A rotary drilling rig for forming a hole for a super-large diameter bored pile and a construction method

Abstract

The application discloses a super-large-diameter rotary drilling rig for hole forming of a bored pile and a construction method, and the rotary drilling rig comprises a main body, a cutting body and a guide body, the cutting body and the guide body are fixed on the main body; the upper part and the lower part of a barrel of the main body are provided with mounting seats, the pressing plates of the mounting seats transmit the pressing force provided by a power head of the rotary drilling rig, and the side surface of the mounting seat forms a square head base body which cooperates with the cutting body to transmit torque. The construction method of the super-large-diameter rotary drilling rig for hole forming of a bored pile comprises the following steps: (1) steel casing burying; (2) Φ4500mm diameter drilling construction; (3) super-large-diameter bored pile reaming construction; (4) using a full-face drilling tool to sweep the hole bottom flat; (5) one-time hole cleaning; (6) lowering a steel reinforcement cage; (7) two-time hole cleaning; and (8) pouring concrete. The application realizes disassembly and transportation of the super-large-diameter rotary drilling rig with a diameter of more than Φ4500mm, fills the gap of the construction method of the rotary drilling rig in the field of the super-large-diameter bored pile, reduces the overall weight of the drilling rig, and reduces the construction cost.

Description

Technical Field

[0001] This invention relates to rotary drilling rigs in the field of building construction technology, and more particularly to a rotary drilling rig and construction method for drilling ultra-large diameter bored piles. Background Technology

[0002] With the rapid development of economic construction and the continuous expansion of infrastructure projects, rotary drilling rigs have been widely used in various infrastructure constructions due to their significant advantages such as convenient construction, high efficiency, low cost, and environmental friendliness. In recent years, with the accelerated pace of large-scale bridge construction, the diameter of bored piles drilled by rotary drilling rigs has been increasing. This has presented unprecedented challenges to the manufacturing and transportation costs of drilling tools and the rotary drilling rig construction methods. The proposed Xihoumen Railway-Highway Bridge's main tower pier foundation design utilizes 18 ultra-large diameter bored piles with a diameter of φ6300mm. However, there are currently no precedents for rotary drilling rigs and construction methods used to drill ultra-large diameter bored piles with a diameter greater than φ4500mm.

[0003] In the construction of traditional large-diameter bored piles with diameters ranging from φ2500mm to φ4500mm, a staged drilling technique is typically used. This involves initially using a small-diameter drill bit, followed by progressively enlarging the hole with an enlarging drill bit until the designed diameter and depth are reached. However, for ultra-large-diameter bored piles with a diameter of φ6300mm, the rotary drilling rigs and construction methods employed using the traditional staged drilling technique have several shortcomings and problems:

[0004] On the one hand, drilling 6300mm diameter bored piles involves multiple stages, increasing the number of rotary drilling tools required. Especially for ultra-large diameter rotary drilling tools, the weight increases dramatically to ensure strength, directly increasing construction costs significantly. On the other hand, rotary drilling tools with diameters ranging from 4500mm to 6300mm have excessively wide transport widths, making transportation difficult, significantly increasing costs and risks, and even making them impossible to transport. Another drawback is that traditional staged drilling technology, with its rotary drilling tools primarily consisting of rock drills and sand scoops, cannot meet the construction requirements of ultra-large diameter bored piles. To ensure drilling quality and safe construction, not only are multiple types of rotary drilling tools needed, but a completely new construction method is also required to achieve this goal. Summary of the Invention

[0005] Objective: To address the technical problems existing in the prior art, this invention proposes a rotary drilling rig and construction method for drilling ultra-large diameter bored piles. It enables the disassembly, transportation, and on-site assembly of rotary drilling tools with diameters exceeding 4500mm. Each disassembled component meets ordinary transportation requirements, solving the problem of difficult transportation of ultra-large diameter rotary drilling rigs and reducing transportation difficulty and construction costs. The construction method of this invention achieves the combined use of various types of drilling tools, including lower guide tools, upper guide tools, and full-section drilling tools, by replacing the guide body and cutting body. This meets the needs of staged drilling construction for ultra-large diameter bored piles exceeding 4500mm, filling a gap in rotary drilling rig construction for ultra-large diameter bored piles, reducing the overall weight of the drilling rig, and lowering construction costs while ensuring drilling speed and quality.

[0006] Technical solution: The rotary drilling rig for drilling ultra-large diameter bored piles of the present invention includes a main body, a cutting body and a guide body, wherein the cutting body and the guide body are fixed on the main body;

[0007] Mounting seats are provided at the upper and lower parts of the main body cylinder. The pressure plate of the mounting seat transmits the pressure provided by the power head of the rotary drilling rig. The side of the mounting seat forms a square head base that cooperates with the cutting body to transmit torque.

