Groundwater Survey And Impact Assessment Of Harbin Metro Line 3

With the acceleration of the process of urbanization in Harbin,the rapid development of urban construction,the continuous expansion of urban development,and the problem of traffic congestion in the city,Metro has been favored due to its high speed and pollution-free characteristics.However,underground construction often faces complex and varied hydrogeological problems.This article takes the 5th bid section of Harbin Metro Line 3 as an example,adopts the drilling technique,conducts pumping tests,surveys the geological conditions of the construction site and groundwater,conducts dynamic observation of groundwater,and calculates various hydrogeological parameters.Identify the groundwater level,type,erosion and dynamic changes,determine the flow of groundwater,calculate the groundwater permeation speed and average flow velocity,and finally analyze the impact of groundwater on the subway buildings and evaluate these impacts.Conclusions are as follows:Erosion of groundwater to buildings includes concrete,steel,and steel structures,but shallow subsurface water in Harbin is mainly submerged in freshwater with low salinity.As a whole,the PH value is generally between 7.0 and 8.0.The groundwater is erosive and corrosive,and it will not cause erosive or corrosive damage to construction projects.The drop of groundwater level causes soft soil settlement.When underground foundation construction is carried out in soft soil,it is necessary to artificially reduce the groundwater level.The influence radius of the pumping well changes with the depth(flow rate).The depth of discharge(flow)is small,the effect radius of the pumping well is small,the depth of discharge(flow)is large,and the pumping well has a large influence radius.Each pumping well uses the Gehart’s formula and the Kusak’s formula to calculate theinfluence radius of the pumping well at different depths.The difference between the two values is small and can be used as a reference value for the influence radius under different flow conditions.