摘要
南京某在建城际铁路隧道明洞段穿越矿山废弃宕口回填区,受极端强降雨和明洞地基开挖卸荷影响,矿坑南侧陡崖下部的截排水沟多处出现变形裂缝,因此,宕口填土边坡稳定性关系到在建铁路的施工和运营安全。对此,在地质分析的基础上,运用数值模拟方法对持续性强降雨天气条件下回填土缓坡渗流场、位移场的变化规律及边坡稳定性进行了研究,探讨不同降雨类型对缓坡稳定性的影响。结果表明,在持续性强降雨天气条件下,降水入渗使缓坡下滑力逐渐增大,同时在弱透水层中形成暂时性承压水,产生渗流力和浮托力,在其共同作用下,边坡稳定性显著降低,出现边坡失稳;前峰型降雨和均布型降雨在较短时间内即会对边坡稳定性造成很大影响,而中峰型降雨和后峰型降雨对边坡稳定性的影响在降雨后期逐渐显现。故此,需要对明洞隧道地基进行加固处理,采取有效的截排水措施,以保证城际铁路施工及运营安全。
The open cut section of an excavating intercity railway tunnel in Nanjing crosses the backfill area of a large abandoned mine.Due to the influence of extremely heavy rainfall and excavation unload-ing of open cut tunnel foundation,many deformation cracks appeared in the intercepting and drainage ditch at the lower part of the steep cliff on the south side of the mine.Therefore,the stability of the backfill gentle slope is related to the construction and operation safety of the railway under construc-tion.In order to solve this problem,on the basis of geological analysis,the numerical method is used to simulate and analyze the changes of the seepage field,displacement field and the slope stability of the gentle backfill slope under continuous heavy rainfall.The influence of different rainfall types on the stability of the gentle slope is discussed.The results show that under the condition of continuous heavy rainfall,precipitation infiltration makes the sliding force of the gentle slope increase gradually,and forms temporary confined water in the aquitard,which results in seepage force and buoyancy force.Under the combined action of the two forces,the slope stability decreases significantly and the slope instability occurs.Besides,it is found that the early-peak rainfall and uniform rainfall will affect the slope stability in a short time,while the influence of the mid-peak rainfall and late-peak rainfall on the slope stability gradually appears in the later stage.Therefore,it is necessary to reinforce the founda-tion of the open cut tunnel and take effective measures to intercept and drain water in order to ensure the safety of the intercity railway during the construction and operation periods.
作者
董聪慧
阎长虹
娄志会
郭建强
郭书兰
俞良晨
万佳佳
张文龙
DONG Conghui;YAN Changhong;LOU Zhihui;GUO Jianqiang;GUO Shuan;YU Liangchen;WAN Jiajia;ZHANG Wenong(School of Earth Sciences and Engineering,Nanjing University,Nanjing 210023,China;Beijing Urban Construction Zhongnan Civil Engineering Group Co.,Ltd.,Beijing 102200,China;Nanjing Metro Group Co.,Ltd.,Nanjing 210008,China)
出处
《防灾减灾工程学报》
CSCD
北大核心
2023年第4期835-844,共10页
Journal of Disaster Prevention and Mitigation Engineering
基金
江苏省科技厅社会发展面上项目(BE2019705)
南京地铁宁句城际科研项目(2020200595)资助。
关键词
回填土缓坡
城际轨道交通工程
渗流
暂时性承压水
边坡稳定性
gentle backfill slope
intercity railway engineering
seepage
temporary confined water
slope stability
