High-pile wharf foundation pile damage diagnosis method based on structural residual modal force

Abstract

The invention discloses a high-pile wharf foundation pile damage diagnosis method based on structural residual modal force. The method includes the steps that a finite element model of a high-pile wharf foundation pile structure is established, the structure is divided into a plurality of units, and each unit comprises two nodes; an acceleration sensor is arranged on each unit, and modal test data detected under natural environment excitation are recorded and saved; modal parameter recognition is performed on the modal test data, and a low-order modal frequency and a vibration mode of previous orders are recognized; model correction is performed, and a reference finite element model is obtained; under the non-damage and damage condition, a rigidity matrix and a mass matrix of each unit are extracted; and each freedom-degree residual modal force vector in each unit is calculated, when the absolute value of each freedom-degree residual modal force vector in each unit is larger than a set value, it is judged that damage exists, and the position where structural damage is located is positioned according to the nodes corresponding to freedom degrees. Only through low-order modal information generated before and after structural damage, damage diagnosis can be performed under the condition that the structure has single damage and multi-site damage.

Description

technical field [0001] The invention relates to a damage diagnosis method for foundation piles of wharf, in particular to a damage diagnosis method for foundation piles of high pile wharf based on structural residual modal force. Background technique [0002] The high-piled wharf is composed of foundation piles and a superstructure. The lower part of the pile is driven into the soil, and the upper part is above the water surface. The high-pile wharf is a hollow structure. Waves and water flow can pass below the wharf plane. It does not reflect waves, does not affect flood discharge, and can reduce siltation. It is suitable for soft soil foundations. Long piles and long-span structures are widely used, and large prestressed concrete pipe columns or steel pipe columns are gradually used to replace piles with smaller sections to form a pipe column wharf. The high-piled wharf uses a series of long piles to drive into the soft soil foundation to form a pile foundation to bear th...

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Problems solved by technology

The existing damage diagnosis methods mostly use the reflected wave method. In the reflected wave method, the wave velocity is the most basic parameter for foundation pile damage diagnosis. In terms of influencing factors, the complexity of the parameters leads to the following problems in this method: First, the waveform curve Affected by different soil layers around the pile, and the soil around the pile will cause stress wave loss, to accurately diagnose the damage, it is necessary to understand the soil quality around the pile; second, the second damage of the foundation pile is difficult to accurately identify, when the first damage When it is relatively large, the upward and downward force waves will be seriously affected, which will directly lead to an increase in the difficulty of identifying the second damage; third, only basic qualitative analysis can be performed on the damage of foundation piles, which cannot reach a quantitative level. Based on a single stress waveform feature, it is difficult to make a quantitative analysis of the thickness of the damaged section of the foundation pile and the width of the crack; in addition, the upper part of the high-piled wharf foundation pile generally has a wharf superstructure such as pile caps, beams, longitudinal beams, panels, etc. , when using the traditional stress reflection wave damage identification method to diagnose the integrity of foundation piles, since the stress waves will There are multiple reflections and propagations at the damage site, which brings great interference to the damage diagnosis of foundation piles and makes it difficult to diagnose foundation pile damage

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