CN-121385105-B - Nondestructive testing method for exposure test of concrete structural member

CN121385105BCN 121385105 BCN121385105 BCN 121385105BCN-121385105-B

Abstract

The invention discloses a nondestructive testing method for a concrete structural member exposure test, which comprises the steps of embedding sensors for detection in the concrete structural member, acquiring detection data of the concrete structural member under the condition of alternating salty and fresh water in real time, calculating by utilizing ultrasonic detector data to obtain the characteristic of relative dynamic elastic modulus change, quantifying distribution characteristic information of a degraded area of the concrete structural member by adopting a high-resolution optical camera system and a three-dimensional laser scanner, establishing a concrete structural member degradation model and a bearing capacity calculation model under the condition of alternating salty and fresh water, predicting the residual service life of the concrete structural member under the condition of alternating salty and fresh water according to a set failure standard, integrating and storing various detection data acquired in the whole exposure test process, and establishing a database.

Inventors

FAN ZHIHONG
YANG HAICHENG
WANG WEI
LI JIAMIN

Assignees

中交四航工程研究院有限公司
中交第四航务工程局有限公司

Dates

Publication Date: 20260508
Application Date: 20250922

Claims (10)

1. The nondestructive testing method for the exposure test of the concrete structural member is characterized by comprising the following steps of: The method comprises the steps of embedding a sensor for detecting in a concrete member, acquiring detection data of the concrete member under the condition of alternating salty and fresh water in real time, fitting out a diffusion coefficient of chloride ions in the concrete member based on Fick's second law, and generating a chloride ion diffusion characteristic set of the concrete member under the condition of alternating salty and fresh water; step two, utilizing an ultrasonic detector to transmit ultrasonic pulse signals with specific frequency to a concrete member, and combining an elastic wave theory of the concrete to calculate the relative dynamic elastic modulus change characteristic of the concrete under the alternating action of the salty and the fresh water; adopting a high-resolution optical camera system and a three-dimensional laser scanner to periodically scan and collect images on the surface of the concrete member, and adopting a multi-mode algorithm to identify and quantify the area, depth and distribution characteristic information of an degraded area on the surface of the concrete member; Step four, based on the analysis results of the detection data of the chloride ion diffusion characteristic set, the relative dynamic elastic modulus and the distribution characteristics, a concrete member degradation model under the alternating condition of the fresh water is established, a bearing capacity calculation model of the reinforced concrete member under the alternating effect of the fresh water is established by combining the actual stress condition and the boundary condition of the concrete member, and the residual service life of the concrete member under the alternating environment of the fresh water is predicted according to the set failure standard; and fifthly, performing system integration and storage on various detection data acquired in the whole exposure test process, establishing a database, and providing data reference of a damage degradation mechanism and a performance evolution rule of the concrete structural member under the condition of alternating salty and fresh water.
2. The nondestructive testing method for exposure test of concrete structural members according to claim 1, wherein the first step comprises the steps of establishing a diffusion model of chloride ions in the concrete structural members based on Fick's second law, determining boundary conditions and initial conditions, fitting the obtained chloride ion concentration under the condition of alternating salty and fresh water into the diffusion model to obtain a diffusion coefficient, and generating a chloride ion diffusion characteristic set of the concrete structural members under the condition of alternating salty and fresh water.
3. The method for nondestructive testing of concrete structural member exposure test according to claim 1, wherein said step three comprises: Removing noise of point cloud data and image data by bilateral filtering, distinguishing a plurality of independent ablation blocks in an image by a segmentation algorithm, identifying and marking an ablation area, and determining the boundary and range of each ablation block; Analyzing curvature change of the point cloud data to detect an irregular surface, and gathering points with similar curvature characteristics by using a clustering algorithm to distinguish an degraded area from a normal area; finding out point cloud data of laser scanning and corresponding feature points of image data acquired by an optical camera system through feature matching, optimizing the matching precision of the feature points by adopting an ICP algorithm, and aligning the point cloud data and the image data to the same coordinate system; And quantifying the degraded area by adopting a multi-mode algorithm, and obtaining the area and depth of the degraded area of the concrete member and the distribution characteristics including the morphological characteristics of the concrete under the alternating condition of the salty and fresh water.
4. A method of nondestructive testing of concrete structure member exposure test according to claim 3, wherein quantifying the degraded area using a multi-modal algorithm to obtain the area, depth, and distribution characteristics including morphological characteristics of the concrete member comprises: projecting an degraded area of a concrete member onto a two-dimensional plane, calculating the area of a convex hull to obtain the area of the degraded area, modeling a local reference surface for the intact area around each degraded block by adopting a local reference surface method to obtain the maximum depth and the average depth, and quantifying the depth characteristics of the degraded area; And carrying out nearest neighbor analysis by using a K function, evaluating the spatial randomness or aggregation of the stripping points, calculating the fractal dimension to quantify the complexity of the stripping boundary, and analyzing the orientation characteristics of the aspect ratio of the stripping shape by utilizing the minimum circumscribed rectangle to obtain the distribution characteristics comprising the morphological characteristics of the concrete.
