Method for analyzing development and change rule of negative friction of ultra-long pile foundation under action of surcharge

A technology of negative friction resistance, analysis method, applied in the field of geotechnical engineering

Inactive Publication Date: 2020-07-07
SHANGHAI UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, various methods have limitations due to their respective characteristics and

Method used

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  • Method for analyzing development and change rule of negative friction of ultra-long pile foundation under action of surcharge
  • Method for analyzing development and change rule of negative friction of ultra-long pile foundation under action of surcharge
  • Method for analyzing development and change rule of negative friction of ultra-long pile foundation under action of surcharge

Examples

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Embodiment 1

[0079] In this example, see Figure 1-Figure 5 , an analysis method for the development and change law of the negative friction resistance of super-long pile foundations under the action of surcharge, the analysis method and model include the following steps:

[0080] (1) Establish negative friction resistance analysis model:

[0081] Consider the three-dimensional consolidation settlement of pile side soil, pile body compression deformation and pile tip soil settlement under the action of pile load, and introduce a three-fold line model that conforms to the three-stage working characteristics of ultra-long pile pile side resistance, based on the principle of pile displacement balance , the analytical model of negative friction resistance of ultra-long piles under surcharge is established;

[0082] (2) Establish a nonlinear numerical model of pile-soil interaction:

[0083] Through the calculation and analysis of engineering examples by theoretical model and numerical simula...

Embodiment 2

[0085] This embodiment is basically the same as Embodiment 1, especially in that:

[0086] In this example, see Figure 1-Figure 5 , an analysis method for the development and variation of the super-long pile foundation negative friction resistance under the heap load, the method of the step (1) is:

[0087] (a) Calculation of pile compression deformation:

[0088] The axial deformation equation of the pile is

[0089]

[0090] In the formula: E p is the elastic modulus of the pile; N is the sum of the self-weight of the pile above any section of the pile body and the load on the pile top, N=P+πR 2 gamma p z; R is the radius of the pile body;

[0091] The pile compression at any depth z is expressed as:

[0092]

[0093] In the formula: L is the pile length; P is the vertical load on the top of the pile; γ p is the bulk weight of the pile;

[0094] Divide the pile into N units equally along the pile body, assuming that the displacement of the midpoint of the i-th...

Embodiment 3

[0138] This embodiment is basically the same as the previous embodiment, and the special features are:

[0139] In this example, the calculation method of the development and change law of negative friction resistance of ultra-long pile foundation under the action of surcharge, the site in the soft soil area around the free pile of a certain project is divided into three layers, from top to bottom are muddy soil layer, silt layer Clay layer and cohesive soil mixed gravel sand layer. The proposed pile length is 64m, the pile diameter is 1m, and the pile tip is located in the cohesive soil-concrete sand layer. The physical and mechanical parameters and calculation parameters of each soil layer on the pile side and pile tip are shown in Table 1. The calculation method is as follows:

[0140] Table 1. The physical and mechanical parameters and calculation parameter table of each soil layer of the pile side and the pile end of the present invention

[0141]

[0142] When a sin...

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Abstract

The invention discloses a method for analyzing the development and change rule of the negative frictional resistance of an ultra-long pile foundation under the action of heaped loads. The method aimsat the condition of large-area stacking; the problem that a building is damaged due to negative frictional resistance caused by pile-soil settlement difference of an ultra-long pile foundation is studied. The calculation method comprises the following steps that by analyzing pile side soil body three-dimensional consolidation settlement, pile body compression deformation and pile end soil body settlement, a load transfer model considering side resistance softening is introduced, and according to the pile body displacement balance principle and based on a matrix transfer method, a super-long pile negative friction analysis model under the pile loading effect is established. Engineering examples are analyzed through a theoretical model and a numerical simulation method, meanwhile, comparisonverification is conducted on the engineering examples and corresponding actual measurement data, the development and change rule of the negative friction resistance of the super-long pile foundationunder the pile loading effect is obtained, and a theoretical basis is provided for super-long pile foundation bearing capacity design.

Description

technical field [0001] The invention belongs to the technical field of geotechnical engineering, and in particular relates to a calculation method for the development and variation law of the negative friction resistance of super-long pile foundations under the action of surcharge. Background technique [0002] In recent years, with the development of economic construction, ultra-long piles (L>50m, L / D>50) with larger single pile bearing capacity have been widely used in high-rise buildings and port engineering construction. For this new structure Some scholars at home and abroad have done some research on its ultimate bearing capacity and buckling stability under unidirectional or complex loads. When encountering a large-area surcharge, because the burial depth of super-long piles is much greater than that of ordinary piles, the compression deformation of the soil on the side of super-long piles is relatively large, resulting in the negative friction resistance of sup...

Claims

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Application Information

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IPC IPC(8): G06F30/20G06F30/13E02D33/00G06F119/14
CPCE02D33/00
Inventor 姚文娟徐赐敏顾毛亮陈君程泽坤
Owner SHANGHAI UNIV
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