Fikriyah, Addinal (2018) Aplikasi Metode Geolistrik Konfigurasi Wenner-Schlumberger, Masw (Multichannel Analysis 0f Surface Wave), Dan Data Mekanika Tanah Untuk Analisis Gerakan Tanah (Studi Kasus: Jembatan Cisomang, Tol Cipularang Km 100 Jawa Barat). Undergraduate thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Gerakan tanah sering kali disebabkan oleh struktur bawah permukaan. Penelitian ini dilakukan untuk penyelidikan bawah permukaan di Jembatan Cisomang yang sebelumnya terjadi pergeseran jembatan pada pilar P0, P1 dan P2. Metode pertama yang digunakan yaitu metode geolistrik konfigurasi Wenner-Schlumberger untuk mengetahui jenis lapisan bawah permukaan melalui nilai distribusi resistivitas terukur hasil pemodelan 2D menggunakan software Res2dinv. Metode kedua yaitu metode MASW untuk mengetahui tingkat lapisan bawah permukaan melalui kecepatan gelombang geser (VS30). Metode ketiga yaitu melalui data mekanika tanah untuk mengetahui nilai faktor keamanan lereng dengan membuat pemodelan lereng software Geostudio 2016 SLOPE/W. Pengukuran metode geolistrik menggunakan sistem multichannel, panjang lintasan 180 m, 36 titik elektroda, jarak masing-masing elektroda 5 m. Dari hasil pemodelan diperoleh distribusi nilai resistivitas terdiri dari 5 lapisan, lapisan pertama 0,868 Ωm - 2.45 Ωm, lapisan ke-2 6.89 Ωm - 19.4 Ωm, lapisan ke-3 54.8 Ωm - 154 Ωm, lapisan ke-4 435 Ωm, dan lapisan ke-5 1226 Ωm. Pengukuran metode MASW dengan panjang lintasan 48 m, 24 geofon jarak masing-masing geofon 1 m, diperoleh hasil kecepatan gelombang geser (VS30) antara lain 40-175 m/s, 175-350 m/s, dan 350-500 m/s. Dari metode geolistrik diketahui terdapat 2 bidang gelincir di kedalaman ±18m pada titik pengukuran 45 m - 110 m dan 45 m - 156 m. Dari metode MASW bidang gelincir di kedalaman ± 18 m. Hasil pemodelan menggunakan 2 sampel tanah yang diuji di laboratorium, berdasarkan bidang gelincir 1 dan 2 metode geolistrik diperoleh nilai faktor keamanan (FK) lereng 0.786 dan 0.518 yang menunjukkan bahwa lereng tersebut dalam kondisi tidak aman. Dari hasil pemantauan menggunakan GPS Trimle terjadi pergeseran setiap periodenya. Pada periode Mei 2017 dan Agustus 2017 pergeseran terbesarnya yaitu 0.133 m, pada periode Agustus 2017 dan Februari 2018 pergeseran terbesarnya yaitu 0.02018 m.
=================================================================================================Soil movement is often caused by subsurface structures. This research was conducted for subsurface investigation at Cisomang Bridge which previously happened bridge shift on pillar P0, P1 and P2. The first method used is geoelectric method with Wenner-Schlumberger configuration to determine the type of subsurface through the measured resistivity distribution value of 2D modeling results using Res2dinv software. The second method is the MASW method to determine the subsurface layer level through the shear wave velocity (VS30). The third method is through soil mechanics data to know the slope factors value by making the modeling through Geostudio 2016 SLOPE / W software. Geoelectric measurements using multichannel system, 180 m length path, 36 electrode point, distance of each 5 m electrode. From the modeling results obtained the resistivity value distribution consists of 5 layers, first layer 0.868 Ωm - 2.45 Ωm, 2nd layer 6.89 Ωm - 19.4 Ωm, 3rd layer 54.8 Ωm - 154 Ωm, the layer to -4 435 Ωm, and the 5th layer of 1226 Ωm. MASW measurement method with path length 48 m, 24 geofon distance of each geofon 1 m, obtained the result of shear wave velocity (VS30), among others 40-175 m / s, 175-350 m / s, and 350-500 m / s. From the geoelectric method it is known that there are two slip fields at depth of ± 18m at the measuring point of 45 m - 110 m and 45 m - 156 m. From the MASW method the field of slip at a depth of ± 18 m. The results of modeling using two soil samples tested in the laboratory, based on the slip fields 1 and 2 geoelectric method obtained the value of the safety factor (FK) slopes 0.786 and 0.518 indicating that the slope is unsafe. From the monitoring result using GPS Trimle done every period. In the period May 2017 and August 2017 the largest shift of 0.133 m, in the period August 2017 and February 2018 the largest shift of 0.02018 m.
| Item Type: | Thesis (Undergraduate) |
|---|---|
| Uncontrolled Keywords: | Geoelectric, MASW, Soil mecanics, Soil movement |
| Subjects: | G Geography. Anthropology. Recreation > GB Physical geography > GB1197.7 Groundwater flow. Reservoirs G Geography. Anthropology. Recreation > GE Environmental Sciences Q Science > QC Physics > QC610.3 Electric conductivity Q Science > QE Geology > QE538.5 Seismic tomography; Seismic waves. Elastic waves Q Science > QE Geology > QE539.2.S4 Seismic models Q Science > QE Geology > QE601 Geology, Structural |
| Divisions: | Faculty of Mathematics and Science > Physics > 45201-(S1) Undergraduate Thesis |
| Depositing User: | Addinal Fikriyah |
| Date Deposited: | 15 Jul 2021 08:33 |
| Last Modified: | 15 Jul 2021 08:33 |
| URI: | http://repository.its.ac.id/id/eprint/55488 |
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