Joint geomorphological and geophysical (electrical resistivity) investigation for the configuration of soil pipe

Abstract

Soil piping is a complex mechanism of subsurface soil erosion, which results underground conduits (cave/tunnel) of varying dimensions. Soil piping associates with severe consequences, such as land subsidence and land slide. Therefore, the investigation of soil pipe is crucial. However, the study of soil pipe is challenging unless characteristic surficial evidences of the pipe are available. Based on the surficial evidences, soil pipe can be configured with geophysical techniques which in-turn aid in designing precursory measures. Therefore, in the present study, we carried out a combined geomorphological and geophysical investigation to configure the soil pipe at Kinanoor village, Kasaragod, Kerala, India. Based on the vital geomorphological information, we carried out resistivity survey and configured an underground soil pipe of diameter ∼6.5 to 7 m that is seated ∼3 m beneath the surface. This hollow pipe is underlain by the only accessible road of that locality which makes the road vulnerable for transportation. Therefore, a bridge like structure is recommended to construct at the pipe location to stabilize the risk factor. Since the study area is situated on a fringe-slope, the geomorphological investigation points out that the disturbance in natural course of the drainage system and the accumulation of water in the up-slope area due to the man-made activities might act as potential causes for the piping in the area. Therefore, it is suggested not to disturb the natural course of the drainage which may lead to subsidence of the area in future.

Examining tunnel erosion using vertical electrical sounding and ground magnetic geophysical techniques in Awka, Nigeria

“…Iso-resistivity Map The estimation of soil pipe extents was accomplished by mapping out the true resistivity values derived from the various geo-electric layers, in conjunction with the corresponding GPS coordinates obtained from the sites, as illustrated in Figures 7 and 8. Based on the comprehensive analysis of the dipole-dipole survey results, the lithological models, and relevant literature sources such as Borah et al (2022) [5] , Gibson et al (2004) [9] , Got et al (2020) [11] , Joshi et al (2021) [13] , Li et al (2015) [15] , Mi et al (2013) [17] , it can be deduced that soil pipes tend to form in very close proximity to the surface. Consequently, for the purpose of mapping, the depth range considered extends from 0 to 5m.…”

Uncovering soil piping vulnerability using direct current geophysical techniques in Awka, Anambra State, Nigeria

“…The extents of the paths created by soil pipes were estimated by mapping out the true resistivity generated from the values of the different geo-electric layers and GPS coordinates from the sites (figure 9 [7,14,16,22] , it is inferred that soil pipes form very close to the surface. Thus, the depth considered for the mapping ranges from 0 -5m.…”