| dc.description.abstract | Geotechnical problems are an important problem, one of the geotechnical problems is the reduction and bearing capacity of soil which is the foundation of the dock. Each dock is planned in such a way that it has a certain load and a certain elevation which sometimes cannot be served by existing soil conditions due to soft soil characteristics. Soil improvement by means of preloading and Prefabricated Vertical Drain (PVD) is one of popular methods used to increase the shear strength of soft soil.
This analysis aims to analyze and compare the size of consolidation reduction analytically using the Terzaghi 1 Dimension method, the finite element method with modeling on Plaxis 2D and 3D using the very fine mesh type with Settlement Plate (S29) data in the field, analyzing and comparing the size of consolidation reduction with Plaxis 2D and 3D finite element methods with several types of mesh, namely very coarse, coarse, medium, fine and very fine with Settlement Plate (S29) data in the field.
From the analysis results it was obtained the size of consolidation reduction using the Terzaghi 1 Dimensional method was 6.928 m, with Plaxis 2D modeling using several types, namely very coarse = 7,432 m, coarse = 7,421 m, medium = 7,466 m, fine = 7,486 m and very fine = 7,491 m while the consolidation reduction with Plaxis 3D modeling on very coarse type = 6,874 m, coarse = 6,983 m, medium = 6,783 m, fine = 6,627 m and very fine = 6,956 m.
So it can be concluded that the size of consolidation reduction using analytical calculation method and 3D Plaxis very fine mesh type is relatively close to the conditions that occur in the field, where the size of settlement plate reduction S29 in the field is 7.19 m. The effect of mesh fineness to prediction of size reduction in Plaxis 2D is relatively linear with percentage ratio on mesh very coarse type = 3.37%, coarse = 3.21%, medium = 3.84%, fine = 4.12% and very fine = 4.19%. Meanwhile, the effect of mesh fineness to prediction of size reduction in Plaxis 3D is fluctuating, with percentage ratio of reduction in the field on mesh type very coarse = -4.39%, coarse = -2.88%, medium = -5.66%, fine = -7 , 83% and very fine = -3.25%. This difference is because the laboratory data does not represent the entire soil layer in the field, where for boring 60 m depth there are only 3 samples with a thickness of 0.5 meters for each sample that is at a depth of 9.5 m - 10 m, 19.5 m - 20 m and 45.5 m - 46 while field observations to collect data for reduction were carried out every day | en_US |
| dc.description.abstract | Permasalahan geoteknik merupakan masalah yang penting, salah satu permasalahan geoteknik adalah penurunan dan daya dukung tanah yang merupakan pondasi dari dermaga. Setiap dermaga direncanakan sedemikian rupa sehingga memiliki beban tertentu dan elevasi tertentu yang terkadang tidak dapat dilayani oleh kondisi tanah eksisting karena karakteristik tanah yang lunak. Perbaikkan tanah dengan cara pembebanan awal (preloading) dan Prefabricated Vertical Drain (PVD) merupakan salah satu metode yang populer yang digunakan untuk meningkatkan kekuatan geser tanah lunak.
Analisis ini bertujuan untuk menganalisis dan membandingkan besar penurunan konsolidasi secara analitis menggunakan metode Terzaghi 1 Dimensi, metode elemen hingga dengan pemodelan pada Plaxis 2D dan 3D menggunakan tipe mesh very fine dengan data Settlement Plate (S29) di lapangan, menganalisis dan membandingkan besar penurunan konsolidasi dengan metode elemen hingga Plaxis 2D dan 3D dengan beberapa tipe mesh yaitu very coarse, coarse, medium, fine dan very fine dengan data Settlement Plate (S29) di lapangan.
Dari hasil analisis diperoleh besar penurunan konsolidasi menggunakan metode Terzaghi 1 Dimensi yaitu 6,928 m, dengan pemodelan Plaxis 2D menggunakan beberapa tipe yaitu very coarse = 7,432 m, coarse = 7,421 m, medium = 7,466 m, fine = 7,486 m dan very fine = 7,491 m sedangkan penurunan konsolidasi dengan pemodelan Plaxis 3D pada tipe very coarse = 6,874 m, coarse = 6,983 m, medium = 6,783 m, fine = 6,627 m dan very fine = 6,956 m.
Sehingga dapat disimpulkan besar penurunan konsolidasi menggunakan metode perhitungan analitis dan Plaxis 3D tipe mesh very fine relatif mendekati kondisi yang terjadi di lapangan, dimana besar penurunan settlement plate S29 di lapangan adalah 7,19 m. Pengaruh kehalusan mesh terhadap prediksi besar penurunan pada Plaxis 2D relatif linier dengan persentasi perbandingan pada mesh tipe very coarse = 3,37%, coarse = 3,21%, medium = 3,84%, fine = 4,12% dan very fine = 4,19%. Sedangkan pengaruh kehalusan mesh terhadap prediksi besar penurunan pada Plaxis 3D adalah fluktuatif, dengan persentasi perbandingan penurunan dilapangan pada tipe mesh very coarse = -4,39%, coarse = -2,88%, medium = -5,66%, fine = -7,83% dan very fine=-3,25%. Perbedaan ini dikarenakan data laboratorium tidak mewakili keseluruhan lapisan tanah di lapangan, dimana untuk boring sedalam 60 m hanya terdapat 3 sampel dengan tebal masing-masing sampel adalah 0,5 meter yaitu pada kedalaman 9,5 m – 10 m, 19,5 m – 20 m dan 45,5 m - 46 sedangkan observasi lapangan pengambilan data untuk penurunan dilakukan setiap hari. | en_US |
