滑坡加固系统中沉埋桩的有限元极限分析研究

采用有限元强度折减法，针对一边坡工程实例进行沉埋桩单桩加固边坡的有限元极限分析，研究了桩长、桩位与潜在滑面、边坡的安全系数及桩身内力之间的关系，研究了边坡滑体与滑带强度之间不同的比例关系与桩长、边坡安全系数的关系。研究结果表明，沉埋桩设在合适的位置上采用较短的桩就可使边坡达到设计要求的安全系数，桩身内力也较全长桩降低，表明沉埋抗滑桩具有良好的应用前景，但是也受到边坡次生滑动面的位置、滑体与滑带强度比例以及桩位置等因素的制约。沉埋桩加固边坡设计中若不考虑这些制约因素，有可能导致工程失败。

LIMIT ANALYSIS OF SLOPE STABILIZED BY DEEPLY BURIED PILES WITH FINITE ELEMENT METHOD

The effects of various lengths and location of deeply buried piles on the stability of a slope are simulated by nonlinear finite element method with shear strength reduction.Conclusions are made from the simulation results as follows:(1) the slope can acquire effective stability by deeply buried piles as other reinforcing structures;(2) when the length of the deeply buried piles is relatively short,the critical slide surface will slip along the top of the pile;and(3) the location of slide surface determines safety of the slope.As the pile length increases,a secondary critical slide surface will displace and the safety factor of the slope will increase.If the location of the secondary critical slide surface is unchangeable with pile length increase,the safety factor of the slope is also unchangeable.Distribution of the internal forces in deeply buried piles is more reasonable than that in traditional full-length piles;and both the maximum bending moment and the maximum shear force in deeply buried pile are much less than those in full-length pile.Deeply buried piles will be widely used in stabilization of slopes.The applications to deeply buried piles are restricted with the ratio of the strength of slide mass with that of slide area,the site of secondary slide surface,and the length of deeply buried piles.It would lead to failure if the limitations of deeply buried piles stabilizing the slope were not considered in the design.