CN110847165A - Construction method of spiral anchor core-inserting cement mixing pile - Google Patents

Abstract

The invention discloses a construction method of a cement mixing pile with a spiral anchor core, wherein the spiral anchor is assembled on site, after the cement mixing pile is constructed and before cement is initially set, the spiral anchor is arranged at the central position of the cement mixing pile, and a spiral anchor core-inserting combined pile is formed after cement is solidified; the length of the spiral anchor can be larger than, equal to or smaller than that of the cement mixing pile, and the diameter of the spiral blade can be larger than, equal to or smaller than the pile diameter of the cement mixing pile. Through the combination of cement mixing stake and screw anchor, play the reinforcing action to the peripheral soil body of screw anchor on the one hand, improved the resistance to plucking bearing capacity of pile foundation, produced soil body disturbance when on the other hand has avoided the screw anchor to penetrate the soil body again improves the resistance to compression bearing capacity of pile foundation. The technical scheme has the advantages of convenience in construction, simple process, low construction noise, environmental friendliness and good economical efficiency.

Description

A kind of construction method of spiral anchor grouting cement mixing pile

technical field

The patent of the present invention relates to a mortising composite pile structure device and a construction method thereof, in particular to a construction method of a screw anchor mortising cement mixing pile. It is mainly used in technical fields such as transmission and transformation line tower foundation and soft foundation treatment.

technical background

As a basic form, the screw anchor (or screw pile) has been applied in engineering practice as early as the middle of the 19th century; in the early days, blades were added outside the circular small-diameter steel pipe, which was applied to the coastal lighthouse mainly for uplift resistance. In basic engineering, screw anchors were gradually extended to include compressive and horizontal load resistance applications, especially in transmission and transformation line tower foundations, photovoltaic power station foundations, and transportation pipeline foundations. The screw anchor has the technical and economic characteristics of convenient construction, simple process, low construction noise, environmental friendliness and good economy.

Before the patent of the present invention, China applied for the invention patent "A spiral anchor composite foundation assembly and its spiral anchor" (application number: 201810203975.2), which proposed a spiral anchor, including an anchor rod and an anchor head arranged at the end of the anchor rod The outer peripheral part of the anchor head is provided with an involute spiral main blade, and the outer peripheral part of the anchor rod is provided with a number of auxiliary blades arranged in sequence along its axial direction. In the process of use, the anchor head and the anchor rod are assembled as independent parts, which can effectively improve the structural strength and tolerance of the anchor head; the main blade of the involute spiral structure is separately set on the outer periphery of the anchor head, which can be used for anchoring. During the operation process, the sand and gravel in the soil layer are removed in time, and the disturbance of the screw anchor to the soil layer is reduced, so as to ensure the effect of the anchoring operation and the structural strength of the components after the operation is completed. However, in the process of penetrating the soil, the spiral anchor structure will inevitably disturb the surrounding soil to a certain extent, and on the other hand, the torque is large when penetrating the soil, and the construction efficiency is not high. China applied for a patent for invention "High-pressure Whirl-Jet Helical Anchor Composite Foundation and Its Manufacturing Method" (Application No.: 201811405268.8), and proposed a Whirl-Jet Helical Anchor Composite Foundation and its manufacturing method, including a swirl-jet screw anchor and a surrounding and wrapping The cement-soil pile of the rotary spraying screw anchor is mainly composed of a hollow bolt and a spiral anchor piece arranged on the bottom of the hollow bolt. The bottom end of the hollow anchor rod is provided with a vertical nozzle, and the spiral anchor piece closest to the bottom end is provided with a horizontal nozzle, and both the vertical nozzle and the horizontal nozzle are communicated with the inside of the anchor rod. During the spin-down process of the rotary jet screw anchor, high pressure is used to simultaneously spray jets in both horizontal and vertical directions to form cement-soil piles. Although this technical solution uses high-pressure rotary spraying to improve the surrounding soil; however, the cement-soil pile formed is poor in uniformity, and the soil improvement effect is limited, and the disturbance to the soil cannot be avoided at the same time. Its screw anchor production and on-site construction are not convenient enough.

Therefore, a new type of core-injection composite pile and its construction method are developed that can fully improve the soil properties around the screw anchor by using the existing equipment and conditions, avoid soil disturbance during the construction of the screw anchor, and greatly improve the bearing capacity of the pile foundation. seems particularly urgent.

