FRACOD模拟软件在岩石工程中的应用及案例分析

Application and verification of FRACOD in rock engineering

岩土工程领域中岩石作为力传播媒介在地下工程中起着至关重要的作用,掌握工程扰动过程中岩石裂纹扩展规律及破坏特征有助于揭示相关灾害发生机理,为防治灾难发生提供研究基础。为此,基于岩石断裂力学理论和位移不连续数值模拟理论,提出能够同时预测拉伸和剪切裂纹传播的F-准则,研发了能够模拟岩石混合裂纹扩展的FRACOD软件。首先从理论背景层面对FRACOD裂纹扩展模拟软件进行了详细的介绍,软件采用间接边界元-位移非连续法,并引入裂纹扩展F-准则及Mohr-Coulomb裂纹起裂准则用以模拟岩石混合裂纹扩展规律及应力场、位移场等物理场的分布规律。为验证该软件在众多工程领域的适用性,进行了地热开发钻孔破裂、岩石力学双轴压缩试验、水压致裂等三个模拟案例的对比分析。通过对模拟试验结果与室内试验或现场观测结果的对比发现,FRACOD不仅可以准确模拟岩石的裂纹扩展规律及岩体破坏特征,同时适用于涉及岩体断裂损伤的多个工程领域。因此,FRACOD研发与应用为岩石工程设计和研究提供了重要的研究工具,对岩体断裂损伤学科的发展具有重要的指导意义和参考价值。

In the field of geotechnical engineering,rock as the propagation medium plays a crucial role in underground engineering.Understanding the propagation principle and failure characteristics of rock fracture in the process of engineering disturbance helps to reveal the initiation mechanisms of relevant disasters and provide the basis for disaster prevention research.In this paper,a F-criterion capable of predicating tensile and shear cracks simultaneously proposed based on rock fracture mechanics and displacement discontinuity numerical simulation.In addition the modelling software FRACOD for predicting mixed mode rock fracture propagation was developed.The theoretical background of FRACOD was firstly described in detail.The indirect boundary element and displacement discontinuity method was adopted.F-criterion for fracture propagation and Mohr-Coulomb criterion for fracture initiation were introduced to simulate the mixed mode fracture initiation and propagation in rocks as well as the distribution of stress field,displacement field and physical field.In order to verify the applicability of the software in various engineering fields,the examples of borehole breakout,biaxial compressive test and hydraulic fracturing were carried out.The comparison between the simulation results with those of laboratory tests and field observations reveals that not only FRACOD can accurately simulate the complex fracture propagation and failure characteristics of rocks,but it also can be applied to many engineering fields involving the fracture and damage of rock mass.Therefore,by providing an important numerical tool in rock engineering design and research,the development and application of FRACOD has important guiding significance and reference value for the development of the discipline of rock mass fracture and damage.