成都市白垩系灌口组富膏盐红层溶蚀特征与机理

成都市白垩系灌口组近地表红层富膏盐地层因富含膏盐、钙芒硝等易溶矿物普遍发育红层类岩溶现象,制约着地下空间的开发利用.为梳理出成都市域灌口组富膏盐红层溶蚀规律与机理,防范红层硫酸盐岩溶相关的工程地质问题,综合利用钻孔岩芯、物探、测井、物性测试、溶解实验等资料,分析区域内富膏盐地层的分布规律、富膏盐红层溶蚀特征、溶蚀发育的...

Dissolution characteristics and mechanism of gypsum-salt-rich-red beds in Cretaceous Guankou formation in Chengdu

Because the red beds in Guankou formation of Cretaceous in Chengdu are rich in gypsum salt， glauberite and other soluble minerals， the red bed karst phenomenon develop extensively in near-surface layer. This phenomenon restricts the exploitation and utilization of underground space. Based on the data of drilling core， geophysical exploration， well logging， physical property test and dissolution experiment， the distribution law of gypsum-salt-rich strata，the dissolution characteristics of gypsum-salt-rich-red beds ， the influencing factors of dissolution development and karst mechanism of red beds are analyzed. The study shows that the dissolution of gypsum-salt-rich-red beds rich in gypsum salt in Guankou formation of Cretaceous in Chengdu generally develop in low hilly areas as well as plain and valley areas. The karst of red beds is comprehensively affected by many factors such as topography， structure， groundwater activity and faults， among which the groundwater activity and fault system are the most key factors. Besides， there are two different dissolution modes， first one， in the low hilly area higher than the plain area， surface water penetrates through the loose gravel layer of Quaternary， and then infiltrates into fissure-growing and weathered Guankou formation of Cretaceous with rich gypsum salt . After dissolving glauberite， gypsum， anhydrite and other minerals， groundwater flows downstream to the low-lying plain and river valley or converges into the surface runoff and finally promotes the dissolution. Second one， in the deeper part below the plain area， the surface runoff flows laterally along the syncline wing and the bedding or infiltrates along the fault system to recharge groundwater， which finally results in the dissolution phenomenon generating in the deeper part below 60 m.