Construction method for controlling perpendicularity and deviation of steel latticed column inserted into cast-in-place pile

Abstract

The invention discloses a construction method for controlling perpendicularity and deviation of a steel latticed column inserted in a cast-in-place pile, and relates to the field of engineering construction. Secondly, cast-in-place pile hole forming and reinforcement cage construction are conducted; 3, inserting construction of the profile steel latticed columns is conducted; fourthly, concrete pouring is conducted; and step 5, quality monitoring and deviation processing. A three-level measurement system is constructed, and the pile position deviation is smaller than or equal to 3 mm; the straightness of the standard jig frame prefabricated latticed column is smaller than or equal to L / 1000 and smaller than or equal to 10 mm, and the perpendicularity of formed holes is controlled to be smaller than or equal to 1% through a rotary drilling rig; a three-dimensional guiding system and dynamic monitoring are utilized, the insertion deviation plane is smaller than or equal to 20 mm (the insertion deviation plane is smaller than or equal to 10 mm in a reverse construction method), and the perpendicularity is smaller than or equal to L A guide pipe method is adopted for concrete pouring, and a composite anti-floating measure is combined to prevent deviation; quantitative monitoring and staged processing are carried out in the whole process, fine control of the whole process is achieved, and precision and safety are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of engineering construction, and specifically to a construction method for controlling the verticality and deviation of a steel lattice column inserted into a cast-in-place pile. Background Art

[0002] In the field of construction engineering, the construction technology of inserting a steel lattice column into a cast-in-place pile, as an efficient composite support and load-bearing system, is widely used in deep foundation pit support projects in urban complex environments (such as basements of super high-rise buildings, deep foundation pits of subway stations, etc.) and reverse construction structures. This technology forms a "pile-column cooperation" force system by inserting a lattice column welded by steel sections into a reinforced concrete cast-in-place pile, which can not only meet the requirements of foundation pit support for stiffness and stability, but also serve as a vertical load-bearing member for the simultaneous construction of above-ground and underground structures in reverse construction, significantly shortening the construction period and improving space utilization rate.

[0003] However, in the prior art, there is a lack of three-level control in measurement positioning, resulting in large pile position deviations, and the equipment debugging is empirical, leading to error accumulation; there is a lack of standardized formwork and rigid constraints in prefabrication, and there are deficiencies in controlling welding deformation and hole forming verticality; there is a lack of three-dimensional guidance and dynamic monitoring during insertion, and the deviation exceeds 20 mm; the anti-floating measures during pouring are single, and insufficient monitoring leads to column body offset; there is a lack of quantitative standards and high-frequency detection in quality monitoring, and there is a lack of scientific solutions for deviation treatment. Summary of the Invention

[0004] The purpose of the present invention is to provide a construction method for controlling the verticality and deviation of a steel lattice column inserted into a cast-in-place pile, so as to solve the problems raised in the above background art.

[0005] To achieve the above purpose, the present invention provides the following technical solutions: A construction method for controlling the verticality and deviation of a steel lattice column inserted into a cast-in-place pile, including the following steps: Step 1, Precise positioning and equipment debugging: Establish a three-level measurement reference system, calibrate the horizontal degree of the drill rig chassis and the lifting tool, and position and weld the steel lattice column through a standardized formwork to control the straightness of the precast column; Step 2, Borehole formation of the cast-in-place pile and construction of the steel reinforcement cage: Use a rotary drilling rig to control the borehole accuracy, and position the center of the steel reinforcement cage through numerical control machining and double-crane hoisting; Step 3, Insertion construction of the steel lattice column: Utilize a three-dimensional positioning guidance system and dynamic monitoring technology to achieve spatial position control and real-time deviation adjustment during the insertion of the lattice column; Step 4, Concrete pouring: Use the conduit method for underwater concrete pouring, control the pouring speed and the depth of the buried pipe, and take anti-floating fixing measures; Step 5, Quality monitoring and deviation treatment: Conduct quality monitoring on each process link, and perform corresponding treatment on the deviation according to the monitoring results.

