Study on earth pressure of deep-buried tunnel in layered ground with centrifuge modelling

Deep-buried tunnels have been increasingly used for transportation infrastructure and underground space development in major metropolitan areas around the world. Evaluation of the earth pressure on deep-buried tunnels is crucial in the design of such urban infrastructure. This paper presents an experimental study using a series of centrifuge model tests undertaken in a beam centrifuge at 150g to provide insight into the earth pressure distribution on deep-buried tunnels after the construction in layered soil strata. The experimental and comparative results indicate the earth pressure at the invert of the deep-buried tunnel is slightly greater than the earth pressure at the crown of the tunnel, and the earth pressure at the springline is less than that at the crown. These results also show that the full overburden theory can reasonably predict the vertical earth pressure of a deep-buried tunnel in the clay layer. However, in the scenarios when sand layers are dominant in the overburden soil, the vertical earth pressure values calculated by the Terzaghi loosening earth pressure theory are more consistent with measured values from centrifuge tests. The insights obtained from this study can provide useful references for improved methods in the load consideration of deep-buried tunnel design.