Project’s Detail

PENGARUH PENAMBAHAN ENDAPAN ALUVIAL TERHADAP NILAI KUAT GESER TANAH LEMPUNG FORMASI KAMPUNG BARU

Abstrak (Abstracts)

On the geological map sheet of Balikpapan city, the sediment structure in this city is composed of several formations, including the Kampung Baru Formation and alluvial sediment units. The Kampung Baru formation is dominated by clay soils which generally have low shear strength characteristics. Therefore, mixing with added materials in the form of alluvial deposits with the aim of knowing the effect of mixing alluvial deposits on soil shear strength. In this study, physical properties testing was carried out consisting of a sieve analysis test, atterberg limits tests, moisture content, volume weight, and specific gravity and mechanical properties of the soil, namely direct shear strength tests with mixed variations of 0%, 10%, 20%, 30%, 40%, 50% alluvial deposits. Based on the results of original soil laboratory tests, the percentage value of passing the filter number 200 = 54,34%, liquid limit (LL) = 45,31%, plastic limit (PL) = 25,72%, plasticity index (PI) = 19,59%, moisture content = 28.64%, volume weight = 3,52 grams/cm3, specific gravity = 2,50, and in the USCS soil classification system (Unified Soil Classification System) this soil is included in the CL group (low plasticity clay). Based on the results of laboratory tests of alluvial deposits, the percentage value of passing the filter number 4 = 95,70%, the percentage value of passing the filter number 200 = 1,84%, moisture content = 28,87%, and in the USCS (Unified Soil Classification System) soil classification system, alluvial deposits are included in the SP group (poorly graded sand). In the addition of variations in alluvial deposits there was a decrease in the cohesion value (c), namely, 0% = 2,7452 kg/cm2, 10% = 2,5380 kg/cm2, 20% = 1,1568 kg/cm2, 30% = 0,9841 kg/cm2, 40% = 0,8460 kg/cm2, and 50% = 0,5007 kg/cm2. In the addition of alluvial sediment variations, there was an increase in the value of the deep shear angle (∅) in the addition of 10% variation of alluvial deposits and a decrease in the addition of variations of 20% to 50% alluvial deposits, namely, 0% = 32,182°, 10% = 59,449°, 20% = 56,319°, 30% = 48,069°, 40% = 45,469°, and 50% = 39,451°. Pada lembar peta geologi kota Balikpapan, struktur endapan yang terdapat di kota ini tersusun atas beberapa formasi, diantaranya Formasi Kampung Baru dan satuan endapan aluvial. Formasi Kampung Baru didominasi oleh tanah lempung yang umumnya memiliki karakteristik kuat geser yang rendah. Oleh karena itu dilakukan pencampuran dengan bahan tambah berupa endapan aluvial dengan tujuan mengetahui pengaruh pencampuran endapan aluvial terhadap kuat geser tanah. Pada penelitian ini dilakukan pengujian sifat fisik yang terdiri dari uji analisis saringan, uji atterberg limits, kadar air, berat volume, dan berat jenis serta sifat mekanik tanah, yaitu uji kuat geser langsung (direct shear) dengan variasi campuran 0%, 10%, 20%, 30%, 40%, 50% endapan aluvial. Berdasarkan hasil uji laboratorium tanah asli diperoleh nilai persentase lolos saringan nomor 200 = 54,34%, batas cair (LL) = 45,31%, batas plastis (PL) = 25,72%, indeks plastisitas (PI) = 19,59%, kadar air = 28,64%, berat volume = 3,52 gram/cm3, berat jenis = 2,50, dan dalam sistem klasifikasi tanah USCS (Unified Soil Classification System) tanah ini masuk dalam kelompok CL (lempung plastisitas rendah). Berdasarkan hasil uji laboratorium endapan aluvial, diperoleh nilai persentase lolos saringan nomor 4 = 95,70%, nilai persentase lolos saringan nomor 200 = 1,84%, kadar air = 28,87%, dan dalam sistem klasifikasi tanah USCS (Unified Soil Classification System) endapan aluvial masuk dalam kelompok SP (pasir bergradasi buruk). Pada penambahan variasi endapan aluvial terjadi penurunan nilai kohesi (c) yaitu, 0% = 2,7452 kg/cm2, 10% = 2,5380 kg/cm2, 20% = 1,6575 kg/cm2, 30% = 0,9841 kg/cm2, 40% = 0,8460 kg/cm2, dan 50% = 0,5007 kg/cm2. Pada penambahan variasi endapan aluvial terjadi kenaikan nilai sudut geser dalam ("∅" ) pada penambahan variasi 10% endapan aluvial dan penurunan pada penambahan variasi 20% sampai 50% endapan aluvial yaitu, 0% = 32,182°, 10% = 59,449°, 20% = 56,319°, 30% = 48,069°, 40% = 45,469°, dan 50% = 39,451°.

Keyword : Alluvial Deposits, Clay Soil, Direct Shear

Nilai Properti

Penulis : DEVIKA PUTRI, NIM : 922020001, Penerbit : Politeknik Negeri Balikpapan, Program Studi : TEKNIK SIPIL, Tahun : 2023, Bahasa : Indonesia, Jenis Penelitian : Tugas Akhir, Lokasi : Prepustakaan Poltekba,

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