Construction method of bored piles using prefabricated casing drilling rig

Abstract

This application discloses a method for constructing bored piles using a prefabricated casing drilling rig, comprising the following steps: erecting a construction platform; arranging auxiliary mechanisms; the auxiliary mechanisms include steel components and multiple sets of guide pipes, the top of which is higher than the construction platform, and the steel components connecting the multiple sets of guide pipes and positioned at the top of the guide pipes; positioning and centering the prefabricated casing drilling rig; installing a steel casing; using the casing gripper of the prefabricated casing drilling rig to grip the steel casing and press it down to the designed depth within the rock mass, the embedment depth of the guide pipe being greater than or equal to the embedment depth of the steel casing; the inner wall of the steel casing contacting the moving end of the adjusting cylinder; dismantling the auxiliary mechanisms; using a rotary drilling rig to perform rock drilling operations, sequentially carrying out staged soil removal and progressively drilling to the designed pile bottom; cleaning the hole, installing the reinforcing cage, and performing secondary hole cleaning; and pouring concrete to the designed elevation. The prefabricated casing drilling rig method for constructing bored piles provided in this specification enables precise positioning and high vertical accuracy of the steel casing, and achieves efficient rock drilling.

Description

Technical Field

[0001] This manual relates to the field of bored pile construction technology, and in particular to a method for bored pile construction using a prefabricated casing drilling rig. Background Technology

[0002] The following challenges exist when constructing bridge pier pile foundations in areas with deep, fast-flowing water and significant seabed undulations:

[0003] 1. Due to the deep and rapid water flow (flow velocity reaches 1.43m / s), obvious tides and large tidal range, and the significant impact of typhoons and monsoons, the positioning of steel casings is difficult.

[0004] 2. Due to the large undulations of the seabed, the tilt of the rock surface, and the highly developed fractures, joints, and fissures, it is very difficult to accurately control the verticality of the steel casing installation.

[0005] 3. The underlying bedrock is dacite with high rock strength (25-70 MPa); the pile diameter is large and the amount of rock embedded in the pile body is large. Summary of the Invention

[0006] In view of the shortcomings of the prior art, one object of this specification is to provide a method for drilling and grouting piles using a prefabricated casing drilling rig, which enables precise positioning and high vertical accuracy of the steel casing, and achieves efficient rock drilling.

[0007] To achieve the above objectives, this specification provides a method for constructing bored piles using a prefabricated casing drilling rig, comprising:

[0008] Build a construction platform;

[0009] An auxiliary mechanism is arranged; the auxiliary mechanism includes steel components and multiple sets of guide pipes, the top of the guide pipes being higher than the construction platform, the steel components connecting the multiple sets of guide pipes and located at the top of the guide pipes; the guide pipes are equipped with adjusting cylinders, the fixed end of the adjusting cylinders being fixedly connected to the guide pipes, and the moving end of the adjusting cylinders being able to move in a direction perpendicular to the vertical direction;

[0010] Position and center the assembled casing drilling rig;

[0011] Install the steel casing; use the pipe gripper of the assembled casing drilling rig to grip the steel casing and press it down to the designed depth in the rock mass, the rock embedment depth of the guide pipe is greater than or equal to the rock embedment depth of the steel casing; the inner wall of the steel casing is in contact with the moving end of the adjusting cylinder;

[0012] Remove the auxiliary mechanism;

[0013] Rotary drilling rigs are used for rock drilling operations, and soil is removed in stages and rock is drilled step by step until the designed pile bottom is reached.

[0014] Hole cleaning, installation of reinforcing cage, and secondary hole cleaning;

[0015] Pour concrete up to the design elevation.

[0016] In a preferred embodiment, in the step of arranging the auxiliary mechanism, each group of guide tubes includes a bottom tube at the bottom, a middle tube in the middle, and a top tube at the top. The bottom of the bottom tube is provided with a cutter head, and the adjusting cylinder is located on the middle tube.

