ABSTRACT
A new three-dimensional finite element model is introduced to enable the calculation of simplified large scale problems on powerful personal computers. The model is applicable to situations in which input and calculation data can be arranged in a planewise manner. In stead of creating a single stiffness matrix for the whole mesh, a number of smaller, plane-related stiffness submatrices are created. By leaving out non-unique submatrices, a significant reduction of the storage requirements may be achieved for problems with highly repetitive properties of the mesh in one direction. The performance of the model for various integration rules is illustrated in two examples. It appears that at the cost of a small error, a significant reduction of the required number of arithmetic operations may be achieved as well. A number of extensions necessary to simulate shield tunnel advancement are discussed, comprising soil plasticity, simulation of shield tunnelling and interface elements. With these extensions, the new model may prove to be a practical tool in the design phase of bored tunnels.
