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

摘要

The writer wishes to thank the discusser for his excellent discussion regarding subsurface drainage and ponding as a major influence driving the heaving damage to the school building. He interprets that more emphasis should be given to the wetting and subsequent expansion of the soil and fill that directly underlie the school, due to the presence of a "bathtub" of granular soil fill that intercepted and was progressively saturated by infiltrating, perched groundwater. It appears from his comments that the discusser has spent time at the school site and has made direct observations of the site and the surrounding neighborhoods. The writer and discusser are in agreement that subsurface moisture, in addition to the presence of expansive materials, is needed to drive the swelling and heaving of those materials. We are also in agreement that the main source of water appears to be a grass-lined drainage swale and a lawn area to the west of the school building. Water that infiltrates into the ground in these areas flows eastward as perched water, following the slope of the preconstruction topography, and flows underneath the school at a point along its western wall. The discusser's observations are welcome as they add further detail to those given by the writer in the article