Three-dimensional analysis of slopes reinforced with piles

Based on the upper bound of limit analysis, the plane-strain analysis of the slopes reinforced with a row of piles to the 3D case was extended. A 3D rotational failure mechanism was adopted to yield the upper bound of the factor of safety. Parametric studies were carried out to explore the end effects of the slope failures and the effects of the pile location and diameter on the safety of the reinforced slopes. The results demonstrate that the end effects nearly have no effects on the most suitable location of the installed piles but have significant influence on the safety of the slopes. For a slope constrained to a narrow width, the slope becomes more stable owing to the contribution of the end effects. When the slope is reinforced with a row of piles in small space between piles, the effects of group piles are significant for evaluating the safety of slopes. The presented method is more appropriate for assessing the stability of slopes reinforced with piles and can be also utilized in the design of plies stabilizing the unstable slopes.

Effective grouting area of jointed slope and stress deformation responses by numerical analysis with FLAC^(3D)

To study the grouting reinforcement mechanism in jointed rock slope, first, the theoretical deduction was done to calculate the critical length of slipping if the slope angle is larger than that of joint inclination; Second, the numerical calculation model was founded by FLAG^3D, so as to find the stress and deformation responses of rock mass in the state before and after grouting, the analysis results show that the range between the boundary of critical slipping block and the joint plane that passes the slope toe is the effective grouting area （EGA）. After excavation, large deformation occurs along the joint plane. After grouting, the displacements of rock particles become uniform and continuous, and large deformations along the joint plane are controlled; the dynamic displacement can re- flect the deformation response of slope during excavation in the state before and after grouting, as well as the shear location of potential slip plane. After grouting, the dynamic displacement of each monitoring point reaches the peak value with very few time steps, which indicate that the parameters of the joint plane, such as strength and stiffness, are improved; the stress field becomes uniform. Tensile area reduces gradually; whole stability of the slope and its ability to resist tensile and shear stress are improved greatly.

考虑桩体变形的最小势能边坡稳定性分析方法

最小势能法是基于系统平衡时势能最小的边坡稳定性分析方法,因而势能的准确求解对计算结果的可靠性至关重要。针对抗滑桩三维加固边坡,考虑了由于桩土相互作用下桩体沿着边坡潜在滑动方向产生的转角变形,进而求得桩土相互作用下桩体以及桩土接触处的势能,然后基于最小势能原理建立抗滑桩加固边坡稳定性分析模型,并得到了与传统分析方法较为一致的结果;同时分析研究了抗滑桩在不同力学参数和边坡类型条件下对边坡安全系数的影响。研究结果表明:抗滑桩弹性模量对安全系数影响不明显;边坡横向相对半径大于4时,抗滑桩对边坡的安全系数影响较小。