Pengaruh Fine Aggregate Angularity dan Persentase Pasir Terhadap Permeabilitas Tanah Residual Tropis yang Dipadatkan
DOI:
https://doi.org/10.5614/jts.2013.20.1.5Keywords:
Campuran tanah residual dan pasir, Nilai FAA, Persentase pasir, Permeabilitas.Abstract
Abstrak. Penelitian ini mempelajari pengaruh Fine Aggregate Angularity (FAA) dan persentase komponen pasir pada permeabilitas arah vertikal campuran tanah lempung residual tropis dan pasir yang dipadatkan. FAA adalah nilai uncompacted void ratio pasir yang nilainya dipengaruhi oleh bentuk partikel dan tekstur permukaannya. Material yang digunakan adalah tanah merah residual tropis dari Jatigede dan tiga jenis pasir dari Galunggung, Growong, dan Cimalaka, Jawa Barat. Penelitian menggunakan metode desain faktorial dengan dua faktor utama dan tiga level untuk masing-masing faktor. Dua faktor yang diteliti adalah persentase kandungan pasir (20, 40, dan 60%) dan nilai FAA pasir (47,67, 57,00, dan 62,89%). Benda uji dibuat dengan cara dipadatkan pada kadar air optimum dengan target berat isi kering maksimum sesuai dengan hasil uji Standard Proctor Compaction (ASTM D698). Pengukuran permeabilitas campuran tanah merah dengan pasir mengacu pada British Standard BS 1377: Part 8:1990. Hasil pengujian pemadatan memperlihatkan bahwa semakin bertambah nilai FAA pasir maka semakin berkurang berat isi kering tanah campuran dan semakin bertambah harga kadar air optimumnya. Hasil pengujian permeabilitas menunjukkan bahwa peningkatan tegangan sel, peningkatan nilai FAA, dan pengurangan persentase pasir pada umumnya menurunkan harga koefisien permeabilitas arah vertikal. Hasil analisis metode ANOVA menunjukkan bahwa pengaruh faktor persentase pasir lebih dominan dibandingkan pengaruh faktor FAA.Abstract. This reseach studied the effect of Fine Aggregate Angularity (FAA) and sand content on the vertical coefficient of permeability of compacted tropical residual soil and sand mixtures. FAA is the uncompacted void ratio of sand which is influenced by particle shape and texture. The material used in this study consisted of tropical residual red clay soil collected from a quary in Jatigede and three different sand types collected from Galunggung, Growong, and Cimalaka, all in West Java area. This experiment was conducted following a factorial design for two factors and three levels for each factor. The two factors are sand contents (20, 40, 60%) and FAA of sand (47.67, 57.00, 62.89%). The test speciments were compacted samples each prepared at the maximum dry density
and optimum water content of Standard Proctor Compaction Test (ASTM D698). The test specimens were subjected to British Standard BS 1337:Part 8:1990 for permeability determination. This study indicated that the tropical red soil-sand mixture with the highest FAA value has the minimum dry density and the maximum optimum water content. The results also show that increasing confining pressure, increasing FAA, and decreasing sandcontent will decrease the vertical coefficient of permeability. The results of statistical analysis of variance (ANOVA) show that the sand content has the more dominant effect than the FAA factor on the coefficient of permeability of the compacted tropical red soil and sand mixtures.
References
ASTM C1252, 1998, Standard Test Methods for Uncompacted Void Content of Fine Aggregate (as Influenced by Particle Shape, Surface Texture, and Grading, Annual Book of ASTM Standards Volume 04.02,
ASTM International, West Conshohocken, PA, 2001.
ASTM D698-91, 1999, Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Standard Effort, Annual Book of ASTM Standard Section 4. Vol. 04.08. ASTM International, West Conshohocken, PA, pp. 78-85.
British Standards 1377: Part 8, 1990, Methods of Test of Soils for Civil Engineering Purposes, Consolidation Section.
Dunn, A.J., and Mehuys. G.R., 1984, Relationship Between Gravel Content of Soils and Saturated Hydraulic Conductivity in Laboratory Tests, p. 55-63. In J.E. Box, Jr. (ed.) Erosion and productivity of soils containing rock fragments. SSSA Spec. Publ. 13. SSSA, Madison, WI.
Indrawan, I.G.B., Rahardjo, H., Leong, E.C., 2005, Effects of Coarse-Grained Materials on. Properties of Residual Soil, Engineering Geology, 82, 154-164.
Jafari, M.K., Shafiee, A., 2004, Mechanical Behavior of Compacted Composite Clays, Canadian Geotechnical Journal, 41 (6), 1152-1167.
NCHRP, 2005, Appendixes to NCHRP Report 555: Test Methods for Characterizing Aggregate Shape, Texture, and Angularity.
Rismantojo, E., Haddock, J.E., White, T.D., 2003, Comparison of Fine Aggregate Uncompacted Voids Content Measured by the ASTM C 1252 and the VTM-5 Devices, Jounal of Testing and Evaluation, Vol. 31, No. 4.
Shafiee, A., 2008, Permeability of Compacted Granule-Clay Mixtures, Engineering Geology 97, 199-208.
Tavakoli, H.R., Shafiee, A., Jafari, M.K., 2010, Hydraulic Conductivity of Compacted Composite Clays, International Journal of Civil and Structural Engineering, Vol. 1, No. 3.