[0006] Preferably, the three - level measurement reference system includes: Primary control network: The GPS - RTK is used to establish the field control network; Secondary traverse network: Closed traverses are laid out along the perimeter of the foundation pit, with the angular measurement error, relative distance measurement error, and the spacing of encrypted control points; Tertiary pile position lofting: The total station polar coordinate method is used to loft the pile positions, and the deviation between the measured coordinates and the design values is measured.

[0007] Preferably, the equipment calibration and commissioning include: The levelness of the drill rig chassis is calibrated using an electronic level to ensure that the levelness ≤ 1 / 1000; The lifting appliance uses a special - shaped steel flat beam. After mechanical calculation, the safety factor ≥ 2.0, the deviation of the lifting point position ≤ 10 mm, and the inspection period of the supporting wire rope flaw detection ≤ 15 days.

[0008] Preferably, in the prefabrication process of the steel lattice column, the jig is welded with H300×300 steel, and a 5 - mm - thick steel plate is laid on the surface; the positioning baffle is welded with positioning angle steel according to the design size of the lattice column; CO2 gas shielded welding is used for welding, with the current of 200 - 250 A, the voltage of 22 - 25 V, the welding speed of 300 - 400 mm / min. After each weld seam is completed, the theodolite is used to monitor the perpendicularity of the column body. When the cumulative deviation > 2 mm, welding is suspended and corrected.

[0009] Preferably, in the control of the hole - forming accuracy, the drilling parameters of the rotary drilling rig are: the rotation speed of 8 - 12 r / min, the drilling pressure of 80 - 120 kN, the flow rate of the mud pump of 80 - 100 m³ / h. The hole perpendicularity is re - checked with an inclinometer every 5 m of penetration, and the accuracy is ±0.1°; For the sand layer, the mud viscosity is increased to 25 - 30 s, and low - speed and slow - progress drilling is adopted, with the drilling time per meter ≥ 3 min; For the rock layer, the pick - type bit is replaced. After a 200 - mm trial drill to confirm the perpendicularity, normal drilling is carried out. When the rock layer dip angle > 15°, the pilot hole is used for assistance, and the diameter of the pilot hole is 50 mm larger.

[0010] Preferably, in the steel cage positioning technology, the spacing of the main steel bars of the steel cage is ±10 mm, the spiral spacing of the stirrups is ±20 mm, the flatness of the stiffening ring is ≤ 5 mm. A set of concrete protection blocks is set every 2 m, with 4 blocks in each ring and a thickness of 50 mm; Double - machine lifting is adopted. When straightening in the air, the theodolite is used to monitor the perpendicularity, and the lowering speed ≤ 0.5 m / s. It is fixed by welding 4 Φ20 positioning steel bars to the casing. The elevation error of the top of the positioning steel bar ≤ 10 mm, and the center deviation ≤ 5 mm.

[0011] Preferably, the three - dimensional positioning and guiding system includes: Orifice guide frame: Made of H400×400 steel, with plane dimension error ≤3mm, welded and fixed with casing, weld length ≥200mm; Deep limit ring: two steel hoops are set at 2m and 5m below the hole mouth, with inner diameter = lattice column outer dimension + 20mm, fixed to the hole wall by expansion bolts, and the horizontality of the hoops is ≤1mm / m; Hydraulic jack group: 4 50t jacks are symmetrically arranged at the four corners of the guide frame, equipped with a PLC synchronous control system, with a displacement accuracy of ±0.5mm and an angle adjustment accuracy of 0.05°; Adjustable positioning bolts: M24 bolts are equipped with spring washers, which allow the plane position of the lattice column to be fine-tuned by ±5mm. A 3mm thick rubber pad is attached to the contact between the bolt and the column.

