Study On Permeability Of Tunnel Shotcrete And Its Blind Pipe Water Volume

Tunnel construction is a particularly important project in urban construction,and it is also the most prone to form congestion in urban roads.The development of the city can not be separated from the construction of road tunnels.With the development of the city,the Advancement of science and technology,the concept of tunnel design is constantly being updated.In this paper,the effects of different injection concrete and different groundwater level on the seepage field and the displacement of circular blind pipe are analyzed by means of theoretical and numerical comparison.The main directions studied in this paper are as follows:(1)We use FLAC3 D software to perform seepage calculation and simulation analysis.At the same time,the software should be used to satisfy the differential equations of seepage balance,motion equations,constitutive equations,and compatible equations under the condition of Darcy's law.Simulated seepage analysis was carried out for C20P8,C25P8,C30P8,and the injection concrete models C25P6,C25P8 and C25P20.Regardless of whether the variable is a different intensity level or an impermeable level,it can be concluded that in the case of the same external conditions,only the injection concrete with different intensity levels and higher intensity levels are considered,and the less water it penetrates,the higher the permeability performance;Similarly,under the same external conditions,only the injection concrete with different impermeability levels and higher impermeability levels are considered,and the less water it penetrates,the higher the permeability.(2)Through FLAC3 D software,comparing and analyzing the infiltration of jet-concrete of different intensities at different water levels,it can be concluded that the lower the groundwater level,the less water it penetrates,and the higher the permeability.After using FLAC3 D software to simulate seepage calculation to achieve equilibrium,due to the deepening of groundwater water level,the pore water pressure around the tunnel will change accordingly,and the pore water pressure will change significantly,and groundwater will move under the effect of pore water pressure.Due to the increase of pore water pressure,groundwater penetrates more easily into the jet concrete,making the water permeated more.And using MATLAB software to fit and analyze the numerical calculation results,the coefficients of the original theoretical formula are corrected,and the revised water inrush formula is obtained.(3)In the experiment and FLAC3 D modeling,blind tube water volume analysiswas conducted respectively.Over time,whether the water level in the test is 5.0 cm,7.5cm,10 cm,12.5 cm,The corresponding water volume is 24.93 mL/s,30.06 mL/s,38.37mL/s,50.14 mL/s,or the groundwater water level of 20 meters,40 meters or 60 meters in the model,and the corresponding water volume is 50.00011 mL/s,50.0011 mL/s,50.0013 mL/s,respectively.Regardless of the test or FLAC3 D simulation analysis,the displacement increases with the deepening of the water level.