Acceptance standard and construction specification of DDC pile!

Deep dynamic compaction pile method in hole Deep dynamic compaction pile method in hole, referred to as DDC (patented by Beijing Ruilitong Company) technology, is a foundation reinforcement technology developed on the basis of dynamic compaction technology and a foundation treatment technology based on "dynamic compaction" mechanism and modern science and technology. Its construction is to form a hole first, then fill it, and then crush and squeeze it in the deep area of the hole with a special high kinetic energy overpressure hammer, so that the filler is squeezed to the periphery and bottom of the hole under strong push. Dynamic compaction and heavy hammer operation are completed from bottom to top in the hole. The tamping energy can reach 20000 kn. m/m2。 The depth can reach more than 30m. The foundation treated by DDC technology does not collapse in case of water and liquefaction in case of earthquake, with small compression deformation, high bearing capacity and uniform stiffness. It can consume a large amount of construction and industrial waste, reinforce the foundation with various inorganic solid wastes, reduce environmental pollution, and turn waste into treasure. This technology has been applied in dozens of foundation treatment projects, eliminating the collapsibility of deep loess foundation, greatly improving the bearing capacity of foundation, reducing the compressibility of foundation, and the foundation treatment effect is remarkable.

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Work instruction for construction of column hammer punching belled pile

1. Objective To clarify the technological process, operation points and corresponding technical standards of DDC pile construction, and to guide and standardize the construction of DDC piles. 2. This standard is based on the Interim Standard for Acceptance of Construction Quality of Railway Subgrade Engineering of Passenger Dedicated Line, Technical Guide for Construction of Railway Subgrade Engineering of Passenger Dedicated Line and Design of fuzhou-xiamen railway New Line Station.

3. The scope of application is applicable to the construction of DDC piles in front of Fuxia Railway Station.

4. Material Requirements Mixed materials should meet the design requirements, and the mixture ratio should be strictly controlled.

5, construction process and technical requirements

5. 1 construction preparation

(1) Check geological data, and select appropriate construction machinery and construction method in combination with design parameters.

⑵ Before construction, clear the topsoil, level the site, remove obstacles, and mark the underground structures and pipelines in the treatment site.

(3) Measure the setting-out, determine the control axis, pile position sideline and mark it.

(4) Before construction, test the pile-forming technology to determine the construction technology and parameters. The number of test piles shall meet the design requirements and shall not be less than 2.

5.2 Construction Technology

(1) Tools in place: construction tools are in place, so that the column hammer is aligned with the pile position.

⑵ Hole-forming: Long auger is used to drill holes with a diameter of 400mm and a depth meeting the design requirements.

⑶ Hole-filling piling: Fill the mixed filler into the pile hole in layers with a standard hopper or truck, and tamp it with a column hammer to form a pile body. When the hammer weight, hammer length and drop distance are determined, the layered filling quantity and tamping times are determined through process test. Each pile hole shall be rammed to at least 0.5m above the design elevation of the pile top, and the upper pile hole shall be rammed with original trench soil. Technicians should be set up during construction to keep records of each pile, and analyze and handle problems in time when found.

(4) Shift: shift the construction tools and repeat the above steps for the next pile construction. The tamping energy of column hammer punching and expanding method is large, which is easy to cause ground uplift, loosen the soil between surface piles and reduce the treatment effect. Therefore, the construction sequence of pore-forming and packing compaction should be carried out at intervals.

5.3 construction process flow chart

Clean and level the site.

Arrange paper pile position

drill

Check the filler in the hole.

Pillar hammer layered compaction

Pile-forming detection

Shift of construction machinery

Construction machinery and tools in place.

Packaging mixing

Preliminary determination of construction parameters