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"Dalam penelitian ini akan diselidiki fenomena stabilitas lereng dengan menggunakan teori mekanika tanah tak jenuh unsaturated soil mechanics pada daerah lereng di Pasir Muncang untuk melihat adanya indikasi pengaruh teori tersebut dalam fenomena kelongsoran yang terjadi di lapangan dengan menggunakan perangkat lunak SEEP/W 2012 dan SLOPE/W 2012. Studi dilakukan lebih jauh untuk meneliti bagaimana memodelkan lereng dengan teori mekanika tanah tak jenuh dan menentukan parameter yang tepat untuk merepresentasikan kondisi kelongsoran lereng akibat hujan yang terjadi pada akhir tahun 2008. Analisis stabilitas lereng dengan ditambahkan hujan harian yang divariasikan 2 jam, 4 jam dan 6 jam masing-masing dengan pola hujan normal, advanced dan delayed menunjukkan bahwa parameter dan pemodelan yang ditentukan memberikan estimasi kondisi longsor terjadi akibat rangkaian hujan lebat yang terjadi pada awal bulan Desember 2008 sehingga mengakibatkan tanah longsor pada 7 Desember 2008 akibat hujan durasi 6 jam pola advanced dimana faktor keamanan turun hingga di bawah faktor keamanan kritis yaitu 1.2. Kelongsoran ini diakibatkan naiknya tegangan air pori dan berkurangnya matric suction tanah. Lebih jauh, dalam penelitian ini juga diselidiki pengaruh intensitas hujan, pola hujan, durasi hujan terhadap kondisi permeabilitas tanah, kadar air tanah dan laju infiltrasi dalam tanah dan hubungannya lebih lanjut terhadap kuat geser dan stabilitas lereng.

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In this research, the slope stability in Pasir Muncang will be studied by using unsaturated soil mechanics theory to observe whether it effects landslide that happened in the field by using SEEP W 2012 and SLOPE W 2012 software. The objective of this study is to explore how to model the slope with unsaturated soil mechanics theory and determine the accurate parameters to represent the landslide condition as the outcome of heavy rain events during late 2008.

The stability analysis concerning the rain that are differentiated into 2 hours, 4 hours and 6 hours of rain each with normal, advanced and delayed rainfall pattern show that the model and determined parameters give estimation that the landslide event was caused by heavy rainfall series during early December of 2008 which caused the landslide on December 7th 2008 after the 6 hours rain with advanced rainfall pattern that caused the drop of factor of safety below critical which is 1.2. This landslide was an outcome of rising of pore water pressure and decreasing of matric suction in soil. Furthermore, this research will examine the effect on rainfall intensity, rainfall pattern, rainfall duration, in regard to soil permeability, soil water content, soil infiltration rate and its connection with shear strength and the stability of the slope."

"Analisis stabilitas lereng pada umumnya dilakukan dalam bentuk dua dimensi 2D dengan asumsi kondisi plane strain tanpa mempertimbangkan dampak analisis tiga dimensi 3D. Namun, dalam analisis stabiltas lereng khususnya lereng alami yang memiliki kompleksitas geometri lereng perlu dilakukan pemodelan dalam bentuk 3D yang dapat menggambarkan kondisi asli lereng. Dalam penelitian ini dilakukan pemodelan 2D dan 3D dengan metode elemen hingga finite element method untuk mengetahui perbedaan hasil analisis stabilitas lereng 2D dan 3D pada lereng alami yang memiliki geometri kompleks. Penelitian yang dilakukan yaitu dengan membandingkan hasil pemodelan 2D dan 3D lereng studi kasus Pasir Muncang serta melakukan verifikasi perilaku dan sensitivitas model 2D dan 3D terhadap beberapa faktor. Hasil analisis menunjukkan bahwa terdapat faktor-faktor yang mempengaruhi nilai faktor keamanan 2D dan 3D yaitu diantaranya nilai parameter tanah, perbedaan jarak kontur, dan tingkat kehalusan. Faktor-faktor tersebut memiliki pengaruh yang berbeda terhadap hasil model 2D dan 3D sehingga didapatkan rasio nilai faktor keamanan 3D dan 2D lereng alami Pasir Muncang sebesar 1.44. Adanya perbedaan nilai faktor keamanan 2D dan 3D ini mengharuskan adanya pertimbangan dalam pemilihan penggunaan analisis stabilitas lereng dalam bentuk 2D atau 3D.