[0012] Preferably, in the insertion process control, the lattice column is hoisted by "two-point lifting + tail rope", the deviation between the center of the shoulder beam and the center of gravity of the lattice column is ≤10mm, and the rope tension is ≥20kN; Before insertion, mark elevation marks every 1m on the surface of the lattice column. When the first section is inserted, the verticality deviation must be ≤0.5% before it can be lowered further. Two theodolites are used on the ground at a 90° angle to observe the center line of the column top, and a laser plumb line is used to project the reference line. The column deviation is marked every 1m of descent. A fixed inclinometer is lowered into the hole with the column, with an accuracy of ±0.02° / m. It transmits the inclination angle at each depth in real time to form a three-dimensional deviation cloud map.

[0013] Preferably, during concrete pouring, a Φ273mm spiral conduit is used, the bottom of the conduit is 300-500mm away from the bottom of the hole, the pouring speed is 1.5-2.5m³ / min, the conduit is lifted once every 50cm of pouring, the lifting height is ≤30cm, and the buried pipe depth is ensured to be 2-6m; Use a total station to re-measure the top coordinates of the column every 10 minutes. When the plane deviation is greater than 10mm or the verticality is greater than 1 / 600, suspend pouring and adjust the jack; The anti-floating fixing measures include welding 4 L100×10 angle steels on the top of the column, embedding them in C30 concrete anchor piers, and using "well" shaped steel clamps to weld them to the guide frame, and then tying them to the surrounding ground anchors through 4 Φ16 steel wire ropes. The pre-tension of the steel wire ropes is 30kN, and the pull-out resistance of the ground anchors is ≥50kN.

[0014] Preferably, in quality monitoring and deviation handling, the monitoring items and allowable deviations of each process link are as follows: Lattice column production: straightness ≤ L / 1000 and ≤ 10mm; Hole formation: verticality ≤ 1%; Insertion positioning: The planar position ≤ 20 mm, and the perpendicularity ≤ L / 500; Concrete pouring: The column top elevation ± 30 mm; The deviation handling process is as follows: Before the concrete initial setting, when the planar deviation is 10 - 20 mm, the column body is pushed by a jack and fine-tuned with a turnbuckle; when the perpendicularity is 1 / 400 - 1 / 500, the hydraulic jack group is started for angle compensation; after the concrete initial setting, when the deviation exceeds the limit, a consultation is organized among the design and supervision parties. When the deviation ≤ 30 mm, steel supports are added to tie with adjacent columns and the corbel steel bars are strengthened; when the deviation > 30 mm, after evaluation, it is decided whether to supplement piles or use carbon fiber cloth hoop reinforcement, and the reinforcement plan needs to be demonstrated by experts.

[0015] Compared with the prior art, the beneficial effects of the present invention are: In the present invention, by constructing a three-level measurement reference system (primary GPS-RTK control network, secondary traverse network, and tertiary total station polar coordinate layout), it is ensured that the pile position layout deviation ≤ 3 mm, solving the problem of insufficient traditional measurement accuracy; using a standardized jig to position and weld the lattice column, combined with the symmetric welding and rigid fixing process, the straightness is controlled ≤ L / 1000 and ≤ 10 mm, and through the parameter regulation of the rotary drilling rig and the targeted treatment of special strata, the hole forming perpendicularity ≤ 1% is achieved; with the help of the hole guiding frame, deep limit ring, hydraulic jack group and dynamic monitoring technology, a three-dimensional deviation cloud map is formed for real-time adjustment, so that the insertion planar position deviation ≤ 20 mm and the perpendicularity ≤ L / 500; for concrete pouring, the catheter method is used to control the pipe embedding depth of 2 - 6 m, combined with the composite anti-floating measures of column top anchor fittings, "well"-shaped section steel clamps and wire rope ties, to prevent floating and offset; throughout the process, quantitative monitoring indicators and a hierarchical deviation handling process are set up to achieve fine control of the whole process from precast to acceptance, significantly improving the construction accuracy and structural safety. Description of the Drawings

