CN-122023591-A - Environment partitioning method for freezing and thawing damage of concrete structure

CN122023591ACN 122023591 ACN122023591 ACN 122023591ACN-122023591-A

Abstract

The invention discloses an environmental division method of a concrete structure freeze-thawing damage, which belongs to the technical field of concrete structure durability assessment and comprises the steps of obtaining material characteristic data of the concrete structure and historical meteorological data of corresponding areas of the material characteristic data, wherein the historical meteorological data comprise atmospheric temperature, solar radiation and wind speed, obtaining meteorological data in a concrete structure design reference period according to historical meteorological prediction based on a Holt-windows method, dividing a map layout into grid points with 0.25 latitude multiplied by 0.25 longitude based on the space-time resolution of ERA5, randomly selecting any grid point as a target point, calculating according to the meteorological data to obtain a concrete surface temperature field of a target point day scale, calculating temperature field change along the depth direction of the concrete structure, obtaining equivalent freeze-thawing times of the target point concrete structure at different depths according to the temperature field change, calculating the total equivalent freeze-thawing times of the concrete structure of the day scale, obtaining the total equivalent freeze-thawing damage of the target point in the concrete structure design reference period according to the total equivalent freeze-thawing times of the day scale, and repeating the steps to generate an environmental division map of the concrete structure freeze-thawing damage according to all the obtained total equivalent freeze-thawing damage.

Inventors

YU QIANQIAN
GU CHAO
WANG LANG
GU XIANGLIN
ZHANG WEIPING

Assignees

同济大学

Dates

Publication Date: 20260512
Application Date: 20260128

Claims (7)

