Measurement of Base and Subgrade Layer Stiffness Using Bender Element Technique

Zeng, Xin; Figueroa, J. Ludwig; Fu, Lei

doi:10.1061/40709(257)3

Cited by 5 publications

(3 citation statements)

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“…The small-strain modulus of soils is routinely measured in earthquake engineering. In pavement engineering, the application of small-strain modulus tests to assess the modulus of pavement materials and structural variability for pavement performance has increased dramatically (Kim and Stokoe 1992;Souto et al 1994;Kim et al 1997;Chen et al 1999;Nazarian et al 1999;Fiedler et al 2000;Yesiller et al 2000;Zeng et al 2002;Nazarian et al 2003;Sawangsuriya et al 2005;Edil and Sawangsuriya 2005). The main advantage of small-strain modulus tests is the ability to noninvasively and nondestructively assess the modulus of pavement materials at the surface or under a free-field condition (i.e., near-zero confining pressure).…”

Section: Introductionmentioning

confidence: 97%

Modulus−suction−moisture relationship for compacted soils

2008

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The ultimate parameter of interest in engineering design of compacted subgrades and support fills for highways, railroads, airfields, parking lots, and mat foundations is often the soil modulus. Modulus of compacted soils depends not only on dry unit weight and moisture but also on matric suction and soil structure (or fabric) resulting from the compaction process. However, these relationships in the as-compacted state (i.e., immediately after compaction) have not yet been extensively explored. This paper presents an experimental laboratory study of the shear modulus -matric suction -moisture content-dry unit weight relationship using three compacted subgrade soils. Compacted subgrade specimens were prepared over a range of molding water contents from dry to wet of optimum using enhanced, standard, and reduced Proctor efforts. A nondestructive elastic wave propagation technique, known as bender elements, was used to assess the shear wave velocity and corresponding small-strain shear modulus (Go) of the compacted subgrade specimens. The matric suctions were measured with the filter paper method. An empirical relation that takes into account the effect of compaction conditions is proposed for the Go -matric suction -molding water content relationship of compacted subgrade soils.Résumé : Le paramètre ultime d'ingéniérie qui est d'intérêt dans le calcul d'ingénieur des infrastructures compactées et des remblais de soutien pour les autoroutes, les voies ferrées, les aéroports, les aires de stationnement, et les nattes de fondations est souvent le module du sol. Le module des sols compactés dépendent non seulement du poids volumique sec et de la teneur en eau mais aussi de la succion matricielle et de la structure du sol (ou fabrique) résultant du processus de compactage. Cependant, ces relations dans l'état tel que compacté (c.-à-d. immédiatement après compactage) n'ont pas encore été abondamment explorées. Cet article présente un étude expérimentale en laboratoire de la relation module de cisaillement -succion matricielle -teneur en eau -poids volumique sec en utilisant ces sols d'infrastructure compactés. Des échantillons d'infrastructure compactés ont été préparés dans une large plage de teneurs en eau de moulage en partant du côté sec au côté mouillé de l'optimum et en utilisant des efforts Proctor augmentés, standard, et réduits. Une technique de propagation d'ondes élastiques non destructives au moyen de languettes piézocéramiques a été utilisée pour évaluer la vitesse de l'onde de cisaillement et le module correspondant de cisaillement à faible déformation (Go) des spécimens d'infrastructure compactés. Les succions matricielles ont été mesurées avec la méthode du papier filtre. On propose une relation empirique qui prend en compte l'effet des conditions de compactage pour la relation Go -matrice de succionteneur en eau de moulage des sols d'infrastructure compactés.

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Section: Introductionmentioning

confidence: 97%

Modulus−suction−moisture relationship for compacted soils

2008

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“…Generally, Go of geomaterials is routinely measured in earthquake engineering. In highway engineering, the application of Go tests to assess the stiffness of highway materials and structural variability for pavement performance has increased dramatically (Kim and Stokoe 1992, Souto et al 1994, Kim et al 1997, Chen et al 1999, Nazarian et al 1999, Fiedler et al 2000, Yesiller et al 2000, Zeng et al 2002, Nazarian et al 2003. The key advantage of Go tests over conventional modulus tests is their ability to rapidly and non-destructively assess the shear modulus of highway materials at the surface or under a free-field condition (i.e., zero confining pressure).…”

Section: Application Of Wave Propagation Methods In Pavement Design Amentioning

confidence: 99%

“…For instance, weak transmitted wave signals, poor coupling between transducer and medium, near field effects, and high operating frequencies reduce the signal-to-noise ratio of the collected signals exacerbating the difficulties in interpreting the waveforms generated with these transducers (SanchezSalinero et al 1986, Brignoli et al 1996, Nakagawa et al 1996, Ismail and Rammah 2005. A number of studies on the use of bender elements in wave-based technique has overcome many of the aforementioned problems and recently become a very popular method to measure the S-wave velocity and small-strain shear modulus (Go) and their evolution with changes in effective stresses, water content, and cementation (Dyvik and Madshus 1985, Thomann and Hryciw 1990, Souto et al 1994, Fam and Santamarina 1995, Cho and Santamarina 2001, Pennington et al 2001, Mancuso et al 2002, Zeng et al 2002, Lee and Santamarina 2005.…”

Section: Astm D 4428mentioning

confidence: 99%