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CN-121992772-A - Efficient pile forming construction method for large-diameter pile foundation in complex geology

CN121992772ACN 121992772 ACN121992772 ACN 121992772ACN-121992772-A

Abstract

The invention relates to the technical field of building construction, in particular to a high-efficiency pile forming construction method for a large-diameter pile foundation of complex geology, which comprises the following steps of S1, early investigation and scheme adaptation, S2, orifice reinforcement and accurate lofting, S3, layered pore forming and dynamic wall protection, S4, composite pore cleaning and sediment prevention and control, S5, prefabrication and rapidness of a reinforcement cage, S6, continuous pouring and quality monitoring, S7, environmental protection treatment and safety monitoring, and S8, after pile forming, the quality of the pile foundation is detected by adopting a low-strain method and a static load test. The invention can realize complete complex stratum adaptation and multi-working-procedure collaborative operation, improve construction efficiency and quality, and reduce environmental protection and safety risks.

Inventors

  • YANG PENG
  • Yu Chuanxi
  • DIAO JINXIANG
  • HU HUAYUE
  • SHI JIAWEI

Assignees

  • 深圳市蛇口招商港湾工程有限公司

Dates

Publication Date
20260508
Application Date
20260311

Claims (10)

  1. 1. A high-efficiency pile forming construction method for a large-diameter pile foundation in complex geology is characterized by comprising the following steps: the method comprises the following steps of S1, pre-investigation and scheme adaptation, namely acquiring detailed geological data of a construction area by combining unmanned aerial vehicle aerial photography with geological drilling, matching drilling process, equipment model and slurry parameters according to the geological data, and making a construction scheme of cooperation of layering process and equipment; S2, orifice reinforcement and accurate lofting, namely pouring a concrete orifice platform, lofting by adopting a total station and GPS dual-mode positioning system, setting an error by 3cm, and installing a guide frame; S3, layering pore-forming and dynamic wall protection, wherein an upper flowing sand layer/silt layer is constructed by adopting a full-casing full-rotary drilling machine and rotary drilling, a middle sand-pebble layer is constructed by adopting a small-diameter pore-guiding and grading reaming process and a high-viscosity modified slurry wall protection, and a lower weathered rock layer/bedrock is constructed by adopting a full-hydraulic rotary reverse-circulation drilling machine and a hob drill; S4, composite hole cleaning and sediment prevention and control, namely reversely circulating to clean holes once after hole forming, lowering a reinforcement cage, adopting gas lift reverse circulation and high-pressure jet flow composite hole cleaning, and pouring concrete within 30 minutes after hole cleaning, wherein the sediment thickness is 30 mm; s5, prefabricating and rapidly hoisting the reinforcement cage, namely prefabricating the reinforcement cage in a factory section, mechanically connecting joints, hoisting in a double-machine cooperative mode, and hoisting for 40 minutes; s6, continuous casting and quality monitoring, namely, casting underwater concrete by a conduit method, initially filling a buried pipe by 1.2m, controlling the buried depth of the conduit to be 2-6m, and continuously casting without interruption; S7, environmental protection treatment and safety monitoring, namely purifying and multiplexing waste slurry, intensively transporting waste residues outwards, installing real-time monitoring equipment, and starting emergency measures when the waste residues are abnormal; and S8, detecting the quality of the pile foundation by adopting a low strain method and a static load test after pile forming.
  2. 2. The method for efficiently piling up a large diameter pile foundation in complex geology according to claim 1, wherein in said step S1, said geological data includes distribution ranges, thicknesses and physical and mechanical parameters of upper flowing sand layer/silt layer, middle sand pebble layer, lower weathered rock layer/bedrock, and said equipment model matching is based on hardness, grain size and hydraulic pressure parameters of each layer of geology.
  3. 3. The method for efficiently piling up a large-diameter pile foundation in complex geology of claim 1, wherein in the step S2, the concrete orifice platform is made of C30 concrete, the size is 2m < 0.5m >, the guide frame is formed by welding profile steel, and the verticality deviation is 0.5%.
  4. 4. The method for efficiently piling up a large-diameter pile foundation in complex geology of claim 1, wherein in step S3, when the upper sand layer/silt layer is constructed, the casing of the full casing full rotary drilling machine is lowered to 0.5m below the top surface of the sand pebble layer, and the drilling speed of the rotary drilling rig is controlled to be 1.2-1.5m/h.
  5. 5. The high-efficiency pile forming construction method for the large-diameter pile foundation of the complex geology is characterized in that in the step S3, when the middle sandy pebble layer is constructed, the specific steps of the small-diameter hole guiding and grading reaming process are that a 800mm drill bit is adopted for hole guiding and then the holes are reamed step by step to the designed pile diameter, and the specific gravity of the high-viscosity modified slurry is controlled to be 1.25-1.3, and the sand content is less than 5%.
  6. 6. The high-efficiency pile forming construction method for the large-diameter pile foundation of the complex geology is characterized in that in the step S3, when the lower weathered rock layer/bedrock is constructed, the drilling pressure of the full-hydraulic rotary reverse circulation drilling machine is dynamically adjusted according to the rock layer hardness, wherein the drilling pressure of the soft rock is 25-35MPa, the drilling pressure of the hard rock is 60-80MPa, the rotating speed adjustment range is 8-12rpm for the soft rock and 5-8rpm for the hard rock, and the slag is discharged in a gas lift reverse circulation mode.
  7. 7. The method for efficiently piling up the large-diameter pile foundation in complex geology according to claim 1, wherein in the step S4, the concrete implementation mode of the gas lift reverse circulation and high-pressure jet flow composite hole cleaning technology is that large-diameter sediments are broken through impact of a high-pressure jet flow device arranged at the bottom of a hole, and a gas lift reverse circulation system is synchronously started to strongly discharge the broken sediments outside the hole.
  8. 8. The method for efficiently piling up the large-diameter pile foundation in complex geology of claim 1, wherein in the step S5, the mechanical connection joints of the reinforcement cage are staggered by a distance of 35d (d is the diameter of the reinforcement), the double-machine cooperative hoisting adopts a hoisting mode of matching a main crane with a secondary crane, and centering is ensured by a guide frame in the process of lowering the reinforcement cage, wherein the deviation is 5cm.
  9. 9. The method for efficiently piling a large-diameter pile foundation in complex geology of claim 1, wherein in the step S6, the diameter of the guide pipe is 300mm, the concrete pouring speed is controlled to be 2.5-3m/h, the over-grouting height after the pouring is completed is 0.8-1.0m, and the pile top quality is ensured after the floating slurry is removed in the follow-up chiseling of the over-grouting part.
  10. 10. The method for efficiently piling a large-diameter pile foundation in complex geology according to claim 1, wherein in the step S7, the real-time monitoring equipment comprises an in-hole sedimentation monitor, a slurry performance monitor and a verticality monitor, the monitoring abnormality judgment standard is that in-hole sedimentation is 5cm, slurry sand content is more than 8% or verticality deviation is more than 3cm, and corresponding emergency measures comprise sleeve supplementing, slurry parameter adjusting or shutdown backfilling.

