Appraisal of the karst development features and engineering geology conditions at a building site in Dayaowan, Liaoning Province

The major bedrocks in Dayaowan are moderate to strong soluble carbonate rock with well developed fissure, so karst is strongly developed under the impact of sea water and groundwater as well as karst fissure water. The surveying drilling proves that the karst cavity discovering rate is 70.27%. The cavities mainly distribute between 20～30 m underground, and between 30～40 m secondly. The karst cavities are divided into 4 classes according to their size (h) in this article: the large scale (h≥4 m), the medium to large scale (2 m≤h＜4 m), the medium (0.5 m≤h ＜2 m) and the small (h＜0.5 m). The statistic result indicates that karst cavities in the location are mainly the medium ones, and secondly are the small or the medium to large scale ones. The growth and distribution of the karst cavities seriously affect the engineering geology conditions of the building site. Regarding the karsts as the major engineering geology problem, the background and forming conditions as well as distribution of karst at the building site are analyzed and e valuated in the paper. Accordingly, it is believed that the groundwork of the building site is karst laterite with moderately or strongly developed karst and the CFG and Vibratory Crushed stone composite piled foundation or some appropriate piled foundation etc. should be adopted in disposal this kind of groundwork in order to keep the engineer safe.