-wear roller 103 is located in the cavity interlayer. Here, the drill bit anti-wear roller 103 can have more contact with the drill bit between the rotary drilling machine, thus achieving a better anti-wear effect.

[0066] Reference Figure 1 and Figure 5The lower casing 2 and the inner casing 201 of the casing are hollow. A reinforcing circular plate 204 is fixedly installed on the inner side of the hollow structure. The bottom inner side of the lower part 203 is rounded. The length of the mud sliding groove 202 is the same as the height of the lower casing 2. Here, the mud sliding groove 202 on the outside of the lower casing 2 can discharge the mud as quickly as possible, so that the lower casing 2 can descend faster, reduce the resistance of its descent, and make more of the hammering force available.

[0067] The inner cavity of the drill bit guide cylinder 105 is designed as an inverted frustum. The inner diameter of the top end of the drill bit guide cylinder 105 is larger than that of the bottom end. This allows the drill bit of the rotary drilling rig to smoothly enter the interior of the main inner casing 101 and be tangent to the drill bit anti-wear roller 103 by being guided by the drill bit guide cylinder 105.

[0068] Reference Figure 4 and Figure 7 The top of the top mounting plate 102 is fixedly provided with a plurality of fixed studs 4 arranged in a ring at equal intervals. Each fixed stud 4 is threadedly connected with a fastening nut 401. The bottom end of the assembled protective sleeve 3 is provided with a plurality of guide holes 306 corresponding one-to-one with the fixed studs 4. The assembled protective sleeve 3 is slidably disposed on the outside of the fixed studs 4 through the guide holes 306. Here, the assembled protective sleeve 3 is sleeved on the fixed studs 4 through the guide holes 306 to achieve a fixed connection between the main outer protective sleeve 1 and the assembled protective sleeve 3. The fastening nut 401 is sleeved on the outside of the fixed studs 4 through the cavity sandwich between the assembled protective sleeve 3 and the assembled inner sleeve 304. The fastening nut 401 is rotated until it contacts the inner bottom end of the assembled protective sleeve 3, thereby achieving a fixed connection between the main outer protective sleeve 1 and the assembled protective sleeve 3. This achieves both the protective effect of the protective sleeve and facilitates the assembly and use of the main outer protective sleeve 1 and the assembled protective sleeve 3.

[0069] Reference Figure 1 and Figure 3The assembled casing 3 has an inner casing 304 on its inner side. A reinforcing rib 303 is provided between the assembled casing 3 and the inner casing 304. The reinforcing rib 303 is fixedly disposed between the inner side of the assembled casing 3 and the outer side of the inner casing 304. A fixing connecting plate is provided directly above each reinforcing rib 303. The fixing connecting plate is fixedly connected to the side wall of the inner casing 304. A limit hole is provided on the upper side wall of the reinforcing rib 303. The upper side wall of the fixing connecting plate is provided with... There is a threaded mounting hole 301, and the axis of the corresponding threaded mounting hole 301 and the limiting through hole coincides. A detachable stud 305 is slidably arranged in the limiting through hole. The lower end of the detachable stud 305 is provided with a thread that matches the threaded mounting hole 301. The top end of the detachable stud 305 is provided with an internal hexagonal groove threaded mounting hole 301. Vent holes 302 are provided on the outer side of both the assembled protective sleeve 3 and the assembled inner cylinder 304. The threaded mounting hole 301 and the guide hole 306 are staggered. Here, after the main outer casing 1 and the assembled casing 3 are assembled, if it is necessary to connect another assembled casing 3 to the end of the assembled casing 3, place the assembled casing 3 to be assembled on the upper side of the assembled casing 3 and align the upper and lower threaded mounting holes 301. Then, insert the detachable stud 305 into the limiting through hole from the upper threaded mounting hole 301. When the detachable stud 305 contacts the lower threaded mounting hole 301, rotate the detachable stud 305 so that the detachable stud 305 is screwed into the lower threaded mounting hole 301. The threaded mounting hole 301 finally realizes the fixed connection of the two assembled casings 3. The internal hexagonal groove opened at the upper end of the detachable stud 305 makes it easy to install and disassemble, so that the assembled casing 3 can be quickly assembled.

