Ultrahigh-pressure large-flow jet grouting pile construction method

Abstract

The invention discloses an ultrahigh-pressure large-flow jet grouting pile construction method. The treatment method comprises the following steps that S1, construction preparation is conducted; s2, hole guiding; and S3, guniting. According to the method, on one hand, the pile position is determined through multi-line intersection, the perpendicularity is detected section by section while drilling is conducted so that the guide hole meeting the technical requirement can be accurately formed, a large-diameter and large-depth formed pile body can be achieved under the combination of ultrahigh-pressure water and ultrahigh-pressure mud, the pile forming quality is good, the seepage isolation and water stop effects are excellent, and the method is very suitable for construction under the water-rich sand layer condition; and on the other hand, hole guiding and pile forming speed is high, construction period is effectively shortened, and cost is saved.

Description

Technical Field

[0001] The invention belongs to the technical field of jet grouting pile construction, and in particular relates to an ultra-high pressure and large flow rate jet grouting pile construction method. Background Art

[0003] In foundation reinforcement, rotary jet grouting is usually adopted, that is, the rotary jet grouting pipe and nozzle are placed at the designed elevation of the pile bottom by using a drilling rig, and the pre-prepared slurry is passed through a high-pressure generating device to make the liquid flow gain huge energy, and then it is ejected at high speed from the nozzle on the side of the grouting pipe to form a liquid flow with highly concentrated energy, which directly destroys the soil. During the spraying process, the drill rod is rotated and lifted at the same time, so that the slurry and the soil are fully mixed, forming a columnar consolidation body of a certain diameter in the soil, thereby strengthening the foundation.

[0004] However, due to the poor geological conditions of water-rich strata, the construction of shield starting and arrival sections is often accompanied by high risks and great construction difficulty. The use of traditional construction methods is prone to serious accidents such as sand blasting and water gushing at the working shaft portal, soil collapse, and tunnel damage caused by improper end reinforcement. Therefore, it is urgent to design a construction method that combines hydrogeological conditions and surrounding environmental conditions to reasonably reinforce the strata in the shield starting and arrival areas. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a new ultra-high pressure and large flow rate jet grouting pile construction method.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0007] A method for constructing ultra-high pressure and large flow jet grouting piles, comprising the following steps:

[0008] S1. Construction preparation

[0009] a) Use measuring tools to determine the installation positions of multiple guard piles. After placing multiple guard piles in place, take every two guard piles as a group and connect them through measuring lines. The point where multiple measuring lines intersect is the pile position;

[0010] b) Set up slurry discharge channels and slurry collection systems at the pile positions;

[0011] S2, lead hole

[0012] c) moving a boring machine to a position and adjusting the drill bit of the boring machine to be aligned with the pile position;

[0013] d) The pilot hole drilling rig starts drilling from top to bottom, bentonite slurry is used to drill the pilot hole, and the verticality of the pilot hole is tested section by section from top to bottom simultaneously, and the verticality of the pilot hole is made less than or equal to 1 / 400 until the pilot hole reaches the designed depth;

[0014] S3, spraying

[0015] e) removing the pilot hole drill and moving the jet grouting pile drill to a position such that the drill bit of the jet grouting pile drill is adjusted to be aligned with the pile position;

[0016] f) Lower the drill bit and shotcrete rod section by section so that the nozzle of the shotcrete rod is at the designed pile bottom height or below the designed pile bottom elevation;

[0017] g) Input ultra-high pressure water and / or mud into the shotcrete rod, and then keep the shotcrete rod gradually lifted from bottom to top. In the initial lifting section, the shotcrete rod sprays ultra-high pressure water to pre-cut the soil. When the shotcrete rod is raised to a certain height, the shotcrete rod sprays ultra-high pressure mud and gradually lifts to form a pile body.

[0018] Preferably, in step a) of S1, two guard piles are respectively arranged in the horizontal direction and the vertical direction, and the two corresponding guard piles are respectively connected by measuring lines, and the two measuring lines intersect to form a cross line shape. Here, the positioning operation is simple and efficient.

[0019] According to a specific implementation and preferred aspect of the present invention, in step d) of S2, after each hole is drilled for a certain distance, an inclinometer is used to detect the verticality of the drill rod inside the drilling rig to ensure the drilling accuracy.

