In this paper, out-of-core solution algorithms are used for analyzing large 3D soil problems. Such problems involve huge number of degrees of freedom. The soil continuum is modeled using 3D multi-region boundary element method. The overall stiffness matrix resulted from the multi-region boundary element problem is large, sparse and non-symmetric. The soil stiffness matrix is divided into series of sub-matrices according to the available computer memory. Each sub-matrix is assembled individually, hence only the non-zero elements are stored on the hard disk (out-of-core). The BiCGStab (l) and GMRES (m) iterative solvers are implemented to solve the overall system of equations. The innovative part in this paper is the coupling of the developed out-of-core solution with these iterative solvers. Read-in algorithms are developed where the non-zero elements of each sub-matrix are read-in element-by-element sequentially, to fit within relevant operations inside the used iterative solvers. Such a procedure reduces the used computer memory and accelerates the solvers time. The presented numerical examples confirm the necessity of the developed algorithms for large soil problems and confirm the efficiency of the used iterative solvers. In addition, the used iterative solvers give similar performance.

在本文中，核心外求解算法用于分析大型3D土壤问题。这些问题涉及大量的自由度。使用3D多区域边界元方法对土壤连续体进行建模。由多区域边界元问题引起的整体刚度矩阵大，稀疏且不对称。根据可用的计算机内存，将土壤刚度矩阵划分为一系列子矩阵。每个子矩阵都是单独组装的，因此只有非零元素存储在硬盘上（核外）。实现BiCGStab（l）和GMRES（m）迭代求解器来求解整个方程组。本文的创新部分是开发的核心解决方案与这些迭代求解器的结合。开发了读入算法，其中每个子矩阵的非零元素依次逐个元素读入，以适合使用的迭代求解器中的相关运算。这样的过程减少了使用的计算机内存并加快了求解器的时间。给出的数值例子证实了针对大土壤问题开发算法的必要性，并证实了所用迭代求解器的效率。此外，使用的迭代求解器具有相似的性能。给出的数值例子证实了针对大土壤问题开发算法的必要性，并证实了所用迭代求解器的效率。此外，使用的迭代求解器具有相似的性能。给出的数值例子证实了针对大土壤问题开发算法的必要性，并证实了所用迭代求解器的效率。此外，使用的迭代求解器具有相似的性能。