[0016] Figure 1 It is a flow chart of the construction method for controlling the perpendicularity and deviation of the steel lattice column inserted into the cast-in-place pile of the present invention. Detailed Embodiments

[0017] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

[0018] Embodiment: Refer to Figure 1 As shown: The construction method for controlling the perpendicularity and deviation of the steel lattice column inserted into the cast-in-place pile includes the following steps: Step 1: Precise positioning and equipment debugging. Include: (1) Establishment of the measurement reference system. By using GPS-RTK to establish the primary control network, arranging the secondary traverse network around the foundation pit, and using the total station polar coordinate method for the third-level pile position lofting, a three-level measurement reference system is constructed to ensure that the deviation of pile position lofting is ≤3mm. At the same time, calibrate the horizontal degree of the drill rig chassis and the lifting appliance to ensure that the equipment performance meets the accuracy requirements. Specifically as follows: 1. Layout of the three-level control network.

[0019] Primary control network: Use GPS-RTK to establish the field control network with a point position accuracy of ±5mm as the reference for pile position measurement and setting out.

[0020] Secondary traverse network: Arrange a closed traverse along the perimeter of the foundation pit with an angular measurement error of ±2.5″ and a relative distance measurement error of 1 / 40000. The spacing of the encrypted control points is ≤50m.

[0021] Third-level pile position lofting: Use a Leica TS60 total station (angular measurement 0.5″, distance measurement 1mm + 1ppm) to loft the pile positions by the polar coordinate method, and the deviation between the measured coordinates and the design values is ≤3mm.

[0022] 2. Equipment calibration and debugging.

[0023] Leveling of the drill rig chassis: Calibrate with an electronic level (accuracy ±0.05°) to ensure that the levelness of the drill rig platform is ≤1 / 1000.

[0024] Inspection of the lifting appliance: The special-shaped steel lifting beam needs to be mechanically checked (safety factor ≥2.0), the deviation of the lifting point position is ≤10mm, and the supporting steel wire ropes are regularly inspected for flaws (cycle ≤15 days).

[0025] (2) Prefabrication process of the steel lattice column. Use a standardized jig to position and weld the steel lattice column, and ensure the straightness of the prefabricated column through symmetric welding, rigid fixation, and process verticality monitoring. Specifically as follows: 1. Standardized production of the jig.

[0026] The jig is welded with H300×300 steel, with a 5mm-thick steel plate laid on the surface, leveled with a level, the flatness error is ≤2mm / m, and the diagonal difference of the jig is ≤5mm.

[0027] Setting of the positioning baffle: Weld positioning angle steels (accuracy ±1mm) on the jig according to the design dimensions of the lattice column to form a rigid constraint mold.

[0028] 2. Welding quality control.

[0029] Welding parameters: CO2 gas shielded welding, current 200 - 250A, voltage 22 - 25V, welding speed 300 - 400mm / min, interlayer temperature ≤150°C.

[0030] Deformation control: Adopt the process of "symmetrical welding + rigid fixation". After each weld pass, use a theodolite to monitor the perpendicularity of the column. When the cumulative deviation > 2mm, stop welding and make corrections.

[0031] Step 2: Bored pile hole formation and steel cage construction: Basic control of perpendicularity. Including: (1) Hole formation accuracy control technology. Use a rotary drilling rig for construction, control parameters such as rotation speed and drilling pressure. Use an inclinometer to recheck the hole perpendicularity every 5m of penetration. Take corresponding treatment measures for special strata such as sand layers and rock layers. After the final hole, detect items such as hole depth, hole diameter, perpendicularity, and sediment thickness according to standards to ensure that the hole formation accuracy meets the requirements. Specifically as follows: 1. Rotary drilling rig construction technology.

[0032] Drilling parameters: Rotation speed 8 - 12r / min, drilling pressure 80 - 120kN, mud pump flow rate 80 - 100m³ / h. Use an inclinometer to recheck the hole perpendicularity (accuracy ±0.1°) every 5m of penetration.

