山区机场高填方边坡滑移过程时空监测与稳定性分析

Time-space monitoring and stability analysis of high fill slope slip process at a airport in mountain region

高填方边坡稳定问题是目前岩土工程界研究的热点,也是尚未解决的一个难点。通过对某山区机场3#高填方边坡滑移变形过程进行监测,首次对这种高填方边坡变形全过程及机制进行时空综合分析;根据推测滑移面位置对滑带土强度参数进行反演分析,同时,采用有限元软件对高填方边坡原地基处理、填筑体压实度、地下水水位升降及加筋等与边坡稳定性的关系进行研究。结果包括:(1)山区高填方边坡变形以沉降为主、兼有明显水平侧向位移,时间演化的三阶段和空间裂缝发展的规律明显,属于典型的人工加载的"后推式"滑坡类型;(2)填筑土体或原地基土体中相对软弱夹层一般最先发展为滑移面,地下水位上升可显著降低滑带土黏聚力和边坡稳定系数;(3)提高填筑土体压实度、降低水位、设置土工织物均能有效提高边坡的稳定性,但原地基处理合格与否直接决定其上部高填方边坡能否稳定;(4)初步提出高填方边坡变形控制建议和稳定性评价标准,可供高填方规范编制和工程实践参考。

The stability problem of high fill slope is one of the hot issues in the field of geotechnical engineering at present,but the relevant theories have not been built up. The paper first execute spatial-temporal analysis to the process of slip deformation as well as its mechanism of high fill slope through monitoring sliding deformation process of #3 high fill slope of an airport in mountain region. According to the presumed position of potential sliding surface,back analysis is used to analyses strength parameter of landsilde slip layer,meanwhile finite element software is used to study the relationship between the slope stability and the original foundation treatment of high fill slope,compactness of fill body,fluctuation of groundwater level and reinforcement. The results include：（1） During creep of high fill slope in mountain region,the deformation with obvious lateral displacement mainly focus on settlement,the three-phase law of landslide deformation with time and the characters of cracks spatial evolution in different deformation periods are significant,and the characters are typical artificial loading back stepping landslide.（2） The sliping surfaces are easily generated in filled soil body or weak intercalation in original foundation soil body. The uprising of underground water level can reduce the soil cohesion and slope stability factor massively.（3） Increasing the compactness of filled soil body,lowering the groundwater water level,setting reinforced geotextile can effectively optimize stability of high embankment slope. But the stability of upper filling body is decided by the qualification of the original foundation treatment.（4） Combining the experience and monitoring,the deformation control recommendations and stability evaluation criteria of high fill slope have been proposed. The results can be referenced to high filling standard writing and engineering practice.