Analysis Of Stability During Construction Of Subway Station With Undermining Method In Weathered Rocks

The stability of the subway station’s construction was based on its design. This paper analyzed the construction stability of Heishijiao station which was located in weathered rock stratum. In this paper the author founded a model which could accurately imitate the construction process of the station using MIDAS software. Besides, the box culvert and the202bridge’s security was researched in this paper. Finally the paper showed the problems which must be cared during the construction of the station in weathered rocks.The result of the simulation showed that the box culvert would settle23.4mm, and the box culvert would damage because of its big tensile stress. The pier of the202bridge would settle8mm unevenly and move6mm laterally, but it would be in a safe status. The local lining would be unsafe because of stress concentration, so the concrete level should be raised in the certain place. Besides the result also showed that the temporary support’s remove would cause the beginning lining’s stress raised by11percent, and the removing space should be controlled by6to12m.This paper also did a research on weathered rock’s parameters. For thoroughly weathered rock, the parameters and constitutive relation should refer to the soil. For the semi-weathering rock, the parameter should be lowered one grade at least. For highly weathered rock, the parameters should refer to the soil too.In order to accurately simulate the construction of the station in weathered rock, thinking of the time effect that the rock would have large deformation before the beginning lining achieved its designed strength, this paper reduced the modulus of elasticity of the beginning lining based on engineering experience and the concrete’s strength mechanism.