A Comparative Study of Soil Suction Measurement Using Two Different High-Range Psychrometers

Cardoso, Rafaela; Romero, E.; Lima, Adilson Celestino de; Ferrari, Alessio

doi:10.1007/3-540-69873-6_8

Cited by 63 publications

(47 citation statements)

References 3 publications

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“…They concluded that for low water contents, SWCCs are controlled by a surface area rather than pore geometry. A dew-point potentiometer device (Decagon Devices Inc.) was used to investigate water retention characteristics of different soil types (e.g., [28][29][30][31]). …”

Section: Methods Used For Determination Of Soil-water Characteristic mentioning

confidence: 99%

Soil-Water Characteristic Curve of Residual Soil from a Flysch Rock Mass

et al. 2018

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Depending on the nature of the material and suction range, laboratory measurements of the soil-water characteristic curve (SWCC) can be time-consuming and expensive, especially for residual soils, in which a wide range of particle sizes and soil structures typically results in SWCCs that cover a wide range of suction. Investigations of the SWCCs of residual soil from flysch rock masses are rare, and so far, no results were presented in the literature which were obtained by performing measurements on undisturbed specimens. In this paper, a detailed examination of water retention characteristics is performed for a specific type of residual soil (CL) formed by the weathering of a flysch rock mass. Measurements performed by using different techniques and devices on intact specimens were successfully combined to obtain the SWCC during both drying and wetting processes, under different stress conditions, and from saturated to air-dried conditions. Used procedures are suitable for the determination of SWCCs of soils that undergo volume changes during the drying or the wetting process, since instantaneous volumetric water content can be determined. Results presented in this paper can be used to assess the influence of desaturation of the residual soil covering flysch slopes during dry summer periods by providing key-in material properties required to analyze the transient rainfall infiltration process.

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Section: Methods Used For Determination Of Soil-water Characteristic mentioning

confidence: 99%

Soil-Water Characteristic Curve of Residual Soil from a Flysch Rock Mass

et al. 2018

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“…There exist several different methods to measure the relative humidity of the water vapour in equilibrium with the bentonite blocks. Besides the installation of a traditional RH sensor at the point of interest (which would disturb the sample and be too large as to be incorporated), it is also possible to measure the RH using a Chilled-Mirror Psychrometer [12]. The psychrometer used in this experimental programme is a product of Decagon Devices, Inc. and is known as a WP4 Dew Point Potentiameter.…”

Section: Methodsmentioning

confidence: 99%

Laboratory Testing of a MEMS Sensor System for In-Situ Monitoring of the Engineered Barrier in a Geological Disposal Facility

Yang¹,

Lunn²,

Tarantino³

et al. 2017

Preprint

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Geological disposal facilities for radioactive waste pose significant challenges for robust monitoring of environmental conditions within the engineered barriers that surround the waste canister. Temperatures are elevated, due to the presence of heat generating waste, relative humidity varies from 20% to 100%, and swelling pressures within the bentonite barrier can typically be 2-10 MPa. Here, we test the robustness of a bespoke design MEMS sensor-based monitoring system, which we encapsulate in polyurethane resin. We place the sensor within an oedometer cell and show that despite a rise in swelling pressure to 2 MPa, our relative humidity (RH) measurements are unaffected. We then test the sensing system against a traditional RH sensor, using saturated bentonite with a range of RH values between 50% and 100%. Measurements differ, on average, by 2.87% RH, and are particularly far apart for values of RH greater than 98%. However, bespoke calibration of the MEMS sensing system using saturated solutions of known RH, reduces the measurement difference to an average of 1.97% RH, greatly increasing the accuracy for RH values close to 100%.

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“…The imposed water content is applied differently for the wetting and drying paths. The total suction readings are carried out by means of a dew-point psychrometer (Decagon, WP4c) [5,6]. The apparatus gives indirect measures of the total suction of a sample by reading the relative humidity established by the sample in a closed environment.…”

Section: Testing Methodologiesmentioning

confidence: 99%