辽宁省大窑湾某建筑场地岩溶发育特征及工程地质条件评价

辽宁省大窑湾地区某建筑场地内基岩为可溶性中等～强的碳酸盐岩,岩体裂隙发育,在海水入侵、潜水与岩溶裂隙水等共同作用下,岩溶发育较强烈。本场地勘察揭露溶洞的见洞率70.27%。溶洞多发育于地表下20～30 m之间,其次为30～40 m。本文根据揭露溶洞的大小将溶洞分成大型溶洞(洞高≥4 m)、中偏大型溶洞(2 m≤洞高4 m)、中型溶洞(0.5 m≤洞高2 m)和小型溶洞(洞高0.5m)等四类,分析表明本场地内溶洞以中型溶洞为主,其次为小型溶洞和中偏大型溶洞,岩溶的发育和分布对场地工程地质条件影响较大。本文围绕场地岩溶发育这一主要工程地质问题,从岩溶发育的地质背景、形成条件、分布特点等方面对场地内的岩溶发育特征进行了分析研究,认为本场地属于岩溶中等～强发育的复杂的岩溶红粘土地基,需采取CFG桩、振冲碎石桩复合地基或采用桩基等措施对地基进行处理,以保证工程安全。

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≤h4 m）,the medium（0.5 m≤h2 m） and the small（h0.5 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 evaluated 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.