基于分析分解模型数值试验的围岩力学参数估算

地下硐室围岩因结构面存在稳定性显著降低,且受结构面影响难以进行力学参数室内试验测定,导致不同围岩力学参数难以准确表示。提出一种采用分析分解模型数值试验估算围岩力学参数的新方法,依据围岩分类体系结果,借助FracSim 3D程序构建不同围岩类别的三维结构面网络模型,并通过x,y,z方向截取二维结构面网络图以反映岩体各向异性特征,实现构建分析分解模型;之后,应用已有试验成果将分别得到的对应的完整岩块及相关结构面的力学参数值作为模型基本输入参数;最后,应用有限元法(Phase 2D程序)建立其对应的岩体结构数值模型,通过有效控制边界条件实现对单轴压缩、三轴压缩等试验的模拟,即实现用宏观等效的岩体模型来预测岩体强度与变形特性,进而完成对不同类别围岩力学参数值的确定。

Estimation of Mechanical Parameters of Surrounding Rocks Based on Numerical Simulation by Analytical Decomposition Model

The surrounding rock quality of underground cavern is reduced because of structural planes. Due to this, the mechanical parameters of surrounding rocks of different classifications are difficult to be decided accurately by in-door tests. A novel method of estimating mechanical parameters by analytical decomposition model is proposed. The model is established by constructing 3-D structural plane network models for different rocks using FracSim 3D program based on the results of surrounding rock classification. The anisotropy of rockmass characteristics is reflected by intercepting the 2-D structural plane network in X, Y, Z coordinates. In subsequence, the mechanical parameters of intact blocks and related structural planes are obtained as the basic input parameters of the model. Finally, Phase 2D program is adopted to establish the numerical model of rockmass structure, and the numerical simulation of uniaxial compression and triaxial compression tests by effective control of boundary conditions is carried out to predict the rock strength and deformation characteristics in macro-equivalent model, hence obtaining the mechanical parameters of surrounding rock.