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

在这项研究生效之前，栗山和水田已经开发了一个用位移不连续法进行三维弹性分析的数值程序，并研究了它的适用性。这种3D-DDM分析具有一个显著的特点，即它对其他方法不易模拟的断层/裂隙等不连续面的模拟是有效的，但对于岩石自由面的模拟是不利的。为此，我们开发了虚拟应力法三维弹性分析的数值程序，该程序通常用于模拟地表或地下洞口的表面。在该程序中，由于不使用数值积分，而是采用解析积分来计算构成边界平面的三角形叶单元之间的影响系数，因此可以得到精确的解，并且计算速度较快。该计算程序是与…相结合的另一方面，利用3D-DDM程序和裂隙内流体流动的瞬变分析计算程序，在岐阜县神冈矿业冶炼株式会社墨水矿进行了磨料水射流钻孔开槽辅助水力压裂现场试验。对水力压裂产生的裂缝进行了注液试验，测量了裂缝张开引起的巷道侧壁流体压力分布和地表位移的变化。为此，利用上述计算系统对注液试验进行了模拟，并与实测值进行了比较，验证了计算结果与实测值的一致性。开发了三维非稳态热传导边界元数值模拟程序。在本程序中，由于所涉及的基本公式不能解析积分，而且即使在流行的数值积分方法中也存在一些奇异性，所以在本程序中，通过考虑我们新开发的格式的数值积分来获得影响系数。然而，在热传导分析中，如果引入特殊方法并将计算结果与相应的严格解进行比较，即使用数值积分也是足够的精度。最后，将该程序结合到DDM-FSM-有限元联合分析中，以考虑岩石由于剪切运动引起的膨胀/收缩以及岩石向流体的热传递。较少

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