Abstract
The mechanical properties of sandy soil depend on both the confining pressure and the state of compactness. Therefore, both the buried depth of the tunnel and the relative density of the sand are key factors that affect the ground deformation induced by the tunneling of a super-large-diameter shield. In this study, the parameters of the SANISAND constitutive model are first calibrated based on triaxial test data for Foshan silty fine sand. Then, based on the actual project, a two-dimensional finite-element analysis model is established to investigate the ground deformation induced by the tunneling of a super-large-diameter shield. The width and maximum value of the settlement trough, the volume loss ratio, and the deformation characteristics of the soil are summarized and analyzed for 13 cases. The results show that as the ratio of the buried depth to the diameter and the relative density of sand increases, the anti-disturbance ability of the sand layer to the tunnel construction increases and the volume loss ratio of the stratum reduces correspondingly. The denser the sand and the smaller the confining pressure of the soil around the tunnel, the more significant the shear-induced expansion of the sand at the tunnel haunch; this expansion partially makes up the volume loss caused by the tunnel excavation and reduces the loss ratio of the stratum at the arch crown.
Subject
Physics and Astronomy (miscellaneous),General Mathematics,Chemistry (miscellaneous),Computer Science (miscellaneous)
Reference21 articles.
1. Model Tests on Longitudinal Surface Settlement Caused By Shield Tunnelling in Sandy Soil;Fang;Sustain. Cities Soc.,2019
2. Peck, R.B. Deep Excavation and Tunnelling in Soft Ground. Proceedings of the 7th International Conference on Soil Mechanics and Foundation Engineering, State of the Arts Volume, Mexico City, Mexico.
3. Prediction of settlement trough induced by tunneling in cohesive ground;Fattah;Acta Geotech.,2013
4. A new modified Peck formula for predicting the surface settlement based on stochastic medium theory;Song;Adv. Civ. Eng.,2019
5. Failure probability of transverse surface settlement induced by EPB Shield tunneling in clayey soils;Zhou;ASCE-ASME J. Risk Uncertain. Eng. Syst. Part A Civ. Eng.,2018