1. The method for dividing the environment of the freeze thawing damage of the concrete structure is characterized by comprising the following steps of: acquiring material characteristic data of a concrete structure and historical meteorological data of a corresponding area of the material characteristic data, wherein the historical meteorological data comprises atmospheric temperature, solar radiation and wind speed; Based on a Holt-windows method, weather data in a concrete structure design reference period is obtained according to historical weather prediction; dividing the map layout into grid points of 0.25 latitude×0.25 longitude based on the spatio-temporal resolution of ERA 5; Randomly selecting any grid point as a target point, calculating according to meteorological data to obtain a concrete surface temperature field of a daily scale of the target point, and calculating the temperature field change along the depth direction of the concrete structure; Obtaining equivalent freeze-thawing times of the concrete structure of the target point under different depths according to the temperature field change, and calculating the integral equivalent freeze-thawing times of the concrete structure of the daily scale; Obtaining the overall equivalent freeze-thawing damage of the target point concrete structure in the design reference period according to the overall equivalent freeze-thawing times of the daily scale; Repeating the steps, and generating an environment demarcation map of the concrete structure freeze-thawing damage according to the obtained overall equivalent freeze-thawing damage of all grid points.
2. The method for environmental division of a concrete structure freeze-thaw damage of claim 1, Based on the Holt-windows method, weather data in a concrete structure design reference period is obtained according to historical weather prediction, and the method comprises the following steps: Obtaining meteorological data in a concrete structure design reference period according to historical meteorological prediction through a Holt-winter addition model, wherein the Holt-winter addition model is as follows: In the formula, Representation of% ) The actual value of the time series of periods, 、 And All of which represent a smooth equation, Indicating the number of backward smoothing phases, Represent the first An exponential smoothing value of the long-term trend after the periodic variation is removed from the time series, Represent the first The exponentially smoothed values of the individual long-term trend variables, Represent the first The periodic variation period is Is a function of the exponentially smoothed values of (c), 、 And All of which represent the smoothing coefficients and, Representing the period length.
3. The method for environmental division of a concrete structure freeze-thaw damage of claim 1, According to meteorological data, calculating a concrete structure surface temperature field of a target point day scale, and calculating temperature field change along the depth direction of the concrete structure, wherein the method comprises the following steps: according to the meteorological data, calculating the surface temperature of the concrete structure, wherein the calculation formula is as follows: In the formula, Representing the position of the target point The surface temperature at the moment in time, Is shown in The external temperature at the moment of time is, Represents the absorption coefficient of solar radiation, Which is indicative of the amount of solar radiation, Representing the overall heat exchange coefficient of the heat exchanger, Indicating wind speed. Dividing along the depth direction of the concrete structure And equally spaced nodes, and calculating temperature data of each node, wherein the nodes comprise surface boundary nodes, internal nodes and internal adiabatic boundary nodes. Wherein, the temperature data of the boundary node of the surface, the computational formula is as follows: In the formula, Representing at time step at surface boundary node The temperature data at the time of the manufacture, The time step is indicated as such, Representing the length of each time step; the temperature data of the internal nodes are calculated as follows: In the formula, Representing internal nodes at time steps The temperature data at the time of the manufacture, Representing internal nodes at time steps The temperature data at the time of the manufacture, Representing internal nodes at time steps Temperature data at the time, i represents the number of divided concrete layers, , And taking an integer. The temperature data of the internal adiabatic boundary node is calculated as follows: In the formula, Representing internal adiabatic boundary nodes at time steps The temperature data at the time of the manufacture, Representing internal adiabatic boundary nodes at time steps The temperature data at the time of the manufacture, Representing the distance between two adjacent nodes, Representing internal adiabatic boundary nodes at time steps ) The temperature data at the time of the manufacture, Representing the thermal diffusivity. Wherein, when calculating the temperature data of the internal adiabatic boundary node and the internal node, the following is shown: and obtaining the temperature field change of the target point along the depth direction of the concrete structure according to the temperature data of the surface boundary node, the internal node and the internal heat insulation boundary node.
4. The method for environmental division of a concrete structure freeze-thaw damage of claim 1, Obtaining equivalent freeze thawing times of the target point concrete structure under different depths according to the temperature field change, wherein the method comprises the following steps: Dividing the concrete structure of the target point along the depth direction according to a preset node dividing rule A concrete structure layer, wherein the concrete structure layer is divided into And each node. Determining the freeze thawing cycle times and the cooling rate of each concrete structure layer according to the temperature field change based on a preset rule; And calculating the equivalent freeze thawing times of each concrete structure layer according to the freeze thawing cycle times and the cooling rate, wherein the calculation formula is as follows: In the formula, Represent the first The equivalent freeze thawing times of the concrete structure layers, Representing the pore parameters of the material, the pore volume, Indicating the indoor cooling rate, Represent the first The cooling rate of the concrete structure layer, And the calculation formula of the pore parameters of the materials is as follows: In the formula, The spacing coefficient of the concrete material representing the target point, The void parameters of the concrete material representing the target point, The radius of the void is indicated as such, Representing the volume fraction of the cement-based matrix, Representing the air content of the concrete.
5. The method for environmental zoning of a concrete structure freeze-thaw damage of claim 4, Calculating the total equivalent freeze thawing times of the concrete structure with the daily scale, comprising the following steps: The volume weight of each concrete structure layer is calculated, and the calculation formula is as follows: In the formula, Represent the first The volume weight of the individual concrete structure layers, Represent the first The depth of the individual concrete structure layers, Indicating the total depth of the concrete structure. And calculating the freeze thawing sensitivity weight of each concrete structure layer, wherein the calculation formula is as follows: In the formula, Represent the first The average temperature of the individual concrete structure layers, Representing the first% ) Average temperature of individual concrete structure layers. According to the volume weight, the freezing and thawing sensitivity weight equivalent freezing and thawing times of the concrete structure layer and the calculated total equivalent freezing and thawing times, the calculation formula is as follows: In the formula, The total equivalent freeze thawing times of the concrete structure in one day are shown, Represent the first Comprehensive weight of each concrete structure layer.
6. The method for environmental zoning of a concrete structure freeze-thaw damage of claim 5, Obtaining the overall equivalent freeze-thawing damage of the target point concrete structure in the design reference period according to the overall equivalent freeze-thawing times of the daily scale, wherein the method comprises the following steps: Obtaining the overall equivalent freeze-thawing damage of the target point concrete structure in the design reference period according to the overall equivalent freeze-thawing times of the daily scale, wherein the calculation formula is as follows: In the formula, Indicating the overall equivalent freeze-thaw damage of the target point in the baseline period, Total days on baseline are indicated.
7. The method for environmental division of a concrete structure freeze-thaw damage of claim 1, Generating an environment demarcation map of the concrete structure freeze-thawing damage according to the obtained overall equivalent freeze-thawing damage in the concrete structure design reference period of all grid points, comprising: Obtaining a one-dimensional data sequence according to the overall equivalent freeze-thawing damage of all grid points; sequencing the one-dimensional data sequences from small to large, calculating the frequency distribution, the mean value and the standard deviation of the one-dimensional data sequences, and identifying dense intervals and blank intervals in the data; iteratively calculating all possible grouping modes to determine a group of break points based on Jenks algorithm; and outputting corresponding break points according to engineering requirements, and marking the map layout with different colors.