[0033] Treatment of special strata: For sand layers, increase the mud viscosity to 25 - 30s, adopt low - speed and slow penetration, and the drilling time per meter ≥ 3min; for rock layers, replace the pick - bit drill, first test - drill 200mm to confirm the perpendicularity and then drill normally. When the rock layer dip angle > 15°, use a pilot hole for assistance (hole diameter 50mm larger).

[0034] 2. Final hole acceptance standards.

[0035]

[0036] (2) Steel cage positioning technology. Control the main bar / stirrup spacing and the flatness of the stiffening ring of the steel cage through numerical control processing. Use double - crane lifting to monitor the perpendicularity and fix it by welding the positioning bars at the hole opening to achieve precise positioning of the center of the steel cage. Specifically as follows: 1. Processing accuracy of the steel cage.

[0037] Main bar spacing: ±10mm (controlled by a scale card), stirrup spiral spacing ±20mm (processed by a numerical control stirrup winding machine), flatness of the stiffening ring ≤5mm (detected with a right - angle ruler).

[0038] Positioning device: Set a group of concrete protection blocks every 2m (4 blocks per ring, thickness 50mm) to ensure that the steel cage is centered.

[0039] 2. Lowering and fixing process.

[0040] Use double-crane lifting (50t truck crane + 25t crawler crane). When straightening in the air, use a theodolite to monitor the verticality, and the lowering speed ≤ 0.5m / s.

[0041] Orifice fixing: Weld the casing through 4 Φ20 positioning steel bars (length 1.5m). The elevation error of the top of the positioning steel bar ≤ 10mm, and the central deviation ≤ 5mm.

[0042] Step 3: Insert the steel lattice column construction: Dynamic monitoring and precise positioning. Including: (1) Three-dimensional positioning and guiding system. Through the H400×400 steel guide frame at the orifice, two deep limiting rings in the hole, a set of four corner hydraulic jacks, and adjustable positioning bolts, precise control of the spatial position during the insertion of the lattice column is achieved. Specifically as follows: 1. Hardware configuration.

[0043] Orifice guide frame: Made of H400×400 steel, the plane size error ≤ 3mm, and welded and fixed to the casing (weld length ≥ 200mm).

[0044] Deep limiting ring: Set two steel hoops (inner diameter = outer dimension of the lattice column + 20mm) at 2m and 5m below the orifice, fixed to the hole wall by expansion bolts, and the levelness of the hoop ≤ 1mm / m.

[0045] 2. Dynamic adjustment device.

[0046] Hydraulic jack group: 4 sets of 50t jacks are symmetrically arranged at the four corners of the guide frame, equipped with a PLC synchronous control system, displacement accuracy ±0.5mm, and angle adjustment accuracy 0.05°.

[0047] Adjustable positioning bolt: M24 bolt with spring washer, allowing a fine adjustment of ±5mm for the plane position of the lattice column. A 3mm thick rubber cushion is pasted at the contact between the bolt and the column body.

[0048] (2) Insertion process control. Use "two-point lifting + tail guy rope" to hoist the lattice column, control the insertion depth through the elevation scale line on the column body and the orifice scale, and use a theodolite, laser plumb bob, and fixed inclinometer to monitor the verticality and plane deviation in real time, forming a three-dimensional deviation cloud map to guide dynamic adjustment. Specifically as follows: 1. Hoisting and initial positioning.

[0049] Hoisting tool design: The deviation between the center of the lifting beam and the center of gravity of the lattice column ≤ 10mm. When hoisting, use "two-point lifting + tail guy rope" to prevent the column body from swinging (guy rope tension ≥ 20kN).

[0050] Initial insertion accuracy: Before insertion, mark elevation lines every 1m on the surface of the lattice column, and control the insertion depth using the hole scale. When the first section is inserted, the verticality deviation must be ≤0.5% before it can be lowered further.