[0020] Preferably, the inclinometer adopts a fiber optic gyro inclinometer. During measurement, each inclinometer is connected and debugged, and the inclinometer is lowered from the center of the hole mouth of the guide hole to a specified depth, and then the verticality inclinometer is measured and the inclinometer data is saved. Finally, after the inclinometer data is saved, the inclinometer rod is recovered, cleaned and stored. The fiber optic gyro inclinometer is used to detect the verticality of the hole in real time, with a detection accuracy far higher than 1 / 400 and a hole qualification rate of 100%. In addition, the operation is simple and portable.

[0021] Specifically, during the measurement process, the top angle value of the inclinometer rod of the fiber optic gyro inclinometer is controlled not to exceed 1°.

[0022] Furthermore, the step of controlling the top angle value of the inclinometer rod includes: controlling the specific gravity of the bentonite mud in the hole to avoid the inclinometer data error caused by the excessively high mud specific gravity leading to the excessively large top angle of the inclinometer rod; adjusting the angle before lowering the inclinometer rod to ensure that the lowering position of the inclinometer rod is at the center of the hole mouth to avoid the inclinometer rod touching the wall during the lowering process, resulting in inaccurate data; controlling the inclinometer rod to be lowered at a uniform speed to avoid the mud in the hole being stirred due to the inclinometer rod being lowered too fast, thereby affecting the angle of the inclinometer top angle and destroying the accuracy of the data; and cleaning and storing the inclinometer rod in time after it is raised from the hole mouth. If the top angle value is too large after the inclinometer rod is lowered, the height of the inclinometer rod can be slightly raised to reduce the top angle of the inclinometer rod to be in a more vertical state.

[0023] According to another specific implementation and preferred aspect of the present invention, in step d) of S2, if it is detected that the verticality of the lead hole is greater than 1 / 400, the hole is scanned until the verticality of the lead hole is less than or equal to 1 / 400, or the hole is re-guided after backfilling.

[0024] According to another specific implementation and preferred aspect of the present invention, the shotcrete rod has an upper nozzle for spraying ultra-high pressure water and a lower nozzle for spraying mud, and in step f) of S3, the shotcrete rod is lowered until the upper nozzle is 8 to 12 cm below the designed bottom elevation.

[0025] Preferably, in step g) of S3, during the initial lifting section, the shotcrete rod synchronously sprays ultra-high pressure water from the upper nozzle, and when the shotcrete rod is lifted to the point where the lower nozzle is 8 to 12 cm below the designed bottom elevation, the shotcrete rod synchronously switches to the lower nozzle to spray ultra-high pressure mud, and waits for the pressure to rise and stabilize to reach the construction parameter value, then the shotcrete rod maintains the height and rotates to spray for more than 60 seconds, and after the slurry emerges from the orifice normally, the shotcrete rod begins to gradually lift and maintains continuous spraying of ultra-high pressure mud; and / or, the diameter of the formed pile body is 3 to 10 m; and / or, the maximum depth of the formed pile body is 65 to 75 m.

[0026] According to another specific implementation and preferred aspect of the present invention, the injection pressure of the ultra-high pressure water is 45±2MPa, and the slurry flow rate is 200-600L / min; the injection pressure of the ultra-high pressure mud is 40±2MPa, and the slurry flow rate is 200-600L / min. Under the joint action of the coaxial high-pressure air ring package ultra-high pressure water and ultra-high pressure slurry secondary cutting, the energy for destroying the soil body is significantly increased, and finally a larger consolidation body is formed in the soil.

[0027] In addition, the lifting speed of the shotcrete rod is 25 min / m.

