在现行条分法的基础上,建立了一种全新的边坡条块力-位移分析方法。现行条分法中条块底边的力学参数采用极限平衡状态力学参数,即每个条块底边均处于极限平衡状态,这种极限平衡状态对于残余应力是较为适宜的。采用理想弹塑性模型和一种全新的本构模型描述土条块底边力学特性,并以不平衡推力法为例,提出了临界状态条块的确定方法,针对可能的破坏模式进行了分析,并提出了边坡整体破坏各条块的应力和位移的确定方法,计算出相应的稳定系数,如传统强度折减法、综合下滑力-抗滑力法、主推力法、综合位移法和富余位移法稳定系数。通过计算分析论证了理想弹塑性模型在不改变力学参数的情况下是难以描述边坡渐近破坏过程的,而一种全新的本构模型可以描述渐近破坏各条块的力学行为。提出的条块力-位移法可以确定边坡在不同荷载和位移条件下的稳定性,也可以获得边坡的推力变化和滑面移动特征,进而实施边坡的应力、位移和稳定性的初步预测预报。
A new slice block force-displacement method for slope stability analysis is established on the basis of current research on slice method. In the traditional slice method, mechanical parameters of the limit equilibrium state are applied to describe behaviors of the sliding surface of slope, which means the sliding plane of each slice block reaches the limit equilibrium stress state, and it is suitable for the residual stress state. An ideal elastic-plastic model and a new constitutive model are employed to characterize mechanical properties of the slip face of slice block. Taking the unbalance thrust method as an example of model application, a new method is proposed for determining critical state slice block. The possible failure types of slope are explored. The methods to determine stress and displacement of slice block are presented during the progressive failure progresses. The corresponding stability coefficients are obtained by traditional strength deduction method, comprehensive sliding-resistance method (CSRM), main thrust method (MTM), comprehensive displacement method (CDM) and surplus displacement method (SDM). It is found that, when mechanical parameters have not been changed, the ideal elastoplastic model is hard to describe the processes of progressive failure of slope, but the newly proposed constitutive model is capable of predicting mechanical behavior of each slice block. The proposed slice block force-displacement method can be used to calculate the stability factors under various loading and displacement conditions, to acquire the thrust force and the movement of sliding surface, and furthermore to forecast the stresses, displacements and stability of slope.