戈壁土路堤边坡稳定性影响因素数值模拟研究

摘要

Research purposes:The stability of embankment slope of high speed railway in Gobi area is affected by filling characteristics,rainfall,slope protection,reinforcing and so on.In this paper,based on the subgrade test sections of the second double-line of Lanzhou-Xinjiang Railway in Gobi desert area,for embankment slope filled with typical filling,the rules of influence factors on slope stability are studied with numerical simulation under different conditions.Research conclusions:(1) The stability of embankment slope filled with Gobi gravel sand and fine gravel soil can meet the requirements of the specification under unsaturated condition.(2) It is a great influence of the rainfall on the slope stability with Gobi desert soil.The rainfall infiltrates into the slope,which will increase the lateral displacement.Different saturated soil thickness in the shallow slope corresponds to different maximum lateral displacement.If the saturated soil thickness in the shallow slope is less than 1 m,the shallow slope is prone to collapse.The greater saturated soil thickness in the shallow slope is,the worse the slope stability is.(3) For embankment slope filled with Gobi desert soil,its performance will be well improved through reinforcing the shallow slope,and the slope stability will be enhanced,too.Reinforcing has an obvious improvement effect on slope shallow slumping.(4) Under the corporate measures of reinforcing and slope protection,the slope stability has been greatly increased,and diseases caused by adverse influence factors can be prevented.(5) The research results can provide the corresponding reference to the engineering construction and design in the similar area.%研究目的:戈壁地区高速铁路路堤边坡稳定性受填料性质、降雨及有无防护、加筋加固等因素影响.本文以兰新铁路第二双线戈壁地区路基试验段工程为依托,针对试验段中代表性填料填筑的路堤边坡,利用数值模拟分析不同状态下各因素对边坡稳定性的影响规律,以期对合理设计边坡防护与加固提供依据.研究结论:(1)采用戈壁砾砂土和细圆砾土所填筑的路堤边坡,在非饱和状态下其稳定性均能满足相关规范的要求;(2)降雨对戈壁土路堤边坡的稳定性有很大影响;当降雨入渗后,边坡侧向位移会增大;浅层饱和土体厚度不同,最大侧向位移不同;浅层饱和土体厚度小于1 m时,易发生边坡的浅层溜坍现象;饱和厚度越大,边坡的稳定性越差;(3)对于戈壁土路堤边坡而言,当边坡在浅层加筋加固后,其性能将得到很大改善,边坡的稳定性得到增强,加筋对边坡的浅层溜坍现象有明显的改善作用;(4)在加筋和边坡防护共同作用下,边坡稳定性得到很大程度提高,能防止或抑制各种不利影响因素所引起的破坏;(5)本研究结果可为同类地区的工程建设及设计提供相应的参考.