紫红色松散土体在不同饱水环境中的化学反应特征试验研究

A test study of the characteristics of chemical reaction between purple unconsolidated soil and water in different saturated environment

以特殊的紫红色土为研究对象,采取三峡地区黄腊石滑坡临江松散土进行室内饱水试验,根据能量最低原则建立热力学反应模型,通过线性规划求解,分析不同饱水环境下随时间积累过程中紫红色松散土矿物反应特征及规律。研究表明:松散土在不同溶液浸泡条件下化学反应类型不同,江水和弱碱性溶液中主要发生白云石矿物的溶解,自来水、纯水和弱酸性溶液中主要发生方解石矿物的溶解和Ca2+与K+的交换吸附。另外,不同浸泡环境中不同时间的水-土化学作用活跃程度明显差异,弱酸性溶液与松散土的化学反应在饱水1~7 d最为强烈,其他四种溶液与松散土的化学反应在饱水7~16 d最为强烈。饱水后期,不同溶液浸泡条件下的水-土化学作用都减弱并最终趋向于平衡。

A kind of special purple soil,which widely occurs in the Three Gorges region,was selected as the object of this study.They were immersed in five different aqueous solutions.According to the minimum energy principle and linear programming,the thermodynamic reaction model was established to analyze the rules of water-soil chemistry interaction in these saturated processes.The results showed that the major soil-water interaction types changed with time in different solutions.Dolomite minerals composition mainly dissolves in river water and alkaline solution and calcite minerals composition dissolution and Ca-K icon exchange adsorption mainly occur in tap water,pure water and acidic solution.The most intense chemical interaction occurs between soil and acid solution at the saturated time of 1-7 days,and others are at the time of 7-16 days.Finally,in the five different solutions,all water-soil chemistry interactions weakened and tended to equilibrium.