Development of Three-dimensional Boundary Element Program for Advanced Designs in Rock Engineeirng and Its Application to Actual Problems.

在此研究生效之前，Kuriyama和Mizuta已经开发了位移不连续法三维弹性分析的数值程序，并对其适用性进行了研究。这种3D-DDM分析方法有一个显著的特点，即对断层/裂缝等其他方法不易建模的不连续面有较好的建模效果，但对岩石自由面的建模效果较差。因此，我们以独特的程序开发了三维弹性分析的虚拟应力法数值程序，这种方法通常用于地表或地下洞口的平面模拟。该方法在计算构造边界面的三角形叶元之间的影响系数时，由于不采用数值积分，而采用解析积分，可以得到精确的解，且计算速度较快。该计算程序与3D-DDM程序和裂缝内流体流动瞬态分析计算程序相结合。另一方面，我们在岐阜县神冈矿业冶炼株式会社墨尾矿进行了磨料水射流钻孔辅助的原位水力压裂实验。我们对水力压裂产生的裂缝进行了注液试验，测量了裂缝打开引起的流体压力分布和巷道侧壁表面位移的变化。因此，利用上述计算系统进行了注液试验模拟，计算结果与实测结果吻合较好。建立了用边界元法求解三维非稳态热传导的数值程序。由于所处理问题的基本公式不能解析积分，而且常用的数值积分方法也存在一些奇异性，因此本文的程序采用我们新开发的格式，通过数值积分得到了影响系数。然而，在热传导分析中，如果引入特殊的方法，即使用数值积分也足够精确，并通过计算结果与相应的严格解的比较证实了这一点。最后，将该程序与DDM-FSM-FEM联合分析相结合，考虑了岩石运动引起的膨胀/收缩以及岩石向流体的传热。少

Before this research takes effect, Kuriyama and Mizuta has developed a numerical code for three dimensional elastic analysis by the Displacement Discontinuity Method and studied the applicability of it. This 3D-DDM analysis has a distinctive feature that it is effective in modeling of discontinuous plane such as fault/crack which is not easy to be modeled by the other methods, but it is disadvantageous in modeling of free surface of rock. Hence, we developed the numerical code for three dimensional elastic analysis by the Fictitious Stress Method, which is usually used in modeling of the surface of the earth or surface plane of underground opening, by an unique procedure. In this procedure, as numerical integration is not used and analytical integration is used in calculation of influence coefficients among the triangular leaf elements which construct the boundary plane, accurate solutions can be obtained and its computation speed is relatively high.This computation code was combined w … More ith the 3D-DDM code and the computation code for transient analysis of fluid flow in the fracture.On the other hand, we carried out an in-situ hydraulic fracturing experiment assisted by abrasive water jet borehole slotting in the Mozumi Mine of Kamioka Mining and Smelting Co.Ltd.in Gifu Prefecture by different Grant-in Aid. We carried out the tests of fluid injection into the fracture which was produced by hydrofracturing and measured the variations of fluid pressure distribution and surface displacement of the side wall of the drift, which was caused by opening of the fracture. Therefore, simulations of the fluid injection tests were carried out by using the computing system mentioned above and it was confirmed that the computed results with the measured results.A numerical code for three dimensional non-steady heat conduction by the Boundary Element Method was developed. In this program, influence coefficients are obtained through the numerical integration taking the scheme newly developed by us into consideration because the basic formula dealt in the problem can not be integrated analytically and some singularity happens even in the popular method for numerical integration. However, in case of heat conduction analysis, accuracy is sufficient even by numerical integration if the special method is introduced and it was confirmed by comparison of a computed result with the corresponding strict solution. Finally, the program was combined into the combined DDM-FSM-FEM analysis in order to take rock expansion/shrinkage due to hear movement and heat transfer from rock to fluid into consideration. Less