考虑预应力损失的锚索加固条件下边坡长期稳定性分析

实际工程中,岩土体存在的蠕变性质使得加固于边坡上的锚索其预应力随时间而发生损失,从而引发边坡长期稳定性问题。为了正确评估预应力锚索加固边坡的长期稳定性,基于滑动面底面应力假设,并融入锚索预应力损失模型,建立一种新的预应力锚索加固条件下边坡长期稳定性极限平衡计算方法,以此来求出预应力锚索加固条件下不同时期边坡安全系数大小,进而反映边坡稳定状况的动态变化。通过工程实例分析,验证了该方法的可行性,并证实了锚索预应力损失可使得边坡长期稳定性变差。同时,经锚索预应力损失对边坡长期稳定性影响的多参数研究,表明提高锚索的初始预应力值是改善边坡长期稳定性的一种可靠有效途径。

A Method of Calculating the Long-term Stability of Slope Reinforced with Anchorage Cable in Consideration of Pre-stress Loss

In actual project, slope’s long-term stability problem is caused by the loss of pre -stress of anchorage ca-ble acting on the slope due to the creep properties of geotechnical body .To correctly estimate the long-term stability of slope reinforced with pre-stressed anchorage cable, a limit equilibrium calculation method is proposed to analyze slope stability based on the assumption of stresses on the slip surface and by integrating the model of anchorage pre -stress loss.By using this method, the factor of safety of slope reinforced with pre-stressed anchorage cable in differ-ent periods are obtained, thus the dynamic change of slope stability can be reflected .By analyzing engineering ex-amples, the feasibility of the method is verified, and the notion that pre-stress loss of anchorage cable worsens the long-term stability of slope is proved.Moreover, parametric analysis on the influence of pre -stress loss of anchorage cable on slope’s long-term stability indicates that increasing the initial pre -stress of anchorage cable is reliable and effective to improving the long-term stability of slope.