Electronic Theses and Dissertation

Banjir bandang mengubah karakteristik tanah akibat pengangkutan dan pengendapan sedimen secara masif. Tanah endapan pasca banjir ini perlu diuji sifat fisisnya sebagai dasar penentuan kelayakan pada bidang konstruksi. Penelitian ini bertujuan mengetahui sifat fisis, menganalisis parameter gradasi ($C_u$ dan $C_c$) serta kesesuaian literatur, dan mengklasifikasikan jenis tanah di Kabupaten Pidie Jaya berdasarkan Unified Soil Classification System (USCS) dan American Association of State Highway and Transportation Officials (AASHTO). Sampel diambil dari enam lokasi, yaitu Gampong Baro, Blang Dalam, Manyang Cut, Beurawang, Meunasah Bie, dan Geunteng. Hasil pengujian menunjukkan nilai berat jenis ($G_s$) sebesar 2,52 (Gampong Baro); 2,54 (Blang Dalam); 2,55 (Manyang Cut); 2,51 (Beurawang); 2,65 (Meunasah Bie); dan 2,67 (Geunteng). Batas cair (LL) tercatat 48,86% (Gampong Baro); 44,10% (Blang Dalam); 35,17% (Manyang Cut); dan 30,69% (Beurawang), sementara Meunasah Bie dan Geunteng bersifat Non-Plastis. Batas plastis (PL) sebesar 30,77% (Gampong Baro); 29,64% (Blang Dalam); 24,13% (Manyang Cut); dan 28,85% (Beurawang). Indeks plastisitas (PI) bernilai 18% (Gampong Baro); 14% (Blang Dalam); 11,03% (Manyang Cut); dan 1,83% (Beurawang). Persentase lolos saringan No. 200 sebesar 99,40% (Gampong Baro); 99,73% (Blang Dalam); 90,63% (Manyang Cut); 90,91% (Beurawang); 64,98% (Meunasah Bie); dan 40,80% (Geunteng), sehingga evaluasi parameter gradasi diabaikan akibat dominasi material halus dan sifat plastisitas penentu. Menurut klasifikasi AASHTO, Gampong Baro dan Blang Dalam termasuk kelompok A-7-5(22) dan A-7-5(18), Manyang Cut A-6(12), sedangkan Beurawang, Meunasah Bie, dan Geunteng tergolong A-4 dengan indeks kelompok masing-masing 11, 6, dan 1. Berdasarkan USCS, Gampong Baro, Blang Dalam, Manyang Cut, Beurawang, dan Meunasah Bie diklasifikasikan sebagai ML (lanau tak organik), sedangkan Geunteng sebagai SM (pasir berlanau). Kesimpulannya, material endapan didominasi butiran halus hingga kasar berplastisitas rendah hingga tinggi, yang memerlukan evaluasi geoteknik lanjutan jika dimanfaatkan untuk material pendukung konstruksi.

Flash floods alter local soil characteristics due to massive sediment transport and deposition. It is necessary to test these post-flood deposited soils' physical properties to determine their construction suitability. This study aims to determine the physical properties, analyze gradation parameters ($C_u$ and $C_c$) alongside literature conformity, and classify soil types in Pidie Jaya Regency based on the Unified Soil Classification System (USCS) and the American Association of State Highway and Transportation Officials (AASHTO). Samples were taken from six locations: Gampong Baro, Blang Dalam, Manyang Cut, Beurawang, Meunasah Bie, and Geunteng. The results showed specific gravity ($G_s$) values of 2.52 (Gampong Baro); 2.54 (Blang Dalam); 2.55 (Manyang Cut); 2.51 (Beurawang); 2.65 (Meunasah Bie); and 2.67 (Geunteng). The liquid limit (LL) was 48.86% (Gampong Baro); 44.10% (Blang Dalam); 35.17% (Manyang Cut); and 30.69% (Beurawang), while Meunasah Bie and Geunteng were Non-Plastic. The plastic limit (PL) was 30.77% (Gampong Baro); 29.64% (Blang Dalam); 24.13% (Manyang Cut); and 28.85% (Beurawang). The plasticity index (PI) was 18% (Gampong Baro); 14% (Blang Dalam); 11.03% (Manyang Cut); and 1.83% (Beurawang). The percentage passing the No. 200 sieve was 99.40% (Gampong Baro); 99.73% (Blang Dalam); 90.63% (Manyang Cut); 90.91% (Beurawang); 64.98% (Meunasah Bie); and 40.80% (Geunteng). Thus, gradation evaluation was omitted due to the dominance of fine materials and plasticity properties. Under AASHTO, Gampong Baro and Blang Dalam are A-7-5(22) and A-7-5(18), Manyang Cut is A-6(12), and Beurawang, Meunasah Bie, and Geunteng are A-4 with group indices of 11, 6, and 1, respectively. Based on USCS, Gampong Baro, Blang Dalam, Manyang Cut, Beurawang, and Meunasah Bie are classified as ML (inorganic silt), and Geunteng as SM (silty sand). In conclusion, these deposited materials are dominated by fine to coarse grains with low to high plasticity, requiring further geotechnical evaluation for construction use.