[0008] The cutting body comprises multiple cutting body units, which together with the main body form a cutting body with an outer circle and an inner square.

[0009] The guide body comprises multiple guide body units, which together with the main body form a guide body with an outer circle and an inner square.

[0010] The main body's square head base works in conjunction with the first square box of the cutting body and the second square box of the guide body to transmit torque and pressure.

[0011] The construction method for forming ultra-large diameter bored piles according to the present invention includes the following steps:

[0012] (1) Install double-layer steel casing: First, use a vibratory hammer and a hydraulic hammer to install the double-layer steel casing in place, and insert the casing into the stable soil layer, especially when constructing on a water platform, to ensure construction safety and accurate hole position;

[0013] (2) Drilling of a Φ4500mm diameter hole: Using conventional drilling tools, the hole was reamed in stages. The process was as follows:

[0014] (2.1) Use a small-diameter sand-scooping bucket to drill and extract soil from the upper soft soil layer;

[0015] (2.2) Core samples were taken from the lower rock strata using a cutting tooth drill or roller cone drill with the same diameter as in the previous step (2.1).

[0016] (2.3) Use a reaming drill bit with a diameter one size larger than that of the borehole in step (2.2) to perform reaming operations, and use a sand scooping bucket of the same specification as the borehole in step (2.2) to scoop out the drill cuttings until the designed depth is reached;

[0017] (2.4) Repeat step (2.3) using a reaming drill bit and a sand scoop with a diameter one size larger than the one used in the previous step to ream and remove slag from the previous step until the designed depth is reached.

[0018] (2.5) After enlarging the hole to a diameter of Φ4500mm, pull out the inner steel casing and carry out enlargement drilling for ultra-large diameter bored piles;

[0019] (3) Expansion construction of ultra-large diameter bored piles: Prefabricated rotary drilling rigs are used to determine the number of stages of expansion.

[0020] (3.1) Use a guide drill bit one size larger than Φ4500mm to enlarge the hole and drill for 3m-5m;

[0021] (3.2) Use an upper guide drill bit that is one size larger than Φ4500mm to continue drilling to the design depth, increase the overall height of the drill bit, and ensure the verticality of the borehole;

[0022] (3.3) Use a Φ4500mm sand-retrieving bucket in conjunction with a guide drill bit to retrieve drill cuttings until the designed depth is reached;

[0023] (3.4) Repeat steps (3.1), (3.2) and (3.3) with a lower guide drill bit, an upper guide drill bit, a hole reaming drill bit and a 4500mm sand scooping bucket that are one size larger than the borehole diameter used in the previous step to enlarge the borehole formed in the previous step until the designed diameter and depth are reached.

[0024] (4) Hole bottom leveling: Use full-section drilling tools to cut the bottom of the hole flat;

[0025] (5) One-time hole cleaning: Use a Φ4500mm sand scoop to remove sediment multiple times;

[0026] (6) Lowering the steel cage: The steel cage is installed using a hole-and-hole connection method, and a detection tube is installed;

[0027] (7) Secondary hole cleaning: Install concrete pouring pipe, set up forward and reverse circulation device on the pipe, and use forward and reverse circulation process to clean the hole. Multiple sets of forward and reverse circulation devices are used according to the diameter.

[0028] (8) Concrete pouring: After the second cleaning of the hole, the forward and reverse circulation device is removed, and concrete is poured using a guide pipe.

[0029] In step (1), the inner diameter of the outer steel casing of the double-layer steel casing is 100-300 mm larger than the diameter of the hole.

[0030] In step (2.2), if a core sample cannot be obtained, a sand scoop of the same diameter is used to crush and retrieve the sample until the designed depth is reached.

[0031] In step (3.1), the cutting body is installed on the upper mounting base, which is mainly composed of the lower guide drill bit, and the guide body is installed on the lower mounting base; the guide body has the same diameter as the hole diameter in the previous step, and the cutting body is one size larger than the drilling diameter used in the previous step.

[0032] In step (3.2), the upper guide drill bit consists of an upper mounting base for mounting the guide body and a lower mounting base for mounting the cutting body; the guide body and the cutting body are one size larger than the borehole diameter used in the previous step.

[0033] In step (4), the full-section drilling tool consists of a guide body with the hole diameter installed on the upper mounting base and a cutting body with the hole diameter installed on the lower mounting base. The cutting body is equipped with multiple cutting teeth plates, and the bottom of the drill hole is milled flat through full-section cutting drilling.

