Distribution Characteristics Of Gypsum Bearing Strata And Zoning Of Special Engineering Properties In Chengdu Area

Gypsum rock(mainly gypsum and glauberite)strata are widely distributed in Chengdu area.Gypsum rock may cause engineering geological problems such as dissolution,corrosion and expansion affected with environmental water.Based on a large number of existing survey data,the distribution characteristics of gypsum rocks and the zoning of special engineering properties in Chengdu are statistically analyzed.The database is established to manage the data,display the results visually,and predict the special engineering properties of gypsum rock.The research results have important guiding significance for the engineering construction in Chengdu,especially for the construction of underground deep engineering.The main research contents and achievements of this paper are as follows:(1)Based on a large number of documents,the geological environment background of Chengdu area is analyzed and summarized,such as stratigraphic structure,sedimentary history,geological structure,hydrogeology and gypsum rock distribution in Western Sichuan depression.(2)The geological characteristics of the red bed gypsum rock in Chengdu area are studied,and the distribution of gypsum rock strata in Chengdu area is calculated,mainly including the initial elevation,bottom elevation and average thickness of gypsum layer and glauberite layer.The distribution characteristics of gypsum bearing rock strata in Chengdu area are obtained.(3)The structure,material composition characteristics and engineering characteristics of gypsum rock are analyzed,including physical,hydraulic and mechanical properties.The range and recommended figures of engineering characteristic index are obtained through statistical analysis.(4)Environmental engineering geological problems of gypsum rocks in Chengdu are analyzed,including groundwater corrosion,expansibility and the dissolution of gypsum bearing rock.The distribution laws of corrosion grade,free expansion rate,expansion force and corrosion cavities were obtained.And the special engineering properties of gypsum strata in Chengdu are zoned.(5)The database system of gypsum rock in Chengdu is developed to realize the function of data warehousing,layer conversion,data query and data output and provide the visual display of the distribution characteristics and special engineering properties of gypsum rock in Chengdu,and predict the special engineering properties of gypsum rock.