论述了水土作用系统中离子的交换吸附等作用，阐明了其对土体膨胀性，液、塑限等的影响．并且论述了在强酸、强碱环境下地下水中的Ｈ＋和ＯＨ－与土体某些矿物成分发生化学反应，改变其化学成分，破坏其连结，使其强度降低的化学机理 The exchange and adsorption of ions in water and soil interaction systems are discussed, and their effects on swelling, liquid and plastic limits of soil are clarified. In addition, the chemical mechanism of the chemical reaction between H+ and OH- in the groundwater and some mineral components in the soil under strong acid and alkali conditions was discussed. The chemical composition was changed and its connection was weakened.