基于可靠度的斜坡软弱地基路堤稳定性极限平衡法分析

Stability analysis of embankment over sloped weak ground with limit equilibrium method based on reliability

通常以确定性分析获得的稳定安全系数作为评价斜坡软弱地基路堤稳定性的指标,忽略实际工程中诸多不确定性因素,无法真实全面反映斜坡软弱地基路堤的稳定性。基于垂直条分极限平衡法Slide软件平台,运用全局最小可靠度分析方法,综合分析路堤和斜坡软弱层土体参数、地下水位、路堤顶部张拉裂缝水分充填量、微型桩纵向桩距和抗剪强度及水平向地震荷载等因素的变异性对斜坡软弱地基路堤稳定性的影响,讨论这些随机变量的敏感性,阐释了室内斜坡软弱地基路堤与水平软弱地基路堤土工离心模型试验现象差异性的机理。使用可靠度能更客观地反映斜坡软弱地基路堤的安全性;可根据各因素对斜坡软弱地基路堤稳定性影响敏感性的正负、强弱采取相应合理工程对策。

Usually the safety factor obtained from traditional deterministic analysis was used to evaluate the stabil- ity of the embankment over slope weak ground, which ignores so many uncertainty factors in autual engineering that it can＇ t reflect its stability, truly and roundly. A probabilistic slope analysis model was established based on vertical Slice limit equilibrium method of software slide to account for the degree of uncertainty parameters, such as embankment and sloped weak layer＇ s material properties, ground water table, the water filling quantity of em- bankment top tension crack, micro - pile support properties and seismic loading. Sensitivity analysis was also carried out to indicate which input parameters may be critical to the assessment of slope stability, and which in- put parameters are less important. Failure mechanical on the geotechnical centrifuge model of embankment over sloped weak ground was illustrated by using reliability. The results show that reliability method can describe the stability of embankment over sloped weak ground more objectively. The corresponding reasonable can be taken according to the influence of each parameter on the stability of embankment over sloped weak groud, engineering measurements are put forward to increate the stability in practice.