Invention patent content

The purpose of the patent of the present invention is to provide a construction method of a spiral anchor ferrule combined pile that improves the occlusal force between the spiral anchor and the surrounding soil.

In order to solve the problems and deficiencies existing in the prior art, the present invention proposes a construction method of a spiral anchor grouting cement mixing pile, wherein the spiral anchor grouting cement mixing pile includes a cement mixing pile, a steel pipe and a spiral blade; The anchor is assembled on site. After the cement-soil mixing pile is constructed and before the cement-soil is initially set, the screw anchor is placed at the center of the cement-soil mixing pile. , equal to or less than the length of the cement mixing pile, and the diameter of the helical blade can be greater than, equal to or less than the diameter of the cement mixing pile.

More specifically, the construction method of the spiral anchor grouting cement mixing pile proposed by the present invention comprises the following steps:

(1) Component production: steel pipes and spiral blades are produced according to the design requirements;

(2) On-site assembly: each component of the screw anchor is transported to the site and assembled, the screw blade is set at the lower part of the steel pipe, and the components are connected by welding or sleeve connection;

(3) On-site stakeout: measure and set out according to the pile position design plan, determine each pile position, and the error requirement is less than the specification requirement;

(4) Drilling rig positioning: position the drilling rig according to the stakeout point, and the drill bit is facing the center of the pile position; use the theodolite to determine that the horizontal rail is perpendicular to the mixing shaft, and level the chassis to ensure that the inclination of the main shaft of the pile driver is not greater than 1%;

(5) Drilling construction of cement mixing pile: adopt the construction technology of two-stirring and four-jetting, start the drilling rig to drill to the design depth, and start the shotcrete pump at the same time, so that the cement slurry is sprayed into the agitated soil through the shotcrete pump, so that the cement and soil Carry out full mixing; the drilling rig can use a one-way mixer or a two-way mixer, and the two-way mixer is constructed into a pile with an upper diameter of 80-120 cm and a lower diameter of 40-70 cm.

(6) Screw anchor construction: before the initial setting of cement and soil, the assembled screw anchor is hoisted to the center of the cement mixing pile, and the horizontal deviation is required to be no more than 50mm. During the lifting process, the theodolite is used to correct the verticality and the depth of the soil, and the screw anchor is required. The inclination of the main shaft is not more than 1%, and the deviation of the depth of the soil is not more than 50mm; screw the screw anchor in the center of the cement mixing pile;

(7) After the cement mixing pile containing the screw anchor is solidified, the screw anchor core cement mixing pile is formed, and the construction is completed.

Specifically, the outer diameter of the steel pipe is 10-20 cm, the wall thickness is 1-2 cm, the length of each steel pipe is 2-3 m, the outer side of the steel pipe is threaded, and the sleeve is connected or welded on site, and 1 to 3 pipes can be connected outside the steel pipe. Spiral blade.

The spiral blades are arranged at the lower part of the steel pipe, with an effective diameter of 30-60 cm and a thickness of 1-2 cm. Each spiral anchor is provided with 1-3 spiral blades, and the spacing between adjacent spiral blades is determined according to design requirements. The diameter of each helical blade can be the same or different.

The cement mixing pile driver is a rotary jet pile driver. The model is selected according to the form of the pile. The single-shaft mixer can use the DML-120D1 rotary jet pile driver, and the pile forming form is the same as the upper and lower diameters; SP-5B-18 Two-way cement mixing pile driver.

The piling form is wide at the top and narrow at the bottom, or wide at the bottom and narrow at the top, or wide in the middle and narrow at both ends, or narrow in the middle and wide at both ends. The rig model can be adjusted according to project requirements.

Preferably, the drilling rig can use a one-way mixer or a two-way mixer, and the two-way mixer is constructed into a pile with an upper diameter of 80-120 cm and a lower diameter of 40-70 cm.

The cement slurry is mixed on site, and the mixing ratio is selected according to the project design requirements; during the use process, it is necessary to keep stirring continuously, and the mixing time and interval time should be controlled to prevent the cement slurry from segregating.