Description

Efficient pile forming construction method for large-diameter pile foundation in complex geology Technical Field The invention relates to a high-efficiency pile forming construction method for a large-diameter pile foundation of complex geology, in particular to a high-efficiency pile forming construction method for the large-diameter pile foundation of complex geology, and belongs to the technical field of building construction. Background Along with the large-scale construction of heavy infrastructure projects such as transportation hubs, super high-rise buildings, offshore wind power platforms and the like in China, the project site selection gradually extends to complicated geological areas such as mountain areas, coasts, valley lands and the like. The areas have uneven soil layer distribution, high sand and pebble content, large fluctuation of weathered rock stratum, abundant groundwater and high water pressure, and partial areas are accompanied with bad geological conditions such as flowing sand, silt clay, karst cavity and the like, so that the construction of pile foundation engineering is severely challenged. The large-diameter pile foundation has the characteristics of strong bearing capacity, excellent anti-sedimentation performance and the like, so that the large-diameter pile foundation becomes a core bearing foundation form of the major engineering, and the construction quality and efficiency directly determine the whole construction period, the construction cost and the structural safety and stability of the engineering. At present, various mature technical schemes are formed in industry aiming at pile forming construction of a large-diameter pile foundation under complex geological conditions, and mainly comprise bored cast-in-place piles, pile sinking of prefabricated pipe piles, impact drilling and rock-socketed pile forming and the like. The rotary drilling mud slurry wall protection process is widely applied to clay, silt and medium breeze rock stratum areas due to flexible maneuvering and wide adaptability, the reverse circulation drilling process is mainly used for ultra-deep and rock-embedded pile foundation construction by virtue of the advantage of high deslagging efficiency, the full-casing full-rotation process can effectively prevent and control hole collapse risks, is applied to poor strata such as sand flow and silt, and is suitable for batch pile forming scenes of partial sand layers and viscous soil strata due to the characteristics of high construction speed and controllable quality of the prefabricated pipe pile hole guiding pile sinking process. However, in the actual complex geological construction process, the prior art scheme still has a plurality of problems to be solved urgently, and the problems are specifically expressed as follows: 1. The method has the advantages of low pore-forming efficiency, poor stability, difficulty in adapting to all-stratum construction by a single drilling process, slow drilling of a sand-gravel layer, easiness in hole collapse of a sand-gravel layer, high rock-socketed construction difficulty, low precision, high deviation of perpendicularity of impact drilling and socketed drilling, easiness in out-of-control drilling pressure and eccentric wear of a drill bit, 3 poor sediment control effect, difficulty in removing sediment with large grain size by a traditional hole-cleaning process, easiness in sediment accumulation, influence on pile foundation quality, 4 poor equipment cooperativity, incoherence in construction flow, long equipment idle time, long single pile construction period, 5, insufficient environmental protection and safety risk management and control, high waste slurry treatment difficulty, lack of real-time monitoring and emergency treatment measures and high safety accident probability. Therefore, there is a need for a high-efficiency piling method for a large diameter pile foundation in complex geology to solve the above-mentioned problems. Disclosure of Invention The invention aims to provide a high-efficiency piling construction method for a large-diameter pile foundation in complex geology, which is used for solving the problems of low pore-forming efficiency, poor stability, insufficient rock embedding precision, poor sediment control effect, poor equipment cooperativity, high environmental protection safety risk and the like in the construction of the large-diameter pile foundation in complex geology in the prior art. In order to achieve the aim, the main technical scheme adopted by the invention comprises a high-efficiency piling construction method of a large-diameter pile foundation of complex geology, which comprises the following steps: the method comprises the following steps of S1, pre-investigation and scheme adaptation, namely acquiring detailed geological data of a construction area by combining unmanned aerial vehicle aerial photography with geological drilling, matching drilling process, equipment model an