[0034] Working principle: The rotary drilling rig for drilling ultra-large diameter bored piles of the present invention includes a main body, a cutting body and a guide body. The cutting body and the guide body are fixed on the main body. Mounting seats are provided on the upper and lower parts of the main body cylinder. The pressure plate of the mounting seat transmits the pressure provided by the power head of the rotary drilling rig. The side of the mounting seat forms a square head base that cooperates with the cutting body to transmit torque.

[0035] The construction method of this invention includes the following steps: (1) steel casing installation; (2) Φ4500mm diameter drilling construction; (3) ultra-large diameter bored pile hole enlargement construction; (4) using full-section drilling tools to level the bottom of the hole; (5) primary hole cleaning; (6) lowering the reinforcing cage; (7) secondary hole cleaning; (8) concrete pouring. Among them, the steel casing installation adopts double-layer steel casing to ensure construction safety and accurate hole position; the Φ4500mm diameter drilling operation uses conventional graded drilling tools and construction methods; the Φ4500mm hole enlargement operation to the designed pile diameter of ultra-large diameter bored pile is completed by using assembled drilling tools, including lower guide drilling tools, upper guide drilling tools, full-section drilling tools, and Φ4500mm sand scooping buckets; the secondary hole cleaning adopts 2-4 sets of forward and reverse circulation hole cleaning devices evenly distributed in the borehole, and mud processors are used during mud circulation to handle the mud, which meets the environmental protection construction requirements.

[0036] This invention solves the problem of transporting ultra-large diameter rotary drilling rigs, reducing transportation difficulty and construction costs. The construction method of this invention's rotary drilling rig achieves the functions of various drilling tools—lower guide tool, upper guide tool, and full-section tool—by changing the guide body and cutting body, meeting the technical requirements of staged drilling construction for ultra-large diameter bored piles.

[0037] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0038] (1) The prefabricated rotary drilling rig of the present invention can be disassembled for transportation and assembled on the construction site. Each disassembled component meets the requirements of ordinary transportation, solving the problem of transportation difficulties of ultra-large diameter rotary drilling tools and reducing the difficulty and cost of transportation.

[0039] (2) By replacing the guide body and the cutting body, the functions of various types of drilling tools such as lower guide drilling tools, upper guide drilling tools, and full-section drilling tools can be realized, which reduces the overall weight of the drilling tools and lowers the construction cost.

[0040] (3) The construction method of the present invention ensures the speed and quality of borehole formation, reduces construction costs, fills the gap in rotary drilling rig construction methods for ultra-large diameter borehole piles, and provides a reference for similar engineering construction. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the structure of the rotary drilling rig for ultra-large diameter bored piles of the present invention;

[0042] Figure 2 This is a schematic diagram of the main structure of the rotary drilling rig for drilling ultra-large diameter bored piles according to the present invention;

[0043] Figure 3 This is a schematic diagram of the cutting body structure of the rotary drilling rig for drilling ultra-large diameter bored piles according to the present invention;

[0044] Figure 4 This is a schematic diagram of the guide body structure of the rotary drilling tool for drilling ultra-large diameter bored piles according to the present invention;

[0045] Figure 5 This is a flowchart of the construction method for forming ultra-large diameter bored piles according to the present invention;

[0046] Figure 6 This is a schematic diagram of the forward and reverse circulation hole cleaning device of the present invention. Detailed Implementation

[0047] In this embodiment of the invention, the pile hole is Φ6300mm and the drilling depth is 100m.

[0048] like Figures 1 to 6 As shown, the rotary drilling rig for drilling ultra-large diameter bored piles of the present invention includes a main body 1, a cutting body 2 and a guide body 3. The cutting body 2 and the guide body 3 are fixed to the main body 1 in a detachable manner by means of a pin 4.

[0049] A set of mounting seats 11 is provided on the upper and lower parts of the outer wall of the main body 1. The pressure plate 111 of each set of mounting seats 11 transmits the pressure provided by the rotary drilling rig power head on the same plane. The side 112 of the mounting seat forms a square head base that cooperates with the cutting body 2 to transmit torque.

[0050] The cutting body 2 includes 2 to 4 cutting body units, which are detachably assembled with the main body 1 via pins 4. After assembly, they are welded and fixed to form a cutting body with an outer circle and an inner square.

[0051] The guide body 3 includes 2 to 4 guide body units, which are detachably assembled with the main body 1 via pins 4. After assembly, they are welded and fixed to form a guide body with an outer circle and an inner square.

[0052] The square head base on the main body 1 cooperates with the first square box 21 of the cutting body 2 and the second square box 31 of the guide body to realize the transmission of torque and pressure.