[0051] 2. Real-time monitoring technology.

[0052] Ground monitoring: Two theodolites are set at a 90° angle to observe the center line of the column top, and a laser plumb line (range 50m, accuracy 1 / 20000) is used to project the reference line. The deviation of the column is marked every 1m of descent.

[0053] In-hole monitoring: A fixed inclinometer (accuracy ±0.02° / m) is lowered along the column, and the inclination angle at each depth is transmitted in real time via a data line to form a three-dimensional deviation cloud map.

[0054] Step 4: Concrete pouring: anti-floating and disturbance control. Including: (I) Underwater concrete pouring process: Use the conduit method to pour underwater concrete, control the pouring speed and buried pipe depth, re-measure the top coordinates of the lattice column every 10 minutes to ensure that the lattice column deviation is within the allowable range during the pouring process. The details are as follows: 1. Conduit configuration: Use Φ273mm spiral conduit, with the bottom of the conduit 300~500mm away from the bottom of the hole, and calculate the volume of the first batch of concrete.

[0055] 2. Pouring control parameters.

[0056] Casting speed: 1.5~2.5m³ / min (lower value for soft soil), lift the pipe every 50cm, lift height ≤30cm, ensure buried pipe depth 2~6m.

[0057] Lattice column monitoring: During the pouring process, the column top coordinates are remeasured with a total station every 10 minutes. When the plane deviation is greater than 10mm or the verticality is greater than 1 / 600, the pouring is suspended and the jack is adjusted.

[0058] (II) Anti-floating fixing measures: by designing the anti-pullout anchors of the column top welded angle steel embedded in the concrete anchor pier, and adopting the rigid fixing measures of welding the steel clamps to the guide frame and tying the surrounding ground anchors with steel wire ropes, the lattice columns can be prevented from floating up during concrete pouring. The details are as follows: 1. Anchor design: 4 L100×10 angle steels (length 1.2m) are welded on the top of the column and embedded in C30 concrete anchor piers (size 1000×1000×800mm). The anchor pier reinforcement is Φ12@150mm and arranged in two directions.

[0059] 2. Rigid fixation: The top of the column is welded to the guide frame using a "well" shaped steel clamp (H300×300), with a weld height ≥10mm. At the same time, 4 Φ16 steel wire ropes (pre-tension 30kN) are used to tie it to the surrounding ground anchors (pull-out force ≥50kN).

[0060] Step 5: Quality monitoring and deviation handling. Including: 1. Quality control indicators for the entire process.

[0061]

[0062] (II) Deviation handling process

[0063] 1. Before initial setting of concrete (≤4h): Plane deviation 10~20mm: Use a jack to push the column and make fine adjustments with the help of the basket bolts. After adjustment, retest and continue pouring.

[0064] Verticality 1 / 400~1 / 500: Start the hydraulic jack group to perform angle compensation, and remeasure every 0.1° adjustment until the requirements are met.

[0065] 2. After initial setting of concrete: Deviation exceeds the limit (plane > 20mm or verticality > 1 / 500): stop the operation immediately, organize design and supervision consultation, and adopt the following measures: Deviation ≤30mm: Add steel support at the top of the lattice column to connect it to the adjacent column, and strengthen it with crown beam steel bars after stress calculation.

[0066] Deviation > 30mm: After evaluation, it is decided to add piles or use carbon fiber cloth hoops for reinforcement. The reinforcement plan needs to be verified by experts.

