断续柱状节理岩体各向异性力学行为与渗流特征试验研究

Baihetan giant hydropower station is 279 meters high and the altitude difference of water intake high slope is 600 meters. Meantime, the geological structure of the dam site bedrock is columnar joint basalt rock mass which has the capacity of easy rip, strong permeability and poor stability of arch dam base. In terms of the above characteristics, explore the damage fracture failure mechanism of columnar joint rock via the true triaxial compress and unload of different stress path on indoor jumbo size, physical simulation, all stress-strain test of triaxial compress and permeate in different structural surface, Scanning Electron Microscope (SEM) of the cracked fracture. In addition, combined with the experiment of local in-situ rigid bearing plate and the detailed description of columnar joint rock mass's structure and based on the theory of anisotropic mechanics, interfacial mechanics, poromechanics, the nonlinear theory of solid mechanics, numerical computation method, the anisotropic constitutive model of discontinuous columnar joint rock mass was established , and the numerical computation method and accordingly calculation procedure of the anisotropic constitutive relation of discontinuous columnar joint rock mass was proposed in this paper. At last, research achievement is applied to estimate the stability of Baihetan hydropower station and high slope of the water inlet which can produce better possible results. The study of this project is a breakthrough and innovation in anisotropic rock mechanics and it has important application value to giant hydropower station which has the similar geologic condition in the west of our country.

针对巨型白鹤滩水电站枢纽工程坝高279m、进水口高边坡高差600m、坝址区基岩为地质构造相对单一的柱状节理玄武岩易劈裂、透水性强、拱坝基础稳定性差之特点，通过室内大尺寸真三轴不同应力路径压缩卸载试验、物理相似模拟试验、含不同结构面三轴压缩渗透全应力应变试验、岩石断裂断口扫描电镜细观试验，探寻柱状节理岩石损伤断裂破坏机制，结合现场原位刚性承压板试验以及柱状节理岩体结构的精细描述，综合运用各向异性力学理论、界面力学、渗流力学、非线性固体力学理论、数值计算方法等，建立断续柱状节理岩体各向异性本构模型，提出非连续柱状节理岩体各向异性本构关系数值计算方法，编制与此相应的三维计算程序。将研究成果应用于白鹤滩水电站坝基和进水口高边坡稳定性评价，可以发挥较大的经济效益。此课题的研究解决是各向异性岩石力学的突破与创新，且对我国西部相类似地质性状的巨型水利工程具有重大应用价值。

针对巨型白鹤滩水电站枢纽工程坝高279m、进水口高边坡高差600m、坝址区基岩为地质构造相对单一的柱状节理玄武岩易劈裂、透水性强、拱坝基础稳定性差之特点，通过室内大尺寸真三轴不同应力路径压缩卸载试验、物理相似模拟试验、含不同结构面三轴压缩渗透全应力应变试验、探寻柱状节理岩石损伤断裂破坏机制。将各向异性力学理论、界面力学、渗流力学、非线性固体力学理论、数值计算方法等有机结合，主要研究工作及成果如下：首先，建立基于Cosserat理论的正六边形柱状节理岩体本构模型，编写了Cosserat各向异性本构程序，将其应用于白鹤滩柱状节理岩层隧道开挖数值模拟中；推导了五棱柱状节理岩体本构关系，引入四棱柱、六棱柱模型，探讨了三种模型下的等效弹性参数值和各向异性特征。其次，基于单节理岩体侧向应力作用效果及渗流作用机理，在单节理岩体渗透性-应力耦合分析模型基础上推导了单节理岩体渗流-应力耦合的理论公式，通过引入等效渗流方法，探究了典型的含正六边形主干节理网络的渗流-应力耦合特性。最后，通过不同应力路径物理相似模型试验，总结了断续柱状节理岩体在不同应力环境下的变形破坏特征。将研究成果应用于白鹤滩水电站坝基和进水口高边坡稳定性评价，可以发挥较大的经济效益。此课题的研究解决是各向异性岩石力学的突破与创新，且对我国西部相类似地质性状的巨型水利工程具有重大应用价值。