[0017] In a preferred embodiment, the length of each bottom pipe section is 3 to 10 m, the length of each middle pipe section is 6.8 to 12.5 m, and the length of each top pipe section is 2.5 to 3 m.

[0018] In a preferred embodiment, the bottom pipe, the middle pipe, and the top pipe are all made of steel sleeves with a diameter of 1.0m or 1.2m, and every two steel sleeves are connected by high-strength bolts.

[0019] In a preferred embodiment, the length of the top of the guide tube above the construction platform is less than or equal to 0.2m.

[0020] In a preferred embodiment, the auxiliary mechanism includes four sets of guide tubes, and the steel component includes four outer frames and two diagonal frames located within the four outer frames. The four outer frames form a square, and the top of the guide tube is connected to the intersection of the adjacent outer frames.

[0021] In a preferred embodiment, during the step of installing the steel casing, an inclinometer for monitoring verticality is installed on the steel casing, and the vertical accuracy of the steel casing is corrected using the adjusting cylinder, with the vertical accuracy controlled within 5‰; while the steel casing is gripped and pressed down using the pipe gripper of the assembled casing drilling rig, the vertical accuracy of the steel casing is corrected using the adjusting cylinder.

[0022] In a preferred embodiment, during the step of installing the steel casing, the steel casing is inserted 1.5m into the strongly weathered rock and / or 0.5m into the moderately weathered rock.

[0023] As a preferred embodiment, the staged soil sampling includes the following steps:

[0024] Using a 4.5m diameter drill bit, remove the seabed cover or soft rock above the rock strata until the drill bit advances relatively slowly, then remove the drill bit and proceed to the next step;

[0025] At the center of the pile, use a 2.5m diameter drill bit to break up the rock mass and remove rock debris down to the top surface of the weakly weathered rock;

[0026] At the center of the pile, use a 3.5m diameter drill bit to break up the rock mass and remove rock debris down to the top surface of the weakly weathered rock;

[0027] Then, using a 4.5m diameter drill bit, the rock mass was broken and rock debris was removed down to the top surface of the weakly weathered rock.

[0028] As a preferred embodiment, the step-by-step rock drilling includes the following steps:

[0029] At the center of the pile, a 1.3m diameter drill bit is used to break up the rock mass and remove rock debris to the designed pile bottom;

[0030] At the center of the pile, a 2.0m diameter drill bit is used to break the rock mass and remove rock debris to the designed pile bottom;

[0031] At the center of the pile, a 2.5m diameter drill bit is used to break the rock mass and remove rock debris to the designed pile bottom;

[0032] At the center of the pile, a 3m diameter drill bit is used to break the rock mass and remove rock debris to the designed pile bottom;

[0033] At the center of the pile, a 3.5m diameter drill bit is used to break the rock mass and remove rock debris to the designed pile bottom;

[0034] At the center of the pile, a 4m diameter drill bit is used to break the rock mass and remove rock debris to the designed pile bottom;

[0035] Finally, a 4.5m diameter rock mass was used to break up the rock and remove the rock debris to the bottom of the designed pile.

[0036] Beneficial effects:

[0037] The prefabricated casing drilling rig method for bored pile construction provided in this embodiment overcomes the problem of inaccurate steel casing positioning caused by deep and rapid water flow by arranging auxiliary mechanisms to assist in the installation of the steel casing, thus ensuring accurate steel casing positioning. The guide pipe of the auxiliary mechanism is equipped with an adjusting cylinder, and the moving end of the adjusting cylinder contacts the inner wall of the steel casing, which can adjust the verticality of the steel casing, thereby improving the vertical accuracy of the steel casing. Using a rotary drilling rig for rock drilling operations, and sequentially carrying out staged soil removal and step-by-step rock drilling to the designed pile bottom, can overcome the problems of high rock strength and large rock embedment in the pile body, achieving efficient rock drilling.

