南京地区火成岩的分布特征及岩土工程勘察

Distribution Characterization of Igneous Rock in Nanjing City and Its Geotechnical Investigation

南京火成岩分布普遍,岩浆岩种类齐全。区域岩浆活动具有活动时间长,活动期次多,涉及范围广,活动形式多样等特点。因火成岩的成因及风化程度不同,其抗压强度相差很大,从极软岩到较坚硬岩均有分布。火成岩的风化带一般较厚,有的全风化及强风化带可能超过20m。进行岩土工程勘察时,应注意查明火成岩的分布变化规律,确定稳定可靠的基础类型。

The igneous rock was widely deposited in Nanjing city and it almost covered the full kind of magma since the properties of the magmatism in this area were of long periods, multi-activities, wide-ranging in the space and various forms etc. Its compressive strength varies widely ranging from very soft to hard rocks due to the different formation and degree of weathering. The weathered zone of the igneous rocks is generally thicker,and among them, it may exceed 20 m in depth especially for the full-weathered and strongly weathered zone.It should be paid attention to identify the distribution of variation of igneous rocks to determine the stable and reliable f foundation type, when the geotechnical investigation is performed.