[0053] In staged drilling, only the cutting body 2 and guide body 3 of different diameters need to be replaced to meet the construction requirements of staged drilling.

[0054] The construction method for rotary drilling of ultra-large diameter pile foundations according to the present invention includes the following specific steps:

[0055] (1) Installing steel casing: First, use a vibratory hammer, hydraulic hammer and other tools to install the double-layer steel casing in place, insert the steel casing into the stable soil layer to ensure construction safety and accurate hole position. Pay attention to the above requirements, especially when installing steel casing on a water platform.

[0056] The outer steel casing has an inner diameter of Φ6500mm and a thickness of 100mm. The inner steel casing has an inner diameter of Φ4700mm and a thickness of 60mm. The inner diameter of the steel casing is larger than the diameter of the drill bit, which facilitates the lowering and lifting of the rotary drilling tool.

[0057] (2) Drilling construction with a diameter of Φ4.500m: conventional drilling tools were used, and the drilling was carried out in stages with enlargement.

[0058] (2.1) For the upper soft soil layer, use a Φ1500mm diameter sand scoop to directly drill and extract soil until the drilling is completed;

[0059] (2.2) Use a Φ1500mm cutting tooth cylinder drill to drill and obtain rock cores in the lower rock strata. If rock cores cannot be obtained, use a Φ1500mm sand scooping bucket to crush and collect the drill cuttings until the designed depth is reached.

[0060] (2.3) Use a larger reaming drill bit than the one used in step (2.2) to perform reaming operations, and use a small-diameter sand scoop to remove drill cuttings until the designed depth is reached;

[0061] (2.4) Repeat step (2.3) using a reaming drill bit and a sand scoop with a diameter one size larger than the one used in the previous step to ream and remove slag from the previous step until the designed depth is reached.

[0062] (2.5) After enlarging the hole to a diameter of Φ4500mm, pull out the inner steel casing and proceed to the next step of enlarging the hole for the ultra-large diameter bored pile.

[0063] (3) Enlargement construction of ultra-large diameter bored piles: Prefabricated rotary drilling tools are used to determine the number of stages of enlargement.

[0064] (3.1) Use a lower guide drill bit with a cutting body of Φ5000mm and a guide body of Φ4500mm to ream and drill for 3-5m;

[0065] (3.2) The upper guide drill bit with a cutting body of Φ5000mm and a guide body of Φ5000mm is used to continue drilling to the design depth. Compared with conventional drill bits, the height of the drill bit is increased under the condition of a certain weight, which ensures the verticality of the borehole.

[0066] (3.3) Use a Φ4500mm sand-retrieving bucket in conjunction with a guide drill bit to retrieve drill cuttings until the designed depth is reached;

[0067] (3.4) Repeat steps (3.1), (3.2), and (3.3) in sequence using a lower guide drill bit, an upper guide drill bit, and a Φ4500mm sand scoop, which are one size larger than the previous step's borehole diameter, to enlarge the borehole formed in the previous step and remove slag until the designed diameter Φ6300mm and borehole depth 100m are achieved.

[0068] (4) Hole bottom leveling: After enlarging the hole to a diameter of Φ6300mm, use a full-section drilling tool to level the bottom of the hole;

[0069] (5) One-time hole cleaning: Use a Φ4500mm sand scoop to remove sediment multiple times;

[0070] (6) Lowering the steel cage: The steel cage is installed using a hole-and-hole connection method, and an ultrasonic detection tube is installed;

[0071] (7) Secondary hole cleaning: Install 3 sets of concrete pouring guide pipes, set up forward and reverse circulation devices on the guide pipes, and use forward and reverse circulation process to clean the hole;

[0072] The guide pipe has a diameter of Φ300mm, a bottom pipe length of ≥4m, and the lengths of the remaining guide pipe sections are 3m each; the air compressor has a rated pressure of 0.8MPa, and the mud processor has a mud processing capacity of 200m³. 3 .

[0073] (8) After the second cleaning of the hole, the forward and reverse circulation devices are removed, and concrete is poured using 3 sets of guide pipes.

[0074] As a preferred embodiment, in step (3.1), the upper mounting base 11 of the lower guide drill bit as the main body 1 is used to install the cutting body 2, and the lower mounting base 11 is used to install the guide body 3; the guide body 3 has the same diameter as the borehole in the previous step, and the cutting body 3 is one size larger than the borehole diameter used in the previous step.

[0075] As a preferred option, in step (3.2), the upper mounting base 11 of the upper guide drill bit 1 is equipped with the guide body 3, and the lower mounting base 11 is equipped with the cutting body 2; the guide body 3 and the cutting body 2 are one size larger than the borehole diameter used in the previous step.