[0038] Specific embodiments of the present invention are disclosed in detail with reference to the following description and accompanying drawings, indicating how the principles of the invention can be employed. It should be understood that the embodiments of the present invention are not limited in scope as a result.

[0039] Features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0040] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, whole, step, or component, but does not exclude the presence or addition of one or more other features, wholes, steps, or components. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a flowchart illustrating the steps of a prefabricated casing drilling rig method for constructing bored piles provided in this embodiment.

[0043] Figure 2 This is a three-dimensional structural diagram of an auxiliary mechanism and a steel casing provided in this embodiment;

[0044] Figure 3 for Figure 2 Top view;

[0045] Figure 4 This is a schematic diagram of the structure of a guide tube tooling provided in this embodiment;

[0046] Figure 5 This is a schematic diagram of another guide tube tooling provided in this embodiment;

[0047] Figures 6A to 6D for Figure 1 Construction diagram of step S20;

[0048] Figure 7 for Figure 1 Construction diagram of step S30;

[0049] Figure 8 for Figure 1 Construction diagram of step S40;

[0050] Figure 9 for Figure 1 Construction diagram of step S50;

[0051] Figure 10 for Figure 1Construction diagram of the S60 stage of soil extraction in the middle step;

[0052] Figure 11 for Figure 1 A schematic diagram of the S30 step-by-step rock drilling construction process;

[0053] Figure 12 For use Figure 1 Elevation view of the pile foundation formed by the prefabricated casing drilling rig bored pile construction method.

[0054] Explanation of reference numerals in the attached figures:

[0055] 1. Construction platform; 2. Auxiliary mechanism; 21. Steel component; 22. Guide pipe; 23. Adjusting cylinder; 24. Guide pipe tooling; 241. Installation hole; 242. Center; 3. Designed pile position; 4. Full-rotation drilling rig; 5. Prefabricated casing drilling rig; 6. Steel casing; 7. Floating crane; 8. Designed pile bottom; 9. Seabed surface; 10. Drilled pile; 11. Silty clay; 12. Silty clay; 13. Completely weathered dacite; 14. Strongly weathered dacite; 15. Weakly weathered dacite; 16. Slightly weathered dacite; 17. Crane; 18. Sea surface. Detailed Implementation

[0056] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0057] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or may be interposed with another element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or may be interposed with another element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementations.

[0058] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0059] Please see Figures 1 to 12 This application provides a method for constructing bored piles using a prefabricated casing drilling rig, comprising the following steps:

[0060] Step S10: Construct construction platform 1.

[0061] Step S10 may also include other preparatory work before pile foundation construction, such as the prefabrication of steel casing 6.

[0062] Step S20: Arrange auxiliary mechanism 2.

[0063] Among them, such as Figure 2 and Figure 3 As shown, the auxiliary mechanism 2 includes a steel component 21 and multiple sets of guide pipes 22. This auxiliary mechanism 2 is deployed using a full-rotation drilling rig 4 and is a temporary independent system. It plays a positioning and guiding role during the subsequent installation of the steel casing 6. It can provide auxiliary positioning for the installation of the extra-large steel casing 6 in rapid flow conditions and forms an independent system with the steel casing 6, without adding extra resistance to the construction platform 1.

[0064] Specifically, the top of the guide pipe 22 is higher than the construction platform 1. The steel component 21 connects multiple sets of guide pipes 22 and is located at the top of the guide pipes 22. The guide pipe 22 is equipped with an adjusting cylinder 23, the fixed end of the adjusting cylinder 23 is fixedly connected to the guide pipe 22, and the moving end of the adjusting cylinder 23 can move in a direction perpendicular to the vertical direction.

