Author Description

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1907 Excerpt:...by cracks running northwest, where the fault line crosses the nose of a hill which naturally projects to form the dam's abutment. There must have been some motion at this point, possibly five or six feet, but it is not clear on the surface. The cracks which were pronounced in this nose or abutment were in the abutment and not in the dam itself. There were a number of smaller cracks running in the same direction at the extreme westerly end of the dam. On the dam's roadway there were small longitudinal cracks to be observed throughout its length, apparently due to the unequal settling of the triangular masses with respect to the core, but they were not serious. I am convinced that an earth dam properly constructed will stand a violent shock. Wherever possible a dam should not cross a geological fault at right angles. The wooden flume starting near the Crystal Springs Pumping Station, which enters the San Andreas reservoir near the east end of its earth dam, completely collapsed just below that dam where the main fault line crosses the flume. At this place the flume was supported on a wooden trestle about fifty feet in height. In the same locality a waste-way conduit built by day labor, of selected brick with cement mortar, provided a dis charge from San Andreas Lake into the valley below the dam to discharge water into Crystal Springs reservoir. The gate-house for this conduit is near the eastern end of San Andreas dam, about 300 feet from the fault line. It is built of selected brick with cement mortar, and exhibits no cracks whatever. About 1,000 feet below the dam the brick conduit curves to the west to its discharge point, and in so doing crosses the fault line. At this crossing the conduit was sheared completely, but due to the excellence of the mortar,...