浙江江山城建区地质条件分析与评价

Geological Characteristics Analyses and Evaluation for City-building Area in Jiangshan city

详细研究了浙江江山城建区的地层、岩性和构造,分析了这些基础地质条件对城市建设的影响。城建区地层复杂,出露了晚元古代以来13个组的地层,还有侵入岩和火山碎屑岩出露。地质体中的层理、接触面以及软弱夹层对地质体的结构强度有很大的影响。城建区内碳酸盐岩分布最广,有岩溶塌陷现象,对城市建设不利。侵入岩、火山碎屑岩和砂岩,坚硬致密,风化裂隙不发育,是很好的建筑基岩。志棠组含砾粗砂岩、硅质岩岩性虽然较坚硬,但多被断裂破碎,对城市建设有一定的影响。页岩、泥岩和粉砂质页岩属软质岩石,易变形。城建区断裂构造发育,对城建区的工程建设有很大的影响,但区内无新的构造活动,无大于4.5级地震的历史记录,地震烈度为Ⅵ度,城建区所在的区域地壳稳定。根据基岩、土层和断裂构造的性质和特点,笔者把城建区划为三个级别:一级区,适宜重大工程的建设;二级区,进行高层建筑时要预先实施岩溶地基处理;三级区,工程条件差,应避开建设重大工程。

This paper deals with the regional geology, strata, rocks and structure of the city planning area in Jiangshan city and analyzes these geologic factors effect on the city building. There are 13 groups of strata in the city planning area, including limestone, lava, sandstone, shale. The city planning area, which regional earth crust is stable, can be built up. The granite, epimetamorphism tuff and sandstone are hard basement rocks. The shale, mudstone and limestone are not good for building. The fault zones are dangerous to any project, where the rocks have been broken into pieces. Sand soil, gravelly soils are beneficial to project, but clay soil is harmful. According to the factors, such as provincial characteristics, fault, rock and soil, we divides the city planning area into three grades field. The first grade field, from Xujiang park to Chen Jianan, is fit for building. In the second grade field, the basement rocks must be preliminary treated before building. The third field, where many faults pass through, is dangerous to building.