单轴条件下节理岩体局部失稳与破坏特征研究

发布时间：2018-03-15 08:54

本文选题：节理岩体　切入点：单轴压缩　出处：《河北工程大学》2017年硕士论文　论文类型：学位论文

【摘要】：节理岩体作为一种复杂岩体,在岩土工程与环境工程中以断层、节理与裂隙等不同的结构面形式频繁出现,这给我国许多的岩土工程项目的安全实施及维护带来很大困扰。而裂隙岩体由于经历了各种地质构造运动,因而裂隙岩体所处的地质环境与应力环境是十分复杂的。裂隙作为一种原始损伤,而且在岩体中呈现的形式具有随机性,会大大降低含裂隙岩体的强度,改变岩体的原有特性。近些年来,对于研究节理裂隙岩体在外载荷作用下,裂隙的扩展规律与多裂隙之间的连接、贯通模式博得了学者的关注与热衷。通过阅读相关文献了解到:含节理裂隙岩体的宏观破坏与失稳的根源是其内部的不连续面的张开、闭合、扩展和贯通所导致的(即局部失稳与破坏引起宏观失稳与破坏);在外载荷一定的情况下,节理裂隙岩体内节理、裂隙的扩展与贯通模式与其所处的状态(节理裂隙的长度、数量、倾角等)有着密不可分的联系。虽然前人对不同裂隙倾角岩体及裂隙长度等因素研究了很多,但对于含裂隙的大尺寸方形试样在外载荷条件下,岩体内部失稳与整体破坏特性室内试验研究不是很多。本文结合前人所研究的内容与成果,做了如下几方面内容:1、通过查阅相关文献与书籍,本文选择从不同裂隙倾角、数量的变量因素来进行室内试验研究,研究内容包括含不同裂隙倾角岩体在单轴条件下局部失稳及整体破坏特征,前者有做过标准试样(50mm×100mm)的节理岩体70mm×70mm×140mm及70mm×90mm×150mm尺寸的试样。本文采用尺寸为150mm×150mm×300mm的试样来进行模拟研究,其中裂隙深度比d/T为1,裂隙长度为50mm,多裂隙试样中选择平行裂隙,裂隙之间间距设为50mm。2、选择合适的相似材料模拟岩体及制作试样的模具与预制裂隙片,并按照设计方案将试样制作完成并进行养护处理。之后将试样进行编号,开始室内试验,对不同情况的试样进行单轴压缩试验,将各个试样的应力应变曲线进行对比分析,并用高像素相机对试验过程中裂隙的萌生、扩展路径与试样破坏特征进行拍摄,为后续分析、总结提供依据。在压缩过程中采用美国声发射PCI-2系统,保证了试验的可靠性。3、通过使用RFPA2D数值模拟软件对各种试样方案进行数值模拟,观测模拟含裂隙试样裂纹的萌生、扩展规律、贯通模式及试样的破坏特征,并与试验结果进行对比分析。经过完成以上的工作内容,试验与模拟对比分析了含裂隙岩体局部失稳与破坏特征,总结出了一些简单的裂纹扩展、贯通模式的规律,为后者继续研究提供一些参考价值及工程实践中指导意义。
[Abstract]:As a kind of complex rock mass, jointed rock mass frequently occurs in geotechnical engineering and environmental engineering in the form of different structural planes, such as faults, joints and fissures, etc. This brings great troubles to the safety implementation and maintenance of many geotechnical engineering projects in China. However, the fractured rock mass has undergone various geological tectonic movements. Therefore, the geological environment and stress environment of fractured rock mass is very complicated. As a kind of original damage, fracture has randomness in the form of rock mass, which will greatly reduce the strength of fractured rock mass. In recent years, the connection between fracture propagation law and multiple fractures has been studied under the external load of jointed fractured rock mass. Through reading the relevant documents, it is found that the root of macroscopic failure and instability of jointed fractured rock mass is the opening and closing of discontinuous plane inside it. Extension and transfixion (i.e., macroscopic instability and failure caused by local instability and failure; under certain external loads, joints in jointed rock, modes of expansion and penetration of fractures and their state (length of joints and fissures), The quantity, inclination, etc.) are closely related. Although many previous studies have been done on the factors such as rock mass and crack length of different fractures, for large square specimens containing cracks under external loading, There are not many indoor tests on the internal instability and overall failure characteristics of rock mass. This paper combines the contents and achievements of previous studies and makes the following contents: 1. By consulting relevant literature and books, this paper chooses different fracture inclination angles. The contents of this study include local instability and global failure characteristics of rock mass with different fracture dip angles under uniaxial conditions. The former has the specimens with the dimensions of 70mm 脳 70mm 脳 140mm and 70mm 脳 90mm 脳 150mm of the standard specimen (50mm 脳 100mm). In this paper, the sample with the size of 150mm 脳 150mm 脳 300mm is used to simulate the study, in which the depth of fracture is 1 and the length of fracture is 50mm. The spacing between fractures is set to 50mm. 2. Suitable similar materials are chosen to simulate rock mass and mould and prefabricated fissures to make samples. The samples are made and treated according to the design plan. Then the samples are numbered and the laboratory tests are started. Uniaxial compression tests were carried out on samples under different conditions. The stress-strain curves of each sample were compared and analyzed. The crack initiation, propagation path and failure characteristics of the specimen were photographed with a high-pixel camera for subsequent analysis. In the process of compression, the American acoustic emission PCI-2 system is used to ensure the reliability of the test. By using the RFPA2D numerical simulation software, various sample schemes are numerically simulated, and the crack initiation of the fractured specimen is observed and simulated. After the above work is completed, the local instability and failure characteristics of fractured rock mass are compared and analyzed with simulation. Some simple rules of crack propagation and through-through mode are summarized, which provide some reference value and guiding significance in engineering practice for the latter to continue to study.
【学位授予单位】：河北工程大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU457

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