5. The nondestructive testing method for exposure test of concrete structural members according to claim 1, wherein the fourth step comprises: According to the chloride ion diffusion characteristic set and by combining the distribution characteristics of the concrete member, calculating by adopting a numerical method to obtain the change rule of the chloride ion concentration on the surface of the concrete member along with time, and obtaining the initial time of erosion of the concrete member; Calculating the erosion speed and the loss sectional area of the concrete member by using the detected relative dynamic elastic modulus data and combining the characteristic of the alternating condition of the salty and fresh water and the starting time, and establishing a concrete member degradation model; According to the actual bearing load type and size of the concrete member and boundary conditions, calculating the damage resistance Guan Jianneng force of the concrete member, and integrating the member degradation into a bearing capacity calculation model; and according to the bearing capacity judging threshold, predicting the total service life of the concrete member by taking the current age of the concrete member as a starting point and based on a bearing capacity degradation function and a failure judging standard, so as to obtain the residual service life of the current concrete member in the alternating salty and fresh water environment.
6. The nondestructive testing method for exposure test of concrete structure member according to claim 5, wherein calculating the erosion rate and the loss cross-sectional area of the concrete member by using the relative dynamic elastic modulus data obtained by the detection in combination with the characteristic of the alternating condition of the fresh water and the start time, and establishing the concrete member degradation model comprises: according to the relative dynamic elastic modulus, the erosion speed and the loss sectional area, and considering the influence of the alternating period T of the salty and fresh water on the degradation process, determining a concrete member degradation model as follows: A loss (T) represents the degree of deterioration of the concrete member, α represents a coefficient related to the geometry and the force characteristics of the concrete member, a 0 represents the initial degree of deterioration, i c (T) represents the erosion rate at time T, E 0 (T) represents the initial relative dynamic elastic modulus, λ represents the decay coefficient, T represents the alternating period of fresh water, and k represents a constant related to the nature of the concrete building material and the environmental concentration.
7. The nondestructive testing method of concrete structure member exposure test according to claim 5, wherein the calculating of the force of the concrete member against the failure Guan Jianneng according to the type and size of the load actually borne by the concrete member and the boundary condition, and the integrating of the member degradation into the load bearing capacity calculation model includes: the load type actually born by the concrete member is divided into a member load, a variable load and an environmental load, and the load combination size is calculated; determining constraint conditions according to an actual supporting mode of a concrete member, and calculating initial bearing capacity, wherein the initial bearing capacity comprises a bending bearing capacity, a shearing bearing capacity and a shaft pressure bearing capacity; And determining a degradation factor according to the degradation degree of the concrete member, calculating the comprehensive bearing capacity, and determining the bearing threshold value of the concrete member.
8. The nondestructive testing method of the concrete structure member exposure test according to claim 7, wherein the comprehensive bearing capacity is denoted by C Z ＝A loss (t)·(M u0 *K dM +V u0 *K dV +N u0 *K dN , wherein C Z is the comprehensive bearing capacity, a loss (t) is the degree of deterioration of the concrete member, M u0 is the flexural bearing capacity, K dM is the deterioration factor corresponding to the flexural bearing capacity, V u0 is the shear bearing capacity, K dV is the deterioration factor corresponding to the shear bearing capacity, N u0 is the axle load capacity, and K dN is the deterioration factor corresponding to the axle load capacity.
9. The nondestructive testing method for exposure test of concrete structure member according to claim 5, wherein predicting the total life of the concrete member based on the load-bearing capacity degradation function and the failure judgment criterion with the current age of the concrete member as a starting point according to the load-bearing capacity judgment threshold value, and obtaining the remaining life of the current concrete member in the alternating salty and fresh water environment comprises: Acquiring the current service age T 0 and the current comprehensive bearing capacity C Z (T) of the concrete member, and considering the chloride ion concentration C l (T) in the environment where the concrete member is positioned, the alternating frequency f e and the current environment temperature T N (T); constructing a bearing capacity degradation function under the alternating condition of the fresh water and the salt water, and gradually predicting the future bearing capacity in a certain time step from the current service age t 0 ; And in each step length, updating the chloride ion concentration, the degradation degree of the concrete member and the bearing capacity according to the bearing capacity degradation function, and recording the time when the bearing capacity is lower than the bearing threshold L for the first time, namely the residual service life t s .
10. The concrete structural member exposure test nondestructive testing method of claim 9, wherein the load bearing capacity degradation function is expressed as: Wherein, C Z (T) represents the current comprehensive bearing capacity, C 0 represents the bearing capacity of the component in the initial state, E represents the weight coefficient of the influence of erosion on the bearing capacity, A s (T) represents the damaged sectional area of the concrete component, A s0 represents the initial sectional area, ζ represents the nonlinear index of the influence of erosion, η represents the weight coefficient of the influence of concrete degradation on the bearing capacity, A loss (T) represents the degradation degree of the concrete component, A 0 represents the initial degradation degree, θ represents the nonlinear index of the influence of concrete degradation, ψ represents the temperature influence coefficient, T N (T) represents the current environment temperature, T C represents the reference temperature, and η h represents the environmental humidity influence coefficient.

