An approach for the geophysical assessment of fissuring of estuary and river flood embankments: validation against two case studies in England and Scotland
An approach for the geophysical assessment of fissuring of estuary and river flood embankments: validation against two case studies in England and Scotland
复制标题
DOI：
10.1007/s12665-012-2026-z
复制
发表时间：
2013-07
影响因子：
2.8
通讯作者：
P. Sentenac;G. Jones;M. Zieliński;A. Tarantino
中科院分区：
文献类型：
--
作者：
P. Sentenac;G. Jones;M. Zieliński;A. Tarantino
本文提出了一个两阶段的地球物理方法来映射的垂直裂缝和结构完整性的洪水防洪堤的粘土地质材料容易开裂。第一阶段是基于“粗分辨率”的调查，使用传统的电阻率层析成像（ERT）设备，以确定在路堤的裂缝区。这一步骤由额外的地球物理技术（电磁）补充，以验证ERT测量结果。第二阶段是基于一个“高分辨率”的调查，使用一个微型ERT系统以前开发的实验室规模的裂缝模式的详细映射。“粗分辨率”阶段是本文的主要重点，并验证了对英格兰和苏格兰的两个案例研究。纵向ERT调查提供了一个断层摄影图片的上部干燥区的裂缝和裂隙区的2-D，验证了电阻率的范围内获得的结果在实验室中的裂隙粘土模型。还完成了横向路堤电阻率层析成像，以详细显示现场裂隙区的位置。电磁技术作为一种快速筛选工具，可以交叉检查ERT结果，也可以有效地检测高和低电导率区，指示山洪暴发和暴雨期间潜在的薄弱地区。英格兰南部堤岸的电导率和电阻率的波动比苏格兰北部堤岸的波动大，这可能是由于两个地点之间的气候、植被和位置特征的差异。还得出结论的潜在弱点，为两个测量和植被的影响电导率测量。
This paper proposes a two-stage geophysical approach to map the vertical cracking and the structural integrity of flood embankments made up of clay geomaterials susceptible to fissuring. The first stage is based on a ‘coarse-resolution’ investigation using conventional electrical resistivity tomography (ERT) equipment to identify the fissured zones in the embankment. This step is complemented by an additional geophysical technique, electromagnetic, to verify the ERT measurements. The second stage is based on a ‘high-resolution’ investigation using a miniature ERT system previously developed at the laboratory scale for detailed mapping of the fissure patterns. The ‘coarse-resolution’ stage is the major focus of this paper and was validated against two case studies in England and Scotland. Longitudinal ERT survey provided a tomographic picture of the upper desiccated zones of the embankments and fissured areas in 2-D, validating the range of resistivity results obtained previously on a fissured clay model in the laboratory. A transversal embankment resistivity tomography was also completed to show the positions of fissured zones in detail in the field. The electromagnetic technique as a fast screening tool allowed cross checking the ERT results and was also efficient in detecting high and low conductivity zones, indicating areas of potential weakness during flash floods and heavy rain. The southern embankment in England showed more fluctuations in the conductivity and resistivity than the north embankment in Scotland, likely to be due to the differences in climate, vegetation and location characteristics between the two sites. Conclusions were also drawn on the potential weaknesses for both embankments and the effect of vegetation on conductivity measurements.