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The vast majority of slope stability analysis is performed in two dimensional 2D under the assumption of plane strain conditions, without much consideration to the impact of three dimensional 3D analysis. However, in slope stability analysis, especially natural slopes that have complexity of slope geometry, 3D modeling is required which can represent more realistic geometry of slope in third dimension.

This study presents finite element method for calculating the 2D and 3D factor of safety for ldquo Pasir Muncang rdquo natural slope. A comparison of different factor of safety in 2D and 3D analysis, and also verification of sensitivity in 2D and 3D models to several factor are presented.

The result of analysis indicate that there are factors that influence the difference of 2D and 3D factor of safety. These factors are soil parameters, contour spacing, and mesh coarseness which have different effects on the 2D and 3D model results. The ratio of 3D and 2D factor of safety differences on Pasir Muncang natural slope is 1.44. The existence of this difference in 2D and 3D factor of safety requires consideration in the use of two dimensional 2D or three dimensional 3D slope stability analysis."

"Tujuan dari penelitian ini adalah untuk mensimulasikan efek dari curah hujan sebagai infiltrasi ke kondisi tanah jenuh melihat perubahan Ketinggian Air Tanah yang mempengaruhi stabilitas lereng. Untuk mengevaluasi efek dari infiltrasi pada stabilitas tanah jenuh, rembesan numerik dan analisis stabilitas lereng dilakukan berdasarkan sifatsifat tanah tak jenuh. Hasil analisis rembesan (SEEP / W) menunjukkan perubahan dari meja air bertengger di bawah air hujan infiltrasi. Selain itu, para reuslts analisis stabilitas lereng (LERENG / W) menunjukkan perubahan Faktor Keselamatan berdasarkan hasil dari analisis rembesan (SEEP / W). Hasil ini menunjukkan bagaimana curah hujan dan tanah penyedotan dapat memberikan beberapa kontribusi berubah dari muka air bertengger dan mempengaruhi stabilitas lereng dalam kondisi jenuh. Di skripsi ini juga akan membandingan pengaruh kepada stabilitas lereng oleh dua faktor yaitu intensitas air hujan dan waktu durasi hujan.

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The objective of this study is to simulate the effect of the rainfall as an infiltration into the unsaturated soil condition to see the change of Ground Water Table that affecting to the stability of the slope. To evaluate the effect of infiltration on the stability of the unsaturated soil, numerical seepage and slope stability analysis were performed based on the unsaturated soil properties.

The results of seepage analysis (SEEP/W) show the changed of a perched water table under rainwater infiltration. Furthermore, the results of slope stability analysis (SLOPE/W) show the change of the Factor of Safety based on the results from seepage analysis (SEEP/W).

These results shows how rainfall and soil suctions can give some contributions of the changed of perched water table and affecting to the slope stability in unsaturated condition. In addition, this study also make a comparation of the significance effect to slope stability by two factors, which are rainfall intensity and rainfall time durations."