Description

Nondestructive testing method for exposure test of concrete structural member Technical Field The invention relates to the technical field of nondestructive testing, in particular to a nondestructive testing method for a concrete structural member exposure test. Background The concrete structure is widely applied to various infrastructures such as bridges, harbors, nuclear power stations and the like due to good bearing performance and economy. In the long-term use process of the structure, the structure can be influenced by various factors such as natural environment, use load and the like, and the problems of performance degradation, defects and the like occur, so that the safety and the durability of the structure are threatened. In order to find and evaluate these problems in time, ensure the safety and reliability of the structure, an effective detection method is required. Many existing detection methods only depend on a single technical means, and although the methods can provide some useful information to a certain extent, due to the complexity and the diversity of defects in the concrete structure, the detection in a single aspect often has difficulty in accurately and comprehensively reflecting the real condition of a component, and the data acquired by different detection means cannot be organically integrated and comprehensively analyzed. Most of the prior art can only provide detection data, but the data are not sufficient in systematic analysis to reveal the degradation rules and damage mechanisms of the concrete structure. The detection result is often only an isolated data point, is difficult to be correlated with the actual stress condition of the structure, the use environment and the like for overall analysis, and cannot provide powerful technical support for maintenance decision of the structure. Because of the incompleteness of the detection data and the limitation of an analysis method, the prior art is difficult to establish an accurate and reliable concrete structure residual service life prediction model based on the detection result. Therefore, engineering personnel lack scientific and reasonable basis when maintaining and managing the structure, and only experience and periodic detection can be relied on to judge the safety of the structure, so that the risk and uncertainty of the structure in the use process are increased. Disclosure of Invention The invention aims to provide a nondestructive testing method for a concrete structural member exposure test, which is used for solving the problems in the prior art. The application is specifically as follows: the nondestructive testing method for the exposure test of the concrete structural member comprises the following steps: The method comprises the steps of embedding a sensor for detecting in a concrete member, acquiring detection data of the concrete member under the condition of alternating salty and fresh water in real time, fitting out a diffusion coefficient of chloride ions in the concrete member based on Fick's second law, and generating a chloride ion diffusion characteristic set of the concrete member under the condition of alternating salty and fresh water; step two, utilizing an ultrasonic detector to transmit ultrasonic pulse signals with specific frequency to a concrete member, and combining an elastic wave theory of the concrete to calculate the relative dynamic elastic modulus change characteristic of the concrete under the alternating action of the salty and the fresh water; adopting a high-resolution optical camera system and a three-dimensional laser scanner to periodically scan and collect images on the surface of the concrete member, and adopting a multi-mode algorithm to identify and quantify the area, depth and distribution characteristic information of an degraded area on the surface of the concrete member; Step four, based on the analysis results of the detection data of the chloride ion diffusion characteristic set, the relative dynamic elastic modulus and the distribution characteristics, a concrete member degradation model under the alternating condition of the fresh water is established, a bearing capacity calculation model of the reinforced concrete member under the alternating effect of the fresh water is established by combining the actual stress condition and the boundary condition of the concrete member, and the residual service life of the concrete member under the alternating environment of the fresh water is predicted according to the set failure standard; and fifthly, performing system integration and storage on various detection data acquired in the whole exposure test process, establishing a database, and providing data reference of a damage degradation mechanism and a performance evolution rule of the concrete structural member under the condition of alternating salty and fresh water. The first step comprises the steps of establishing a chloride ion diffusion model in a concrete member based