[0028] Due to the implementation of the above technical solution, the present invention has the following advantages compared with the prior art:

[0029] Due to the poor geological conditions of water-rich strata in the prior art, the construction of the shield starting and arrival sections is often accompanied by high risks and great construction difficulty. The use of traditional construction methods is prone to serious accidents such as sandblasting and water gushing at the working shaft portal, soil collapse, and tunnel damage caused by improper end reinforcement. The present application makes an overall design for the ultra-high pressure and large-flow rotary jet pile construction method, which cleverly solves the shortcomings and defects of the prior art. After adopting this construction method, construction preparations are first made, and measuring tools are used to determine the installation positions of multiple guard piles. After the multiple guard piles are placed in place, every two guard piles are grouped together and connected by measuring lines. The point where multiple measuring lines intersect is the pile position, and a slurry discharge channel and a mud collection system are set at the pile position; then the guide hole drill is moved into place, and the drill bit of the guide hole drill is adjusted to Relative to the pile position, the guide hole drilling rig then starts to drill the guide hole from top to bottom, bentonite slurry is used to drill the guide hole, and the verticality of the guide hole is simultaneously checked from top to bottom section by section, and the verticality of the guide hole is made to be less than or equal to 1 / 400, until the hole is drilled to the designed depth; the guide hole drilling rig is then removed, and the rotary jet pile drilling rig is moved into position, so that the drill bit of the rotary jet pile drilling rig is adjusted to be relative to the pile position, the drill bit and the shotcrete rod are lowered section by section, so that the nozzle of the shotcrete rod is at the designed pile bottom height or below the designed pile bottom elevation, ultra-high pressure water and / or mud is input into the shotcrete rod, and then the shotcrete rod is kept gradually lifted from bottom to top, and in the initial lifting section, the shotcrete rod sprays ultra-high pressure water to pre-cut the soil, and when the shotcrete rod is raised to a certain height, the shotcrete rod sprays ultra-high pressure mud and is gradually lifted to form a pile body. Therefore, compared with the prior art, the present invention, on the one hand, determines the pile position by intersecting multiple lines and checks the verticality section by section while drilling to accurately form a guide hole that meets the technical requirements, and realizes large-diameter and deep-formed pile bodies under the combination of ultra-high-pressure water and ultra-high-pressure mud. The pile quality is good and the seepage-proof and water-stopping effects are excellent, which is very suitable for construction under water-rich sand layer conditions. On the other hand, the guide hole and pile-forming speed are fast, which effectively shortens the construction period and saves costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a flow chart of the ultra-high pressure and large flow rate jet grouting pile construction method of the present invention; DETAILED DESCRIPTION

[0031] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0032] In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "center" are used interchangeably.

[0033] The directions or positional relationships indicated by “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc. are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, they should not be understood as limitations on the present invention.

[0034] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0035] In the present invention, unless otherwise clearly defined and specified, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0037] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0038] like Figure 1 As shown, the ultra-high pressure and large flow rate jet grouting pile construction method involved in this embodiment includes the following steps: S1, construction preparation; S2, hole drawing; S3, grouting.

[0039] Specifically, step S1 includes a) using a measuring tool to determine the installation position of multiple guard piles, and after placing the multiple guard piles in place, each two guard piles are grouped together and connected by measuring lines. The point where multiple measuring lines intersect is the pile position, and the plane error of the pile position is required to be no more than 50mm; b) setting a slurry discharge channel and a mud collection system at the pile position.

[0040] In step a) of S1, two guard piles are respectively arranged in the horizontal direction and in the vertical direction, and the two corresponding guard piles are respectively connected by measuring lines, and the two measuring lines intersect to form a cross line shape. Here, the positioning operation is simple and efficient.

[0041] In this example, step S2 includes c) moving the lead hole drill to the position, using a plumb bob to adjust the drill bit to the center of the crosshairs, so that the drill bit is aligned with the pile position; d) the lead hole drill starts to drill the lead hole from top to bottom, bentonite slurry is used to lead the hole, and the verticality of the lead hole is detected from top to bottom section by section, and the verticality of the lead hole is made less than or equal to 1 / 400 until the hole is drilled to the designed depth. If the verticality of the lead hole is detected to be greater than 1 / 400, the hole is swept until the verticality of the lead hole is less than or equal to 1 / 400, or the hole is re-drilled after backfilling.

[0042] In step d), after drilling a certain distance each time, an inclinometer is used to detect the verticality of the drill pipe of the drilling rig to ensure the drilling accuracy.