Beneficial effects: The present invention, through the combination of the cement mixing pile and the screw anchor, on the one hand strengthens the soil around the screw anchor, improves the uplift bearing capacity of the pile foundation, and on the other hand prevents the screw anchor from penetrating into the soil. The soil disturbance caused by the time increases the compressive bearing capacity of the pile foundation. The technical scheme of the invention has the advantages of convenient construction, simple process, low construction noise, environmental friendliness and good economy.

Description of drawings

Fig. 1 is the structural form diagram of the one-way cement mixing pile with screw anchor ferrule;

Fig. 2 is the structural form diagram of the two-way cement mixing pile with screw anchor core;

Among them, 1 is steel pipe, 2 is soil, 3 is spiral blade, and 4 is cement soil.

Detailed ways

The invention proposes a construction method of a spiral anchor grouting cement mixing pile, wherein the spiral anchor grouting cement mixing pile comprises a cement mixing pile, a steel pipe and a spiral blade. The screw anchor is assembled on site. After the cement-soil mixing pile is constructed and before the cement and soil is initially set, the screw anchor is placed in the center of the cement mixing pile. Greater than, equal to or less than the length of the cement mixing pile, the diameter of the helical blade can be greater than, equal to or less than the diameter of the cement mixing pile.

Specifically, the technical solution of the present invention is realized through the following steps

(1) Component production: make steel pipes and spiral blades according to the design requirements. The outer diameter of the steel pipes is 10-20 cm, the wall thickness is 1-2 cm, the length of each steel pipe is 2-3 m, the effective diameter of the spiral blades is 30-60 cm, and the thickness is 1-2 cm. 2cm;

(2) On-site assembly: The components of the screw anchor are transported to the site and assembled, and the components are connected by welding or sleeve connection. Each screw anchor is provided with 1 to 3 screw blades, and the diameter of each screw blade can be the same, It can also be different.

(3) On-site stakeout: According to the pile position design plan, measure and set out the line, and determine each pile position, and the error requirement is less than the specification requirement.

(4) Drilling rig positioning: position the drilling rig according to the stakeout point, and the drill bit is facing the center of the pile position; use the theodolite to determine that the horizontal rail is perpendicular to the mixing shaft, and level the chassis to ensure that the inclination of the main shaft of the pile driver is not greater than 1%.

(5) Drilling construction of cement mixing pile: adopt the construction technology of two-stirring and four-jetting, start the drilling rig to drill to the design depth, and start the shotcrete pump at the same time, so that the cement slurry is sprayed into the agitated soil through the shotcrete pump, so that the cement and soil Carry out full mixing; the drilling rig can use a one-way mixer or a two-way mixer, and the two-way mixer is constructed into a pile with an upper diameter of 80-120 cm and a lower diameter of 40-70 cm.

(6) Screw anchor construction: before the initial setting of cement and soil, the assembled screw anchor is hoisted to the center of the cement mixing pile, and the horizontal deviation is required to be no more than 50mm. During the lifting process, the theodolite is used to correct the verticality and the depth of the soil, and the screw anchor is required. The inclination of the main shaft is not more than 1%, and the deviation of the depth of the soil is not more than 50mm; screw the screw anchor in the center of the cement mixing pile. The cement mixing pile driver is a rotary jet pile driver. The model is selected according to the form of the pile. The single-shaft mixer can use the DML-120D1 rotary jet pile driver. -18 Two-way cement mixing pile machine, the pile form is wide at the top and narrow at the bottom, or wide at the bottom and narrow at the top, or wide in the middle and narrow at both ends, or narrow in the middle and wide at both ends. The model of the drilling rig can be adjusted according to project requirements.

(7) After the cement mixing pile containing the screw anchor is solidified, the screw anchor core cement mixing pile is formed, and the construction is completed.

The idea of the present invention is further described below with reference to a specific embodiment of a typical pile-forming form.

