LABORATORY TESTING ON COMPACTED, PARTIALLY SATURATED SILTY AND SANDY SOILS

G.E. Scarcella, I. Giusti, S. Giusti, D. Lo Presti

Аннотация


This Technical note summarizes some experimental results concerning the effective strength parameters (c’ – j’) and the saturated coefficient of hydraulic conductivity (k) of silty and sandy soil specimens that have been compacted at different compaction degrees. The tested soils were used for the construction/refurbishment of existing levees. The effective strength parameters were obtained from conventional triaxial loading compression tests. Specimens were compacted at different percentages of the maximum (optimum) dry density and at the optimum water content. The maximum dry density and optimum water content were determined according to the Modified Proctor method. Specimens with different percentages of the maximum dry density at the optimum water content were obtained in the Proctor mold by using different compaction energy. Levees (and more generally any type of earthworks) can increase their water content because of intense rainfall or repeated floods. Therefore, the strength parameters of fully saturated specimens have also been experimentally determined. The saturated coefficient of hydraulic conductivity has been inferred from variable head permeability measurements that were performed in specially equipped oedometers. This coefficient has been measured in the case of specimens compacted at different compaction degrees and at different initial water contents (i.e. saturation degrees). The effect of compaction degree on strength and permeability parameters has been shown. As for the strength parameters, the effect of partial saturation (suction) has also been shown.

Литература


AASHTO M 145 1991. (R1995) (R2000) - Standard Specification for Classification of Soils and Soil-Aggregate Mixtures for Highway Construction Purpose, HM-22: PART IA.

AGI (1997) Raccomandazioni sulle Prove Geotecniche di Laboratorio. SGE Padova 56 pp

ALONSO, O. S., VAUNAT, J., AND PEREIRA, J. M. (2010) - A microstructurally based effective stress for unsaturated soils. Géotechnique, 60(12), pp. 913–925.

ALONSO, E.E., GENS, A., and JOSA, A., (1990), “A Constitutive Model for Partially Saturated Soils,” Géotechnique, Vol. 40, No. 3, pp. 405–430

ASTM D698-12e1. (2012) Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Standard Effort (12 400 ft-lbf/ft3 (600 kN-m/m3)). ASTM International, West Conshohocken, PA.

ASTM D1557-12. (2012) Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort (56,000 ft-lbf/ft3 (2,700 kN-m/m3)). ASTM International, West Conshohocken, PA.

ASTM D4318-10e1. (2010) Standard Test Method for Liquid Limit, Plastic Limit, and Plasticity Index of Soils. ASTM International, West Conshohocken, PA.

ASTM D2487 (2011) Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System). ASTM International, West Conshohocken, PA.

CETIN H., FENER M., SÖYLEMEZ M. & GÜNAYDIN B. (2007) - Soil structure changes during compaction of a cohesive soil. Engineering Geology, 92: 38-48

COCKA E., EROL O. & ARMANGIL F. (2004) - Effects of compaction moisture content on the shear strength of an unsaturated clay. Geotechnical and Geological Engineering, 22: 285 297, Kluwer Academic Publisher.

CARRAI L (2016) Determinazione sperimentale del coefficiente di permeabilità dei materiali utilizzati per gli argini fluviali del Torrente Certosa. B.Sc Thesis, Università di Pisa

FIORENTINI T.(2015) Determinazione del coefficiente di permeabilità dei terreni da prove di laboratorio e in sito e tramite correlazioni empiriche. B.Sc Thesis, Università di Pisa

GIUSTI I. (2017) Improvement of CPT interpretation for partial drainage conditions and for unsaturated soils. PhD Thesis University of Pisa, International Doctorate of Civil & Environmental Engineering.

HAZEN A. (1911) Discussion on Dams on Sand Foundations. Trans. ASCE, Vol. 73

LANCELLOTTA R. (1993) - Geotecnica. Edizioni Zanichelli, seconda edizione.

MATTEUCCI A. (2016) Caratterizzazione geotecnica di terre compattate. B.Sc Thesis, Università di Pisa

PRUGH (1959) - Moretrench Handbook. Priv. Publication. Rockaway, New York

ROSENQVIST, O. TH. (1955), Physico – Chemical Properties of Soils: Soil Water Systems, Journal of the Soil Mechanics and Foundations Division, Proceedings of the American Society of Civil Engineers, pp.31-53.

SEED, H. B., MITCHELL, J.K. and CHAN, C.K. (1961), The Strength of Compacted Cohesive Soils, Conf. Shear Strength of Soils, Colorado, pp. 879-961.

SEED H.B. & CHAN C.K. (1959) - Structure and strength characteristics of compacted clays. Journal of the Soil Mechanics and Foundations Division, Proceedings of the American Society of Civil Engineers, 85 (5): 87-128

TATSUOKA, F. (2015) - Compaction Characteristics and Physical Properties of Compacted Soils Controlled by the Degree of Saturation Proc. Of the Sixth International Symposium on Deformation Characteristics of Geomaterials. IS Buenos Aires 15-18 November 2015

TAYLOR D.W. (1948) - Fundamerntals of Soil Mechanics. John Wiley and Sons

VARSEI M. MILLER G.A. AND HASSANIKHAH A. (2016) Novel Approach to Measuring Tensile Strength of Compacted Clayey Soil during Desiccation. International Journal of Geomechanics, ASCE, ISSN 1532-3641. May 17, 2016.


Ссылки

  • На текущий момент ссылки отсутствуют.