摘要
作为地下施工过程中应用最多的支护材料之一,混凝土在养护期间容易受到周边振动荷载的影响。针对这一现象,利用直径为75 mm的霍普金森压杆(SHPB)设备研究C30混凝土在3 d、7 d、14 d和28 d龄期下的力学特性。试验结果表明,在早龄期,混凝土具有较好的塑性特征,随着龄期增加,脆性特征逐渐增加。此外,混凝土的动态强度以幂指数关系随应变率的增加而增长,而应变率指数随龄期增长而降低。考虑到随龄期的变化,混凝土的力学特性由塑性转变为脆性这一特征,提出改进的黏弹性损伤本构模型,该模型能够很好地体现这一变化。利用该模型获得的应力-应变曲线与试验曲线基本一致。
As one of the most common support materials for underground structures,concrete is inevitably affected by dynamic loads such as blasting after pouring.In this study,a Hopkinson compression bar(SHPB)device with a diameter of 75 mm is used to study the mechanical properties of C30 concrete at the ages of 3 d,7 d,14 d,and 28 d.The results show that concrete has good plastic characteristics in the early stage,and as the age increases,this phenomenon significantly weakens while the brittleness increases.In addition,the dynamic strength of concrete increases exponentially with the increase of strain rate,while the strain rate index decreases with the extension of age.Based on the fact that the mechanical properties of concrete exhibit a transition from plasticity to brittleness with age,an improved viscoelastic damage constitutive model was established,which can well reflect the changes in mechanical properties of concrete with age.The theoretical stress-strain curve obtained using this model is almost consistent with the experimental curve.
作者
杨建
YANG Jian(China Railway Urban Construction Group 1st Engineering Co.Ltd.,Taiyuan Shanxi 030024,China)
出处
《铁道建筑技术》
2025年第6期124-128,共5页
Railway Construction Technology
基金
中铁城建集团有限公司科技研究开发计划项目(ZTCJZ-2025-02)。
作者简介
杨建(1979-),男,山西太谷人,高级工程师,主要从事土木工程方面的工作,E-mail:yangjian.cj@crcc.cn。
