根据蒙脱石的层间水化状态探讨南京仙林盆地的地面沉降及其趋势

An Exploration for Land Subsidence and Its Trend Based on the Hydrous States of Montmorillonite Interlayer Water in the Sedimentary Basin of Xianlin Area,Nanjing

引用Brown等和Fitts等提出的蒙脱石层间水化状态修正的土壤孔隙率的计算方程,以此建立蒙脱石层间脱水作用所产生的次要地面沉降量的数学表达式,对位于山间沟谷型沉积盆地的南京仙林新市区可能产生的地面沉降量进行了模拟计算.结果表明:该地区由蒙脱石层间水部分释出而产生的次要沉降量为6.85 cm,估计该地区过去曾发生34～46 cm的地面沉降;如果蒙脱石残余层间水全部释出,那么该地区可能还存在96.47 cm的地面沉降.虽然96.47 cm的地面沉降在真实的外界环境下不可能实现,但对下一步地面沉降灾害的防治具有一定的警示作用.蒙脱石层间脱水作用及其对地面沉降影响的研究,对地面沉降趋势的预测具有启示作用.

This paper cites the calculation equation of soil porosity corrected by means of the hydrous states of montmorillonite interlayer water, then the mathematic expression is set up to calculate the amount of secondary land subsidence resulted from montmorillonite interlayer dehydration. The model is applied to Xianlin area which is a new city of Nanjing and belongs to the sedimentary basin with channels and vales. The calculation results show that the amount of secondary land subsidence resulted from part interlayer water release of montmorillonite is 6. 85 cm. It is estimated that, 34 to 46 cm total amounts of land subsidence would have happened in the area before. It is also indicated that, if the remainder interlayer water in montmorillonite interlayer is wholly released, there would be 96.47 cm of land subsidence in the area. Although it would be impossible to come to pass in the real geological environment, this would give us a caution to the prevention of land subsidence ha- zard. The research on montmorillonite dehydration and its effect on land subsidence would also show us a revelation to the prediction of land subsidence trend.