Soil Suction Measurement of Unsaturated Soils with a Sensor Using Fixed-Matrix Porous Ceramic Discs

Tripathy, Snehasis; Al-Khyat, Sahar; Cleall, Peter John; Baille, Wiebke; Schanz, Tom

doi:10.1007/s40098-016-0200-z

Cited by 33 publications

(19 citation statements)

References 11 publications

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“…According to Briaud et al. (2003), expansive clays are generally subjected to 3000 kPa of high suction values at surface levels due to desiccation (dry climates) and this fact was verified by Tripathy et al. (2016).…”

Section: Resultsmentioning

confidence: 95%

Oedometer based estimation of vertical shrinkage of expansive soil in a large instrumeted soil column

Udukumburage

Gallage

Dawes

2019

Heliyon

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The moisture variations in expansive soils cause shrink-swell behaviour, resulting in distress to the structures founded in/on problematic soils. The oedometer based tests can be used to determine swell behaviour of soil; however, limited research has been conducted for vertical shrinkage estimations. In this study, a series of conventional oedometer tests were conducted to investigate the vertical shrinkage of grey Vertosol due to soil moisture variations under different surcharges. A statistically strong relationship (R 2 = 0.99) was observed for shrinkage per unit change in volumetric water content under shallow overburden pressures (surcharges). The validation of the shrinkage was conducted by simulating field conditions under induced drying cycle. Derived shrinkage prediction equation and Aitchison's method showed underestimations of 10.1% and 44.0% of the actual shrinkage respectively. Briaud's and Dhowian's models overestimated the value by 59.0% and 44.5% respectively. This study emphasizes the applicability of the conventional oedometer based shrinkage test for a reasonable estimation of vertical shrinkage for a given expansive soil. Thereby, proposing a simple and practical approach to obtain shrinkage characteristics for geotechnical engineering applications.

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Section: Resultsmentioning

confidence: 95%

Oedometer based estimation of vertical shrinkage of expansive soil in a large instrumeted soil column

Udukumburage

Gallage

Dawes

2019

Heliyon

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“…Two moisture sensors (EC-5; Decagon Devices, Inc., USA) and one suction sensor (TEROS-21; Decagon Devices, Inc., USA) were installed in each potted sample. Acceptable accuracy and reliability have been validated for kaolin and bentonite (Tripathy et al., 2016). Actually, suction sensor calibration is not affected by soil type theoretically, because only water potential of the ceramic discs in equilibrium with the clay is measured by the sensor.…”

Section: Methodsmentioning

confidence: 99%

“…Actually, suction sensor calibration is not affected by soil type theoretically, because only water potential of the ceramic discs in equilibrium with the clay is measured by the sensor. Sensor limitations are listed for caution: (1) good hydraulic contact with the surrounding soil is required for suction sensor during measurement, (2) sensor reading is affected by temperature and applied supply voltage, and (3) hysteresis related to wetting and drying of ceramic discs would be reﬂected on suction data (Sreedeep and Singh, 2005, 2011; Tripathy et al., 2016). Volumetric water content and suction were measured by ProCheck (Decagon Devices, Inc., USA) with stable applied supply voltage under 25 ± 2 °C temperature.…”

Section: Methodsmentioning

confidence: 99%

Expansive soil-biochar-root-water-bacteria interaction: Investigation on crack development, water management and plant growth in green infrastructure

Wang

Zhang

Gan

et al. 2020

International Journal of Damage Mechanics

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The objectives of the study are to explore fundamental mechanism of expansive soil-biochar-root-water-bacteria interaction, and investigate crack development and hydraulic properties of biochar amended soils aiming at green infrastructures. The physical, chemical and biological effects of biochar on expansive soil have been comprehensively explored. Crack development is investigated quantificationally, and mechanism of soil damage evolution is briefly discussed base on micro-chemical analyses. During outdoor vegetation period, photosynthesis light response curves were measured to evaluate plant growth. After period of vegetation, hydraulic properties of root-soil composites and unplanted soils were compared. The study reveals that soil crack intensity factor decreases by 33.5%, 48.5% and 47.3% due to 5%, 10% and 15% biochar introduction respectively after 5 wetting-drying cycles. 15% biochar amendment helps to restrain both initiation and propagation of soil cracks. Biochar amendment of up to 5% contributes well to residual water content and plant growth (i.e., light saturation point and light compensation point). Excessive biochar addition would restrain roots elongation, and increase saturated water content. Spatial root distribution is changed due to biochar addition, which further influences hydraulic properties and crack development. Hydraulic conductivity and soil dry density share negative correlations, 5% biochar enhances hydraulic conductivity remarkably at relatively loose condition. Biochar amendment also contributes to preventing nitrogen loss and forming more complex bacterial community in soils. The study adds to our knowledge of physio-chemical interactions of biochar with expansive clay, vegetation, water and microorganism.

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“…However, the major challenge in developing the SWCC of a given soil is the accurate measurement of the soil matric suction in the eld or in the laboratory. Techniques such as osmotic method (Delage et al 1998, Gapak et al 2017, Gapak and Tadikonda, 2018, chilled mirror hygrometer (Leong et al 2003), vapor equilibrium technique (Delage et al 1998 Recent studies showed that the continuous evaluation of transient suction data by xed-matrix porous ceramic disc sensor in a loose soil state is erroneous (Tripathy et al 2016, Karagoly et al 2018) due to insu cient hydraulic equilibrium time between the sensor disc and the soil. Thus, the stability analysis based on the instantaneous measurement of suction by tensiometer, a commonly used eld technique for riverbanks and slopes (Nam et al 2009), requires reevaluation of the applicability in a compacted state.…”

Section: Introductionmentioning

confidence: 99%

Influence of Hydraulic Response Time of Tensiometer in Hydraulic Characteristics Estimation for Riverbank Sand

Patwa

Bharat

2022

Geotech Geol Eng

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The knowledge of the continuous evolution of soil hydraulic characteristics is required for several environmental geotechnical applications such as capillary barrier systems and river bank slope stability analysis. Such data are obtained in the eld by embedding suction sensors in slopes for stability analysis. The hydraulic equilibrium time and other limitations of sensors in establishing the hydraulic characteristics are not available for the compacted soils. Thus the in uence of initial soil moisture content, initial wetting condition of the suction sensor, and soil compaction density on the hydraulic equilibrium time of the tensiometer was studied on riverbank sand. A laboratory method considering the equilibrium data at each saturation/drying state was proposed for establishing the equilibrium-SWCC data. The hydraulic equilibrium time of the tensiometer for the studied soil was found to vary from few hours to several days depending upon the magnitude of suction and state of the sensor. The conventional method for estimating the instantaneous SWCC severely overestimated the suction values at a given water content. The sensor response time was found to be the single most in uencing factor in the estimation of soil hydraulic characteristics. The in-situ tensiometer application should be replaced with the moisture sensor readings combined with the lab-based proposed equilibrium SWCC approach.

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Soil Suction Measurement of Unsaturated Soils with a Sensor Using Fixed-Matrix Porous Ceramic Discs

Cited by 33 publications

References 11 publications

Oedometer based estimation of vertical shrinkage of expansive soil in a large instrumeted soil column

Oedometer based estimation of vertical shrinkage of expansive soil in a large instrumeted soil column

Expansive soil-biochar-root-water-bacteria interaction: Investigation on crack development, water management and plant growth in green infrastructure

Influence of Hydraulic Response Time of Tensiometer in Hydraulic Characteristics Estimation for Riverbank Sand

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