基于大型渡槽原型试验的混凝土徐变参数反演

Inversion Analysis of Concrete Creep Parameters Based on Large-Scale Aqueduct Prototype Tests

混凝土徐变对结构应力和变形有重要影响,是结构设计关键参数之一。徐变参数通常通过在实验室开展试验后获取,试验周期长、成本高,尤其是受空间和试验加载能力限制,试件尺寸通常较小,不能充分反映实际情况。本文结合某大型预应力渡槽原型结构试验,利用槽身纵向和环向布置的应变计,配合温度计和无应力计观测数据,建立混凝土应变分析模型,分离各荷载作用并获取纵向和环向预应力荷载下混凝土徐变量,据此反演混凝土徐变参数。结果表明,反演分析模型得到的应变拟合曲线与实测应变曲线吻合度较高,可有效反映混凝土应变变化规律。

The creep of concrete plays a crucial role in determining the stress and deformation of structures,and is one of the key parameters in structural design.Typically,creep parameters are derived from laboratory experiments.However,the test cycle is long and costly,especially due to limitations in space and experimental loading capacity,these experiments are often conducted on small-scale specimens.As a result,the obtained results may not fully represent the actual behavior of concrete under real-world conditions.In this paper,the study combines a prototype structural test of a large prestressed aqueduct with an extensive array of strain gauges arranged both longitudinally and circumferentially on the channel body.Additionally,thermometer and non-stress gauge observation data are incorporated to establish a concrete strain analysis model.This model effectively separates the effects of different loads and obtain the creep values of concrete under longitudinal and circumferential prestressed loads.By using inversion analysis techniques,the creep parameters of concrete are derived.The results indicate that the strain fitting curve obtained by the inverse analysis model is in high accordance with the measured strain curve,which can effectively reflect the strain variation law of concrete.