Tunnel deformation and stress response under the bilateral foundation pit construction: a case study

Bilateral deep foundation pit excavation would cause the stress redistribution and large deformation of the adjacent tunnel, and even induce the lining structure cracking. This paper aims to investigate the deformation and stress response of tunnel to bilateral foundation pit construction. The Zhengzhou East High-speed Railway Station (Zhengzhou East HRS) was taken as an example to conduct the analysis. First, the numerical calculation software Midas GTS/NX was used to simulate the foundation pit construction progress, the deformation and stress of tunnel structure were discussed. Then, some field work about tunnel deformation was conducted and the deformation characteristics was studied. The results show that under the repeated disturbance of the bilateral foundation pit construction, the tunnel deformation increased fluctuatingly, with the cumulative uplift and convergent deformation of about 26 mm and 16 mm, respectively. In addition, the cumulative change of the lining stress at DM16 section inside the foundation pit was 6.02% greater than that at DM30 section outside of the foundation pit, indicating the effectiveness of the reinforcement measures.