考虑结构面细观力学特性的节理岩体宏观力学模型与应用研究

It’s a key issue in tunnel and underground engineering that how to effectively prevent deformation, failure and collapse caused by jointed rock mass during the tunnel construction. In this research project, jointed rock mass is regarded as a complex structure composed of rock and structure surface with different levels and scales. Starting with the research of the structure surface’s meso-mechanical properties from different scales of engineering, structure surface shear test measuring meso-properties and jointed rock mass mechanical and deformation 3D load and unload test are conducted, the research project will search the relationship between the meso-macro interrelated mechanical characteristics, and equivalently simplify the number of structure surfaces which are distributed randomly to a few deterministic structure surfaces. An equivalent simplified method in engineering based on the structure surface will be established. The macro-mechanical constitutive model and the method of determining its mechanical parameters of jointed rock mass will be set up. What’s more, the methods are more practical and consider its meso-mechanical properties. Based on the further development of finite element software like Abaqus, the jointed rock mass’ elastic-plastic and the structure surface’s mechanical deformation behaviors of yield, slip, open etc. will be simulated numerically and analyzed finely. Then the physical models and the practical engineering applications on the construction stability and deformation of jointed rock mass are studied, and the equivalent simplified method of structure surface and the macro-mechanical model of jointed rock mass are verified and improved by comparing them with each other.

如何有效防治节理岩体在隧道建设过程中导致的变形破坏和塌方行为，是隧道及地下工程中面临的关键问题。本课题将节理岩体视为岩石和不同级别、不同规模的结构面构成的复杂结构体，从研究不同工程尺度结构面的细观力学特性入手，通过结构面细观特征观测的岩体剪切试验以及节理岩体力学与变形性态的大型三向加卸载试验，寻找细观与宏观关联的力学性态关系，把节理岩体中众多随机分布的结构面等效简化为少数确定性结构面，建立结构面工程等效简化理论分析方法，进而建立实用性更强的考虑细观力学特性的节理岩体宏观力学本构模型及其力学参数的确定方法。基于Abaqus等软件进行二次开发，实现节理岩体的弹塑性及结构面屈服、滑移、张开等各种力学变形性态的精细化数值模拟分析，并进行节理岩体隧道施工稳定与变形的物理模型试验与实际工程应用研究，对结构面等效简化理论方法和节理岩体宏观力学新模型进行对比验证与完善。

节理岩体隧道及地下工程经常发生变形破坏或塌方问题的主要因素是节理面强度弱、剪切滑移大等性态。在本项目经费资助下，基于三维激光扫描与3D打印技术，通过结构面三维细观特征观测的节理岩体剪切试验，建立了考虑节理面粗糙程度、法向应力与节理面摩擦特性的节理峰值剪切位移计算公式。提出了一种将岩体结构面进行细观网格化处理方法，编写了结构面3D表面细观形态参数计算程序，提出了考虑剪切方向的三维结构面抗剪强度计算新公式。研制完成了节理岩体裂隙可视化注浆模型试验系统，为进一步的拓展研究提供了试验基础。建立了结构面细观-宏观关联的力学关系、一组及两组层状节理岩体工程等效简化分析方法，进而形成了实用性更强的考虑三维结构面细观特性的节理岩体宏观力学等效模型及其参数确定方法。项目共计发表学术论文18篇（其中SCI收录9篇、中文核心期刊论文8篇），获得授权发明专利3项，授权实用新型专利1项，完成节理岩体结构面三维表面细观形态参数计算方法与程序1个，结构面等效简化方法、节理岩体结构面三维表面细观形态的宏观抗剪强度计算新方式及其数值计算方法。培养博士4名，硕士3名；协办国际会议2次，承办国内会议1次，项目相关成果国内学术会议特邀报告5个，一般学术会议报告6个。相关成果指导了深圳东部过境高速公路连接线工程复杂环境下浅埋大断面互通节理岩体隧道设计施工、云南功东高烈度区域山区高速公路节理岩体隧道安全施工的工程应用研究，项目完成了要求的全部考核指标与成果。