井壁混凝土在早期荷载作用下的损伤劣化研究

Study of the Deterioration for the Shaft Concrete in the Early-Age Loads

在井壁施工期间,随着井筒穿越冲积层厚度的增加,井壁混凝土所受到的冻结应力、自重应力等各种早龄期荷载也随之增加.这些荷载极可能对早龄期混凝土产生不利影响.现通过空间轴对称问题的弹性力学解答得到施工期间井壁混凝土所受早期荷载的具体数值,并以此为基础自行设计应力加载装置以及尽量符合现实施工条件的试验方案.结果表明,这些早期荷载可混凝土内部缺陷增加,在一定程度上可使井壁混凝土微结构产生损伤,可能降低抗化学侵蚀能力.当荷载控制在一定比例下,这种损伤对结构安全性影响不大.

Abstract： During the period of shaft construction, with the thickness of the alluvial layer increases, various kinds of the early age load such as the freezing pressure and gravity stress will increase. These loads will cause an adverse impact on the early age concrete very likely. In this paper, the numerical values of the early age loads of concrete are obtained through elasticity mechanics solutions to space axisymmetric problems. And, on this basis, a stress loading device and a test plan are designed as close to the reality of the construction conditions as possible. The results show that these early age loads would cause enough cracks which cannot heal inside the concrete. The cracking creates conditions for chemical erosion, which would lead to serious damage degradation of the shaft concrete.