A Preliminary study on construction of a high capacity tensiometer and its use in measurement of matrik suction in unsaturated soils

Download

index.pdf

Date

2013

Author

Köksalan, Ali Okan

Metadata

Show full item record

Item Usage Stats

254
views

127
downloads

Soil suction is one of the main state parameters that governs unsaturated soil behaviour. Tensiometers are the only type of probe that can measure soil suction directly, but only up to 90 kPa. In the past two decades, a new type of tensiometer with much greater measurement range (up to 2 MPa) has appeared in the literature. The measurement range (i.e. capacity) of a tensiometer is limited by (i) how well it is saturated, and (ii) the air entry value of its porous interface. In this study, the first high capacity tensiometer of Turkey was designed and built. For the purpose of increasing the measurement capacity of the tensiometers, a novel saturation setup that uses a hydraulic pressurization system with capacity of 10 MPa was designed and built. A vacuum-and-pressure saturation procedure was developed. To calibrate the 10 MPa pressure transducers that form the core of the tensiometers, a high-pressure calibration setup capable of pressurizing up to 11 MPa was designed and built. By varying designs of tensiometer bodies, porous interfaces and seals, ways of increasing the suction capacity are investigated. Over a dozen tensiometer design variations are developed, and tried by exposing to atmospheric evaporation. A maximum suction measurement of 870 kPa was achieved with a conventional design; however, none of the new designs were successful. 3 successful designs were also briefly tried on soil samples

Subject Keywords

Soil mechanics., Settlement of structures., Soil stabilization., Tensiometers., Measuring instruments.

URI

http://etd.lib.metu.edu.tr/upload/12615637/index.pdf
https://hdl.handle.net/11511/22347

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Swell pressure prediction by suction methods Kandemir, A; Erol, O; Erzin, Y (1997-09-12) Soil suction is the most relevant soil parameter for characterization of the swell behaviour. An attempt has been made to predict the swell pressures from soil suction measurements. Bentonite-Kaolinite clay mixtures were prepared to obtain soils in a wide range of plasticity indices. Suction measurements using thermocouple physchrometer technique and constant volume swell tests in oedometers were made on statically compacted specimens. Soil suction is correlated to plasticty index, water content and dry den...
Swell pressure prediction by suction methods Erzin, Yusuf; Erol, Orhan (2007-07-10) Soil suction is the most relevant soil parameter for characterization of the swell behavior. An attempt was made to predict swell pressures from soil suction measurements. In this study, Na-bentonite was mixed with kaolinite in the ratios of 5, 10, 15, 20 and 25% of dry kaolinite weight to obtain soils in a wide range of plasticity indices (i.e. 30, 50, 68, 84 and 97%). Suction measurements using thermocouple psychrometer technique were made on statically compacted specimens. The dependence of soil suction ...
A laboratory study of anisotropy in engineering properties of Ankara clay İspir, Mustafa Erdem; Ergun, Mehmet Ufuk; Department of Civil Engineering (2011) Anisotropy in engineering properties of soils occurs due to the depositional process forming the soil fabric and/or different directional stresses in soil history. This study investigates the anisotropy in undrained shear strength and drained compressibility of preconsolidated, stiff and fissured Ankara Clay. The compressibility behavior is determined using standard oedometer testing while the shear strength anisotropy is investigated through large diameter unconsolidated-undrained triaxial testing on undis...
Comparative study of soil water characteristic curve prediction methods Ahmadiadli, Mohammad; Huvaj Sarıhan, Nejan; Toker, Nabi Kartal; Kürkçü, Mefküre Gamze (2012-06-30) The soil-water characteristic curve (SWCC), which defines the relation between soil suction and water content, plays a key role in geotechnical studies of the unsaturated soils. Some researchers such as Brooks & Corey (1968), Van Genuchten (1982) and Fredlund& Xing (1994) have proposed curve fitting equations for SWCC. Fitting equations to the laboratory test data obtained from direct measurement of water content versus changes in matric suction is the most reliable method, but it is expensive and time cons...
A probabilistic model for CPT-based soil classification Çetin, Kemal Önder (2003-07-09) Due to lack of soil sampling during a conventional cone penetration testing, it is necessary to classify soils based on recorded tip and sleeve friction values. Currently available semi-empirical methods of Robertson and Wride (1997) and Olsen and Mitchell (1995) exhibit a significant variability in the estimation of soil type based on cone penetration test (CPT) data. Thus within the confines of this paper it is attempted to present a new probabilistic CPT-based soil classification methodology which addres...

Citation Formats

A. O. Köksalan, “A Preliminary study on construction of a high capacity tensiometer and its use in measurement of matrik suction in unsaturated soils,” M.S. - Master of Science, Middle East Technical University, 2013.