[0076] As a preferred option, in step (4), the upper mounting base 11 of the full-section drilling tool 1 is equipped with a guide body 3 of the hole diameter, and the lower mounting base 11 is equipped with a cutting body 2 of the hole diameter; the cutting body is equipped with multiple cutting tooth plates 22 to perform full-section cutting drilling and mill the bottom of the hole flat.

[0077] The forward and reverse circulation device used in step (7) consists of an injection conduit, an air compressor, a mud processor, and their connecting pipelines.

Claims

1. A construction method for forming ultra-large diameter bored piles, characterized in that: The drilling is carried out by a rotary drilling rig for drilling large-diameter bored piles. The rotary drilling rig includes a main body (1), a cutting body (2) and a guide body (3), and the cutting body (2) and the guide body (3) are fixed on the main body (1). Mounting seats (11) are provided on the upper and lower parts of the cylinder of the main body (1). The pressure plate (111) of the mounting seat (11) transmits the pressure provided by the power head of the rotary drilling rig. The side (112) of the mounting seat (11) forms a square head base that cooperates with the cutting body (2) to transmit torque. The cutting body (2) includes multiple cutting body units, and the cutting body units and the main body (1) form a cutting body with an outer circle and an inner square. The guide body (3) includes multiple guide body units, and the guide body units and the main body (1) form a guide body with an outer circle and an inner square. The square head base of the main body (1) cooperates with the first square box (21) of the cutting body (2) and the second square box (31) of the guide body (3) to transmit torque and pressure; The method includes the following steps: (1) Installing double-layer steel casing: First, use a vibratory hammer and a hydraulic hammer to install the double-layer steel casing in place, and insert the steel casing into the stable soil layer; the inner diameter of the outer steel casing of the double-layer steel casing is 100 to 300 mm larger than the diameter of the hole. (2) Drilling of a Φ4500mm diameter hole was carried out, with staged reaming drilling. The process was as follows: (2.1) Use a sand-dredging bucket to drill and extract soil from the upper soft soil layer; (2.2) Core samples were taken from the lower rock strata using a cutting tooth drill or roller cone drill with the same diameter as in step (2.1); (2.3) Use a reaming drill bit with a diameter one size larger than that of the borehole in step (2.2) to perform reaming operations, and use a sand scooping bucket of the same specification as the borehole in step (2.2) to scoop out the drill cuttings until the designed depth is reached; (2.4) Repeat step (2.3) using a reaming drill bit and a sand scoop with a diameter one size larger than the previous step to ream and remove slag from the previous step until the designed depth is reached. (2.5) After enlarging the hole to a diameter of Φ4500mm, pull out the inner steel casing and carry out enlargement drilling for ultra-large diameter bored piles; (3) Expansion construction of ultra-large diameter bored piles: Prefabricated rotary drilling rigs are used to determine the number of stages of expansion. (3.1) Use a lower guide drill bit that is one size larger than Φ4500mm to enlarge the hole and drill for 3m-5m; install the cutting body on the upper mounting base with the lower guide drill bit as the main body, and install the guide body on the lower mounting base; the guide body has the same diameter as the hole diameter in the previous step, and the cutting body is one size larger than the hole diameter used in the previous step; (3.2) Continue drilling to the designed depth using an upper guide drill bit that is one size larger than Φ4500mm to ensure the verticality of the borehole; the upper guide drill bit consists of an upper mounting base for mounting the guide body and a lower mounting base for mounting the cutting body; the guide body and the cutting body are one size larger than the borehole diameter used in the previous step; (3.3) Use a Φ4500mm sand scooping bucket in conjunction with a guide drill bit to scoop up drill cuttings until the designed depth; (3.4) Repeat steps (3.1) to (3.3) with a reaming drill bit one size larger than the previous drilling diameter and a Φ4500mm sand scoop to enlarge the hole formed in the previous step until the designed diameter and depth are reached; (4) Use a full-section drilling tool to level the bottom of the hole; the full-section drilling tool is a guide body with the hole diameter installed on the upper mounting base and a cutting body with the hole diameter installed on the lower mounting base; (5) One-time hole cleaning: Use a Φ4500mm sand scoop to remove sediment multiple times; (6) Lowering the steel cage: The steel cage is installed using a hole-and-hole connection method, and a detection tube is installed; (7) Secondary hole cleaning: Install concrete pouring pipe, set up a forward and reverse circulation device on the pipe, and use forward and reverse circulation process to clean the hole; (8) Concrete pouring: After the second cleaning of the hole, the forward and reverse circulation device is removed, and concrete is poured using a guide pipe.

Images