Electronic Theses and Dissertation

Banjir bandang merupakan bencana yang dapat mengubah karakteristik tanah akibat proses pengangkutan dan pengendapan sedimen. Tanah endapan pasca banjir perlu diuji untuk mengetahui sifat fisisnya sebagai dasar dalam menentukan potensi pemanfaatannya di bidang konstruksi. Penelitian ini bertujuan untuk mengetahui sifat-sifat fisis tanah endapan pasca banjir bandang di Kabupaten Bireuen serta mengklasifikasikan tanah berdasarkan sistem Unified Soil Classification System (USCS) dan American Association of State Highway and Transportation Officials (AASHTO). Penelitian dilakukan dengan mengambil sampel tanah pada enam lokasi, yaitu Desa Keurumbok, Cot Ara, Lueng Danen, Pante Baroe Kumbang, Meunasah Pulo, dan Garot. Hasil pengujian menunjukkan bahwa nilai berat jenis (Gs) berkisar antara 2,51–2,54, dengan nilai tertinggi di Desa Lueng Danen dan terendah di Desa Keurumbok. Nilai batas cair (LL) berkisar antara 41,50–66,44%, dengan nilai tertinggi di Desa Garot dan terendah di Desa Cot Ara. Nilai batas plastis (PL) berkisar antara 26,23–36,90%, dengan nilai tertinggi di Desa Garot dan terendah di Desa Cot Ara, sedangkan nilai indeks plastisitas (PI) berkisar antara 15,28–29,81%, dengan nilai tertinggi di Desa Meunasah Pulo dan terendah di Desa Cot Ara. Persentase lolos saringan No. 200 berkisar antara 96,75-99,91%, yang menunjukkan bahwa tanah didominasi oleh butiran halus, seperti lempung dan lanau. Berdasarkan klasifikasi AASHTO, tanah di Desa Pante Baroe Kumbang, Lueng Danen, Meunasah Pulo, dan Garot termasuk kelompok A-7-5, sedangkan Desa Keurumbok dan Cot Ara termasuk A-7-6. Berdasarkan klasifikasi USCS, sebagian besar sampel, yaitu Desa Pante Baroe Kumbang, Keurumbok, Lueng Danen, Meunasah Pulo, dan Garot, termasuk kelompok OH, sedangkan Desa Cot Ara termasuk kelompok CL.

Flash floods are disasters capable of altering soil characteristics through sediment transport and deposition processes. Post-flood alluvial soil requires testing to determine its physical properties, which serve as a basis for assessing its potential use in construction. This study aimed to determine the physical properties of post-flash flood alluvial soil in Bireuen Regency and to classify the soil according to the Unified Soil Classification System (USCS) and the American Association of State Highway and Transportation Officials (AASHTO) system. Soil samples were collected from six locations: Keurumbok, Cot Ara, Lueng Danen, Pante Baroe Kumbang, Meunasah Pulo, and Garot villages. Test results indicated that specific gravity (Gs) values ​​ranged from 2.51 to 2.54, with the highest value found in Lueng Danen Village and the lowest in Keurumbok Village. Liquid limit (LL) values ​​ranged from 41.50% to 66.44%, with the highest value in Garot Village and the lowest in Cot Ara Village. Plastic limit (PL) values ​​ranged from 26.23% to 36.90%, with the highest value in Garot Village and the lowest in Cot Ara Village; meanwhile, plasticity index (PI) values ​​ranged from 15.28% to 29.81%, with the highest value in Meunasah Pulo Village and the lowest in Cot Ara Village. The percentage of material passing the No. 200 sieve ranged from 96.75% to 99.91%, indicating that the soil is dominated by fine-grained particles, such as clay and silt. Based on the AASHTO classification, the soil in Pante Baroe Kumbang, Lueng Danen, Meunasah Pulo, and Garot villages falls into the A-7-5 group, whereas the soil in Keurumbok and Cot Ara villages falls into the A-7-6 group. Based on the USCS classification, the majority of the samples—specifically those from the villages of Pante Baroe Kumbang, Keurumbok, Lueng Danen, Meunasah Pulo, and Garot—fall into the OH group, whereas the sample from Cot Ara Village falls into the CL group.