[0070] Working principle: First, the main outer casing 1 and the assembled casing 3 can be connected. Because multiple fixing studs 4 are fixedly installed at the top of the top mounting plate 102, the assembled casing 3 must be installed before it can be hammered and sunk into the ground. After the assembled casing 3 is fitted onto the outside of the fixing studs 4 through the guide hole 306, the fixing studs 4 are used to fix the main outer casing 1 and the assembled casing 3. The fastening nut 401 is fitted onto the outside of the fixing studs 4 from the interlayer between the assembled casing 3 and the assembled inner cylinder 304. Then, the fastening nut 401 is rotated until the fastening nut 401 is flush with the assembled casing 3. The inner bottom end contacts and thus fixes the main outer casing 1 and the assembled casing 3. This achieves both the protective effect of the casing and facilitates the assembly and use of the main outer casing 1 and the assembled casing 3. Then, the assembled casing 3 can be hammered to make the main outer casing 1 and the assembled casing 3 descend synchronously. When the main outer casing 1 and the casing lower pressure shell 2 are inserted into the hole, the assembled casing 3 assembled at the top of the main outer casing 1 is hammered, allowing the main outer casing 1 and the casing lower pressure shell 2 to descend. The mud sliding groove 202 on the outside of the casing lower pressure shell 2 can quickly expel the soil, allowing the casing lower pressure shell 2 to descend faster, reducing its descent resistance, and increasing the hammering force. More quantity can be utilized to achieve a better reduction effect. If it is necessary to assemble the assembled sleeves 3 together, place one assembled sleeve 3 on top of the other assembled sleeve 3, and then insert the removable stud 305 into the inside of the assembled sleeve 3 from the top of the threaded mounting hole 301 until it can no longer be inserted. Then rotate the removable stud 305, and one end of the removable stud 305 can be screwed into the inside of the threaded mounting hole 301 at the bottom of the assembled sleeve 3, fixing the two assembled sleeves 3 together. The internal hexagonal groove at the other end of the removable stud 305 facilitates installation and disassembly. The assembled casing 3 can be easily installed without affecting the use of the rotary drilling rig. When the drill bit of the rotary drilling rig enters the main outer casing 1, it will contact the drill bit guide tube 105. The drill bit guide tube 105 allows the drill bit of the rotary drilling rig to enter the main inner casing 101 more accurately and then become tangent to the drill bit anti-wear roller 103. When the drill bit rotates, the drill bit anti-wear roller 103 will also rotate, thereby reducing the friction between the drill bit and the inside of the main inner casing 101. This eliminates the need to install the drill bit anti-wear roller 103 multiple times, reduces the impact of drill bit vibration on the drill bit anti-wear roller 103, and thus achieves a better anti-wear effect and improves work efficiency.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A prefabricated casing for rotary pile drilling, comprising a main outer casing (1) and a prefabricated casing (3), characterized in that, The assembled casing (3) is installed at the upper end of the main outer casing (1). A main inner casing (101) is provided inside the main outer casing (1). The top end of the main inner casing (101) is fixedly connected to the top end of the main outer casing (1) through a top mounting plate (102). The bottom end of the main inner casing (101) is fixedly connected to the bottom end of the main outer casing (1) through a bottom mounting plate (104). Between the top mounting plate (102) and the bottom mounting plate (104) The rotary drilling machine is equipped with multiple drill bit anti-wear rollers (103) arranged in a ring at equal intervals. The top mounting plate (102) is fixedly provided with a drill bit guide cylinder (105). The drill bit of the rotary drilling machine enters the interior of the main inner casing (101) through the drill bit guide cylinder (105) and comes into frictional contact with the drill bit anti-wear rollers (103). When the drill bit rotates, the drill bit anti-wear rollers (103) rotate with it, thereby reducing the friction between the drill bit and the interior of the main inner casing (101) and achieving a better anti-wear effect. The inner cavity of the drill bit guide cylinder (105) is arranged in the shape of an inverted frustum. The inner diameter of the top end of the drill bit guide cylinder (105) is larger than the inner diameter of its bottom end. The inner wall of the bottom end of the drill bit guide cylinder (105) is tangent to the outer wall of the drill bit anti-wear roller (103). A cavity interlayer is provided between the main outer casing (1) and the main inner casing (101). The drill bit anti-wear roller (103) is located in the cavity interlayer. The side wall of the main inner casing (101) is provided with a plurality of vertical strip holes that match the drill bit anti-wear roller (103). The side wall of the drill bit anti-wear roller (103) extends through the corresponding vertical strip holes into the inner cavity of the main inner casing (101). The bottom mounting plate (104) is fixedly provided with a protective sleeve lower pressure shell (2). The side wall of the protective sleeve lower pressure shell (2) is provided with a plurality of mud sliding grooves (202) distributed in an annular pattern at equal intervals. The bottom end of the protective sleeve lower pressure shell (2) is fixedly provided with a lower pressure part (203). The inner side of the protective sleeve lower pressure shell (2) is provided with a lower pressure inner shell (201). The casing lower pressure shell (2) and the lower pressure inner shell (201) are hollowly arranged. A reinforcing circular plate (204) is fixedly arranged on the inner side of the hollow structure. The bottom inner side of the lower pressure part (203) is rounded. The height of the drill bit anti-wear roller (103) is the same as the height of the main inner casing (101). The length of the mud groove (202) is the same as the height of the casing lower pressure shell (2). The top of the top mounting plate (102) is fixedly provided with a plurality of fixed studs (4) arranged in a ring at equal intervals, and each fixed stud (4) is threaded with a fastening nut (401); the bottom of the assembled protective sleeve (3) is provided with a plurality of guide holes (306) corresponding one-to-one with the fixed studs (4), and the assembled protective sleeve (3) is slidably disposed on the outside of the fixed studs (4) through the guide holes (306).

