Study On The Influence By Shallow Ground Water On Tianjin Metro Project

Since the 21st century, the use of underground space become the direction of the urban planning in future, but underground engineering ware often affected by groundwater. As a result, analysis of the influence of shallow groundwater in Tianjin metro project and the countermeasures was more important.This paper studied on hydrochemical characteristics and hydrogeological of the shallow groundwater in the metro line 2 by the mathematical statistics, hydrogeochemical simulation Some corresponding measures were proposed aiming at the possible impact of the subway construction, the main results were as follows:1, The fuzzy cluster analysis showed that:between the same and different aquifer, there were hydraulic connection, but degree was different; the similar was strong, water-rock interaction is similar.2, Tidal had an impact on groundwater level:water level rose rapidly and down slowly; amplitude decreases along with the tidal activity and groundwater level had a phase of cosme.3, Groundwater cation was given priority to with Na++K+, anion was given priority to with Cl-, groundwater type was given priority to with brackish water and salt water, the percentage of weak neutral water and alkaline water is higher, SO4+Cl、HCO3+Cl type water account for 72.98% of the total.4, Piper diagram showed that:relatively high content of SO42-、Cl- had related to weak runoff alternating, water chemical composition, pollution and transgression.5, Na+and Cl- was the dominant factor of shallow groundwater; hydrochemistry type of different aquifer was basic similar, there was a difference between hydrochemical types of individual aquifers, HCO3- content in 11-20m is significantly higher than other level.6, Shallow groundwater won’t corrode concrete but there was weak SO42- type corrosion; micro confined water had weak corrosion to the concrete and medium corrosion to the steel structure.