An approach to construct the weathering profile in a hilly granitic terrain based on electrical imaging

Giao, Pham Huy; Weller, Andreas; Hien, Doan Huy; Adisornsupawat, K.

doi:10.1016/j.jappgeo.2008.03.004

Cited by 24 publications

(19 citation statements)

References 15 publications

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“…1). This result is consistent with the review by Giao et al (2008), who found that the resistivity of granitic rock varies across a relatively wide range and considerably from site to site (1.3-160 × 10 6 ohm-m). Previous studies have demonstrated that ρ values of several types of soil and rock are primarily affected by pore-water electric conductivity, effective porosity, degree of water saturation, and clay content (Archie, 1942;Patnode and Wyllie, 1950;Chiba and Kumada, 1994;Nishimaki et al, 1999).…”

Section: Evaluation Of Er Profiles Based On Borehole Evidencesupporting

confidence: 93%

Combined geophysical methods for detecting soil thickness distribution on a weathered granitic hillslope

et al. 2012

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Section: Evaluation Of Er Profiles Based On Borehole Evidencesupporting

confidence: 93%

Combined geophysical methods for detecting soil thickness distribution on a weathered granitic hillslope

et al. 2012

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“…As a first approach and considering a typical granite weathering profile (Giao et al . ), a large acoustic contrast between overburden (including alluvial and colluvial deposits as well as grus) and a low‐fractured bedrock is expected. Low‐fractured bedrock is defined as granite with 90% rock and residual debris along a joint.…”

Section: Results and Interpretationmentioning

confidence: 99%

“…Taking into account that the methodology relies on using information from soil resonance frequency we need to find a large acoustic contrast causing the soil resonance we are measuring. As a first approach and considering a typical granite weathering profile (Giao et al 2008), a large acoustic contrast between overburden (including alluvial and colluvial deposits as well as grus) and a low-fractured bedrock is expected. Low-fractured bedrock is variation in the frequency of the peaks can be used for a first draft of bedrock geometry as shown in Fig.…”

Section: Bedrock Depth Estimation From Resistivity and Velocity Modelsmentioning

confidence: 99%

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Integrated geophysical profiles and H/V microtremor measurements for subsoil characterization

Benjumea¹,

Macau²,

Gabàs³

et al. 2011

Near Surface Geophysics

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Mapping bedrock structure beneath overburden is crucial for understanding geological and hydrogeological processes. Acquiring this information is generally done using well drilling or geophysical surveys; but these studies are expensive and require large periods of acquisition and processing time. In addition, geophysical data acquisition can be logistically challenging in urban zones with limited available areas for instrumentation deployment. Under favourable conditions (1D structure and high acoustic impedance contrast) the H/V microtremor technique can provide estimates of bedrock depth. This technique is used to obtain the soil resonance frequency in seismic microzonation studies. It is based on the computation of the horizontal to vertical spectral ratio of microtremor recordings acquired at a single station. The soil resonance frequency is related to soil shear‐wave velocity and thickness. Here we investigate the capability of combining microtremor and traditional exploration geophysical techniques (electrical resistivity and seismic tomography) to obtain an empirical relationship relating soil resonance frequency and overburden thickness. Subsequently we propose to extend microtremor measurements to adjacent areas that have not been covered by geophysical surveys. This methodology has been applied at a test site located in a granitic environment where alluvial/colluvial sediments cover the granite weathering profile. This area is characterized by urban development and sectors having rugged topography. A priori, this area has suitable conditions to apply the H/V microtremor technique. Overburden thickness has been estimated to range between 20–50 m. The proposed methodology has been validated at the test site, encouraging us to apply the H/V method as an exploration tool in similar geological environments.

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“…The multistage test has been adapted to both triaxial and direct shear tests, especially when there are difficulties in sampling and sample preparation. It has been applied to rocks, undisturbed submarine soils, undisturbed silty sand and undisturbed residual soils [17]. The benefit of multi-stage test we expected in this study includes (1) the effects of sample variability are eliminated, (2) the time required for sample preparation and testing is minimized, and (3) the overall cost for the tests is reduced [18].…”

Section: Multi-stage Direct Shear Testmentioning

confidence: 99%

Geological and engineering analysis of residualsoil for forewarning landslide from highland areain northern Thailand

et al. 2015

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Abstract:One devastating landslide event in northern Thailand occurred in 2006 at Ban Nong Pla village, Chiang Klang highland of Nan province after, a massive amount of residual soil moved from upstream to downstream, via creek tributaries, into a main stream after five days of unusual heavy rainfall. In this paper, the geological and engineering properties of residual soil derived from sedimentary rocks were analyzed and integrated. Geological mapping, electrical resistivity survey and test pits were carried out along three transect lines together with systematic collection of undisturbed and disturbed residual soil samples. As a result, the average moisture content in soil is 24.83% with average specific gravity of 2.68, whereas the liquid limit is 44.93%, plastic limit is 29.35% and plastic index is 15.58%. The cohesion of soil ranges between 0.096-1.196 ksc and the angle of internal friction is between 11.51 and 35.78 degrees. This suggests that the toughness properties of soil change when moisture content increases. Results from electrical resistivity survey reveal that soil thicknesses above the bedrock along three transects range from 2 to 9 m. The soil shear strength reach the rate of high decreases in the range of 72 to 95.6% for residual soil from shale, siltstone and sandstone, respectively. Strength of soil decreases when the moisture content in soil increases. Shear strength also decreases when the moisture content changes. Therefore, the natural soil slope in the study area will be stable when the moisture content in soil level is equal to one, but when the moisture content between soil particle increases, strength of soil will decrease resulting in soil strength decreasing.

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An approach to construct the weathering profile in a hilly granitic terrain based on electrical imaging

Cited by 24 publications

References 15 publications

Combined geophysical methods for detecting soil thickness distribution on a weathered granitic hillslope

Combined geophysical methods for detecting soil thickness distribution on a weathered granitic hillslope

Integrated geophysical profiles and H/V microtremor measurements for subsoil characterization

Geological and engineering analysis of residualsoil for forewarning landslide from highland areain northern Thailand

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