Academic literature on the topic 'Prefabricated vertical drain'

PVD (Prefabricated Vertical Drain) merupakan teknik perbaikan tanah dengan prinsip mengeluarkan kadar air pori di dalam tanah sehingga mempercepat waktu penurunan tanah. Saat ini metode prefabricated vertical drain banyak digunakan untuk pembangunan khususnya yang berdiri di atas tanah lunak. Selama ini, waktu pekerjaan prefabricated vertical drain ditentukan berdasarkan pengalaman pekerjaan prefabricated vertical drain di proyek-proyek terdahulu. Metode time study dapat digunakan sebagai perhitungan dalam menentukan produktivitas pada pekerjaan konstruksi, contohnya pada pekerjaan pemasangan prefabricated vertical drain. Penelitian ini bertujuan untuk menghitung produktivitas prefabricated vertical drain yang meliputi pekerjaan pembuatan titik, pemancangan PVD, pemotongan PVD dengan menggunakan metode time study, yang berdasarkan faktor-faktor yang mempengaruhi pemasangan PVD salah satunya yaitu ketinggian rig. Dilakukan pengamatan pada proyek dengan ketinggian rig 18 m dan 24 m. Dari hasil penelitian didapatkan waktu pelaksanaan untuk kedalaman pemasangan 14 m, ketinggian rig 18 m serta mesin dasarnya excavator PC 200 didapatkan standard time pada produktivitas pekerjaan prefabricated vertical drain per-m panjang yaitu 0,089 menit (5,340 detik). Sedangkan pada kedalaman pemasangan 21 m, ketinggian rig 24 m serta mesin dasarnya PC 300 didapatkan standard time pada produktivitas pekerjaan prefabricated vertical drain per-m panjang 0,084 menit (5,040 detik). Berdasarkan perhitungan didapatkan bahwa semakin besar mesin dasar maka semakin besar nilai produktivitas pekerjaanya.

Prefabricated vertical drains are often used to accelerate the consolidation and to gain strength in soft clayey soils. The consolidation process depends on several uncertain parameters including the coefficients of consolidation and coefficients of permeability in vertical and horizontal directions and the discharge capacity of the vertical drains. A sensitivity analysis of the degree of consolidation to these uncertain parameters is presented for clayey deposits. Results of the analysis suggest that the most important uncertain parameter that affects the consolidation process is the horizontal coefficient of consolidation. The implication of this uncertain parameter in the design of prefabricated vertical drains for soil improvement is discussed. Two approaches are proposed for selecting drain spacing employing a design value of the horizontal coefficient of consolidation. One of the approaches is probability based and the other is minimum expected cost based.Key words: consolidation, prefabricated vertical drains, drain spacing, probability, expected cost, optimal design.

This study describes the effect of unsaturation at a drain boundary on the behaviour of a single prefabricated vertical drain subjected to vacuum preloading based on a two-dimensional plane strain finite element model incorporating the modified Cam–Clay model. Unsaturation of soil adjacent to the drain can occur due to mandrel withdrawal or application of vacuum pressure through prefabricated vertical band drains (PVDs). Following initial laboratory simulation in a large-scale radial drainage consolidometer, the authors have attempted to explain the observed retardation of pore pressure dissipation through a series of models, which consider the effect of unsaturation at the drain-soil interface. The results indicate that the introduction of an unsaturated soil layer adjacent to a PVD improves the accuracy of numerical predictions. Lastly, a multidrain analysis is conducted to study the behaviour of an embankment stabilized with vertical drains subjected to vacuum preloading, and the field measurements are compared with a series of numerical model predictions.Key words: consolidation, embankment, finite element method, settlement, soft clay, vacuum preloading, vertical drains.

