秦岭隧道地下水水化学异常的形成机理

在分析秦岭隧道地区地质背景及水体水化学组成的变化规律的基础上，确定了平导地下水化学异常的基本特征及形成机理，研究表明水中硫根离子的审围岩中黄铁矿氧化所致钙离子的升高则归因于氧过程形成的大量氢离子促使含钙矿物水角或次生的碳酸盐矿物溶解，而两者浓度的增大导致地下水水化学类型的改变，矿化度及总硬度的异常。

MECHANISM OF HYDROCHEMICAL ANOMALY OF GROUNDWATER IN QINLING TUNNEL

On the basis of analysis of the geological background and the changing regularity of hydrochemical compositions in Qinling tunnel area, the paper dears with essential features and formation mechanism of chemical anomaly of groundwater. It is indicated from the research that SO 4 2- anomaly is caused by oxidation of pyrite in the tunnel surrounding and Ca 2 increase is attributed to a great number of H , produced in the oxidation, which results in hydrolysis of calcareous minerals and dissolution of secondary carbonate minerals. The increase of SO 4 2- and Ca 2 brings about the change of hydrochemical type the anomaly of total dissolution solid (TDS) and hardness in groundwater.