全级配混凝土静动态轴拉断裂试验  

Static and Dynamic Axial Tensile Fracture of Fully-Graded Concrete

作　　者：张亚洲 钟红 李春雷[1] 王海波[1] 李德玉[1] 李志远 ZHANG Yazhou;ZHONG Hong;LI Chunlei;WANG Haibo;LI Deyu;LI Zhiyuan(China Institute of Water Resources and Hydropower Research,Beijing 100048,China)

机构地区：[1]中国水利水电科学研究院,北京100048

出　　处：《硅酸盐学报》2024年第2期569-578,共10页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金面上项目(51979292)。

摘　　要：以高混凝土坝抗震为背景,全级配混凝土断裂试验存在欠缺。为研究全级配混凝土静态和动态荷载作用下的断裂特性,对含有环切预制裂缝的圆柱体全级配混凝土进行了单轴拉伸试验。通过位移加载方式控制,获得了静态和动态加载条件下的试件荷载-裂缝张开口位移曲线,据此得到了峰值荷载并计算了吸能能力、断裂能和特征长度,进而综合基于扩展有限元的数值模拟求得试件的断裂韧度。结果表明:所测试件均大致沿预制裂缝方向开裂,但静态加载时多表现为骨料与水泥砂浆界面开裂,而快速加载时裂缝来不及沿着最薄弱的方向发展,而可能切断粗骨料,断面上可看到有较多粗骨料破坏。相比于静态加载情形,动态荷载作用下试件的峰值荷载、吸能能力、断裂能和断裂韧度均显著提高,而特征长度略微减小。Introduction As a non-homogeneous material,concrete has a large number of microcracks and even macro-defects on its surface and inside.Cracks in concrete dams can impair the integrity of the dam,change its stress state,and shorten its service life.In practical engineering,most concrete structures are subjected to dynamic loads such as earthquakes and dynamic water pressure.Dynamic loading has uncertainty and complexity,which has an important impact on the load-carrying capacity and durability of concrete structures.Research on the crack resistance of concrete is conducive to delaying and mitigating the cracking of concrete as well as taking measures to stop the cracking of cracked concrete,thus improving the durability and safety of concrete structures.Dam concrete is usually fully-graded concrete,subject to various conditions usually uses wet-screening concrete to carry out experimental research,but its test results do not fully reflect the mechanical properties of fully-graded concrete due to the sieve out of the large aggregate.It is thus necessary to carry out the fracture test of fully-graded concrete.In addition,many concrete high dams in China are constructed in the southwest and northwest earthquake areas,and the existing research on the fracture under dynamic loading is seriously lack.This paper was to carry out tests during rapid loading to obtain the dynamic fracture parameters of fully-graded concrete.Methods Fully-graded concrete specimens were prepared using the same mix ratio as the Baihetan Arch Dam.The 15MN dynamic and static material was used and an axial tensile fracture test was carried out.The specimens had a diameter of 450 mm and a height of 450 mm.The central part of the concrete specimen was cut by a cutting machine to form a ring prefabricated crack with a depth of 45 mm and a ratio of the length of the prefabricated crack to the length of the ligament of 0.2.To compare the fracture properties of fully-graded concrete under static and dynamic loading,a strain rate of 10^(-6) s^(-1) was s

关 键 词：全级配混凝土 轴拉断裂试验 动态荷载 断裂韧度 扩展有限元法 

分 类 号：TV431[水利工程—水工结构工程] TV313