2. The assembled casing for rotary pile drilling according to claim 1, characterized in that, An inner assembly cylinder (304) is provided on the inner side of the assembled casing (3). A reinforcing rib (303) is provided between the assembled casing (3) and the inner assembly cylinder (304). The reinforcing rib (303) is fixedly provided between the inner side of the assembled casing (3) and the outer side of the inner assembly cylinder (304). A fixed connecting plate is provided directly above each reinforcing rib (303). The fixed connecting plate is fixedly connected to the side wall of the inner assembly cylinder (304). The upper sidewall of the reinforcing rib (303) is provided with a limiting through hole, and the upper sidewall of the fixed connecting plate is provided with a threaded mounting hole (301). The corresponding threaded mounting hole (301) and the limiting through hole have the same axis. A detachable stud (305) is slidably provided in the limiting through hole. The lower end of the detachable stud (305) is provided with a thread that matches the threaded mounting hole (301), and the top end of the detachable stud (305) is provided with an internal hexagonal groove.

3. The assembled casing for rotary pile drilling according to claim 2, characterized in that, Vent holes (302) are provided on the outer sides of both the assembled casing (3) and the assembled inner cylinder (304); the threaded mounting hole (301) and the guide hole (306) are arranged in an alternating structure.

4. The assembled casing for rotary pile drilling according to claim 3, characterized in that, The main outer casing (1), the casing lower pressure shell (2), the main inner casing (101), the drill bit guide cylinder (105), the lower pressure inner shell (201), and the lower pressure part (203) are arranged coaxially; the assembled casing (3) is arranged coaxially with the main outer casing (1); the inner diameters of the main inner casing (101), the lower pressure inner shell (201), and the assembled inner cylinder (304) are equal; the outer diameters of the main outer casing (1), the casing lower pressure shell (2), and the assembled casing (3) are equal.

5. The method of using the assembled casing for rotary pile drilling according to claim 4, characterized in that, Includes the following steps: To assemble an assembled sleeve (3) onto the upper end of the main outer sleeve (1), specifically: the assembled sleeve (3) is fitted onto the fixing stud (4) through the guide hole (306). At this time, the fastening nut (401) is fitted onto the outside of the fixing stud (4) from the cavity between the assembled sleeve (3) and the assembled inner sleeve (304). The fastening nut (401) is rotated sequentially until the fastening nut (401) contacts the inner bottom end of the assembled sleeve (3), thereby achieving a fixed connection between the main outer sleeve (1) and the assembled sleeve (3). If it is necessary to connect another assembled casing (3) to the end of the assembled casing (3), first, place the assembled casing (3) to be assembled on the upper side of the assembled casing (3) and align the threaded mounting holes (301) on the upper and lower sides. Then, insert the detachable stud (305) into the limiting through hole from the upper threaded mounting hole (301) in sequence. When the detachable stud (305) contacts the lower threaded mounting hole (301), rotate the detachable stud (305) so that the detachable stud (305) is screwed into the lower threaded mounting hole (301), and finally achieve the fixed connection of the two assembled casings (3). When the drill bit of the rotary drilling rig enters the main outer casing (1), it enters the main inner casing (101) under the guidance of the drill bit guide tube (105) and is tangential to the drill bit anti-wear roller (103). When the drill bit rotates, the drill bit anti-wear roller (103) rotates accordingly, thereby reducing the friction between the drill bit and the inside of the main inner casing (101).

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