Analisis Sifat Fisis Dan Mekanis Lempung Dalam Penentuan Daya Dukung Tanah (Studi Kasus: Kecamatan Manyar, Kabupaten Gresik)

Kawasan reklamasi di Kecamatan Manyar, Gresik merupakan daerah dengan kondisi tanahnya yang didominasi oleh tanah lempung. Sebelum dilakukan pembangunan dan pembebanan, perlu dilakukan investigasi untuk mendapatkan kapasitas atau daya dukung tanah lempung tersebut. Tujuan dari penelitian ini ialah untuk mendapatkan karakter fisis dan mekanis lempung di lokasi penelitian, yang kemudian dilakukan pemodelan pembebanan dengan model tanah lempung dan timbunan di software. Sehingga didapatkan kurva penurunan terhadap pembebanan, yang digunakan dalam penentuan nilai daya dukung optimum tanahnya. Penelitian ini menggunakan sampel lempung dari lapangan untuk dilakukan pengukuran sifat fisis secara langsung di laboratorium. Didapatkan hasil densitas 1,448 gr/cm3, porositas 70,046 %, specific gravity 2,565, kohesi 5,238 kN/m2, dan koefisien konsolidasi 0,0339 m2/hari. Hasil analisis hubungan antar parameter didapatkan bahwa antara specific gravity – porositas, kohesi – specific gravity, koefisien konsolidasi – specific gravity, dan koefisien konsolidasi – kohesi berbanding lurus. Kemudian antara kohesi – porositas didapatkan hubungan berbanding terbalik. Sedangkan parameter yang tidak menunjukkan adanya korelasi ialah antara porositas – densitas, specific gravity – densitas, kohesi – densitas, koefisien konsolidasi – densitas dan koefisien konsolidasi – porositas. Dari 4 model tanah dasar dan timbunan yang dimodelkan didapatkan hasil daya dukung optimum untuk model 1 sebesar 35 kN/m2, model 2 variasi 1 sebesar 40 kN/m2, model 2 variasi 2 sebesar 43 kN/m2, model 2 variasi 3 sebesar 47 kN/m2, model 3 sebesar 45 kN/m2, dan model 4 sebesar 7000 kN/m2. ================================================================================================================================= Reclamation area in Manyar Subdistrict, Gresik is an area with base soil dominated by clay. Before construction and loading carried out, an investigation is needed to obtain the bearing capacity of clay. The purpose of this study was to obtain physical and mechanical characteristics of clay at the site, and then performed loading modeling with clay models and embankments in software. So obtained the curve of settlement vs loading, which is used in determining the value of the optimum bearing capacity of soil. This study used clay samples from the field to measure physical properties directly in the laboratory. Obtained density results is 1,448 gr/cm3, porosity is 70,046 %, specific gravity is 2,565, cohesion is 5,238 kN/m2, and coefficient of consolidation is 0.0339 m2/day. The results of analysis of the correlation between parameters found that between specific gravity – porosity, cohesion – specific gravity, coefficient of consolidation – specific gravity, and coefficient of consolidation – cohesion are directly proportional. Then between cohesion – porosity is inversely proportional. While the parameters that do not indicate a correlation are between porosity – density, specific gravity – density, cohesion – density, coefficient of consolidation – density and coefficient of consolidation – porosity. From the 4 base soil models and the embankments model the optimum bearing capacity for model 1 is 35 kN/m2, model 2 1st variation is 40 kN/m2, model 2 2nd variation is 43 kN/m2, model 2 3rd variation is 47 kN/m2, model 3 is 45 kN/m2, and model 4 is 7000 kN/m2