LONG-TERM ABILITIES TO RESIST WEATHERING OF ROCK BLOCKS AND SHELL-LIME MOTAR IN XIAOXI GATE OF QUZHOU ANCIENT CITY WALL FROM SURFACE RECESSION MEASUREMENT

The abilities of different rocks to resist weathering in the same weathering condition are different. How to assess the ability of rock to resist weathering is one of the research topic of great concern in recent years, which has important scientific value for analyzing weathering mechanism of rocks and long-term protection of rock culture relics. The Xiaoxi gate wall of Quzhou ancient city wall was built in late of Ming dynasty(1368～1644A.D.).There are a variety of lithologies in rock blocks of Xiaoxi gate wall. The differences in their depths of surface recession are also large. The three-dimensional(3D)laser scanner is used to measure the depths of surface recession of rock blocks with different lithologies in a particular study area on Xiaoxi gate wall. Based on the measure data, the long-term abilities of different lithologic rocks to resist weathering were assessed and the corresponding sort is attained. It is also found that compared with the rock blocks studied, the ability of shell-limes motar adhered between blocks are stronger.