[0067] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. Construction method for controlling the verticality and deviation of the steel lattice column inserted into the cast-in-place pile, characterized in that, It includes the following steps: Step 1, Precise positioning and equipment debugging: Establish a three - level measurement reference system, calibrate the levelness of the drill rig chassis and the lifting tackle, and position and weld the steel lattice columns through a standardized tire rack to control the straightness of the precast columns; Step 2, Bored pile hole formation and steel cage construction: Use a rotary drilling rig to control the hole formation accuracy, and position the center of the steel cage through numerical control machining and double - machine lifting; Step 3, Insertion construction of steel lattice columns: Use a three - dimensional positioning and guiding system and dynamic monitoring technology to achieve spatial position control and real - time deviation adjustment during the insertion of the lattice columns; Step 4, Concrete pouring: Use the conduit method for underwater concrete pouring, control the pouring speed and the depth of the buried pipe, and take anti - floating fixing measures; Step 5, Quality monitoring and deviation treatment: Conduct quality monitoring on each process link, and perform corresponding treatment on the deviations according to the monitoring results.

2. The construction method for controlling the verticality and deviation of the steel lattice column inserted into the cast-in-place pile according to claim 1, characterized in that, The three - level measurement reference system includes: Primary control network: Establish a field control network using GPS - RTK; Secondary traverse network: Layout a closed traverse along the perimeter of the foundation pit, with the angular error of measurement, the relative error of distance measurement, and the spacing of encrypted control points; Tertiary pile position lofting: Use the total station polar coordinate method to loft the pile positions, and measure the deviation between the actual coordinates and the design values.

3. The construction method for controlling the verticality and deviation of the steel lattice column inserted into the cast-in-place pile according to claim 1, characterized in that, Equipment calibration and debugging include: The levelness of the drill rig chassis is calibrated using an electronic level to ensure that the levelness ≤ 1 / 1000; The lifting tackle uses a special steel section beam. After mechanical calculation, the safety factor ≥ 2.0, the deviation of the lifting point position ≤ 10mm, and the detection period of the supporting steel wire rope flaw detection ≤ 15 days.

4. The construction method for controlling the verticality and deviation of the steel lattice column inserted into the cast-in-place pile according to claim 1, characterized in that, In the prefabrication process of the steel lattice column, the tire rack is welded with H300×300 steel sections, and a 5mm - thick steel plate is laid on the surface; the positioning baffle is welded with positioning angle steels according to the design dimensions of the lattice column; the welding uses CO2 gas shielded welding, with the current 200 - 250A, the voltage 22 - 25V, and the welding speed 300 - 400mm / min. Use a theodolite to monitor the perpendicularity of the column body after each weld. When the cumulative deviation > 2mm, stop welding and correct it.

5. The construction method for controlling the verticality and deviation of the steel lattice column inserted into the cast-in-place pile according to claim 1, characterized in that, In the control of hole formation accuracy, the drilling parameters of the rotary drilling rig are a rotation speed of 8 - 12r / min, a drilling pressure of 80 - 120kN, a mud pump flow rate of 80 - 100m³ / h. Use an inclinometer to review the hole perpendicularity every 5m of penetration, with an accuracy of ±0.1°; For the sand layer, increase the mud viscosity to 25 - 30s, adopt low - speed and slow - penetration, and the drilling time per meter ≥ 3min; For the rock layer, replace the pick - type bit, first drill 200mm for trial to confirm the perpendicularity and then drill normally. When the rock layer dip angle > 15°, use a pilot hole for assistance, and the diameter of the pilot hole is 50mm larger.

6. The construction method for controlling the verticality and deviation of the steel lattice column inserted into the cast-in-place pile according to claim 1, characterized in that, In the steel cage positioning technology, the spacing of the main steel bars of the steel cage is ±10mm, the spiral spacing of the stirrups is ±20mm, the flatness of the stiffening ring ≤ 5mm, and a set of concrete protection blocks is set every 2m, with 4 blocks per ring and a thickness of 50mm; Adopt double - machine lifting. Use a theodolite to monitor the perpendicularity during straightening in the air, the lowering speed ≤ 0.5m / s, and fix it by welding 4 Φ20 positioning steel bars to the casing. The elevation error of the top of the positioning steel bars ≤ 10mm, and the center deviation ≤ 5mm.

