Corrosion And Testing Researh On Shenyang Subway Tunnel Lining Concrete

The subway tunnel has large investment and high durability requirements,which has more than100years’s design working life.Because of the subway tunnel lining concrete directly contact with external environment and underground environment and has special characteristic,which made the subway tunnel lining concrete structure subjected to damp environment and groundwater seepage pressure effect frequently. With all kinds of corrosion impurities intrusion, tunnel lining concrete will suffer from corrosion damage in long term. Strength testing had been timely made in corrosion of subway tunnel to ensure the safety of subway tunnel structure. There are many strength testing method.The core sampling method belong to distress detection,which due to cause further damage so in the test application is restricted. Ultrasonic method, rebound method, ultrasonic-rebound synthesis method belong to nondestructive testing, which have many distinct advantages and very few report of strength testing on corrosion of tunnel lining concrete, which still belong to blank stage.The project adopt raw materials of shenyang subway tunnel lining concrete to product80groups of tunnel lining concrete specimen. First of all investigating and analyzing the corrosion of subway tunnel lining concrete.Second determine the selection of sodium sulfate, magnesium chloride, sodium nitrate on tunnel lining concrete under dry-wet alternate accelerated corrosion test.The corrosion of tunnel lining concrete in the process of macro and micro performance change was described.Through the non destructive testing(NDT) of rebound method, ultrasonic method, ultrasonic-rebound synthesis method detecting the strength of tunnel lining concrete after corrosion of sodium sulfate, magnesium chloride, sodium nitrate.Through the universal pressure testing machine to detect the compression strength of damaged testing. Establishing the regression relationship of nondestructive parameter (rebound value, ultrasonic wave velocity) and the damage parameter (compressive strength) on corrosion of tunnel lining concrete. We got240groups of indexes, including C25, C30two strength grade and0d-72d ten corrosion ages.Finally, we can draw the conclusion,detected by strength test curve of existing nondestructive testing procedures,which got mean relative error(δ) and relative standard error (er) outside the specification. The existing non destructive testing procedures shall not apply to strength testing of tunnel lining concrete which subjected to corrosion test.We got mean relative error(δ) and relative standard error (er) inside the specification through linear function, power function and exponential function, quadratic polynomial function regression analysis on non destructive testing and damage testing. The regression results show that strength test curve has good applicability to the corrosion of tunnel lining concrete.Raising the strength formula of shenyang subway tunnel lining concrete subjected to corrosion test.Results of the study can be used as the strength testing reference of shenyang subway tunnel lining concrete after corrosion.