在动静载荷作用下混凝土的抗破坏性实验研究

发布时间：2018-03-06 17:51

本文选题：混凝土　切入点：抗破坏性　出处：《昆明理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：混凝土在建筑工程、水利工程、军事工事以及道路工程中得到广泛应用。在构筑物受到地震载荷作用或因特大火灾发生坍塌、军事防护设施受到轰炸、民用构筑物受到爆炸袭击时,混凝土构筑物的安全受到严峻考验。目前对混凝土在不同载荷作用下的抗破坏性的高低主要依据定性判断,没有基于某种特定方法来定量描述混凝土在不同载荷作用下其抗破坏性的强弱。因此,研究不同强度等级混凝土在不同载荷作用下的抗破坏性很有必要,这对评估混凝土构筑物安全性和如何经济地使用混凝土材料很有指导意义。本文对C25、C35、C45混凝土在动静载荷作用下的力学特性进行研究。通过实验所得数据对不同强度等级混凝土在静载荷、不同动载荷(冲击和爆破载荷)作用下的抗破坏性进行表征,定量地比较和分析在不同载荷作用下强度等级对混凝土抗破坏性的影响。主要研究内容如下:1)通过静压实验得到不同强度等级混凝土的力学参数,进而对不同强度等级混凝土抗破坏性进行表征,来定量地分析其抗破坏能力的大小。2)通过SHPB实验得到不同强度等级混凝土试件的动态力学参数,进而对不同强度等级混凝土的抗破坏性进行表征,来定量地分析其抗破坏能力的大小;并且通过数值模拟辅助分析实验结果并且与室内实验进行验证对比。3)通过混凝土块爆破实验块度分布,利用G-G-S分布回归计算的结果对不同强度等级混凝土块抗破坏性进行表征,进而定量地分析其抗破坏能力的大小;并且通过数值模拟辅助分析实验结果。主要研究成果如下:本文通过室内外实验所得实验数据对不同强度等级混凝土的抗破坏性进行定量表征,得到静态最大抗压强度、动态最大抗压强度和分维数等参数能够合理地对混凝土抗破坏性的强弱进行定量分析;通过模拟SHPB实验分析不同强度等级混凝土的应力应变曲线,发现C25、C35、C45的最大应力增加到自身强度的2倍左右后变化不大,其抗破坏性的增强并不是随着加载幅值地增加而无限增大;在爆炸载荷作用下,计算结果表明C35、C45比C25混凝土抗破坏能力高25.7%、60.6%。
[Abstract]:Concrete is widely used in construction, water conservancy, military and road engineering. When civil structures are attacked by explosion, the safety of concrete structures is severely tested. At present, the damage resistance of concrete under different loads is mainly judged qualitatively. There is no specific method to quantitatively describe the anti-destructive strength of concrete under different loads. Therefore, it is necessary to study the resistance of concrete of different strength grades under different loads. It is very instructive to evaluate the safety of concrete structures and how to use concrete materials economically. The mechanical properties of C25C35C45 concrete under dynamic and static loads are studied in this paper. Grade concrete under static load, The destructiveness of different dynamic loads (shock and blasting loads) was characterized. The influence of strength grade on concrete resistance to destructiveness under different loads is compared and analyzed quantitatively. The main research contents are as follows: (1) the mechanical parameters of concrete with different strength grades are obtained by static compression test. Then, the destructiveness of concrete with different strength grades is characterized to quantitatively analyze the strength of concrete. 2) the dynamic mechanical parameters of concrete specimens with different strength grades are obtained by SHPB experiment. Then, the destructiveness of concrete with different strength grades is characterized to quantitatively analyze the magnitude of its anti-failure ability. And through the numerical simulation analysis of the experimental results and compared with the laboratory experiments. 3) through the concrete block blasting experiment block size distribution, using G-G-S distribution regression calculation results of the different strength of concrete blocks are characterized. Furthermore, the magnitude of its ability to resist damage is analyzed quantitatively. The main research results are as follows: the static maximum compressive strength of concrete with different strength grades is quantitatively characterized by the experimental data obtained from indoor and outdoor experiments. The parameters such as dynamic maximum compressive strength and fractal dimension can be used to quantitatively analyze the strength of concrete against destructiveness, and the stress-strain curves of concrete of different strength grades can be analyzed by simulating SHPB experiment. It is found that the maximum stress of C25 C35C45 does not change much when the maximum stress of C25 C35C45 increases to about 2 times of its own strength, and its anti-destructive enhancement does not increase infinitely with the increase of loading amplitude. The results show that C 35N C 45 is 25. 7% higher than C 25 concrete in anti-failure ability, and it is 60.6% higher than that of C 25 concrete.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

【参考文献】