Abstract Base heaving and tunnel settlement due to the excavation and backfilling of open-cut tunnels in deep soft soil have always been of great concern. Using the Wenzhou intercity railway tunnel as an example, this paper studies the issues of base heaving and settlement induced by the excavation and backfilling of open-cut tunnels in deep soft soil. Based on the layer-wise summation method, the value of base heaving after unloading due to foundation pit excavation and the settlement value of a tunnel with a composite foundation after backfilling are studied using the rebound modulus method and the composite modulus method. A comparison analysis of base heaving values and tunnel settlement values under different construction conditions is conducted. The study results show that base heaving of the open-cut tunnel and the settlement of the operated tunnel are controllable, and the vertical deformation decreases and the ground strength improves after applying a composite foundation in deep soft soil. Appropriate control measures against tunnel settlement are adopted considering certain engineering characteristics.
Abstract：
Base heaving and tunnel settlement due to the excavation and backfilling of open-cut tunnels in deep soft soil have always been of great concern. Using the Wenzhou intercity railway tunnel as an example, this paper studies the issues of base heaving and settlement induced by the excavation and backfilling of open-cut tunnels in deep soft soil. Based on the layer-wise summation method, the value of base heaving after unloading due to foundation pit excavation and the settlement value of a tunnel with a composite foundation after backfilling are studied using the rebound modulus method and the composite modulus method. A comparison analysis of base heaving values and tunnel settlement values under different construction conditions is conducted. The study results show that base heaving of the open-cut tunnel and the settlement of the operated tunnel are controllable, and the vertical deformation decreases and the ground strength improves after applying a composite foundation in deep soft soil. Appropriate control measures against tunnel settlement are adopted considering certain engineering characteristics.
NING Mao-Quan
.Research on and Control Measures for Base Elevation Variations of Open-Cut Tunnels in Deep Soft Soil[J] MODERN TUNNELLING TECHNOLOGY, 2015,V52(3): 31-38
2015, Vol. 52 