昆明长水国际机场团山残积红土边坡稳定性分析

发布时间：2018-10-05 08:01

【摘要】：云南地区的地质构造、地形地貌极其复杂,昆明长水国际机场场址位于高原丘陵岩溶地貌区,地势起伏变化较大,场址涉及的工程地质单元多,机场建设过程中产生了深挖高填。机场西侧的团山因取土开挖形成的残积红土高边坡的稳定性直接影响到机场的二期工程—西次跑道的施工与运行；团山残积红土边坡的稳定性是西次跑道建设过程中必须研究并处治的问题。本文以长水国际机场西侧的团山残积红土边坡为研究对象,在系统的野外地质调查基础上,采取土样、进行室内试验分析,深入研究分析了边坡的区域地质条件及残积红土的力学特征,综合研究了边坡的稳定性影响因素,并选取边坡的典型剖面,运用GeoStudio-Slope/W、QUAKE/W软件和ANSYS软件,对边坡在天然工况、地震工况下的稳定性进行数值模拟分析,为边坡的处治提供建议。通过以上的分析研究,本文主要得出了以下结论和认识：(1)此边坡属于开挖的台阶状边坡,边坡土体是下古生界寒武系中统陡坡寺组的砂页岩(∈2d)风化的残积红土；影响此边坡的稳定因素包括边坡体固有的几何形态特征、自重应力、红土物理力学参数等；及可能诱发边坡失稳的外部因素：地震应力、地下水位上升及后期暴雨冲刷渗入等。(2)GeoStudio-Slope/W软件计算结果显示,天然状态下,边坡的最小安全稳定性系数为：Janbu法-1.518；边坡处于稳定状态；结合QUAKE/W软件分析边坡在地震工况下的稳定性系数,最大安全系数为Bishop法—1.133,边坡处于失稳破坏的临界状态。Slope/W软件在分析台阶状边坡时有着方便、快捷、准确的优点,对台阶状边坡的稳定性分析有着一定的借鉴意义。(3)基于有限元强度折减法原理的ANSYS软件数值模拟结果表明,在自重应力情况下,坡顶坡脚均无明显变形,边坡处于稳定状态；在抗剪强度折减的情况下(Fc≠Fφ),当Fc=1.86,Fφ=1.42时；边坡的失稳破坏规律更加明显,因此采用1.86作为边坡的稳定性安全系数。这种双系数强度折减(FcFφ),才更适合超固结类残积红土边坡。经过对比研究分析,对于坡比为1：1.5的残积红土边坡,以Fc=1.3 Fφ来进行强度折减分析,会获得更精确的稳定性安全系数,这一折减比例,对此类型边坡的研究具有一定的参考价值。(4)当前状况下,边坡是稳定的,在发生破坏性地震的情况下,有可能发生滑移失稳,应做好坡顶的防渗防冲刷等防护措施,坡面建议采用土工格室加固,植灌草护坡等植被防护措施,坡脚修建截水沟等确保边坡的稳定及西次跑道长期安全运营。
[Abstract]:The geological structure, topography and geomorphology of Yunnan area are very complicated. The site of Changshui International Airport in Kunming is located in the karst geomorphology area of plateau hilly area. The topography fluctuates greatly, and the site involves many engineering geological units. During the construction of the airport, deep excavation and high fill were produced. The stability of the high slope of residual red soil formed by excavation of the Tuanshan on the west side of the airport has a direct impact on the construction and operation of the second phase of the airport project-the West Runway. The stability of Tuanshan residual laterite slope is a problem that must be studied and dealt with during the construction of the west runway. Taking the Tuanshan residual laterite slope on the west side of Changshui International Airport as the research object, on the basis of systematic field geological investigation, the soil samples are taken for laboratory test and analysis. The regional geological conditions of the slope and the mechanical characteristics of the residual laterite are studied in depth, and the influencing factors of the slope stability are comprehensively studied. The typical sections of the slope are selected, and the natural working conditions of the slope are analyzed by using GeoStudio-Slope/W,QUAKE/W software and ANSYS software. The stability of the slope under seismic conditions is analyzed by numerical simulation, which provides some advice for the treatment of slope. Through the above analysis and research, the following conclusions and understandings are obtained: (1) the slope belongs to the bench slope excavated, and the soil mass of the slope is the residual laterite weathered from the sand shale (鈭，

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