Study On Dissolution Of Mirabilite/gypsum In Guankou Formation,Tianfu New Area,Chengdu

There is a large area of thin layer of glauberite in Guankou Formation in Tianfu New Area.Its easy dissolution limits the construction of urban engineering.This paper,based on the multi-factor urban geological survey project in Chengdu,takes 200 meters cores of Tianfu New Area as the research object,combined with XRD semi-quantitative analysis and mirabilite dissolution experiment,discusses the dissolution law of gypsum and mirabilite in the formation of Guankou formation in the area,and predicts the future dissolution law of mirabilite by using multiple linear regression model.The concrete results achieved are as follows:(1)The content of mirabilite is the highest in the depth 95-137 meters,and it is easy to dissolve.(2)The dissolution process of glauberite can be divided into three parts: low speed-acceleration-stationary.Under the static water condition,the first 6 hours time period is the low speed period of dissolution,the dissolution process accelerates from about 6 hours,and enters the stable period after about 48 hours,and then the dissolution rate basically enters the stable state.(3)The velocity rate of solvent is positively correlated with the rate of dissolution,and it always reaches the maximum in about 48 hours,and the most significant acceleration period of dissolution is between 15-48 hours.(4)Multivariate linear regression model of mirabilite/gypsum dissolution was established by statistical method,and its reliability was confirmed by calculation.