Description

Environment partitioning method for freezing and thawing damage of concrete structure Technical Field The invention belongs to the technical field of concrete structure durability assessment, and particularly relates to an environment partitioning method for freeze thawing damage of a concrete structure. Background Freeze thawing damage is one of the key factors inducing deterioration of durability of concrete structures in severe cold and cold regions. The concrete service environment action presents obvious space-time randomness and complex coupling characteristics, so the method quantitatively characterizes the performance evolution rule of the concrete structure under the service environment action, and is a very challenging key scientific problem in the civil engineering field. The prior art is mainly based on historical climate statistical characteristics of recent decades, a concrete material freeze-thawing zone system taking indoor equivalent freeze-thawing cycle times as core indexes is constructed, but the method has obvious limitations that the accuracy of historical climate data is insufficient and is difficult to support the requirements of the refined zone, the method is suitable for deviation between the indoor equivalent indexes of the concrete material and the freeze-thawing damage response of an actual engineering structure, the structural damage assessment distortion is easy to be caused, the evolution trend of a climate system is not considered, and the method cannot be suitable for the structural durability analysis in future climate situations. Therefore, there is a need for an environmental partitioning method for freeze thawing damage of concrete structures to solve the problems in the prior art. Disclosure of Invention In view of the above, the invention provides an environment partitioning method for freeze thawing damage of a concrete structure, which is used for solving the problem that the prior art cannot be coupled with future climate evolution rules and realizing accurate partitioning of the service environment of the freeze thawing damage of the concrete structure in different areas. In order to achieve the above purpose, the invention provides an environmental partitioning method for freezing and thawing damage of a concrete structure, comprising the following steps: acquiring material characteristic data of a concrete structure and historical meteorological data of a corresponding area of the material characteristic data, wherein the historical meteorological data comprises atmospheric temperature, solar radiation and wind speed; Based on a Holt-windows method, weather data in a concrete structure design reference period is obtained according to historical weather prediction; dividing the map layout into grid points of 0.25 latitude×0.25 longitude based on the spatio-temporal resolution of ERA 5; Randomly selecting any grid point as a target point, calculating according to meteorological data to obtain a concrete surface temperature field of a daily scale of the target point, and calculating the temperature field change along the depth direction of the concrete structure; Obtaining equivalent freeze-thawing times of the concrete structure of the target point under different depths according to the temperature field change, and calculating the integral equivalent freeze-thawing times of the concrete structure of the daily scale; Obtaining the overall equivalent freeze-thawing damage of the target point concrete structure in the design reference period according to the overall equivalent freeze-thawing times of the daily scale; Repeating the steps, and generating an environment demarcation map of the concrete structure freeze-thawing damage according to the obtained overall equivalent freeze-thawing damage of all grid points. As one embodiment of the invention, based on the Holt-windows method, weather data in a concrete structure design reference period is obtained according to historical weather prediction, and the method comprises the following steps: Obtaining meteorological data in a concrete structure design reference period according to historical meteorological prediction through a Holt-winter addition model, wherein the Holt-winter addition model is as follows: In the formula, Representation of%) The actual value of the time series of periods,、AndAll of which represent a smooth equation,Indicating the number of backward smoothing phases,Represent the firstAn exponential smoothing value of the long-term trend after the periodic variation is removed from the time series,Represent the firstThe exponentially smoothed values of the individual long-term trend variables,Represent the firstThe periodic variation period isIs a function of the exponentially smoothed values of (c),、AndAll of which represent the smoothing coefficients and,Representing the period length. As one embodiment of the present invention, calculating a concrete surface temperature field of a target poin