基于非线性徐变模型的DAPEIN重力坝温控仿真

Thermal stress simulation of DAPEIN concrete gravity dam based on improved nonlinear creep model

目前常采用线弹性徐变模型进行混凝土坝施工期温度应力的仿真分析.当混凝土应力较小时,采用线弹性徐变模型是可行的,但当混凝土应力超过相应龄期抗拉强度的一半时,混凝土的徐变变形与应力之间呈现出明显的非线性关系.改进的非线性徐变模型能考虑徐变变形与应力的非线性关系,将改进的混凝土非线性徐变模型应用到缅甸DAPEIN大坝的施工期温度应力仿真分析中,仿真结果表明,采用线弹性徐变模型与改进的非线性徐变模型计算的徐变温度应力差别较大,采用传统线弹性徐变模型计算的温度应力偏大.

Linear elastic creep model has been used in the thermal stress simulation of concrete dam during construction period.This model is reasonable when the thermal stress is low.However,the creep deformation of concrete is no longer to be linear with thermal stress when the thermal stress is larger than half of the concrete tensile strength;and the relation between creep and the thermal stress shows a strong nonlinearity.The influence of stress is taken into account in the improved concrete nonlinear creep model;the improved creep model is then adopted in the thermal stress simulation of DAPEIN concrete gravity dam.The simulation results show that there is a significant difference between the thermal stresses calculated by linear elastic creep model and nonlinear creep model respectively;and the thermal stress calculated with linear creep model is larger.