Abstract:Common shapes of excavations include strip,rectangle,circle and pistol. When other conditions are the same,excavations with different shapes have different safety coefficients of heave-resistant stability. However,all recommended methods from existing guidelines for heave-resistant stability analysis ignore the influence of excavation shape on the safety coefficient. In this paper,based on an unloading model of excavation,a new safety coefficient has been defined which takes into account the plane shape,dimensions and embedment ratio. The safety coefficients for various excavation shapes,such as strip,rectangular and pistol,can be calculated analytically based on the definition. For circular excavations,the coefficient can be calculated by numerical integration,so the challenging problem of analyzing the stability of circular excavations is solved. When the diameter of circular excavations is large enough,the safety coefficient will be identical to that of extra wide strip excavations,indicating the wide applicability of the proposed safety coefficient. For excavations with a small embedment ratio of retaining wall in clay stratum,the proposed safety coefficient converges to the result from the Terzaghi method. The variation of the bearing capacity coefficient of foundation soil calculated using the proposed method is consistent with that of recommended values,and its rationality can be validated by field data and results from the strength reduction method. Field statistics indicate that there is a definite relationship between the safety coefficient and the deformation of circular excavations and the relationship can be used to determine the acceptable safety coefficient of excavations.
王洪新. 考虑基坑形状和平面尺寸的抗隆起稳定安全系数及异形基坑的稳定性分析[J]. 岩石力学与工程学报, 2015, 34(12): 2559-2571.
WANG Hongxin. A COEFFICIENT OF HEAVE-RESISTANT STABILITY CONSIDERING SHAPES AND PLANE SIZES AND ITS APPLICATION TO THE STABILITY ANALYSIS OF SHAPED EXCAVATIONS. , 2015, 34(12): 2559-2571.
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