"Metode yang banyak digunakan dalam melakukan analisis stabilitas lereng seperti Limit Equilibrium Method (LEM) dan Finite Element Method (FEM) lebih banyak memperhatikan nilai faktor keamanan lereng. LEM tidak dapat memprediksi perilakuk tanah setelah keruntuhan, sedangkan FEM hanya dapat digunakan untuk menghitung deformasi material sebelum keruntuhan. Metode Smoothed Particle Hydrodynamics (SPH) saat ini sudah mulai digunakan sebagai alternatif untuk mengatasi distorsi mesh yang berlebih dalam analisis FEM akibat deformasi besar pasca kegagalan dalam analisis stabilitas lereng. Dalam penelitian ini, perilaku material tanah akan dimodelkan sebagai partikel menggunakan metode SPH dengan mengacu pada beberapa penelitian sebelumnya. Model konstitutif tanah Drucker-Prager digunakan dalam prosedur SPH elasto-plastic sebagai alternatif model fluida Bingham dalam prosedur SPH Hydrodynamics yang sudah dikembangkan di Universitas Indonesia. Algoritma ini menggunakan hubungan tegangan-regangan untuk menggambarkan perilaku elastis-plastis dari partikel tanah. Simulasi dilakukan pada partikel tanah yang dimodelkan sebagai tanah kohesif dengan sudut kemiringan terhadap sumbu horizontal.

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The methods that are widely used in conducting slope stability analysis such as the Limit Equilibrium Method (LEM) and Finite Element Method (FEM) pay more attention to the value of the slope safety factor. LEM cannot predict soil behavior after failure, while FEM can only be used to calculate material deformation before failure. The Smoothed Particle Hydrodynamics (SPH) method currently has begun to be used as an alternative to overcome excess distortion of the mesh in FEM analysis due to post-failure large deformations in slope stability analysis. In this study, the behavior of the soil material will be modeled as particles using the SPH method with reference to several previous studies. The Drucker-Prager constitutive soil model is used in the elasto-plastic SPH procedure as an alternative to the Bingham fluid model in the SPH Hydrodynamics procedure which has been developed at the University of Indonesia. This algorithm uses the stress-strain relationship to describe the elastic-plastic behavior of soil particles. Simulations were carried out on soil particles which were modeled as cohesive soils with a slope angle to the horizontal axis."

"For centuries humankind has wondered at the instability of earth material, especially clays; one day they are dry and hard, and the next wet and soft. The result are usually excessive deflections and diffrential movements resulting in damage to foundation systems structural elements and architectural features. Foundation materials that exhibit volume change from change in soil moisture are referred to as expansive or swelling clay soils. Expansive soils many parts of the United States a significant hazard to foundations for light buildings. Swelling clays derived from residual soils can exert uplift pressures of as much as 5.500 psf to 15,000 psf. In the United States alone the damage caused by the shrinking and swelling soils amounts to about 9 billion dollars per year, which is greater than the combined damages from natural disasters such as floods, hurricanes, earthquakes and tornados.South Sumatra local Government is planning to build a new International and Modem Trading Port including Industrial and Ware Housing Estate at Tanjung Api-Api area. Most of soils around Tanjung Api-Api area are expansive soils, so the objective of this study to analize and obtain suitable foundation on unsaturated expansive soil, that can be implemented in Tanjung Api-Api area. From the result ofOedometer test, it can be concleded that the swelling potential value is about 15 percent, and the soil uplift pressure is about 2,0000 psf."

"Soil nailing merupakan teknik stabilisasi tanah yang paling efektif dan efisien dibanding teknik-teknik perkuatan tanah konvensional lain. Skripsi ini membahas soil nailing yang meliputi teori dasar yang berhubungan dengan soil nail wall, aplikasi software Geoslope/W dan Snailz dalam menyelesaikan permasalahan lereng di Politeknik Pertanian Negeri Samarinda, analisis hasil yang didapat, serta kesimpulannya. Skripsi ini menggunakan metode iterasi dalam penentuan datadata masukan untuk Geoslope/W dan Snailz. Desain dan spesifikasi soil nail wall ditentukan berdasarkan properti tanah, geometri lereng, dan hasil perhitungan Geoslope/W dan Snailz.

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Compared with other soil improvement techniques, soil nailing is the most effective and efficient technique of soil stabilization. This paper studies and investigates the basic theories related to soil nail wall, application of Geoslope/W and Snailz in solving slope stability at Politeknik Pertanian Negeri Samarinda, analysis of calculation output, and also the conclusion of this research. This paper is using iterative method in determining the input datas for Geoslope/W and Snailz. Soil nail wall design and specification can be defined based on soil property, slope geometry, and Geoslope/W and Snailz outputs."