As shown in Figure 2 left (upper wide and lower narrow) spiral anchor ferrule two-way cement mixing pile, the factory prefabricated components are transported to the construction site, the steel pipes 1 are connected by sleeves or welded on site, and the steel pipes 1 and the helical blades 3 are connected. It is factory welded. The stakeout work should be completed before piling, and the error should be less than the specification requirements. Position the drilling rig according to the stakeout point and check the performance and stability of the drilling rig, connect the shotcrete pump to the pile driver, and make the drill bit face the center of the pile position after completion. Use the theodolite to confirm that the horizontal rail is perpendicular to the mixing shaft, and level the chassis to ensure that the inclination of the main shaft of the pile driver is not more than 1%. Start the drilling rig and shotcrete pump, drill to the design depth, pull up, replace with a large-diameter mixing head, drill down to 50-100mm below the design position of the uppermost spiral blade, and then pull up. In the process of drilling down and pulling up, the shotcrete work has been carried out and the staff is on the side to record the changes of the reading table. At this point, the construction of the cement mixing pile is completed, and the pile driver is moved to the next stakeout point for construction. At the same time, the screw anchor is hoisted with a crane before the initial setting of the cement and soil, and it is hoisted to the center of the cement mixing pile in time. Use the theodolite to adjust its position and verticality so that its position deviation is not greater than the construction requirements. Turn in the screw anchor to the design depth to complete the construction.

Claims (8)

1. A construction method of a spiral anchor core-inserting cement mixing pile comprises a cement mixing pile, a steel pipe and spiral blades, and is characterized in that: the spiral anchor is assembled on site, after the cement-soil mixing pile is constructed and before the cement-soil is initially set, the spiral anchor is placed at the central position of the cement-soil mixing pile, and a spiral anchor core-inserting combined pile is formed after the cement-soil is set; the length of the spiral anchor can be larger than, equal to or smaller than that of the cement mixing pile, and the diameter of the spiral blade can be larger than, equal to or smaller than the pile diameter of the cement mixing pile.

2. The construction method according to claim 1, comprising the steps of:

(1) manufacturing a part: manufacturing a steel pipe and a helical blade according to design requirements;

(2) assembling on site: transporting each component of the spiral anchor to the site and assembling, arranging the spiral blade at the lower part of the steel pipe, and connecting each component in a welding or sleeve connecting mode;

(3) and (3) field lofting: measuring and setting out according to the pile position design plan, and determining each pile position, wherein the error requirement is smaller than the standard requirement;

(4) positioning a drilling machine: positioning the drilling machine according to the lofting point, wherein the drill bit is over against the center of the pile position; determining that a layer direction rail is vertical to a stirring shaft by using a theodolite, leveling a chassis, and ensuring that the inclination of a main shaft of the pile machine is not more than 1%;

(5) drilling construction of the cement mixing pile: starting a drilling machine to a designed depth by adopting a two-stirring four-spraying construction process, and simultaneously starting a guniting pump to spray cement slurry into stirred soil through the guniting pump so as to fully mix the cement and the soil;

(6) and (3) construction of a spiral anchor: hoisting the assembled spiral anchor to the center of the cement mixing pile before initial setting of cement soil, wherein the horizontal deviation is required to be not more than 50mm, correcting the verticality and the soil penetration depth by using a theodolite in the hoisting process, wherein the inclination of a main shaft of the spiral anchor is required to be not more than 1%, and the deviation of the soil penetration depth is not more than 50 mm; screwing a spiral anchor into the center of the cement mixing pile;

(7) and (5) forming the spiral anchor inserting core cement mixing pile after the cement mixing pile containing the spiral anchor is solidified, and finishing construction.

3. The construction method according to claim 1 or 2, wherein the outer diameter of the steel pipe is 10-20 cm, the wall thickness is 1-2 cm, the length of each section of the steel pipe is 2-3 m, the outer side of the steel pipe is threaded, and sleeve connection or field welding is adopted.

4. The construction method according to claim 1 or 2, wherein the helical blades are arranged at the lower part of the steel pipe, the effective diameter is 30-60 cm, the thickness is 1-2 cm, each helical anchor is provided with 1-3 helical blades, and the distance between every two adjacent helical blades is determined according to design requirements.

5. The construction method according to claim 2, wherein the cement mixing pile driver is a jet grouting pile driver.

6. The construction method according to claim 2, wherein the pile-forming form is wide at the top and narrow at the bottom, or wide at the bottom and narrow at the top, or wide at the middle and narrow at both ends, or wide at both ends.

7. The construction method according to claim 2, wherein the drilling machine can adopt a one-way mixer or a two-way mixer, and the two-way mixer is constructed into a pile with an upper diameter of 80-120 cm and a lower diameter of 40-70 cm.

8. The construction method according to claim 2, wherein the cement paste is prepared on site, and the mixing proportion is selected according to project design requirements; stirring is kept continuously during the use process, and the stirring time and the interval time are controlled to prevent the water mud from being separated.

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