EVALUASI STABILITAS BENDUNGAN AKIBAT REMBESAN SERTA METODE PERBAIKAN PADA BENDUNGAN PULO, KABUPATEN BANDUNG, JAWA BARAT

Hendra Ardhana Putra, Dr. Sc. Tech. Ir. Adhy Kurniawan, S.T., IPU.

2026 | Tugas Akhir | D4 TEKNIK PENGELOLAAN DAN PEMELIHARAAN INFRASTRUKTUR SIPIL

Bendungan Pulo merupakan bendungan urukan tanah homogen di Situ Cileunca, Kabupaten Bandung, Jawa Barat yang mengalami rembesan pada area woulbak dekat saluran outlet. Penelitian ini bertujuan untuk mengevaluasi kondisi rembesan, keamanan terhadap piping, serta stabilitas lereng Bendungan Pulo sebelum dilakukan penanganan dan sesudah dilakukan penanganan menggunakan perangkat lunak GeoStudio Seep/W, Slope/W, dan Sigma/W dengan mengacu pada SNI 8064:2016 dan SNI 8065:2016. Analisis dilakukan pada kondisi elevasi tinggi muka air waduk normal, elevasi tinggi muka air waduk banjir, dan surut cepat dengan mempertimbangkan pengaruh pembebanan  gempa maupun tanpa pembebanan gempa.

Hasil analisis menunjukkan bahwa debit rembesan yang terjadi di kondisi elevasi air waduk normal sebesar 2,76 × 10-5 m3/s atau sekitar 0,00045?ri debit inflow sungai sebesar 6 m3/s sehingga masih dalam kriteria kondisi aman. Nilai faktor keamanan terhadap piping di kondisi elevasi air waduk normal sebesar 13,23 dan di kondisi elevasi air waduk banjir sebesar 6,37 sehingga memenuhi syarat keamanan lebih dari 4,00. Pada kondisi gempa OBE sesuai persyaratan dengan kala ulang gempa 100 tahun, lereng hilir menghasilkan angka faktor keamanan sebesar 1,146 < 1>

Alternatif perkuatan yang dianalisis meliputi metode counterweight dan flattening. Kedua metode mampu meningkatkan stabilitas lereng hingga memenuhi persyaratan keamanan, dengan angka faktor keamanan minimum sebesar 1,286 untuk counterweight dan 1,285 untuk flattening. Berdasarkan analisis biaya konstruksi, metode counterweight dinilai lebih efisien dengan total biaya sebesar Rp 2.407.556.000,00 dibandingkan metode flattening sebesar Rp 2.596.572.000,00, sehingga direkomendasikan sebagai metode perkuatan yang paling efektif untuk Bendungan Pulo.

Pulo Dam is a homogeneous earthfill dam located in Situ Cileunca, Bandung Regency, West Java, which experiences seepage in the woulbak area near the outlet structure. This study aims to evaluate the seepage condition, piping safety, and slope stability of Pulo Dam before and after remedial treatment using GeoStudio Seep/W, Slope/W, and Sigma/W software in accordance with SNI 8064:2016 and SNI 8065:2016. The analyses were conducted under conditions of normal reservoir water level, flood reservoir water level, and rapid drawdown., considering both seismic and non-seismic loading conditions.

The analysis results indicate that the seepage discharge under normal water level conditions is 2,76 × 10-5 m³/s, or approximately 0.00045% of the river inflow discharge of 6 m3/s, which is still within the safe limit. The factor of safety against piping under normal and flood water level conditions are 13,23 and 6,37, respectively, both exceeding the minimum safety requirement of 4.00. However, under the Operating Basis Earthquake (OBE) condition with a 100-year return period, the downstream slope exhibits a factor of safety of 1.146 < 1>

The reinforcement alternatives analyzed in this study include the counterweight and flattening methods. Both methods were able to improve slope stability to satisfy the required safety criteria, with minimum factors of safety of 1.286 for the counterweight method and 1.285 for the flattening method. Based on the construction cost analysis, the counterweight method was found to be more efficient, with a total cost of Rp 2.407.556.000,00 compared to Rp 2.596.572.000,00 for the flattening method. Therefore, the counterweight method is recommended as the most effective reinforcement alternative for Pulo Dam.

Kata Kunci : bendungan urukan, rembesan, piping, stabilitas lereng, counterweight, flattening, GeoStudio