Discussion of 'Case History of Damage to a School Building Caused by Differentially Heaving Bedrock' by David C. Noe

摘要

The author presents a history to establish the principal cause of damage to a school building by determining whether the cause was due to settlement or expansive bedrock heave. The discusser suggests that the most likely cause of failure was continuous swelling of expansive soils responding to a dammed-up aquifer that was created by locating the building in an historic drainage way and constructing the building on a granular "bathtub-shaped" fill, that was constructed within an impermeable clay fill with no underdrainage outlet and was underlain by expansive clays and clay stone formations. In the discussion about the history of the facility the author notes that the school site was in a small, eastward-draining swale; however, when one examines the author's Fig. 2 and the entire school site it is evident that the entire site is not located in a old drainage channel, and there is a large area of school property north of the historic drainage swale that was available for construction but was not used for building construction. The contours shown in the author's Fig. 2 indicate that the natural slope of the historic drainage swale was 2 to 3 percent to the east. The bedrock incised along the channel alignment has a similar slope to the east and is approximately 8 to 10 ft below the original grade of the drainage way.