[0065] In step S20, each group of guide pipes 22 may include a bottom pipe at the bottom, a middle pipe in the middle, and a top pipe at the top. This embodiment does not limit the number of bottom pipes, middle pipes, and top pipes; they can be selected reasonably as needed. The length of each bottom pipe section is 3–10 m, the length of each middle pipe section is 6.8–12.5 m, and the length of each top pipe section is 2.5–3 m. The lengths of different bottom pipes, different middle pipes, and different top pipes can vary.

[0066] Specifically, the bottom pipe at the very bottom is equipped with a specially designed cutter head, which is embedded in the bedrock, and the embedment depth of the bottom pipe is not less than the embedment depth of the steel casing 6. The adjusting cylinder 23 is located on the middle pipe. The bottom pipe, the middle pipe, and the top pipe are all composed of specially designed steel sleeves with a diameter of 1.0m or 1.2m, and every two steel sleeves are connected by specially designed high-strength bolts.

[0067] Preferably, the length of the top of the guide pipe 22 above the construction platform 1 is less than or equal to 0.2m.

[0068] In one embodiment, such as Figure 2 and Figure 3As shown, the auxiliary mechanism 2 includes four sets of guide tubes 22. The steel component 21 is used for temporary top fixation, and each set of guide tubes 22 is connected to the others via the steel component 21. The steel component 21 includes four outer frames and two diagonal frames located within the four outer frames, forming a square. The top of each guide tube 22 is connected to the intersection of adjacent outer frames and to the end point of one diagonal frame.

[0069] In other embodiments, the number of guide tubes 22 can be appropriately increased or decreased according to factors such as the diameter of the steel casing 6 or the flow rate; this application does not impose a unique limitation on this. This embodiment also provides a method such as... Figure 4 and Figure 5 The guide pipe fixture 24 shown can be placed on the construction platform 1 before the auxiliary mechanism 2 is arranged, and can be used to assist in the installation of the guide pipe 22.

[0070] Specifically, the guide pipe fixture 24 is approximately square, with a center 242 corresponding to the pile center. Multiple mounting holes 241 are provided around the center 242 for the guide pipe 22 to pass through. The minimum distance between the mounting hole 241 and the designed pile position 3 should be less than or equal to 500 mm. Figure 4 As shown, when the auxiliary mechanism 2 is equipped with four sets of guide tubes 22, the guide tube fixture 24 is provided with four mounting holes 241 evenly distributed circumferentially; as Figure 5 As shown, when the auxiliary mechanism 2 is equipped with three sets of guide tubes 22, the guide tube fixture 24 is provided with three mounting holes 241 evenly distributed along the circumference.

[0071] The construction diagram for step S20 is as follows: Figures 6A to 6D As shown. Figure 6A This indicates that the guide pipe tool 24 and the full-rotation drilling rig 4 are in place; Figure 6B This indicates that crane 17 and full-rotation drilling rig 4 are working together to begin installing guide pipe 22; Figure 6C This indicates that the guide tube 22 is installed to the required depth; Figure 6D This indicates that auxiliary mechanism 2 has been installed.

[0072] exist Figures 6A to 6D In the middle, the geological conditions below the seabed surface 9 are as follows: from top to bottom, they include silty clay 11, silty clay 12, silty clay 11, completely weathered dacite 13, strongly weathered dacite 14, weakly weathered dacite 15, and slightly weathered dacite 16.

[0073] Step S30: Position and center the prefabricated casing drilling rig 5. A construction diagram for step S30 is shown below. Figure 7 As shown.

[0074] Step S40: Install steel casing 6. A construction diagram for step S40 is shown below. Figure 8 As shown.

[0075] The steel casing 6 is transported and installed using a large floating crane 7. The prefabricated casing drilling rig 5 uses a pipe gripper to hold the steel casing 6 and press it down to the designed depth within the rock mass. The embedment depth of the guide pipe 22 is greater than or equal to the embedment depth of the steel casing 6. The inner wall of the steel casing 6 is in contact with the moving end of the adjusting cylinder 23. The guide pipe 22 is equipped with a hydraulic system connected to the adjusting cylinder 23. This hydraulic system allows for the movement of the moving end of the adjusting cylinder 23, thereby adjusting the verticality of the steel casing 6 during installation. Adjusting the verticality of the steel casing 6 using the adjusting cylinder 23 is the most crucial step in controlling the verticality of the steel casing 6 and the entire pile body.

