Analisa Stabilitas Lereng Ditinjau Dari Aspek Pembasahan- Pengeringan Dan Infiltrasi Air Hujan Tanah Lempung Khas Bobonaro

Saleh, Muh (2023) Analisa Stabilitas Lereng Ditinjau Dari Aspek Pembasahan- Pengeringan Dan Infiltrasi Air Hujan Tanah Lempung Khas Bobonaro. Masters thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Jalan Dafala-Laktutus STA.149+140 merupakan ruas jalan nasional yang dikelola olah BPJN Nusa Tenggara Timur yang terletak pada formasi lempung Bobonaro yang dikenal sebagai lempung tanah bermasalah. Hal ini diindikasikan bahwa sepanjang ruas jalan tersebut sudah terjadi kelongsoran. sehingga penting kami dilakukan sebagai suatu penelitian. Hasil pengujian awal properties tanah menunjukkan lempung Bobonaro sangat mudah terdeformasi karena memiliki konsistensi yang buruk dengan nilai Liquid Limit (LL), Plastic Limit (PL) dan Plastic Index (PI) yang tinggi serta menurut USCS sebagai clay with high plasticity (CH) dan menurut AAHSTO terklasifikasi A-7-6. Penerapan siklus pembasahan-pengeringan berdampak pada parameter fisik dan parameter mekanis lempung Bobonaro yakni pada Berat Volume Kering, γd [kN/m3] terjadi penurunan nilai dari siklus ke-1 ke siklus ke-3 sebesar 4,043%, pada Angka Pori, e terjadi peningkatan dari siklus ke-1 ke siklus ke-3 sebesar 13,82% dan pada Kuat Tekan bebas, qu [Kg/cm2] mengalami penurunan sebesar 20,51% serta menyebabkan Tegangan Air Pori Negatif (suction), -Uw juga menurun dari siklus ke-1 hingga siklus ke-3 sebesar 66,71%. Perubahan yang signifikan mulai terlihat pada kondisi kadar air, w sebesar 13,5%, akan tetapi antara siklus ke-2 ke siklus ke-3 tidak terjadi perubahan signifikan. Analisa stabilitas lereng berdasarkan konsistensi tanah menggunakan aplikasi Geostudio untuk menghitung kondisi eksisting pada saat longsor dan pemodelan dengan intensitas dan durasi hujan. Hasil analisa balik dapat diperkirakan bahwa kondisi tanah saat terjadi longsor mempunyai berat volume tanah (γt)18,5 kN/m3 dengan nilai kohesi (C’)<33,1 kPa dan sudut geser (ϕ°) 0°. Hasil analisa stabilitas lereng pada parameter inisial ke-1 sama dengan kondisi di inisial ke-6 dengan variasi infiltrasi hujan normal dan hujan deras untuk durasi 3 jam dan 5 jam didapatkan kondisi lereng dalam keadaan sudah longsor/runtuh dengan faktor keamanan (SF)<1.
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Dafala-Laktutus road STA.149+140 is a national road section managed by the East Nusa Tenggara BPJN which is located on the Bobonaro clay formation, which is known as problematic soil clay. This indicates that along the road segment there has been a landslide. So it's important that we do it as a study. The initial test results for soil properties show that Bobonaro clay is very easily deformed because it has a poor consistency with high Liquid Limit (LL), Plastic Limit (PL) and Plastic Index (PI) values and according to USCS as clay with high plasticity (CH) and according to AAHSTO is classified A-7-6. The application of the wetting-drying cycle had an impact on the physical parameters and mechanical parameters of the Bobonaro clay namely on the Dry Volume Weight, γd [kN/m3] there was a decrease in value from the 1st cycle to the 3rd cycle of 4.043%, in the Pore Number, e there was an increase from the 1st cycle to the 3rd cycle of 13.82% and in the free compressive strength, qu [Kg/cm2] decreased by 20.51% and caused a negative pore water stress (suction), -Uw also decreased from cycle 1st to 3rd cycle of 66.71%. Significant changes began to be seen in conditions of water content, w of 13.5%, but between the 2nd cycle to the 3rd cycle there was no significant change. Slope stability analysis based on soil consistency using the Geostudio application to calculate the existing conditions at the time of landslides and modeling with rain intensity and duration. The results of the back analysis can be estimated that the soil conditions at the time of the landslide had a unit weight (γt) of 18.5 kN/m3 with a cohesion value (C') <33.1 kPa and a shear angle (ϕ°) of 0°. The results of the analysis of slope stability in the 1st initial parameter are the same as those in the 6th initial with variations in normal rain infiltration and heavy rain for a duration of 3 hours and 5 hours, it is found that the slope conditions are in a state of landslide/collapse with a safety factor (SF) <1.

Item Type:	Thesis (Masters)
Uncontrolled Keywords:	Lempung Bobonaro, longsor, Siklus pengeringan-pembasahan (drying-wetting), propertis fisis, propertis mekanis, suction, infiltrasi hujan, stabilitas lereng, Bobonaro clay, landslides, drying-wetting cycle, physical properties, mechanical properties, suction, rain infiltration, slope stability, safety factor.
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) > TA418.16 Materials--Testing. T Technology > TA Engineering (General). Civil engineering (General) > TA455.S6 Soil (Materials of engineering and construction)
Divisions:	Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Civil Engineering > 22101-(S2) Master Thesis
Depositing User:	Muh. Saleh
Date Deposited:	03 Feb 2023 03:06
Last Modified:	03 Feb 2023 03:06
URI:	http://repository.its.ac.id/id/eprint/96089

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