A Numerical Analysis Method for Limit Expansion Shear Force of Pile Foundation in Expansive Soil Area

Abstract

The invention discloses an expansive soil region pile foundation extremity expanding cutting force numerical analysis method. Firstly, based on an expansive soil indoor testing result, expansive soilparameter indexes are obtained and comprise intensity parameters, expansion rate parameters and basic physical parameter indexes such as density, modulus and the like; and then finite element numerical analysis software is used for building an electric transmission line cast-in-situ bored pile foundation and expansive soil foundation model, the material attribute and pile-soil contact are arranged, a crustal stress equilibrium analysis step and an expanding computational analysis step are built, the moisture content of a soil body within the expansive soil foundation earth surface atmosphericeffect layer depth range is changed in the expanding computational analysis step, and the expanding cutting force of expansive soil to a pile body due to moisture absorption expanding is simulated. Depending on the numerical analysis method, based on calculating parameters obtained through an indoor test, the pile foundation extremity expanding cutting force change rule under the conditions that the pile lengths, the pile diameters, the moisture contents and the atmospheric layer depths are different are simply and effectively calculated and analyzed, and the reference basis is provided for pile foundation design and optimization.

Description

technical field [0001] The invention belongs to the fields of engineering application and design of pile foundations in expansive soil areas, and in particular relates to a numerical analysis method for limit expansion and shear force of pile foundations in expansive soil foundations. Background technique [0002] Expansive soil is a kind of highly plastic cohesive soil that has strong water absorption expansion, volume increase, strength reduction, water loss shrinkage, volume reduction and strength improvement. Expansive soils are widely distributed in my country. Relevant research data show that expansive soils with different strengths and weaknesses are distributed in varying degrees from Hebei, Henan, to Sichuan, Yunnan, Guizhou and other places. These areas are deep inland of the motherland, and the climate and rainfall seasons are distinct, so the expansive soil in the natural state is often in an unsaturated state and fluctuates within a certain range of moisture con...

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Problems solved by technology

[0009] In view of this, the purpose of the present invention is to address the deficiencies in the prior art and provide a numerical simulation method for the ultimate expansion and shear force of pile foundations in expansive soil areas, which solves the problem of swelling in the depth range of the surface atmospheric influence layer in actual engineering. Soil absorbs moisture and expands to cause the pile body to pull out, so as to generate vertical uplift force calculation problems on pile top buildings and structures, and this method can be used to further analyze different pile lengths, different moisture contents, different pile diameters, different regions (different Atmospheric influence layer depth), the change law of the expansion force and limit expansion shear force on the pile foundation, so as to provide a reference for the design and optimization of pile foundations in expansive soil areas

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