摘要
灰岩区滑坡勘查通常采用物探查明覆盖层厚度、岩溶洞穴、滑面位置等工程地质条件,分析滑坡形成机制,但物探解译往往没有结合工程地质分析和力学机制分析进行,使解译的成果与工程实际差别较大.我们利用高分辨率电阻率成像技术,勘查了江西省南部的九连山山脉某复杂滑坡,识别了滑体与基岩之间的不连续面,并圈定了可能存在岩溶的区域和潜在滑面;对这个地质条件复杂、岩溶多点分布的滑坡进行定线定点钻探,并对视电阻率色谱图与工程地质剖面进行对比分析,确定了岩溶存在区域、滑动地层岩性和埋藏深度;最后,考虑高密度电法和钻孔约束的关键滑面和岩溶分布范围,利用FLAC2D对进行滑坡二维应力应变动态响应分析,反演复活滑坡变形破坏的全过程.发现该类型滑坡为深埋的重力斜坡,兼具圆弧滑动和平滑两种方式,明显地具有倾向于中前缘的岩溶洞穴沉降塌陷引起的牵引式滑动特征.该综合方法的运用结果表明:灰岩区滑坡勘查,应充分考虑地质条件-岩溶分布对斜坡稳定性的影响,重点位置多重布线、主滑方向平行布线,可获得切合实际双极-偶极数据生成的电法成像;等间距高密度电法视电阻率色谱图可初步划分出地层岩性和灰岩区的分布区域;钻探法可约束地层的分布情况及滑面位置;而GMD法计算结果可验证上术两种方法确定的地层参数,反演复活滑坡的动态响应全过程,提高物理参数解译的可靠性.该方法对灰岩区滑坡勘查设计和科学治理具有积极意义.
The geological conditions such as overburden thickness, karst caves and slide surface location, etc. are usually used for landslide exploration in limestone areas to analyze the landslide formation mechanism. However, geophysical interpretation is often not combined with engineering geological analysis and mechanical mechanism analysis, which makes the results of interpretation differ greatly from the actual engineering. Using high-resolution resistivity imaging technology, we explored a complex landslide in the Jiulian mountain range in southern Jiangxi province, identified discontinuities between the sliding mass and bedrock, and delineated possible karst regions and potential slip surfaces. This landslide with complex geological conditions and multi-point karst distribution is drilled at fixed line and fixed point, and the apparent resistivity chromatogram is compared with the engineering geological section to determine the karst region, the lithology of sliding stratum and burial depth. Finally, in consideration of the key slip surface and karst distribution range of high-density electrical method and borehole constraint, FLAC2 D was used to analyze the dynamic response of two-dimensional stress-strain of landslide, and the whole process of reactivation landslide deformation and failure was retrieved. It is found that this type of landslide is a deep buried gravity slope, which has both circular sliding and smooth, and has the characteristics of tractive sliding caused by karst cave subsidence which tends to the front of the middle. The application result of the integrated method shows that the influence of geological condition and karst distribution on the slope stability should be fully considered in the landslide exploration in limestone area. The distribution areas of stratigraphic lithology and limestone areas can be preliminarily divided by the iso-spacing high-density electrical resistivity chromatogram. The distribution of restricted formation and position of sliding surface by drilling method;GMD cal
作者
甘建军
陈炳贵
刘晓
罗藏青排
彭晟
GAN Jian-jun;CHEN Bin-gui;LIU Xiao;LUOZANG Qing-pai;PENG Cheng(National-Local Joint Engineering Laboratory of Water Engineering Safety and Efficient Utilization of Resources in Poyang Lake Watershed,Nanchang Institute of Technology,Nanchang 330099,China)
出处
《地球物理学进展》
CSCD
北大核心
2019年第6期2429-2436,共8页
Progress in Geophysics
基金
江西省教育厅科技研究项目(GJJ151124)
江西省科技厅第一批科技计划项目(20161BBG70051,20171BBG70046)
江西省交通运输厅科技项目(2016H0022)
江西省水工程安全与资源利用工程研究中心开放基金项目(OF201603)
国家自然科学基金项目(51869012,41641023)联合资助
关键词
高密度电法
灰岩区滑坡
GMD法
动力响应
稳定性
High density electrical method
Landslide in limestone area
GMD method
Dynamic response
Stability
