基于率相关的混凝土动态断裂韧度试验及其声发射特性研究

Concrete cracks is the major problem of water conservancy constructions.The fracture toughness is the ability of concrete to resist crack propagation, and the effective way to elaborate crack failure mechanism.However,a precise parameter of characterizing the fracture toughness of concrete hasn't been found and the method for determination of dynamic fracture toughness is not yet ripe.thus it is the main limitation of the indicator's promotion and application.In this project, the Initial crack point and the instability crack point were judged by the acoustic emission parameters in concrete fracture experiments. The best specimen size and best seam height ratio were established with Trials under this method.Then the more accurate characteristic signal parameters and typical waveform of concrete fracture can be picked up in the course of concrete fracture.Meanwhile, Rate correlation of The concrete dynamic fracture toughness was studied in this project. Under considering the acoustic emission rate and loading rate,conversion equation about concrete static fracture toughness and dynamic fracture toughness can be derived.A fine measurement method might be put forward for concrete dynamic fracture toughness.In the end, a criterion of acoustic emission parameters with concrete cracks was established .The project is to reveal the discipline of static fracture toughness and dynamic fracture toughness, complements and improves the concrete double-K fracture theory.Thus it can plays an more important role in cracking resistance,design of anti-cracking and assessment and analysis of cracks in water conservancy constructions.

混凝土裂缝是水利工程建设面临的重大难题，断裂韧度是混凝土抵抗裂缝扩展的能力，也是阐述裂缝破坏机理的有效途径。然而，还未找到一个可测定的物理量来表征混凝土的断裂韧度，且动态断裂韧度的测定方法还不成熟，成为制约该项指标推广应用的主要瓶颈。本项目基于声发射法判断混凝土断裂试验中的起裂点和失稳点，通过试验确立该方法中最佳试件尺寸及最佳缝高比，进而在混凝土断裂过程中提取出更准确的声发射特征信号。同时研究混凝土动态断裂韧度的率相关性，推导出考虑声发射率和加载率的混凝土静动态断裂韧度之间的转换方程，提出一种混凝土动态断裂韧度的精细化测定方法，最终建立混凝土裂缝状态的声发射参量判别准则。本项目旨在进一步补充和完善混凝土双K断裂理论，使其在水电水利工程防裂设计及裂缝评定分析中发挥更大的作用。

混凝土裂缝是水利工程建设面临的重大难题，断裂韧度是混凝土抵抗裂缝扩展的能力，也是阐述裂缝破坏机理的有效途径。然而，还未找到一个可测定的物理量来表征混凝土的断裂韧度，且动态断裂韧度的测定方法还不成熟，成为制约该项指标推广应用的主要瓶颈。本项目基于声发射法判断混凝土断裂试验中的起裂点和失稳点，通过试验确立该方法中最佳试件尺寸及最佳缝高比，进而在混凝土断裂过程中提取出更准确的声发射特征信号。同时研究混凝土动态断裂韧度的率相关性，推导出考虑声发射率和加载率的混凝土静动态断裂韧度之间的转换方程，提出一种混凝土动态断裂韧度的精细化测定方法，最终建立混凝土裂缝状态的声发射参量判别准则。本项目旨在进一步补充和完善混凝土双K断裂理论，使其在水电水利工程防裂设计及裂缝评定分析中发挥更大的作用。项目执行过程中发表学术论文14篇（SCI、EI收录7篇），授权国家发明专利1项，参加国内学术交流1次，获得国家技术发明二等奖1项。