Pendekatan Geoteknik–Statistik dalam Evaluasi Pengaruh Pelapukan Massa Batuan terhadap Stabilitas Lereng Lava Andesit di Bantul, Yogyakarta, Indonesia

Arie Noor Rakhman; Fivry Wellda  Maulana; Jarwanto

doi:10.23960/jgrs.ft.unila.645

Arie Noor Rakhman Program Studi Teknik Geologi, Universitas AKPRIND Indonesia
Fivry Wellda Maulana Program Studi Teknik Geologi, Universitas AKPRIND Indonesia
Jarwanto Program Studi Teknik Geologi, Universitas AKPRIND Indonesia

DOI: https://doi.org/10.23960/jgrs.ft.unila.645

Keywords: Lava andesit, pelapukan massa batuan, pendekatan kuantitatif–statistik, Rock Mass Rating (RMR), stabilitas lereng batuan

Abstract

Stabilitas lereng batuan merupakan faktor krusial dalam mitigasi risiko longsor, khususnya pada kawasan perbukitan vulkanik yang tersusun oleh massa batuan terdiskontinu dan terlapukkan. Ruas Jalan Goa Jepang, Kabupaten Bantul, berada pada lereng curam yang berkembang di lava andesit dan dipengaruhi oleh struktur geologi aktif, sehingga rentan terhadap ketidakstabilan lereng. Penelitian ini bertujuan mengevaluasi pengaruh pelapukan massa batuan, yang diwakili oleh berat unit batuan, terhadap nilai Rock Mass Rating (RMR) dan implikasinya terhadap kestabilan lereng. Pendekatan kuantitatif–statistik diterapkan melalui survei lapangan dan pengujian laboratorium pada tujuh lokasi. Kualitas massa batuan dievaluasi menggunakan RMR, sedangkan hubungan antar parameter dianalisis melalui grafik sebar dan regresi linier. Hasil menunjukkan nilai RMR berkisar 25–72, mencerminkan variasi kualitas massa batuan dari buruk hingga baik. Analisis statistik mengindikasikan hubungan sedang antara berat unit dan RMR (R² = 0,468), meskipun tidak signifikan secara statistik. Temuan ini menegaskan bahwa pelapukan mempengaruhi kestabilan lereng terutama melalui degradasi kondisi diskontinuitas, kekuatan batuan, dan RQD. Hasil penelitian ini mengindikasikan bahwa integrasi parameter pelapukan dalam kerangka klasifikasi RMR dapat meningkatkan keandalan evaluasi stabilitas lereng batuan pada lingkungan vulkanik terlapukkan.

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