[0043] In some specific embodiments, the inclinometer uses a fiber optic gyro inclinometer. During measurement, each inclinometer is connected and debugged, and the inclinometer is lowered from the center of the hole mouth of the guide hole to a specified depth, and then vertical inclinometer is measured and the inclinometer data is saved. Finally, after the inclinometer data is saved, the inclinometer rod is recovered, cleaned and stored. During the measurement process, the inclinometer rod vertex value of the fiber optic gyro inclinometer is controlled not to exceed 1°. The fiber optic gyro inclinometer is used to detect the verticality of the hole in real time, with a detection accuracy far higher than 1 / 400, and a hole qualification rate of 100%. In addition, the operation is simple and portable.

[0044] The steps of controlling the top angle value of the inclinometer rod include: controlling the specific gravity of the bentonite mud in the hole to avoid the inclinometer data error caused by the excessively high specific gravity of the mud resulting in the excessively large top angle of the inclinometer rod, wherein the amount of mud used is: cement content 46%, cement adopts ordinary Portland cement with strength grade ≥42.5, and water-cement ratio 1.0; adjusting the angle before lowering the inclinometer rod to ensure that the lowering position of the inclinometer rod is at the center of the hole mouth to avoid the inclinometer rod touching the wall during the lowering process, resulting in inaccurate data; controlling the inclinometer rod to be lowered at a uniform speed to avoid the mud in the hole being stirred due to the inclinometer rod being lowered too fast, thereby affecting the angle of the inclinometer top angle and destroying the accuracy of the data; and cleaning and storing the inclinometer rod in time after it is raised from the hole mouth. If the top angle value is too large after the inclinometer rod is lowered, the height of the inclinometer rod can be slightly raised to reduce the top angle of the inclinometer rod to be in a more vertical state.

[0045] In this example, step S3 includes: e) removing the hole drill and moving the jet grouting pile drill into position so that the drill bit of the jet grouting pile drill is adjusted to be relatively centered with the pile position; f) lowering the drill bit and the shotcrete rod section by section so that the nozzle of the shotcrete rod is at the designed pile bottom height or below the designed pile bottom elevation; g) inputting ultra-high pressure water and / or mud into the shotcrete rod, and then keeping the shotcrete rod gradually lifted from bottom to top, and in the initial lifting section, the shotcrete rod sprays ultra-high pressure water to pre-cut the soil, and when the shotcrete rod is raised to a certain height, the shotcrete rod sprays ultra-high pressure mud and gradually lifts to form a pile body.

[0046] In some specific embodiments, the shotcrete rod has an upper nozzle for spraying ultra-high pressure water and a lower nozzle for spraying mud, and in step f) of S3, the shotcrete rod is lowered until the upper nozzle is 8 to 12 cm below the designed bottom elevation. In this embodiment, the preferred height is 10 cm below the designed bottom elevation.

[0047] In step g) of S3, during the initial lifting section, the spraying rod synchronously sprays ultra-high pressure water from the upper nozzle, and when the spraying rod is lifted to the point where the lower nozzle is 8 to 12 cm below the design bottom elevation, in this embodiment, the preferred height is that the lower nozzle is 10 cm below the design bottom elevation, the spraying rod synchronously switches to the lower nozzle to spray ultra-high pressure mud, and adopts a graded pressurization method to gradually increase the injection pressure to increase the stability to reach the construction parameter value, and then the spraying rod maintains the height and rotates to spray for more than 60 seconds, and after the hole mouth is normal, the spraying rod begins to gradually lift and maintain continuous spraying of ultra-high pressure mud; the diameter of the formed pile body is 3 to 10m; the maximum depth of the formed pile body is 65 to 75m, and further, the diameter of the formed pile body is 2 to 3m, and the maximum depth is 70 to 72m. In order to ensure the stability of the spraying host equipment during the grouting process, a steel plate or a roadbed box is laid at the bottom of the host to prevent uneven settlement due to weak foundation during the grouting process.

[0048] At the same time, in order to ensure the elevation and quality of the pile top, when the lower nozzle of the grouting rod is lifted to 80-120 mm above the designed pile top elevation, preferably, when the lower nozzle is lifted to 100 mm above the designed pile top elevation, the rotary spraying is stopped, the drill rod is lifted and removed section by section, the drill rod, grouting pump and delivery pipeline are cleaned, and then the drilling rig is moved to the next hole and the above steps are repeated.

