摘要
安装GNSS变形监测点的某大渡河左岸工程边坡经历了2022年“9·5”泸定地震(主震)及其余震事件,为揭示地震作用下工程边坡变形响应规律及原因提供了宝贵数据。在梳理地震背景及其灾害的基础之上,整理并分析了边坡碎石土与基岩上监测点的变形历时数据,得到了如下主要发现:在主震激发下,碎石土的水平变形量变化过程总体呈S型,先后出现了震前平稳段、震后增长段与震后收敛段,且震后增长段碎石土的水平变形量增幅可达20 mm;震级比主震小的余震在震后收敛段并未对碎石土的水平变形量造成显著实质性影响,与声发射现象中的“凯赛尔效应”极相似;主震激发了碎石土的水平变形方向由北偏东8.5°快速大幅增加至北偏东30.5°,但这种对碎石土层水平变形方向的改变具有弹性可恢复性;地震作用下边坡碎石土的水平变形响应比基岩的水平变形响应更显著,分析认为岩性与坡度的差异是两者水平变形响应差异的主要原因;边坡碎石土与基岩的竖向变形以及基岩水平变形在地震作用下并无显著变化,最新变形数据表明监测点处边坡处于相对稳定状态。鉴于复杂因素对边坡的潜在不利影响,还应基于多源监测数据开展边坡的动态稳定性分析判断。研究成果可为地震时边坡安全施工与灾害风险防控提供一定参考。
The left engineering slope of Dadu River where GNSS deformation monitoring points were installed has experienced the‘9·5’Luding earthquake(the main shock)in 2022 and its aftershocks,which provides valuable data for the deformation response analysis of engineering slope under the action of earthquake.On the basis of sorting out the earthquake background and disasters,the deformation duration data of monitoring points on the slope gravelly soil and bedrock were sorted and analyzed,and the following main findings are obtained.Under the excitation of the main earthquake,the horizontal deformation of gravelly soil is generally Sshaped,and there are pre-earthquake stable section,post-earthquake growth section and post-earthquake convergence section,and the horizontal deformation of gravelly soil in the post-earthquake growth section increases by 20mm.The aftershocks with a smaller magnitude than the main shock have no significant substantive impact on the horizontal deformation of gravelly soil in the post-earthquake convergence section,which is very similar to the“Kaiser effect”in the acoustic emission phenomenon.The horizontal deformation direction of gravelly soil excited by the main earthquake increased rapidly and substantially from 8.5°north by east to 30.5°north by east,but this change in the horizontal deformation direction of gravelly soil has elastic resilience.The horizontal deformation response of slope gravelly soil under seismic action is more significant than that of bedrock,and the analysis shows that the difference between lithology and slope is the main reason for the difference between them.The vertical deformation of slope gravelly soil and bedrock and the horizontal deformation of bedrock have no significant changes under the earthquake.The latest deformation data show that the slope at the monitoring point is in a relatively stable state.In view of the potential adverse effects of complex factors on the slope,the dynamic stability analysis and judgment of the slope should also be carried out based on multi-source monitoring data.The research results can provide some reference for the safety construction of slope and disaster risk prevention and control during earthquake.
作者
孙巍锋
兰恒星
包含
田朝阳
晏长根
SUN Weifeng;LAN Hengxing;BAO Han;TIAN Chaoyang;YAN Changgen(School of Geological Engineering and Geomatics,Chang an University,Xi’an 710054,China;Center for Post-doctoral Studies of Geological Resources and Geological Engineering,Chang an University,Xi’an 710054,China;Key Laboratory of Ecological Geology and Disaster Control,Xi’an 710054,China;State Key Laboratory of Resources and Environmental Information System,Institute of Geographic Sciences and Natural Resources Research,Chinese Academy of Sciences,Beijing 100101,China;School of Highway,Chang an University,Xi’an 710064,China)
出处
《工程地质学报》
CSCD
北大核心
2024年第5期1654-1668,共15页
Journal of Engineering Geology
基金
国家自然科学基金项目(资助号:41941019,42041006,41927806,41807291)
青藏高原第二次科考项目(资助号:2019QZKK0904)
中央高校基本科研业务费(资助号:300102262901)。
关键词
工程边坡
变形响应
强震
GNSS监测
位移转向
Engineering slope
Deformation response
Strong shock
GNSS monitoring
Displacement steering
