KERENTANAN LIKUIFAKSI WILAYAH KOTA BANDA ACEH BERDASARKAN METODE UJI PENETRASI KONUS

Adrin Tohari; Khori Sugianti; Arifan Jaya Syahbana; Eko Soebowo

doi:10.14203/risetgeotam2015.v25.204

KERENTANAN LIKUIFAKSI WILAYAH KOTA BANDA ACEH BERDASARKAN METODE UJI PENETRASI KONUS

Adrin Tohari, Khori Sugianti, Arifan Jaya Syahbana, Eko Soebowo

Abstract

Pengetahuan mengenai kerentanan likuifaksi di suatu wilayah kota pesisir yang rawan gempabumi besar sangat diperlukan dalam perencanaan tataruang untuk mengurangi bencana seismik. Makalah ini menyajikan hasil evaluasi potensi likuifaksi di wilayah Kota Banda Aceh berdasarkan metode uji penetrasi konus untuk menghasilkan mikrozonasi kerentanan penurunan lapisan tanah akibat likuifaksi di wilayah ini. Hasil analisis menunjukkan bahwa potensi likuifaksi terdapat pada lapisan tanah pasir dan campuran pasir dan lanau, yang dicirikan oleh nilai tahanan konus dan hambatan setempat masing-masing lebih kecil dari 15 MPa dan 150 kPa pada kedalaman dan ketebalan yang bervariasi. Berdasarkan hasil perhitungan penurunan tanah, wilayah Banda Aceh dapat dibagi menjadi lima zona kerentanan. Zona kerentanan tinggi terutama terdapat di Kecamatan Kuta Alam dan Syah Kuala, sedangkan zona kerentanan rendah terutama terdapat di wilayah Kecamatan Banda Raya. Dengan demikian, investigasi geoteknik detil sangat diperlukan untuk mencegah kerusakan pada bangunan dan infrastruktur akibat likuifaksi di wilayah Kota Banda Aceh.

Knowledge of liquefaction susceptibility is very important for spatial planning of a coastal city prone to big earthquakes. This paper presents the results of liquefaction potential evaluation based on cone penetration test to produce a microzonation map of liquefaction-induced ground settlement for Banda Aceh City. Results of the analysis show that liquefaction would occur in layers of loose to medium sand and silt-sand mixtures with the values of tip resistance and sleeve friction of less than 15 MPa and 150 kPa, respectively, at various depths. On the basis of ground settlement calculation, the city can generally be divided into five zones. High susceptible zone to ground settlement is mainly concentrated within the Kuta Alam and Syah Kuala Sub-District. Meanwhile, the zone of low susceptibility is within the Banda Raya Sub-District. Thus, detailed geotechnical investigation is necessary to mitigate liquefaction damage on buildings and infrastructures in Banda Aceh City.

Keywords

gempabumi, likuifaksi, mikrozonasi, penurunan tanah, uji penetrasi konus.

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DOI: http://dx.doi.org/10.14203/risetgeotam2015.v25.204