基于相似分析的不同围压-温度的混凝土抗压强度研究

Compressive Strength of Concrete under Different Confining Pressures and Temperatures Based on Similarity Analysis

摘要:

为了研究混凝土在不同的围压和温度耦合作用下的抗压强度，根据相似分析原理，对混凝土抗压强度σ_max的控制参数进行无量纲化，得到相关的相似准数；以C40混凝土为例，进行有限元计算得到相似准数之间的关系。结果表明：抗压强度σ_max和残余强度随着围压的增大而增加，且最大偏应力与围压呈线性关系；在围压小于20 MPa时，应力-应变曲线可以分成两段，而在围压大于20 MPa时，应力-应变曲线可以划分成三段，出现明显的屈服；在不同的围压作用下温度对抗压强度的影响明显不同，且最大偏应力与温度近似为线性关系；三个无量纲参数σ_max/E、F/E和αθ在三维坐标近似形成了一个平面，说明σ_max/E随αθ和F/E基本呈线性变化。

Abstract:

To study the compressive strength of concrete under the coupling action of different confining pressure and temperature, the control parameters of compressive strength σ_max of concrete were processed with no-dimensions according to the similar analysis principle, and related similarity criteria were obtained. The relationship between those similarity criteria was obtained by finite element calculation, taking C40 concrete as an example. Results show that (1) The compressive strength σ_max and residual strength increase with the increase of confining pressure, and the maximum deviator stress is linear with the confining pressure; (2) When the confining pressure is less than 20 MPa, the stress-strain curve can be divided into two sections, and when the confining pressure is greater than 20 MPa, the stress-strain curve can be divided into three sections, showing obvious yield; (3) The influence of temperature on compressive strength is obviously different under different confining pressure, and the maximum deviator stress and temperature are approximately linear; (4) Three dimensionless parameters (σ_max/E, F/E, and αθ) form a plane in the three-dimensional coordinate, which shows that σ_max/E has a linear relationship with αθ and F/E.