含节理岩体在高加载率条件下的裂隙扩展实验及机理研究

With the construction of large-scale livelihood projects, such as hydropower stations, in the mountain valley area with complex geological structures, the frequency and scale of rock fracture under dynamic loadings become severe and notable, threatening the security and stability of these large rock mass engineering practices. So it is necessary to conduct research on the opening and propagation of closed cracks that cause the failure of the rock masses and thus the whole engineering project due to external disturbance such as blasting and earthquakes. In this project, the rock mass with closed joint is proposed as the object of the study. The research includes the initiation and propagation criterion of the closed cracks under the dynamic loadings, the influence of loading rate on the propagation mechanism of the cracks, and how the change of the angle between the joint fissure and the loading direction leads to different failure mode of the rock mass. The results cannot only reveal the realistic response of rock joints and crack propagation under dynamic loadings, but are also helpful for the reinforcement of rock mass engineering constructions, to prevent joint rock damage and loss of life and property. It can also provide theoretical and technical support for oil and shale gas production. Thus the proposed research has both high theoretical value and high social value of application.

我国一些重大民生、国防项目通常坐落在地质结构复杂的高山峡谷地区， 在地震、爆破等动态荷载作用下，基建范围内岩体裂隙的发展尤为剧烈，频次、规模也明显增多，且更具突发性，严重威胁着大型岩体工程的安全。因此，研究含有节理结构面岩体在动荷载作用下裂隙的起裂及扩展机理十分必要。本项目基于断裂动力学理论，拟取含闭合节理的岩体作为研究对象，结合SHPB动力加载系统，揭示闭合节理岩体在动态加载条件下的裂纹起裂准则及扩展规律，建立多角度节理裂隙条件下岩体力学破坏模型，真实反应岩体在动态荷载下的裂隙扩展机理，为工程建设及地质灾害防治等领域提供一定的理论支撑。同时，研究成果还能扩展应用到石油增产、页岩气开采等矿产开采领域，具有一定的社会应用价值。

本项目以分离式霍普金森杆(SHPB)为动力加载系统，利用数字图像相关技术，模拟复杂地质条件下的含节理岩体，分析多加载率、裂纹多角度条件下花岗岩试样的失稳破坏，探索含节理岩体在高加载率条件下的裂纹起裂及扩展规律，解释岩体在动态荷载下的破坏机理，主要研究内容如下：(1)研究了张开型单节理类岩石材料板动态压缩破坏机制；(2)研究了充填型单节理类岩石材料板动态压缩破坏机制；(3)研究了充填型平行节理类岩石材料板动态压缩破坏破坏机制；(4)研究了充填型交叉节理类岩石材料节理类岩石材料版动态压缩破坏机制；(5)通过使用超高速摄像机和DIC诊断系统方法来记录变形场的演变，采用数字标记剖面精确地获取局部坐标系下的数据结果，进而区分断裂模式，定量分析出四种断裂模式。通过对应分析确定断裂模式与断裂角度之间的耦合关系。研究成果能扩展应用到石油增产、页岩气开采等矿产开采领域，具有一定的社会应用价值。