[0049] In addition, in this embodiment, the injection pressure of ultra-high pressure water is 45±2MPa, and the slurry flow rate is 200-600L / min; the injection pressure of ultra-high pressure mud is 40±2MPa, and the slurry flow rate is 200-600L / min. Under the combined effect of the coaxial high-pressure air ring package ultra-high pressure water and ultra-high pressure slurry secondary cutting, the energy of destroying the soil body is significantly increased, and finally a larger consolidation body is formed in the soil. At the same time, the lifting speed of the shotcrete rod is 25min / m.

[0050] Taking a project for water-blocking and water-stopping construction in a water-rich sand layer as an example, the project requires the construction of 188 ultra-high pressure and large flow jet grouting piles. The ultra-high pressure and large flow jet grouting pile construction method of the present embodiment and the traditional ultra-high pressure slurry jetting and mixing pile forming process (N-JET) are used, as shown in Table 1:

[0051] Table 1

[0052]

[0053] Obviously, compared with the traditional method, the ultra-high pressure and large flow rate rotary jet pile construction method of this embodiment can greatly improve the hole-making efficiency, significantly improve the construction progress, and greatly save the construction cost.

[0054] In summary, after adopting this construction method, first make construction preparations, use measuring tools to determine the installation positions of multiple guard piles, and after placing multiple guard piles in place, take every two guard piles as a group and connect them through measuring lines. The intersection of multiple measuring lines at one point is the pile position, and set up a slurry discharge channel and a mud collection system at the pile position; then move the guide hole drill rig to its position, and adjust the drill bit of the guide hole drill rig to be relative to the pile position, then start the guide hole drilling from top to bottom, use bentonite slurry to guide the hole, and simultaneously check the verticality of the guide hole section by section from top to bottom, and make the verticality of the guide hole less than or =1 / 400, until the hole is bored to the designed depth; then remove the boring rig, and move the jet pile rig into position, so that the drill bit of the jet pile rig is adjusted to be relatively centered with the pile position, lower the drill bit and the shotcrete rod section by section, so that the nozzle of the shotcrete rod is at the designed pile bottom height or below the designed pile bottom elevation, input ultra-high pressure water and / or mud into the shotcrete rod, and then keep the shotcrete rod gradually lifted from bottom to top, and in the initial lifting section, the shotcrete rod sprays ultra-high pressure water to pre-cut the soil, and when the shotcrete rod is raised to a certain height, the shotcrete rod sprays ultra-high pressure mud and is gradually lifted to form a pile body. Therefore, compared with the prior art, the present invention, on the one hand, determines the pile position by the intersection of multiple lines and detects the verticality section by section while drilling to accurately form a guide hole that meets the technical requirements, and realizes large-diameter and large-depth forming of piles under the combination of ultra-high pressure water and ultra-high pressure mud. The pile quality is good and the seepage and water-proof effect is excellent, which is very suitable for construction under water-rich sand conditions; on the other hand, the guide hole and pile forming speed are fast, which effectively shortens the construction period and saves costs; thirdly, the verticality of the hole is detected in real time by the fiber optic gyro inclinometer, the detection accuracy is much higher than 1 / 400, and the hole qualification rate is 100%. In addition, the operation is simple and portable.

[0055] The above detailed description of the present invention is intended to enable persons familiar with the art to understand the contents of the present invention and implement them. It does not limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for constructing ultra-high pressure and large flow jet grouting piles, characterized in that: It includes the following steps: S1. Construction preparation a) Use measuring tools to determine the installation positions of multiple guard piles. After placing multiple guard piles in place, take every two guard piles as a group and connect them through measuring lines. The point where multiple measuring lines intersect is the pile position; b) Set up slurry discharge channels and slurry collection systems at the pile positions; S2, lead hole c) moving a boring machine to a position and adjusting the drill bit of the boring machine to be aligned with the pile position; d) The pilot hole drilling rig starts drilling from top to bottom, bentonite slurry is used to drill the pilot hole, and the verticality of the pilot hole is simultaneously tested from top to bottom section by section, so that the verticality of the pilot hole is less than or equal to 1 / 400, until the pilot hole reaches the designed depth; S3, spraying e) removing the pilot hole drill and moving the jet grouting pile drill to a position such that the drill bit of the jet grouting pile drill is adjusted to be aligned with the pile position; f) Lower the drill bit and shotcrete rod section by section so that the nozzle of the shotcrete rod is at the designed pile bottom height or below the designed pile bottom elevation; g) Input ultra-high pressure water and / or mud into the shotcrete rod, and then keep the shotcrete rod gradually lifted from bottom to top. In the initial lifting section, the shotcrete rod sprays ultra-high pressure water to pre-cut the soil. When the shotcrete rod is raised to a certain height, the shotcrete rod sprays ultra-high pressure mud and gradually lifts to form a pile body.