[0076] In step S40, an inclinometer for monitoring verticality is installed at an appropriate position on the steel casing 6, and the vertical accuracy of the steel casing 6 is corrected using the adjusting cylinder 23, with the vertical accuracy controlled within 5‰. The vertical accuracy of the steel casing 6 can be corrected using the adjusting cylinder 23 while the casing gripper of the assembled casing drilling rig 5 is used to hold and press down the steel casing 6. Specifically, the steel casing 6 is inserted 1.5m into strongly weathered rock and / or 0.5m into moderately weathered rock.

[0077] Because the steel casing 6 is deeply embedded in the rock and has a large diameter (e.g., 3.8m, 4m, or 5m), it is prone to deformation during installation. To avoid this problem, the cutter head of the steel casing 6 can be specially modified to increase its rock-cutting ability. An anti-deformation mechanism can also be installed inside the steel casing 6, with its stroke aligned with that of the pipe gripper, to prevent uneven stress and deformation of the steel casing 6.

[0078] Step S50: Remove the auxiliary mechanism 2. A construction diagram of step S50 is shown below. Figure 9 As shown.

[0079] Step S60: Use a rotary drilling rig to perform rock drilling operations, and carry out staged soil removal and rock drilling step by step until the designed pile bottom 8.

[0080] In step S60, the staged soil removal includes removing the seabed cover, completely weathered rock, and strongly weathered rock at the designed pile location 3. For example... Figure 10 As shown, the staged soil sampling includes the following steps:

[0081] Step S611: Using a 4.5m diameter drill bit, remove the seabed cover layer or soft rock above the rock strata until the drill bit advances relatively slowly, then remove the drill bit and proceed to step S612.

[0082] Step S612: At the center of the pile, use a 2.5m diameter drill bit to break the rock mass and remove rock debris down to the top surface of the weakly weathered rock;

[0083] Step S613: At the center of the pile, use a 3.5m diameter drill bit to break the rock mass and remove rock debris down to the top surface of the weakly weathered rock;

[0084] Step S614: Use a 4.5m diameter drill bit to break the rock mass and remove rock debris down to the top of the weakly weathered rock.

[0085] In step S60, step-by-step rock drilling includes removing weakly weathered rock and slightly weathered rock at the designed pile location 3.

[0086] like Figure 11 As shown, the step-by-step rock drilling includes the following steps:

[0087] Step S621: At the center of the pile, use a drill bit with a diameter of 1.3m to break the rock mass and remove rock debris to the designed pile bottom 8;

[0088] Step S622: At the center of the pile, use a drill bit with a diameter of 2.0m to break the rock mass and remove rock debris to the designed pile bottom 8;

[0089] Step S623: At the center of the pile, use a 2.5m diameter drill bit to break the rock mass and remove rock debris to the designed pile bottom 8;

[0090] Step S624: At the center of the pile, use a 3m diameter drill bit to break the rock mass and remove rock debris to the designed pile bottom 8;

[0091] Step S625: At the center of the pile, use a drill bit with a diameter of 3.5m to break the rock mass and remove rock debris to the designed pile bottom 8;

[0092] Step S626: At the center of the pile, use a 4m diameter drill bit to break the rock mass and remove rock debris to the designed pile bottom 8;

[0093] Step S627: Finally, use a 4.5m diameter rock mass to break up the rock mass and remove the rock debris to the bottom of the designed pile 8.

