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"Likuifaksi adalah fenomena hilangnya sebagian besar tahanan geser pada masa tanah ketika mengalami pembebanan monotonic atau beban siklik dalam waktu singkat yang mengalir menjadi cair yang didukung dengan meningkatnya tegangan air pori tanah sehingga tegangan geser pada masa tanah menjadi rendah, penurunan daya dukung tanah berakibat tanah menjadi jenuh (saturated), air yang terdapat diantara pori-pori tanah membentuk tekanan air pori. Potensi likuifaksi tersusun atas material yang didominasi berukuran pasir. Pergerakan tanah terjadi akibat partikel tanah berpasir terdisipasi pada lapisan tanah dengan permeabilitas yang tinggi. Studi terkait likuifaksi dikembangkan dengan pemodelan tiga dimensi (3D) menggunakan metode Smoothed Particle Hydrodynamics (SPH) yang memodelkan dan memvisualisasikan perilaku partikel fluida dan solid. Pada penelitian ini akan memodelkan simulasi perilaku pergerakan interaksi lapisan fluida diantara lapisan tanah impermeable dengan kondisi batas pada permuakaan miring.

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Liquefaction is a phenomenon in which the strength and stiffness of a soil is reduced by earthquake shaking or other rapid loading, where saturated sand and silt take on the characteristics of a liquid during the intense shaking of an earthquake. This is because a loose sand tends to compress, in response to soil compressing, in the pore water pressure and water attempts to flow out from the soil. Soil deforms easily and heavy objects such as structure can be damaged from the sudden loss of support from below. The research includes a liquefaction with Smoothed Particle Hydrodynamics (SPH) method for modelling and visualizing movement of fluid layer interaction between impermeable soil layers with boundary conditions sloping surface.

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"Penentuan desain sistem Impressed Current Cathodic Protection di bagian dasar tanki T-1301 A/B/C/D dan AB Rerun Tank di PT XX Kalimantan Timur yang meliputi proses perhitungan kebutuhan arus dan jumlah tegangan DC keseluruhan sistem struktur serta pengaruh penambahan struktur lain yang meliputi electrical grounding system telah berhasil dilakukan dan secara efektif telah dikontrol di lapangan. Selain proses desain engineering, variasi lapisan tahanan tanah terhadap ketidakseimbangan IR Drop pada sistem Impressed Current Cathodic Protection di bagian dasar tanki T-1301 A/B/C/D dan AB Rerun Tank di PT XX Kalimantan Timur dan pengaruhnya terhadap distribusi potensial telah dipelajari.

Dari hasil pembuktian di lapangan menunjukkan bahwa dibutuhkan 10 anoda tambahan dengan total kebutuhan arus DC 154 Ampere dan kebutuhan tegangan DC 32 Volt , selain itu tahanan tanah yang tinggi diatas 3000 ohm cm akan menyebabkan pembacaan error yang tinggi.pH tanah yang rendah berkisar 5-7 akan mengurangi tahanan tanah, dan meningkatkan distribusi arus proteksi katodik.

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Engineering design calculation for bottom section of T-1301 A/B/C/D dan AB Rerun Tank at PT XX Santan Terminal including current requirement and DC voltage calculation followed by additional structure such electrical grounding system has been already successfully implemented and controlled at field. Furthermore, effect of soil layer resistivity and pH of soil against disproportion of IR Drop voltage including its effect to potential distribution has been already successfully observed. Another influences such depth and location of anode groundbed determination along with establishment of impressed current cathodic protection main tools and equipments as external corrosion control method has been defined as the most effective way for controlling potential distribution against structure.

As per verification results from site, the results showed that the cathodic protection required 10 additional anode (MMO), with minimum amperage DC supply is 154 A, minimum voltage supplied is 32 Volt, it has been identified that high soil resistivity above 3000 ohm.cm would cause error reading. Naturally, acid soil in about pH 5-7, would decrease soil resistivity and enhanced potential distribution from anode to tank structure."