对变应力作用下的拉压异性徐变的弹性徐变方程的求解进行了探讨，基于混凝土的徐变度与混凝土的龄期有关和线性叠加假设，采用应力增量法，推导了变应力作用下的拉压异性徐变的弹性徐变问题的有限元计算公式。由于拉伸和压缩徐变速率相近，假设拉伸和压缩徐变一致时的徐变应变增量递推公式，与假设拉伸和压缩徐变异性的徐变应变增量的递推公式形式上一样，仅当某时刻的应力增量主量为负时，采用压应力下的徐变度，当某时刻的应力增量主量为正时，采用拉应力下的徐变度。实际混凝土工程的拉压异性徐变应力仿真分析表明，在高温季节浇筑混凝土时，昼夜温差将引起应力周期性加卸载变化，假设拉伸和压缩异性徐变时计算的混凝土温度拉应力较拉压相同徐变时计算的混凝土温度拉应力更大，且这个应力随着仓面间歇时间的延长而逐渐增大。
Abstract
The solution of elastic creep equation under varying stresses with tensile and pressure different creep was studied; the finite element method calculation formula of elastic creep equation under varying stresses with tensile and pressure different creep was deduced by stress increment on the basis of the theory of concrete creep depending on concrete age and the assume of linear superposition in this paper. Since the creep rates of tensile and pressure were the same, it was assumed that the creep strain increment recursion formula of tensile and pressure same creep was the same in form with that of tensile and pressure different creep. When the principal stress increment was negative value, the pressure creep was adopted; when the principal stress increment was positive value, the tensile creep was adopted. It is indicated by tensile and pressure different creep simulation in practical concrete engineering that concrete block’s stress loadingandunloading periodicity is influenced by diurnal amplitude in high temperature seasons. The concrete temperature stress calculated by tensile and pressure different creep is bigger than that calculated by tensile and pressure same creep, and this stress will increase as the pouring interval prolongs.
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