[0094] During the step-by-step rock drilling process, the prefabricated casing drilling rig 5 can be used simultaneously to hold the steel casing 6 and press it down to the designed position (the prefabricated casing drilling rig 5 presses down the steel casing 6 while adjusting the verticality to meet the requirements, and the vertical accuracy can be controlled within 5‰).

[0095] After completing the rock drilling operation at a designed pile position 3 and passing the acceptance inspection, the prefabricated casing drilling rig 5 and the rotary drilling rig will be moved to the next pile position to be constructed.

[0096] Step S70: Clean the hole, install the reinforcing cage, and clean the hole again.

[0097] Before cleaning the hole, the top of the steel casing 6 can be temporarily fixed.

[0098] Step S80: Pour concrete to the design elevation.

[0099] In addition to the initial setting time of 48 hours, pile head protection can also be carried out after step S80.

[0100] In one embodiment, the elevation view of the pile foundation formed using the above-described prefabricated casing drilling rig 5 bored pile construction method is as follows: Figure 12 As shown. Specifically, this pile foundation consists of 8 bored piles 10. The length of each bored pile 10 is 58m, with a rock penetration length of 11.7m. The diameter of the steel casing 6 is 5m, the length of the steel casing 6 is approximately 45m, and the rock penetration depth of the steel casing 6 is approximately 1.3m. The height of the construction platform 1 is approximately 5.4m, the length from the top of the construction platform 1 to the bottom of the pile is approximately 70.4m, and the length from the top of the construction platform 1 to the bottom of the steel casing 6 is approximately 57.4m. The total length is 464m, and the rock penetration length is 93.6m. The total volume is 8718.21m. 3 The rock penetration depth is 1487.89m. 3 The weight of the steel casing 6 for a single pile is 281t. The wall thickness of the steel casing 6 can be reasonably selected according to its diameter; in this application, the wall thickness of the steel casing 6 can be 3cm. The recommended wall thickness of the cutting edge of the steel casing 6 is 6cm, and the length with the cutting edge is greater than or equal to 1.5m.

[0101] exist Figure 12 In the middle, the elevation of the sea surface 18 is +4.00m, the elevation of the top surface of the construction platform 1 is +9.40m, the elevation of the seabed surface 9 located in the center is -26.537m, and the elevation of the design pile bottom 8 is -61.0m.

[0102] The prefabricated casing drilling rig 5 drilling and grouting pile construction method provided in this embodiment can overcome the problem of inaccurate positioning of the steel casing 6 caused by deep and rapid water flow by arranging auxiliary mechanism 2 to assist in the installation of the steel casing 6, thus making the steel casing 6 accurately positioned. The guide pipe 22 of the auxiliary mechanism 2 is equipped with an adjusting cylinder 23. The moving end of the adjusting cylinder 23 contacts the inner wall of the steel casing 6, which can adjust the verticality of the steel casing 6, thereby improving the vertical accuracy of the steel casing 6. Using a rotary drilling rig for rock drilling operations, and carrying out staged soil removal and step-by-step rock drilling to the designed pile bottom 8, can overcome the problems of high rock strength and large rock embedment in the pile body, and achieve efficient rock drilling.

[0103] In this embodiment, the full-rotation drilling rig 4 has a drilling diameter of 800–1700 mm, a rotation torque of 1880 / 970 / 549 kNm, a rotation speed of 1.0 / 1.7 / 2.9 rpm, a casing lowering pressure of a maximum of 360 kN (adjustable) + its own weight of 180 kN, a casing pulling force of 2690 kN, a pulling stroke of 500 mm, and a main unit weight of 27 t. The equipped hydraulic power station uses a Cummins QSC8.3-C260 engine with a power output of 205 kW / 1800 rpm, a power station weight of 6 t, and is controlled by wired remote control.

[0104] In this embodiment, the relevant parameters of the customized high-power rotary drilling rig are detailed in Table 1 below. The width of the single-side track of the rotary drilling rig is 1.5m, and 6.6m in the working state (where the width refers to the distance from the outer edge of one track to the outer edge of the other track).

