BY RALPH B. PECK

Stanley DeWolf Wilson, international consultant in geotechnics and cofounder of Shannon and Wilson, Inc., and the Slope Indicator Company, died on November 17, 1985, of complications resulting from a particularly virulent form of malaria that he had contracted on a consulting assignment in West Africa three weeks earlier.

Stan Wilson was born in Sacramento, California, on August 12, 1912. He attended Sacramento Junior College from 1930 to 1932 and for the following nine years was employed as an engineer for the California Division of Highways. After the attack on Pearl Harbor, he joined the U.S. Army Corps of Engineers, which assigned him to study civil engineering at the University of Minnesota. Later, while he was attached to Fort Belvoir, the corps assigned him to attend the course in airfield engineering under Professor Arthur Casagrande at Harvard University. Wilson so impressed his teacher that Dr. Casagrande persuaded the corps to extend his stay, to allow him to instruct subsequent classes of airfield engineers and to help prepare a soil identification manual for the corps to use for construction of airfields in forward combat zones.

Following his discharge as a first lieutenant, Wilson remained at Harvard where, despite his lack of the usual prerequisite of a baccalaureate degree, he earned an M.S. in civil engineering and rose to the rank of assistant professor in the Graduate School of Engineering.

In 1953 the trustees of Harvard decided to discontinue the program in soil mechanics. The following year, Stan joined with his Harvard colleague William L. Shannon to form the Seattle consulting firm of Shannon and Wilson, Inc. The firm developed into one of the world's leading engineering organizations specializing in geotechnical engineering. In 1978 he retired from active participation in the firm but continued to serve it as a staff consultant while pursuing his own active international consulting practice.

At Harvard, Wilson developed portable miniature equipment for performing moisture-density tests on soils for airfields and, at the suggestion of Karl Terzaghi, devised and built the first model of the slope indicator, an instrument for measuring soil displacements in the interior of soil masses. This device satisfied an important need in the study of existing or incipient landslides and in determining the deformations in dams and in soils around excavations and tunnels. To manufacture this device and other geotechnical laboratory and field equipment, much of which he invented or developed himself, he became a cofounder of the Slope Indicator Company, which developed into an international leader in its field.

Stanley Wilson's practice was characterized by his fundamental knowledge of physics and mechanics, coupled with his ability to measure forces and deformation of soil masses under field conditions. Fully capable of using or developing applicable theory, he was a master at solving engineering problems by the interpretation of quantitative field observations against a background of theory.

A pioneer in soil and rock dynamics, he was largely responsible for devising practical means for estimating ground motions of missile installations under the loading of nuclear blasts and for evaluating the suitability of the Titan and Minuteman sites selected by the U.S. Air Force. He substantially advanced our knowledge of the response to earthquakes of earth dams, slopes, and foundations and was the principal U.S. Corps of Engineers investigator of the landslides caused by the Alaskan earthquake of 1964.

Stan Wilson's greatest area of interest, however, was in the design and behavior of earth and rockfill dams. Among the major dam projects on which he served as consultant are the Karnafuli and Tarbela dams in Pakistan; the Tres Marias and Furnas dams in Brazil; the Akosombo Dam in Ghana; the Infiernillo, Malpaso, and many other dams in Mexico; the Gardiner Dam in Canada; the Bandama River Project in the Ivory Coast; the Lesotho Highlands Water Project; the Uribanti-Caparo Project in Venezuela; the Colbun Hydroelectric Project in Chile; and the seismic evaluation of the High Aswan Dam in Egypt.

In the United States, his consulting activities involved the Brownlee and Oxbow dams in Idaho, the Mammoth Pool Project in California, the Muddy Run and Seneca pumped storage projects in Pennsylvania, the Ludington pumped storage reservoir in Michigan, and the stability problems at the Libby Dam site in Montana.

Stanley Wilson gave generously of his time to young engineers and was a regular and frequent lecturer at the University of Illinois and at the University of California at Berkeley. He was also an affiliate professor at the University of Washington. In addition, he contributed more than sixty technical papers and served on numerous advisory boards to the U.S. Army Corps of Engineers, the Nuclear Regulatory Commission, and the National Research Council.

He was an honorary member of the American Society of Civil Engineers (ASCE) and the Mexican National Society of Soil Mechanics. He was a member of Sigma Xi, the American Society for Testing and Materials, the Boston Society of Civil Engineers, the Consulting Engineers Council of Washington, the Harvard Society of Engineers and Scientists, the International Society of Soil Mechanics and Foundation Engineering, the U.S. Committee on Large Dams, the Associación Argentina de Géologia Aplicada a La Ingenieria, and the American Institute of Consulting Engineers. In 1967 he was elected to the National Academy of Engineering.

The American Society of Civil Engineers awarded him the Walter L. Huber Research Prize (1961), the Arthur M. Wellington Prize (1968), the Karl Terzaghi Award (1978), and the Rickey Medal (1985). He was the Karl Terzaghi Lecturer of ASCE (1969), the State-of-the-Art Reporter on Earth and Rockfill Dams at the Seventh International Conference on Soil Mechanics and Foundation Engineering at Mexico City (1969), and the Miles Kirsten Lecturer at the University of Minnesota (1983). For his contributions to the Corps of Engineers, he was awarded the Outstanding Civilian Service Medal (1973).

The topics of his numerous publications ranged from investigations of the laboratory and field behavior of soils and rock and the means for observing them to a wide variety of practical soil displacement applications. One of his most influential publications, a monograph written with Raul J. Marsal of Mexico on "Current Trends in Design and Construction of Embankment Dams," was prepared in 1979 for the International Commission on Large Dams and the Geotechnical Division of ASCE.

Those who knew him best appreciated him for more than his technical competence. In the words of one of his fellow consultants who had worked with him often in the field: Stan reveled in these field visits—often made by small plane, helicopter, jeep, and a fair amount of climbing. There was no hill too steep, no shaft too deep, no swinging foot bridge too narrow to stop Stan from making his inspection. I don't ever recall hearing him say, "I think I've seen enough." He wanted to see all the soils being used in the dam, all the lab tests being run, all the results being obtained, and to observe the contractor's operation in preparing the foundation, placing the fill, and, in particular, the compaction of the fill for the dam embankment. Stan entered into frank but always courteous discussions with the field engineers, lab engineers, or the designers about any point of concern.

Although he traveled extensively, he was devoted and attentive to his family. He and his wife Margaret, to whom he had been married forty years at her death in 1983, were active supporters of the Seattle Symphony. Their three children and five grandchildren were a cohesive unit in which he took great pleasure and with whom he spent many lively times at home or at the family retreat, a cabin near Cle Elum.