Lusela, Yonathan Anung and Dr. Ir. Runi Asmaranto, ST., MT., IPM. and Dr. Eng. Andre Primantyo, H., ST., MT. (2022) Kajian Alternatif Penanganan Muka Airtanah yang Tinggi untuk Mendukung Stabilitas Embung Handulung. Magister thesis, Universitas Brawijaya.
Abstract
Dalam kegiatan konstruksi, kondisi muka airtanah tinggi menyebabkan pekerjaan konstruksi harus dimulai dari zona jenuh air yang pada dasarnya terdapat tekanan air pori yang besar. Tekanan air pori dapat terjadi secara vertikal, yaitu dari arah kiri dan kanan struktur, dan horizontal, yaitu dari arah bawah menekan ke atas. Data penyelidikan geologi di sekitar Embung Handulung menunjukkan posisi muka airtanah yang tinggi, yaitu pada kedalaman 0,4 m dari permukaan tanah. Konsep desain Embung Handulung menggunakan bentuk kolam/ground reservoir karena areal lokasi studi yang relatif datar. Tahapan pertama penelitian adalah identifikasi karakteristik geologi dan karakteristik aliran airtanah. Karakteristik geologi dapat diketahui dari Peta Geologi Permukaan, hasil pengeboran, dan hasil pengujian laboratorium. Karakteristik aliran airtanah dapat diketahui dari hasil pengeboran dan tes pit, serta dibantu oleh perangkat lunak Visual Modflow Flex versi 6.1. Tahapan kedua adalah penentuan geometri lereng dan analisis stabilitas akibat beban sendiri. Penentuan geometri lereng menggunakan bantuan perangkat lunak GeoStudio 2018 R2, sedangkan analisis stabilitas ditinjau terhadap uplift dan daya dukung tanah sendiri. Tahapan ketiga adalah analisis terhadap alternatif penanganan, yaitu penambahan tiang pancang, dewatering metode deep well, dan kombinasi tiang pancang dan dewatering. Dalam alternatif penambahan tiang pancang, terdapat sub-alternatif, yaitu penambahan 1 tiang, penambahan 2 tiang, penambahan 3 tiang, dan penambahan 4 tiang. Dalam alternatif dewatering metode deep well, perlu dipertimbangkan kapasitas pompa dan muka air minimum sebelum pengoperasian dewatering. Masing-masing alternatif ditinjau terhadap stabilitas lereng dan stabilitas strukturnya, baik saat muka air tampungan kosong maupun normal. Hasil analisis stabilitas akibat beban sendiri menunjukkan stabilitas lereng tidak aman dan stabilitas struktur tidak aman, baik saat kondisi kosong maupun normal. Hasil analisis alternatif penambahan tiang pancang menunjukkan stabilitas lereng dengan penambahan 1 tiang dan penambahan 2 tiang tidak aman, tetapi penambahan 3 tiang dan penambahan 4 tiang aman dengan angka keamanan 1,504 dan 1,728. Stabilitas struktur tidak aman pada kondisi kosong, tetapi aman pada kondisi normal. Hasil analisis alternatif dewatering metode deep well menunjukkan stabilitas lereng tidak aman, tetapi stabilitas struktur aman, baik saat kondisi kosong maupun normal. Pengoperasian dewatering perlu dilakukan secara terus menerus. Hasil analisis kombinasi tiang pancang dan dewatering menunjukkan stabilitas lereng dengan penambahan 3 tiang dan penambahan 4 tiang aman dengan angka keamanan 1,740 dan 2,003. Stabilitas struktur aman, baik saat kondisi kosong maupun normal. Pengoperasian dewatering sub-alternatif penambahan 3 tiang dilakukan ketika muka air tampungan setinggi 4,0 m, sedangkan dewatering sub-alternatif penambahan 4 tiang dilakukan ketika muka air tampungan setinggi 3,0 m. Alternatif yang dipilih yaitu kombinasi penambahan 4 tiang pancang dan dewatering.
English Abstract
In construction activities, high groundwater table causes construction work to start from the saturated zone, which basically has a large pore water pressures. Pore water pressure can occur vertically, i.e. from the left and right side of the structure, and horizontally, i.e. from the bottom pressing up. Geological investigation data around Embung Handulung show a high groundwater table, at a depth of 0,4 meters from the ground surface. The basic design of Embung Handulung is in the form of a pond or ground reservoir because the area of interest is relatively flat. The first stage of the research is the identification of geological characteristics and groundwater flow characteristics. Geological characteristics can be known from The Geological Map, core drilling results, and laboratory test results. Groundwater flow characteristics can be known from the results of core drilling and pit tests, and assisted by Visual Modflow Flex software version 6.1. The second stage is the determination of slope geometry and stability analysis due to self-weight of the structure. Determination of slope geometry assisted by GeoStudio 2018 software version R2, while stability analysis is reviewed on the uplift force and soil bearing capacity. The third stage is stability analysis of alternative treatments, i.e. piles addition, deep well dewatering, and a combination of piles and dewatering. In the pile addition alternative, there are sub-alternatives, i.e. the addition of 1 pile, the addition of 2 piles, the addition of 3 piles, and the addition of 4 piles. In the deep well dewatering alternative, it is necessary to consider the pump capacity and minimum water level prior to the operation of dewatering. Each alternative is reviewed for slope stability and structural stability, both at the lowest reservoir water level and normal reservoir water level. The results of the stability analisis due to self-weight of the structure show that the Factor of Safety (FS) is below 1,5 and the uplift force is greater than the self-weight of the structure, both at the lowest water level and normal water level. The results of the pile addition alternative show that the FS of 1 pile addition and 2 piles addition is below 1,5, but the FS of 3 piles addition and 4 piles addition is 1,504 and 1,728. The uplift force is greater than the weight of the structure at the lowest water level, but less at the normal water level. The results of the deep well dewatering alternative show that the FS is below 1,5, but the uplift force is less than the weight of the structure, both at the lowest water level and normal water level. The operations of dewatering need to be carried out continuously. The results of the combination of piles and dewatering alternative show that the FS of 3 piles addition and 4 piles addition is 1,740 and 2,003. The uplift force is less than the weight of the structure, both at the lowest water level and normal water level. The dewatering of subalternative 3 piles addition is operated when the reservoir water level is 4,0 meters, while the dewatering of sub-alternative 4 piles addition is operated when the reservoir water level is 3,0 meters. The chosen alternative is a combination of 4 piles addition and dewatering.
Other obstract
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| Item Type: | Thesis (Magister) |
|---|---|
| Identification Number: | 0'422070004 |
| Uncontrolled Keywords: | Kata kunci: muka airtanah, stabilitas lereng, uplift, tiang pancang, dewatering |
| Subjects: | 600 Technology (Applied sciences) > 627 Hydraulic engineering > 627.5 Reclamations, Irrigation, related topics > 627.52 Irrigation |
| Divisions: | S2/S3 > Magister Teknik Pengairan, Fakultas Teknik |
| Depositing User: | yulia Chasanah |
| Date Deposited: | 07 Jun 2022 04:06 |
| Last Modified: | 07 Jun 2022 04:06 |
| URI: | http://repository.ub.ac.id/id/eprint/190843 |
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