INTRODUCTION
The advent of the digital computer is hardly a new development in engineering practice. It has been generally available for about a quarter of a century, and the last fifteen years have seen a great deal of research into the use of computers for geotechnical engineering and rock mechanics. The results include a significant number of papers in journals and in the proceedings of conferences, as well as increased sophistication on the part of recent engineering graduates. Many engineers and geologists now leave school with considerable training in computer methods, and they are eager to apply their learning in practice. The computers themselves have become both more powerful and cheaper to the point that the mini-computer of today rivals the most expensive machine of a decade ago. Thus, the significant questions are not whether the computer can be applied in geotechnical practice but how it can be most effectively employed and what commitments are needed to achieve that effective use.
Most geotechnical engineering is done by small groups, either as independent consulting firms or as divisions within larger organizations. Much of the practice is dictated by local traditions or regulations. As a result, there has not evolved a group of recognized computer programs used by the profession at large and readily available through service bureaus. An examination of the catalogue of almost any service bureau or distribution center will reveal that, while the structural engineer or stress analyst can choose from many programs to aid him in his work, the geotechnical engineer has few documented and maintained programs available to him. He must develop or acquire his own library of programs and must maintain and upgrade them himself.
The following remarks are concerned with the use of computers in the routine practice of geotechnical engineering rather than with the development of new computer programs for solution of unusual problems. The computer programs described here involve very little in the way of advances in the art of numerical analysis, finite element theory, or other aspects of current research. The computational methods on which they are based are generally well known to those competent in rock mechanics and geotechnical engineering. Nevertheless, making the power of the computer available to the practicing engineer or geologist has presented a number of challenges and emphasized several insights into the way engineering is actually done.
Three examples have been chosen to illustrate recent experience in practical application of computers. The first involves an analytical procedure that is as well known in structural geology as it is tedious: the stereographic plotting of joint pattern and the contouring of the results. The second is the evaluation of the stability of jointed systems by vector analysis. The third concerns the effective use of graphical output to make the results of finite element analyses of flow through geologic media available to the engineer. Following these examples, some observations are made about the need for an environment that is congenial to the user, for meaningful documentation and testing of programs, and for devotion of sufficient resources to maintain the computer programs in usable form.