[0105] Table 1 Rotary Drilling Rig Parameters

[0106]

[0107] In this embodiment, a prefabricated pipe rolling machine can also be used to embed the steel casing 6. The prefabricated pipe rolling machine has a maximum drilling diameter of 5000mm, a rotation torque of 34400kNm, a rotation angle of 24 degrees, a casing pulling force of 13300kN, a pressing and pulling stroke of 550mm, a clamping force of 6700kN, and a working device weight of 145t.

[0108] It should be noted that in the description of this specification, the terms "first," "second," etc., are used only for descriptive purposes and to distinguish similar objects; there is no order between them, nor should they be construed as indicating or implying relative importance. Furthermore, in the description of this specification, unless otherwise stated, "a plurality of" means two or more.

[0109] Any numerical values ​​cited herein include all values ​​ranging from a lower limit to an upper limit, increasing by one unit, with at least two units between any lower and any higher value. For example, if the quantity of a component or the value of a process variable (e.g., temperature, pressure, time, etc.) is described as being from 1 to 90, preferably from 20 to 80, more preferably from 30 to 70, the purpose is to illustrate that values ​​such as 15 to 85, 22 to 68, 43 to 51, 30 to 32 are also explicitly listed in this specification. For values ​​less than 1, a unit is appropriately considered to be 0.0001, 0.001, 0.01, 0.1, etc. These are merely examples intended for explicit expression, and it can be assumed that all possible combinations of values ​​listed between the minimum and maximum values ​​are similarly explicitly stated in this specification.

[0110] Unless otherwise stated, all ranges include the endpoints and all numbers between them. The terms "approximately" or "about" used with ranges apply to both endpoints of the range. Thus, "approximately 20 to 30" is intended to cover "approximately 20 to approximately 30," including at least the specified endpoints.

[0111] All articles and references disclosed herein, including patent applications and publications, are incorporated herein by reference for various purposes. The term “substantially constitutes…” used to describe a combination should include the identified elements, components, parts, or steps, as well as other elements, components, parts, or steps that do not substantially affect the essential novelty of the combination. The use of the terms “comprising” or “including” to describe combinations of elements, components, parts, or steps herein also contemplates embodiments substantially constituted by such elements, components, parts, or steps. The use of the term “may” herein is intended to indicate that any described attribute included by “may” is optional.

[0112] Multiple elements, components, parts, or steps can be provided by a single integrated element, component, part, or step. Alternatively, a single integrated element, component, part, or step can be divided into multiple separate elements, components, parts, or steps. The use of "a" or "an" to describe an element, component, part, or step does not imply the exclusion of other elements, components, parts, or steps.

[0113] It should be understood that the above description is for illustrative purposes and not for limitation. Many embodiments and applications beyond the provided examples will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this teaching should not be determined by reference to the above description, but rather by reference to the appended claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the preceding claims is not intended as a waiver of that subject matter, nor should it be construed as an indication that the inventors have not considered that subject matter as part of the disclosed inventive subject matter.

Claims

1. A method for constructing a cast-in-situ pile by using a fabricated casing drilling rig, characterized in that, The method comprises the following steps: erecting a construction platform; arranging an auxiliary mechanism; the auxiliary mechanism comprises steel members and multiple groups of guide pipes, the top of the guide pipes is higher than the construction platform, the steel members connect the multiple groups of guide pipes and are located at the top of the guide pipes; the guide pipes are provided with adjusting oil cylinders, the fixed end of the adjusting oil cylinder is fixedly connected to the guide pipe, and the moving end of the adjusting oil cylinder can move in a direction perpendicular to the vertical direction; positioning and centering a fabricated casing drill rig; installing a steel casing; using a pipe gripper of the fabricated casing drill rig to hold the steel casing and lower the steel casing into a rock body to a designed depth, the rock-socketing depth of the guide pipe is greater than or equal to the rock-socketing depth of the steel casing; the inner wall of the steel casing is in contact with the moving end of the adjusting oil cylinder; removing the auxiliary mechanism; using a rotary drilling rig to perform rock drilling, and sequentially performing stage soil removal and step-by-step rock drilling to a designed pile bottom; hole cleaning, installation of a steel reinforcement cage, and secondary hole cleaning; pouring concrete to a designed elevation.