7. The construction method for controlling the verticality and deviation of the steel lattice column inserted into the cast-in-place pile according to claim 1, characterized in that, The three - dimensional positioning and guiding system includes: Orifice guide frame: Made of H400×400 steel, with plane dimension error ≤3mm, welded and fixed with casing, weld length ≥200mm; Deep limit ring: two steel hoops are set at 2m and 5m below the hole mouth, with inner diameter = lattice column outer dimension + 20mm, fixed to the hole wall by expansion bolts, and the horizontality of the hoops is ≤1mm / m; Hydraulic jack group: 4 50t jacks are symmetrically arranged at the four corners of the guide frame, equipped with a PLC synchronous control system, with a displacement accuracy of ±0.5mm and an angle adjustment accuracy of 0.05°; Adjustable positioning bolts: M24 bolts are equipped with spring washers, which allow the plane position of the lattice column to be fine-tuned by ±5mm. A 3mm thick rubber pad is attached to the contact between the bolt and the column.

8. The construction method for controlling the verticality and deviation of the steel lattice column inserted into the cast-in-place pile according to claim 1, characterized in that, During the insertion process control, the lattice column is hoisted by "two-point lifting + tail rope", the deviation between the center of the shoulder beam and the center of gravity of the lattice column is ≤10mm, and the rope tension is ≥20kN; Before insertion, mark elevation marks every 1m on the surface of the lattice column. When the first section is inserted, the verticality deviation must be ≤0.5% before it can be lowered further. Two theodolites are used on the ground at a 90° angle to observe the center line of the column top, and a laser plumb line is used to project the reference line. The column deviation is marked every 1m of descent. A fixed inclinometer is lowered into the hole with the column, with an accuracy of ±0.02° / m. It transmits the inclination angle at each depth in real time to form a three-dimensional deviation cloud map.

9. The construction method for controlling the verticality and deviation of the steel lattice column inserted into the cast-in-place pile according to claim 1, wherein, During concrete pouring, a Φ273mm spiral conduit is used, with the bottom of the conduit 300~500mm away from the bottom of the hole, a pouring speed of 1.5~2.5m³ / min, and the conduit is lifted once every 50cm of pouring, with a lifting height of ≤30cm, to ensure that the buried pipe depth is 2~6m; Use a total station to re-measure the top coordinates of the column every 10 minutes. When the plane deviation is greater than 10mm or the verticality is greater than 1 / 600, suspend pouring and adjust the jack; The anti-floating fixing measures include welding 4 L100×10 angle steels on the top of the column, embedding them in C30 concrete anchor piers, and using "well" shaped steel clamps to weld them to the guide frame, and then tying them to the surrounding ground anchors through 4 Φ16 steel wire ropes. The pre-tension of the steel wire ropes is 30kN, and the pull-out resistance of the ground anchors is ≥50kN.

10. The construction method for controlling the verticality and deviation of the steel lattice column inserted into the cast-in-place pile according to claim 1, characterized in that, In quality monitoring and deviation handling, the monitoring items and allowable deviations of each process are as follows: Lattice column production: straightness ≤ L / 1000 and ≤ 10mm; Hole formation: verticality ≤ 1%; Insertion positioning: plane position ≤ 20mm, verticality ≤ L / 500; Concrete pouring: column top elevation ±30mm; The deviation handling process is as follows: before the initial setting of the concrete, when the plane deviation is 10~20mm, the column is pushed by the jack and fine-tuned with the basket bolts. When the verticality is 1 / 400~1 / 500, the hydraulic jack group is started to compensate for the angle. After the initial setting of the concrete, when the deviation exceeds the limit, organize the design and supervision consultation. When the deviation is ≤30mm, add steel supports to tie the adjacent columns and strengthen the crown beam steel bars. When the deviation is >30mm, it is decided after evaluation to add piles or use carbon fiber cloth hoop reinforcement. The reinforcement plan needs to be verified by experts.

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