Major diameter pile longitudinal vibration analysis method in axisymmetric radial inhomogeneous medium soil

Abstract

The invention provides a major diameter pile longitudinal vibration analysis method in axisymmetric radial inhomogeneous medium soil. The method comprises the following steps that soil body around pile adopts a three-dimensional axisymmetric model to consider a vertical fluctuation effect; the soil body around pile is divided into an internal disturbance area and an external area, the internal disturbance area is divided into random layers, each layer of the soil body is a respective homogeneous isotropy linear viscoelastic body, the soil body of the outer area infinitely extends in the axialdirection, and soil body material damping adopts viscous damping; constant displacement and balanced stress are achieved on pile-soil interfaces and two sides of each layer of soil interface and pile-soil interfaces, and pile-soil system vibration is small in deformation; pile body concretes are linear elasticity, and stress wave propagation in the pile body meets plane cross-section assumption; asoil body around pile and pile body longitudinal vibration function is constructed under the condition of constructing three-dimensional axial symmetry; Laplace conversion and a variable separation method are used for solving the vibration function, and a time domain speed responding function that any exciting force is applied to a pile top. The method is closer to a realistic model and can provide theoretical guidance and reference for pile foundation dynamic detection.

Description

technical field [0001] The invention relates to the field of civil engineering, in particular to a pile foundation longitudinal vibration analysis method based on a three-dimensional axisymmetric radial heterogeneous viscous damping soil model considering the transverse inertia effect of a pile body. Background technique [0002] The study of pile-soil coupled vibration characteristics is the theoretical basis of engineering technology fields such as seismic design of pile foundations and dynamic testing of pile foundations, and has always been a hot issue in geotechnical engineering and solid mechanics. [0003] As we all know, in the process of pile foundation construction, due to the influence of soil compaction, relaxation and other disturbing factors, there is a certain inhomogeneity in the soil around the pile along the radial direction of the pile foundation, that is, the radial heterogeneity effect. In order to consider this radial heterogeneity effect, many scholars...

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Problems solved by technology

However, for the problem of anharmonic vibration (transient vibration or random vibration), the hysteretic damping model is not suitable, especially when studying the time domain response of piles under transient excitation conditions, the soil damping force is also related to the amplitude Related to the strain rate, the use of the hysteretic damping model will cause contradictions in the concept, resulting in the so-called "non-causality of dynamic response", while the viscous damping model is more suitable and more reasonable in physics

[0009] In summary, when considering the lateral inertia effect of the pile body to study the vibration response of the pile body, the plane strain model theory is used, but this model ignores the changes of the soil stress and displacement components along the depth, and cannot reflect the soil in the radial direction. The connection between layers cannot take into account the three-dimensional stress state of the soil around the pile and the three-dimensional dynamic coupling effect between the pile and the soil.

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