"Pada tahun 2019, sebuah sistem perkuatan lereng ground anchor pada lereng batuan curam di Bogor, Jawa Barat dirancang untuk menstabilkan lereng di bawah struktur jembatan yang melintasi sungai. Dikarenakan kesulitan dalam tahap konstruksi maka desain ground anchor dievaluasi dan dilihat pengaruhnya terhadap stabilitas lereng. Penelitian ini bertujuan untuk menganalisis kondisi inisial lereng sebelum diberi perkuatan dan efek dari pemasangan perkuatan lereng ground anchor dan efek dari alternatif perkuatan lain berupa soil nailing. Selain itu, dilakukan variasi geometri pada perkuatan berupa letak, kemiringan dan panjang untuk melihat pengaruhnya terhadap stabilitas lereng dan mendapatkan konfigurasi pemasangan perkuatan yang efektif.  Proses analisis dibantu menggunakan aplikasi berbasis elemen hingga (MIDAS GTS NX), menghasilkan faktor keamanan lereng dan pola keruntuhan. Hasil dari analisis yang dilakukan menunjukkan kondisi awal lereng memiliki nilai faktor keamanan yang melebihi standar (FK=2,019) dan terjadi keruntuhan kritis lereng yang terjadi di bagian atas lereng dengan tipe non-sirkular. Penambahan perkuatan ground anchor dan soil nailing meningkatkan nilai faktor keamanan lereng. Pemasangan ground anchor di area kaki lereng tidak menunjukkan nilai faktor keamanan yang memiliki pola kecenderungan pada rentang kemiringan 10o-30o dan cenderung menurun setelah melebihi 30o. Pemasangan ground anchor di puncak lereng menunjukkan peningkatan nilai faktor keamanan pada rentang kemiringan ground anchor 10o-30o namun cenderung menurun pada rentang 30o-45o. Letak anchor memiliki pengaruh besar pada perubahan permukaan keruntuhan kritis dan nilai faktor keamanan. Letak optimal ground anchor adalah pada lokasi dimana deformasi tertinggi terjadi. Pemasangan soil nailing di sepanjang permukaan meningkatkan nilai faktor keamanan secara signifikan. Hasil analisis soil nailing menunjukkan peningkatan nilai faktor keamanan seiring bertambahnya panjang dan kemiringan soil nailing.

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In 2019, a ground anchor slope reinforcement system was designed to stabilize a steep rock slope in Bogor, West Java, Indonesia, beneath a bridge structure that crossed a river. Due to construction difficulties, the design of the ground anchor was evaluated, considering its impact on slope stability. This study aims to analyze the initial condition of the slope before reinforcement and the effects of implementing ground anchor slope reinforcement, as well as the effects of an alternative reinforcement method known as soil nailing. Additionally, variations in the geometry of the reinforcements, including their placement, inclination, and length, were examined to determine their influence on slope stability and identify effective reinforcement configurations. The analysis process was aided by a finite element-based software called MIDAS GTS NX, which yielded slope safety factors and failure patterns. The analysis results showed that the initial condition of the slope had a safety factor value exceeding the standard (SF = 2.019) and experienced critical slope failure at the upper part of the slope with a non-circular failure type. The addition of ground anchors and soil nailing increased the slope safety factor. When ground anchors were installed in the foot area of the slope, the variations in geometry did not exhibit a consistent safety factor pattern within the slope inclination range of 10o-30o, and it tended to decrease after exceeding 30o. Installing ground anchors at the peak of the slope showed an increase in the safety factor within the ground anchor inclination range of 10o-30o, but it tended to decrease within the range of 30o-45o. The placement of anchors had a significant impact on changes in the critical failure surface and safety factor value. The optimal location for ground anchors was where the highest deformation occurred. The installation of soil nails along the surface significantly increased the safety factor value. The analysis of soil nails demonstrated an increase in the safety factor as the length and inclination of the soil nails increased."