花岗岩材料在动静组合加载下的断裂机理研究

项目名称： 花岗岩材料在动静组合加载下的断裂机理研究

项目编号： No.11202232

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 数理科学和化学

项目作者： 陈荣

作者单位： 中国人民解放军国防科学技术大学

项目金额： 26万元

中文摘要： 在深部工事开挖过程中，坑道顶板不仅承受着很高的静载荷，还受到爆破、震动等动载荷的影响，容易诱发塌方等灾害。现有研究表明，在初始静载荷与动载荷叠加后，其强度准则不能简单叠加。这是因为静载荷导致岩石内部微裂纹发生变化，进而影响其力学性能。因此需要研究岩石材料在动静组合加载下的断裂机理，为工程设计提供理论依据。本研究首先建立基于霍普金森杆的动静组合加载实验方法，研究动静组合加载下裂尖应力强度因子的求解方法。选取一种花岗岩材料，采用两种不同预制裂纹方式的半圆盘三点弯试样构型，通过Micro-CT结合声发射实验技术观测静载荷下花岗岩内部微裂纹分布及变化规律；分析不同动静组合条件下裂纹的起裂韧度和传播机理。结合常规的力学实验，建立统计裂纹模型，并将计算预测结果与实验结果进行比较分析，验证模型的有效性。重点解决花岗岩动静组合加载下的裂纹起裂扩展规律研究和花岗岩统计裂纹模型及参数获取方法两个关键科学问题。

中文关键词： Hopkinson杆；动静组合加载；断裂性能；岩石；

英文摘要： In the process of deep mining and deep digging, the top of sap subject to not only high levels of static pressure, but also dynamic loads such as explosions and micro earthquakes, which may cause disasters such as tunnel collapse. Recent reports show that the total strength of the preload static stress and the measured dynamic strength doesn't equal to neither the pure static strength nor the pure dynamic strength with similar loading rate, because the static load changes the micro cracks in rock, and then changes the mechanical properties. It is thus required to study rock fracture mechanics subjected to coupled static and dynamic loads. This project will set up the experimental techniques of coupled static and dynamic loads with the Split Hopkinson Pressure Bars (SHPB) system, such as the calculation of stress intensity factors in the crack tip with coupled static and dynamic loads. Two kinds of granite samples, the Cracked Semi-Circular Bending (NSCB) specimen and the cracked Chevron Notched Semi-Circular Bend (CCNSCB) specimen, are selected in this project. The micro cracks distribution and the micro crack opening process with preloads in the granite can be obtained by Micro-CT and acoustic emission (AE) methods. The crack initiation and propagation properties will be investigated with different preload stat

英文关键词： Hopkinson Bar；coupled static and dynamic loading；fracture mechanics；rock；