As a city develops, less areas will be available for constructions. Out of these available lands, a large quantity of areas has low soil bearing capacity and great amount of settlement. For this type of soil, loading is required in order to stabilize it. This will push out porewater contained inside the soil. However, reaching the expected settlement requires a long time, which can be solved by using prefabricated vertical drain to speed up the process. This is possible because prefabricated vertical drain decreases the travel distance of porewater to half of the vertical drain. Calculations for this thesis are done using one dimensional consolidation method, finite element method, and asaoka method for actual data calculation from the field. Using one dimensional consolidation method, with prefabricated vertical drain distance of 1.2 m in triangular pattern, resulted in settlement level of 2.048 m for 110 days. Using finite element method resulted in settlement level of 2.604 m for 120 days. On the other hand, using asaoka method resulted in settlement level of 1.422 m for 102 days. This difference is caused by lack of depth data from the laboratory.Semakin berkembangnya jaman maka pembangunan semakin banyak sehingga lahan untuk dilakukannya pembangunan semakin sedikit. Sekarang banyak tanah yang memiliki daya dukung kecil dan penurunan yang besar contohnya seperti tanah lunak. Agar tanah model ini dapat memiliki kondisi yang stabil , maka solusinya diberi beban sehingga air pori dari dalam tanah dapat tertekan keluar. Namun untuk mencapai penurunan yang diinginkan membutuhkan waktu yang cukup lama, disini digunakan metode prefabricated vertical drain untuk mempercepat penurunan. Prefabricated vertical drain disini membuat jarak tempuh air pori tanah yang sebelumnya setebal tanah lunak, menjadi setengah jarak antar prefabricated vertical drain. Perhitungan analisa pada skripsi ini menggunakan metode one dimensional consolidation, metode elemen hingga, dan metode asaoka sebagai perhitungan hasil aktual dari data lapangan. Penurunan total menggunakan metode one dimensional consolidation dengan jarak antar prefabricated vertical drain 1.2m dengan pola segitiga sebesar 2.048 m selama 110 hari, sedangkan dari metode elemen hingga didapatkan penurunan sebesar 2.604 m selama 120 hari. Dari data settlement recording yang dihitung menggunakan metode asaoka terjadi penurunan sebesar 1.422 m selama 102 hari. Perbedaan disini disebabkan oleh kurang banyaknya sample kedalaman dari data laboratorium.

The report will introduce a new technology using Prefabricated Horizontal Drain (called Super Board Drain -SBD) which is replaced for Sand Mat in soft soil treatment by using Prefabricated Vertical Drain (PVD) with preloading method and sand filled layer (Sand Mat) designed as the horizontal drainage for PVD through East-West Highway Construction Project.

To help the process of consolidation of the soil, On the port access road Trisakti using Prefabricated Vertical Drain (PVD) materials. Of the work (PVD) thing to note is the horizontal drainage, because it was feared the absence of Horizontal Drain work item function of PVD become non-optimal even it might does not work, so the necessary design analysis of Horizontal Drain that can be used on the project. Analysis of Horizontal Drain design is intended to get the Horizontal Drain design alternatives the most optimal based on quality, cost and time.The methods used in the analysis of the design of Horizontal Drain this is a soft soil improvement method using PVD with attention to soil degradation and the planning of the heap.In the design of the installation of PVD method using static, obtained the degree of consolidation of 90% takes 9.33 months. The calculation of Horizontal Drain in the discharge value must be in flush in one horizontal drain line is (minimum permeability). From the results of the analysis there is some material horizontal drain of qualified (in terms of time, cost and quality of workmanship) then get : Rough sand (10.93, Rp. 24.050.000.000,-, and 9.4 months), Fine sand (16.24, Rp-16,835,000,000.0, and 9.4 months), PHD (Horizontal Prefabricated Drain) (74.01, Rp-13,101,140,000.0, and 5.6 months) so that it can be concluded that the material PHD (Horizontal Prefabricated Drain) the most efficient in terms of quality, cost, and time. Keywords: Consolidation, Degrees of consolidation, Horizontal Drain, Preloading, Prefabricated Vertical Drain (PVD), Prefabricated Horizontal Drain (PHD).