滨海新区地下水腐蚀因子垂向分布特征研究

Vertical Distribution Characteristics of Hydrochemistry for Shallow Groundwater and Its Effect on Engineering Construction in Binhai Area Tianjin Geological Mineral Test Center

地下水腐蚀是沿海地区的主要地质灾害之一。选取位于滨海新区中东部的中新生态城北部荒滩区及南部盐田区为典型场地,首次通过原状土孔隙液的水化学特征对浅层地下水腐蚀性开展垂向分布特征研究。在此基础上,对40m以浅地下水的工程腐蚀性进行定量分析。结果表明,中新生态城区浅层地下水主要腐蚀性因子在垂向上呈现出浅层聚集性和随深度递减并逐渐趋于稳定的规律:18m以浅地下水TDS变化幅度较大,北部荒滩区,呈现先增大后减小的规律,浓度峰值出现在10-12m,南部盐田区,呈现先急剧减小后局部回升的规律,浓度峰值出现在表层2-3m;18-40m两区的地下水TDS变化规律一致,呈现出总体随深度递减,局部震荡衰减的规律。主要腐蚀因子Cl^-、SO_4^(2-)变化趋势与TDS一致,相关系数大于0.9。40m以浅地下水腐蚀性等级具有明显的高-低双层结构。

Groundwater corrosion is one of the most important geological hazards in Binhai Area Taking north desolate beach area and south salt field area of Sino-Singapore Tianjin Eco-city in mid- eastern Binhai Area as typical examples, the paper studies on the corrosive vertical distribution characteristics of shallow ground-water, by soil pore water chemistry characteristics. Based on the analyzed ground-water within 40 meters corrosion of engineering construction in different depth, the results show that surface accumulation, decreasing with depth and tending to stability are obvious in vertlcal direction. That is large varied amplitude of groundwater TDS within 18 meters. It increased at the beginning then decreased with depth and the peak concentration is from 10 meters to 12 meters in north desolate beach area. It decreased rapidly and then partially returned in south salt field area, the peak concentration is between 2 meters to 3 meters. The variation of TDS from 18 meters to 40 meters is consistent in both of the north and south area. It decreased with depth overall and was a damping oscillation partially. The variation of corrosion factors such as Cl-, SO42- is similar to the TDS＇ s, the correlation coefficient is greater than 0.9. The level of groundwater corrosive within 40 meters is significant bilayer structure that is high in top and low in bottom.