Estimasi Volume Unconsolidated Zone Menggunakan Metode Ground Penetrating Radar (GPR) Sebagai Upaya Mitigasi Longsor Pada Area Helipad Mp66 PT Freeport Indonesia

Anjani, Dewi Wanda (2025) Estimasi Volume Unconsolidated Zone Menggunakan Metode Ground Penetrating Radar (GPR) Sebagai Upaya Mitigasi Longsor Pada Area Helipad Mp66 PT Freeport Indonesia. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Area helipad PT Freeport Indonesia (PTFI) memiliki fungsi vital dalam menjalankan operasional perusahaan, yakni sebagai zona pendaratan dan aktivitas transportasi udara. Sebab area helipad ini berada di atas Pegunungan Sudirman, area ini berpotensi mengalami gangguan stabilitas akibat keberadaan zona lemah di bawah permukaan. Oleh karena itu, metode Ground Penetrating Radar (GPR) digunakan sebagai metode geofisika non-destruktif test untuk mengidentifikasi potensi zona lemah bawah permukaan. Akuisisi data dilakukan menggunakan antena 124 MHz. Area helipad diukur sebanyak 20 lintasan dengan lintasan sepanjang 37,8 meter dan spasi antar lintasan 2 meter. Data pengukuran GPR diproses melalui beberapa tahapan move start time dan filtering (background removal, bandpass filter, dan FK-filter), untuk meningkatkan kualitas refleksi sinyal. Hasil interpretasi menunjukkan adanya anomali refleksi tidak kontinu dan amplitudo rendah pada jarak 1-6 meter, 8-12 meter, 13-17 meter, 20-22 meter, 27-30 meter, dan 34-40 meter dengan kedalaman sekitar 7-15 meter. Anomali ini mengindikasikan keberadaan zona lemah atau rongga akibat perbedaan kepadatan material di bawah permukaan. Selanjutnya, volume void ratio zona lemah diestimasi sebesar 200,14-287,27 m^3.
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The helipad area operated by PT Freeport Indonesia (PTFI) serves a critical role in supporting aerial transportation essential to the company’s operational activities. Situated in the high-altitude region of the Sudirman Mountains, the site is inherently susceptible to geotechnical instability, particularly due to the potential development of subsurface weak zones. To investigate this condition, a non-destructive geophysical survey utilizing the Ground Penetrating Radar (GPR) method was employed to delineate potential weak zones beneath the helipad. Data acquisition was performed using a 124 MHz antenna over 20 parallel survey lines, each measuring 37.8 meters in length with 2-meter spacing between lines. The acquired GPR data underwent several preprocessing steps, including move-start time correction and filtering techniques such as background removal, bandpass filtering, and frequency–wavenumber (FK) filtering, to enhance the signal-to-noise ratio and improve subsurface imaging clarity. The interpretation results revealed discontinuous reflections and low-amplitude anomalies across multiple intervals (1–6 m, 8–12 m, 13–17 m, 20–22 m, 27–30 m, and 34–40 m) at depths ranging from approximately 7 to 15 meters. These anomalies are interpreted as indicative of weak zones or subsurface voids associated with heterogeneous material density. The estimated volume of these void zones ranges between 200.14 and 287.27 m³, suggesting the need for remedial action to ensure the structural integrity and long-term stability of the helipad facility.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Gelombang Elektromagnetik, GPR, Tanah Longsor, Unconsolidated Zone,Electromagnetic Wave, GPR, Landslide, Unconsolidated Zone
Subjects:	T Technology > TN Mining engineering. Metallurgy > TN269 Prospecting--Geophysical methods
Divisions:	Faculty of Science and Data Analytics (SCIENTICS) > Physics > 45201-(S1) Undergraduate Thesis
Depositing User:	Dewi Wanda Anjani
Date Deposited:	04 Aug 2025 11:45
Last Modified:	04 Aug 2025 11:45
URI:	http://repository.its.ac.id/id/eprint/124809

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