2. The ultra-high pressure and large flow jet grouting pile construction method according to claim 1, characterized in that: In step a) of S1, two guard piles are respectively arranged in the horizontal direction and the vertical direction, and the corresponding two guard piles are respectively connected by measuring lines, and the two measuring lines intersect to form a cross line shape.

3. The ultra-high pressure and large flow jet grouting pile construction method according to claim 1, characterized in that: In step d) of S2, after drilling a certain distance each time, an inclinometer is used to detect the verticality of the drill pipe of the drilling rig.

4. The ultra-high pressure and large flow jet grouting pile construction method according to claim 3 is characterized in that: The inclinometer adopts a fiber optic gyro inclinometer. During measurement, various inclinometer components are connected and debugged, and the inclinometer is lowered from the center of the hole mouth of the guide hole to a specified depth, and verticality inclinometer is measured and the inclinometer data is saved. Finally, after the inclinometer data is saved, the inclinometer rod is recovered, cleaned and stored.

5. The ultra-high pressure and large flow rate jet grouting pile construction method according to claim 4, characterized in that: During the measurement process, the top angle of the inclinometer rod of the fiber optic gyro inclinometer is controlled to be no more than 1°.

6. The ultra-high pressure and large flow jet grouting pile construction method according to claim 5, characterized in that: The steps of controlling the top angle value of the inclinometer rod include: controlling the specific gravity of the bentonite mud in the hole; adjusting the angle of the inclinometer rod before lowering it to ensure that the lowering position of the inclinometer rod is at the center of the hole mouth; controlling the inclinometer rod to be lowered at a uniform speed; and cleaning and storing the inclinometer rod in time after it is raised from the hole mouth.

7. The ultra-high pressure and large flow jet grouting pile construction method according to claim 1, characterized in that: In step d) of S2, if it is detected that the verticality of the lead hole is greater than 1 / 400, the hole is scanned until the verticality of the lead hole is less than or equal to 1 / 400, or the hole is re-guided after backfilling.

8. The ultra-high pressure and large flow jet grouting pile construction method according to claim 1, characterized in that: The shotcrete rod has an upper nozzle for spraying ultrahigh pressure water and a lower nozzle for spraying mud, and in step f) of S3, the shotcrete rod is lowered until the upper nozzle is 8 to 12 cm below the designed bottom elevation.

9. The ultra-high pressure and large flow rate jet grouting pile construction method according to claim 7, characterized in that: In step g) of S3, during the initial lifting section, the shotcrete rod synchronously sprays ultra-high pressure water from the upper nozzle, and when the shotcrete rod is lifted to the point where the lower nozzle is 8 to 12 cm below the designed bottom elevation, the shotcrete rod synchronously switches to the lower nozzle to spray ultra-high pressure mud, and waits for the pressure to rise and stabilize to reach the construction parameter value, then the shotcrete rod maintains the height and rotates to spray for more than 60 seconds, and after the slurry emerges from the hole normally, the shotcrete rod begins to gradually lift and maintains continuous spraying of ultra-high pressure mud; and / or, the diameter of the formed pile body is 3 to 10 m; and / or, the maximum depth of the formed pile body is 65 to 75 m.

10. The ultra-high pressure and large flow rate jet grouting pile construction method according to claim 1, 7 or 8, characterized in that: The injection pressure of the ultra-high pressure water is 45±2MPa, and the slurry flow rate is 200-600L / min; and / or, the injection pressure of the ultra-high pressure mud is 40±2MPa, and the slurry flow rate is 200-600L / min; and / or, the lifting speed of the spraying rod is 25min / m.

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