ISSN 1000-3665 CN 11-2202/P

    某机场飞行区土工格栅加筋高边坡优化设计

    Optimal design of the high geogrid-reinforced slope at the airfield of an airport

    • 摘要: 土工格栅加筋土边坡是一种新型的边坡支护结构,对于提高边坡稳定性、节约工程用地、保护生态环境意义重大。为了对机场加筋高填方边坡加固方案进行优化设计,本文以某机场跑道西北角的6#高填方边坡为例,首先基于边坡的地质条件和高填方边坡的实际情况,提出3种不同边坡坡率的加筋土边坡设计方案;其次采用简化Bishop法、Spencer楔形体法以及Morgenstern-Price法分别计算在天然、暴雨以及地震工况下的边坡稳定系数;最后利用有限元法分析3种加固方案下的加筋土边坡在天然工况下的变形特征以及筋材轴力分布规律。结果表明:3种设计方案在天然、暴雨以及地震工况下均能满足边坡稳定性要求,贴坡填筑的多级加筋土边坡的筋材轴力分布规律沿着竖向呈现锯齿状分布,最大筋材轴力在每级边坡的坡脚处突变增大。与加筋土缓坡(坡率1∶1.5)设计方案相比,加筋土挡墙(坡率1∶0.25)在坡高、筋材使用量、护坡面积以及挖填方量等方面均有明显减小。综合考虑稳定性、工程造价以及施工周期,采用加筋土挡墙的设计方案更合理。

       

      Abstract: Geogrid reinforced soil slope is a new type of slope supporting structure, which is of great significance for improving the slope stability, saving construction land and preserving the ecological environment. In order to provide the optimal design solution of the reinforced soil slope for high fill slopes, a case study is conducted on the No.6 slope at the northwest corner of the airport runway. Three design schemes with different slope ratios are carried out firstly based on the geological conditions of the slope and the field situation of the high fill slope. Secondly, the simplified Bishop method, Spencer wedge method and Morgenstern price method are used to calculate the stability factors of the reinforced slopes under the natural, rainstorm and earthquake conditions. Finally, the deformation characteristics of the slope and tensile force in reinforcements are investigated based on the finite element method under the natural conditions. The results show that all the proposed design schemes can meet the requirements of slope stability under different working conditions. A zigzag distribution of the tensile force in reinforcements in the multi-stage reinforced soil slope is observed along the slope height, and the maximum axial force of reinforcement increases abruptly at the toe of each slope. Compared with the design scheme of the gentle reinforced soil slope with the slope ratio of 1∶1.5, the reinforced retaining wall with the slope ratio of 1∶0.25 shows obvious advantages in reducing the slope height, consumption of geosynthetics, filling and excavation amount as well as slope protection area. The key issues including the slope stability, construction cost and duration are comprehensively considered, and the design scheme of the reinforced earth wall is reasonable.

       

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