Device and method for negative friction resistance reduction and positive friction resistance transmission of prefabricated piles

A technology of negative friction resistance and prefabricated piles, which is applied in the direction of sheet pile wall, foundation structure test, construction, etc., can solve the problem of reducing negative friction resistance of pile foundation, economic waste, distribution of negative friction resistance of pile body, resistance size and jamming The groove matching problem is difficult to determine and other problems, so as to reduce the negative friction resistance and promote the sliding effect

Active Publication Date: 2021-11-12
NANJING INST OF TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the negative frictional resistance on the pile side can be reduced, the length of the card slot is still determined, the distribution of the negative frictional resistance of the pile body, the matching of the resistance and the card slot are difficult to determine, and the installation of devices with no difference above the neutral point along the pile body will lead to economical problems. waste
Or, use grouting bags to lay between the pile and the soil to reduce the negative friction of the pile foundation. This method is suitable for on-site cast-in-place piles, but not for prefabricated piles.

Method used

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  • Device and method for negative friction resistance reduction and positive friction resistance transmission of prefabricated piles
  • Device and method for negative friction resistance reduction and positive friction resistance transmission of prefabricated piles
  • Device and method for negative friction resistance reduction and positive friction resistance transmission of prefabricated piles

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Experimental program
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Effect test

Embodiment

[0100] It is known that the composite foundation adopts prefabricated tubular pile foundation, rock-socketed piles, diameter 400mm, length 24m, pile spacing 1.5m, upper load 150kPa, pile-soil stress ratio n=8, groundwater is located 1.0m below the ground.

[0101] Parameters of deep soft soil layer: thickness 10m, gravity γ s =18kN / m 2 , saturation gravity γ sat =19.2kN / m 2 , internal friction angle φ=10°, compression modulus E s = 3MPa.

[0102] calculation steps:

[0103] (1) Earth pressure on pile top plane

[0104]

[0105]

[0106] (2) Ultimate frictional resistance and plastic zone of pile side

[0107] At the top of the pile: τ u1 =0.6×(10+86.8tan10)=15.2kPa

[0108] z=1.2m, τ u2 =0.6×(10+65.6tan10)=12.9kPa

[0109]

[0110] That is, the depth of the plastic zone is 1.2m, and the limit value of negative friction resistance is 14.1kPa.

[0111] When the depth z=5.2m, σ sz ≥0.2σ cz

[0112]

[0113] The elastic zone is 1.2m to 5.2m deep and 4m lo...

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Abstract

The invention discloses a prefabricated pile negative friction resistance reduction and positive friction resistance transmission device and use method, comprising: a fixing part 1 sequentially arranged on the outside of the prefabricated pile from top to bottom, a degradable random fiber laminated fiberboard and a fixing part 2. Both the fixed part 1 and the fixed part 2 are provided with a cavity, and the two cavities are connected by a sliding link, and the two ends of the sliding link are provided with a sliding part, and the sliding part is limited up and down in the cavity Sliding; the outside of the degradable random-filament laminated fiberboard is provided with a porous permeable plate, which is used to wrap and fix the degradable random-filament laminated fiberboard on the outside of the prefabricated pile. Advantages: It enriches the existing prefabricated pile foundation construction technology, and develops a device and application technology that can reduce the negative friction resistance of prefabricated piles; through the degradable random fiber laminated fiberboard, the slippage is promoted to further reduce the negative friction resistance, and there is no pollution biodegradable.

Description

technical field [0001] The invention relates to a device for negative friction resistance reduction and positive friction resistance transmission of prefabricated piles and a use method thereof, belonging to the technical field of civil engineering prefabricated pile foundations. Background technique [0002] Due to the development of urban construction and the increasing expansion of civil engineering, engineering construction has gradually extended to the suburbs of cities and areas with poor soil quality. Unfavorable soil such as newly filled soil layer, under-consolidated soil layer, deep soft soil layer, collapsible loess, large-area piled on the side of the pile top, groundwater level drop, permafrost thawing and other factors will cause soil self-compression If the amount is relatively large, pile foundations are often used in such bad soil layers. When the soil compressive settlement is greater than the load-bearing pile sinking, negative friction resistance will be...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): E02D5/24E02D33/00
CPCE02D5/24E02D33/00
Inventor 徐奋强李庆辉
Owner NANJING INST OF TECH
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