The History of the Earth's Crust

ALEXANDRE COLLIN

Alexandre Collin (born July 29, 1808) was a French civil engineer, a pioneer of geotechnical engineering, especially for the soil mechanical behavior of clays. Collin was the son of a local building contractor and from 1828 attended the École polytechnique in Paris. After graduation, he went to the Corps Royal des Ponts et Chaussées, where he was involved in canal construction work on the Canal de Bourgogne from 1883. He was also able to measure a slide in the stiff local lias clay at the construction site after the autumn rains (according to Collin they were in the form of a cycloid), the first time that sliding surfaces in the clay were examined so precisely. Collin continued his observations in tone on other embankment breaks. He also carried out experimental studies of the shear strength of the clays (their cohesion) as a function of the water content and gave a method for calculating the slope stability. Collin wrote a treatise on his research, which was finally published in 1846. As a result, the treatise was occasionally cited, but was replaced in the 19th century by the methods developed by Jean-Victor Poncelet (1840) and William John Macquorn Rankine (1857) on sandy soils (and not applicable to clay soils). The basic analysis of Collin, based on Skempton, was independently redeveloped in the 20th century and Collin's work was rediscovered. Collin continued his career with his authority, becoming chief engineer for the Loire region in 1855 and general inspector in 1867. He retired in 1873. He published several more works mostly on hydrology and hydraulic engineering, but no longer on soil mechanics. In 1866, an experimental work on evaporation won a prize from the Paris Academy of Sciences. He retired from archaeological and historical research and was at times president of the Archaeological and Historical Society of Orleans.