Influence of Prevailing Wind Direction on Sapping Quantity of Rammed Earth Great Wall of the Ming Dynasty

Sapping caused by prevailing wind erosion is one of the most significant factors in deterioration earthen sites located Datong County, Qinghai Province, China. Long-term effects may cause surface erosion, or even serious damage to Great Wall Ming Dynasty. Difference sapping quantity should be attributed variability directions. To better understand direction on meteorological data study area for fifty-two years (from 1961 2013) were collected and statistically analyzed. structure was measured field investigation along ridge whose azimuth ranges from 95°–244° mainly concentrated 140°–210°. Results showing obvious difference could observed at both sides under directions (ESE, SE SSE). Further, divided into small segments with a length 20 m comparison maximum found an angle 30° wind. The aim this provide reference long-term pressure, targeted conservation method structure.