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Analysis on the Deep Soil Deformation Induced by Construction of Narrowlong Excavation Pit in Soft Ground Area
(1 China Railway 14th Bureau Group Shield Engineering Co., Ltd., Jinan 250000; 2 College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058)
Abstract Construction of narrow-long excavation pits in deep and thick soil ground has significant impacts on sur? rounding environments. A three-dimensional finite element model is established, the characteristics of soft soil deformation are simulated by a HS-Small constitutive model and the law of displacement development of adjacent deep soil is studied during construction of the narrow-long excavation pit. It is found that both vertical and horizontal displacements of adjacent soil mass are sensitive to the depth of excavation pit and they increase with an increase of excavation depth; the curve of lateral displacement of soil mass is of V or arch form and the position of the maximum lateral displacement is in accordance with the excavation depth; settlements are observed at the soil mass above excavation depth and heaves are observed at the soil mass below the excavation depth due to unloading effect of excavation; the support stiffness decreases if support is removed and new beam is not constructed immediately to replace it and this will result in lateral and vertical displacements of stratum. Due to the excavation spatial effect, the orders of lateral and vertical displacements of the monitoring points are the long side, short side and pit corner of excava? tion pit in terms of displacement magnitude.
Abstract：
Construction of narrow-long excavation pits in deep and thick soil ground has significant impacts on sur? rounding environments. A three-dimensional finite element model is established, the characteristics of soft soil deformation are simulated by a HS-Small constitutive model and the law of displacement development of adjacent deep soil is studied during construction of the narrow-long excavation pit. It is found that both vertical and horizontal displacements of adjacent soil mass are sensitive to the depth of excavation pit and they increase with an increase of excavation depth; the curve of lateral displacement of soil mass is of V or arch form and the position of the maximum lateral displacement is in accordance with the excavation depth; settlements are observed at the soil mass above excavation depth and heaves are observed at the soil mass below the excavation depth due to unloading effect of excavation; the support stiffness decreases if support is removed and new beam is not constructed immediately to replace it and this will result in lateral and vertical displacements of stratum. Due to the excavation spatial effect, the orders of lateral and vertical displacements of the monitoring points are the long side, short side and pit corner of excava? tion pit in terms of displacement magnitude.
LI Fulin1,
2
.Analysis on the Deep Soil Deformation Induced by Construction of Narrowlong Excavation Pit in Soft Ground Area[J] MODERN TUNNELLING TECHNOLOGY, 2019,V56(6): 121-127
2019, Vol. 56 