Analisis Geologi Teknik Longsor di Desa Kuatae, Kecamatan Kota Soe, Nusa Tenggara Timur

Heri Syaeful, Dhatu Kamajati, Yoshi Rachael, Ebenheser Damaledo

DOI: http://dx.doi.org/10.55981/eksplorium.2021.6081

Abstract


ABSTRAK Bencana alam longsor di Desa Kuatae, Kecamatan Kota Soe sering terjadi pada musim hujan. Longsor telah menyebabkan rusaknya rumah dan infrastruktur lainnya. Penelitian longsor dilakukan dengan pemetaan geologi teknik, pengeboran geologi teknik, uji laboratorium, analisis kestabilan lereng, dan identifikasi opsi penanggulangan. Berdasarkan hasil pemetaan, longsor terjadi dalam dua model, yaitu blok batugamping terumbu yang mengalami longsor translasi di atas napal dan batulempung serta longsor rotasi pada napal yang dikontrol oleh lapisan dasar yang kontak dengan batulempung. Hasil uji penetrasi standar pada batulempung dan napal menunjukkan nilai konsistensi yang sangat tinggi. Hasil analisis kestabilan lereng menunjukkan lereng dalam keadaan stabil tapi ternyata longsor masih terjadi di beberapa tempat pada area napal dan batulempung. Hal tersebut mengindikasikan bahwa material batuan mengalami degradasi kuat geser pada beberapa kondisi. Penelitian lebih lanjut terkait degradasi material batuan, seperti sifat tahan lekang dan lempung mengembang sangat penting untuk menentukan opsi penanggulangan yang paling tepat dilakukan pada kasus longsor di Desa Kuatae.


ABSTRACT Landslides in Kuatae Village, Kota Soe District often occur during the rainy season. The slope failures cause damage to houses and other infrastructures. The research of slope failure has been carried out by using engineering geological mapping, engineering geological drilling, laboratory test, slope stability analysis, and identification of countermeasure options. Based on the mapping results, slope failures occur in two models, the first one was coral limestone blocks translation failure over marl and claystone, and the second one was rotation failure on marl that controlled by the base layer which contact with claystone. The result of the standard penetration test on claystone and marl showed a very high consistency value. The slope stability analysis had shown the slope is in a stable state, but slope failure occurred in several places on the marl and claystone area. Those indicated that the material had encounter shear strength degradation under several circumstances. Further investigation on the degradation of the rock material, such as slake durability and swelling clay are very important to determine the most appropriate countermeasure option to be applied in the landslide case of Kuatae Village.

Keywords


Kota Soe; longsor; translasi; rotasi; degradasi kuat geser

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