2. The method according to claim 1, wherein, In the step of arranging the auxiliary mechanism, each group of the guide pipes comprises a bottom pipe located at a bottom, a middle pipe located at a middle, and a top pipe located at a top, the bottom pipe located at the bottom is provided with a cutter head, and the adjusting oil cylinder is arranged on the middle pipe.

3. The method according to claim 2, wherein, The length of each section of the bottom pipe is 3-10 m, the length of each section of the middle pipe is 6.8-12.5 m, and the length of each section of the top pipe is 2.5-3 m.

4. The method according to claim 2, wherein, The bottom pipe, the middle pipe and the top pipe are all composed of steel casings with a diameter of 1.0 m or a diameter of 1.2 m, and each two steel casings are connected through high-strength bolts.

5. The method according to claim 1, wherein, The length by which the top of the guide pipe is higher than the construction platform is less than or equal to 0.2 m.

6. The method according to claim 1, wherein, The auxiliary mechanism comprises four groups of the guide pipes, the steel members comprise four outer frames and two diagonal frames located in the four outer frames, the four outer frames form a square, and the top of the guide pipe is connected to the intersection of adjacent outer frames.

7. The method according to claim 1, wherein, In the step of installing the steel casing, an inclinometer for monitoring the verticality is installed on the steel casing, the vertical accuracy of the steel casing is corrected by using the adjusting oil cylinder, and the vertical accuracy is controlled within 5‰; while the pipe gripper of the fabricated casing drill rig is used to hold and lower the steel casing, the vertical accuracy of the steel casing is corrected by using the adjusting oil cylinder.

8. The method according to claim 1, wherein, In the step of installing the steel casing, the steel casing enters 1.5 m of strongly weathered rock and / or 0.5 m of moderately weathered rock.

9. The method according to claim 1, wherein, The stage soil removal comprises the following steps: when a drill bit with a diameter of 4.5 m is used to remove the seabed cover layer or soft rock at the upper part of the rock layer and the drill bit penetration is relatively slow, the drill bit is removed, and the next step is performed; at the center of the pile, a drill bit with a diameter of 2.5 m is used to break the rock mass and remove the rock debris to the top surface of the weakly weathered rock; at the center of the pile, a drill bit with a diameter of 3.5 m is used to break the rock mass and remove the rock debris to the top surface of the weakly weathered rock; then, a drill bit with a diameter of 4.5 m is used to break the rock mass and remove the rock debris to the top surface of the weakly weathered rock.

10. The method according to claim 9, wherein, The step-by-step rock drilling comprises the following steps: at the center of the pile, a drill bit with a diameter of 1.3 m is used to break the rock mass and remove the rock debris to the designed pile bottom; at the center of the pile, a drill bit with a diameter of 2.0 m is used to break the rock mass and remove the rock debris to the designed pile bottom; At the center of the pile, a drill bit with a diameter of 2.5m is used to break the rock mass and remove the rock debris to the designed pile bottom; At the center of the pile, a drill bit with a diameter of 3m is used to break the rock mass and remove the rock debris to the designed pile bottom; At the center of the pile, a drill bit with a diameter of 3.5m is used to break the rock mass and remove the rock debris to the designed pile bottom; At the center of the pile, a drill bit with a diameter of 4m is used to break the rock mass and remove the rock debris to the designed pile bottom; Finally, a drill bit with a diameter of 4.5m is used to break the rock mass and remove the rock debris to the designed pile bottom.

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