摘要
利用工程地质层次分析方法,对不稳定斜坡的成因、潜在不利要素进行定性识别;利用定量分析,评估初始地形、改变地形和考虑长历时降雨的坡体稳定性系数劣化规律;利用多期次地面调查和安全监测,评估不稳定斜坡的运动方向、范围和厚度,结合现场情况,提出综合处置建议。主要结论如下:不稳定斜坡是后部陡崖岩体崩落向前滑移演化而成的崩滑堆积体,坡体表层的膨胀土+土岩界面+全强风化砂页岩等易崩解扰动岩体是坡体变形蠕滑的物质基础;自然状态下,初始地形斜坡稳定性系数1.071,三级坡开挖下斜坡稳定性系数1.049,开挖使得坡体由基本稳定变为欠稳定状态。降雨到6月中旬,坡体处于临界状态。因此,工程开挖是诱发因素,长时间降雨造成滑面岩土体饱水劣化和前缘来不及疏排形成超孔压才是坡体加剧蠕滑的主导因素。研究成果可以为临近工程提供类比依据和借鉴。
The qualitative analytic hierarchy process of engineering geology,the causes and potential unfavorable factors of unstable slope are identified.Based on quantitative analysis,the change laws of initial topography,changing topography and considering long-term rainfall slope stability are evaluated.The moving direction,range and thickness of the unstable slope are evaluated by means of multi-stages ground investigation and safety monitoring,simultaneously the optimal comprehensive treatment suggestions are proposed according to the site conditions.The main conclusions are as follows:The unstable slope is formed by the collapse and sliding of the steep rock mass at the back.The easily disintegrated and disturbed rock mass such as expansive soil+soil rock interface+completely strongly weathered sand shale on the surface of the slope is the material basis for the deformation and creep of the slope.Under natural conditions,the slope stability coefficient of the initial topography is 1.071,that of the third-grade slope excavation being 1.049,the slope stability is changing from basically stable to less stable.Long time rainfall may cause the slope in a critical state on June 14.So highway excavation is an triggering factor,high groundwater level in slope body,super pore pressure in front free face,slip surface strength degradation caused by the rainfall infiltration are the leading factor for the aggravation of the creep of the slope.The research results can provide analogy basis and salutary lessons for adjacent projects.
作者
罗世毅
黄黎明
唐修益
LUO Shiyi;HUANG Liming;TANG Xiuyi(Guangxi Transportation Science and Technology Group Co.,Ltd.,Nanning,Guangxi 530007,China;Guangxi Xinliunan Expressway Co.,Ltd.,Nanning,Guangxi 530029,China)
出处
《水利与建筑工程学报》
2022年第4期233-239,共7页
Journal of Water Resources and Architectural Engineering
基金
国家重点研发计划项目“膨胀土滑坡与工程边坡防治技术标准化及生态防护综合技术”(2019YFC1509800)。
关键词
不稳定斜坡
工程地质定性分析
长历时降雨
稳定性量化分析
变形破坏机制
unstable slope
engineering geology qualitative analysis
long term rainfall
stability quantitative analysis
deformation failure mechanism
