Electronic Theses and Dissertation

Tanah longsor merupakan salah satu ancaman geoteknik utama di kawasan Bangunan Pengarah Bendungan Tiro, Kabupaten Pidie, provinsi Aceh yang memiliki topografi curam serta kondisi hidrogeologi yang kompleks. Penelitian ini bertujuan untuk mengidentifikasi dan mengkarakterisasi bidang gelincir di kawasan pembangunan Bendungan Tiro, Pidie, menggunakan metode geolistrik resistivitas 2D dengan konfigurasi wenner- Schlumberger. Metode ini memanfaatkan aliran arus listrik untuk merepresentasikan struktur bawah permukaan yang berpotensi menjadi zona lemah penyebab longsor, sehingga dapat digunakan dalam analisis kestabilan lereng dan strategi mitigasi bencana. Hasil penelitian menunjukkan adanya variasi nilai resistivitas yang mencerminkan lapisan tanah berupa pasir, lempung, lempung pasiran dan boulder. Bidang gelincir terdeteksi pada kedalaman rata-rata 2–3 meter dengan resistivitas berkisar antara 1–100 Ωm dan porositas 30–50% pada setiap lintasannya. Keberadaan lempung jenuh air sebagai material dominan pada bidang gelincir meningkatkan tekanan pori, sehingga mempercepat terjadinya longsor. Faktor eksternal seperti curah hujan tinggi dan kemiringan lereng yang curam semakin memperburuk kondisi kestabilan lereng. Oleh karena itu, diperlukan langkah mitigasi seperti sistem drainase untuk mengontrol infiltrasi air, stabilisasi lereng dengan metode rekayasa geoteknik, serta pemantauan geofisika secara berkala guna meminimalisir risiko bencana tanah longsor.

Landslides represent a significant geotechnical hazard in the Intake Structure area of the Tiro Dam, located in Pidie Regency, Aceh Province, Indonesia. This region is characterized by steep topography and complex hydrogeological conditions, making it highly susceptible to slope failures. The objective of this study is to identify and characterize the potential slip surfaces within the Tiro Dam construction site using the two-dimensional (2D) electrical resistivity method, employing the Wenner-Schlumberger electrode configuration. The resistivity method functions by injecting electrical current into the ground and measuring the resulting potential differences, allowing the delineation of subsurface resistivity variations that may indicate structurally weak zones prone to failure. The data acquired were processed and interpreted to produce 2D resistivity cross-sections, facilitating the analysis of subsurface conditions relevant to slope stability assessments. The results indicate distinct resistivity variations associated with different subsurface materials, including sand, clay, sandy clay, and boulders. A slip surface was identified at an average depth of 2–3 meters, characterized by low resistivity values ranging from 1-100 Ωm and porosity estimates between 30%-50% along all survey lines. The dominance of water-saturated clay within this zone significantly increases pore water pressure, thereby reducing shear strength and accelerating slope instability. External factors such as high rainfall intensity and steep slope gradients further exacerbate the instability of the terrain. Based on these findings, it is recommended that appropriate mitigation measures be implemented, including the installation of drainage systems to control water infiltration, slope stabilization through geotechnical engineering techniques, and continuous geophysical monitoring to minimize the risk of landslide occurrence in the study area.