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Yulvi Zaika - One of the best experts on this subject based on the ideXlab platform.
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analisis perbandingan penurunan tanah terhadap fungsi waktu pada perbaikan tanah lunak dengan Prefabricated Vertical Drain pvd
Jurnal Mahasiswa Jurusan Teknik Sipil, 2020Co-Authors: Farhan Prima Chandra, Yulvi Zaika, Arief RachmansyahAbstract:Jalan Tol Pasuruan-Probolinggo merupakan salah satu pembangunan infrastruktur di Indonesia, dimana tanah yang berada di daerah tersebut berupa tanah berbutir halus yang memiliki karakteristik tanah yang tidak stabil karena mempunyai kandungan air tanah berlebih sehingga tanah menjadi lunak, daya dukung tanah yang rendah serta proses penurunan yang lama. Oleh karena itu, dibutuhkan suatu usaha perbaikan tanah agar struktur tanah menjadi lebih kuat dan kokoh dalam menahan beban konstruksi. Usaha perbaikan tanah pada tanah lunak dapat dilakukan dengan perlakuan pra-pembebanan dan dipadukan dengan Prefabricated Vertical Drain (PVD) sebagai alat untuk mempercepat proses penurunan tanah. Pra-pembebanan pada penelitian ini akan diberikan secara bertahap di laboratorium selama 5 hari yang kemudian divariasikan terhadap variabel jarak antar PVD, kedalaman PVD, dan pola pemasangan PVD. Hal tersebut bertujuan untuk mengetahui kinerja maksimum PVD dalam mempercepat proses penurunan tanah. Selanjutnya, data karakteristik tanah yang telah diperbaiki akan di bandingkan terhadap sampel tanah tanpa PVD ( benchmark ), terutama dalam segi waktu dan penurunan konsolidasi berdasarkan perhitungan konsolidasi satu dimensi Terzaghi, perhitungan analisis PVD dengan mempertimbangkan efek smear dan perhitungan konsolidasi dengan proyeksi Asaoka. Dari hasil pengolahan data, dapat diketahui bahwa nilai penurunan terbesar setelah 5 hari pembebanan konsolidasi adalah pada variasi kedalaman PVD 40 cm berpola segitiga. Hal tersebut dibuktikan dengan capaian penurunan aktual skala laboratorium sebesar 42,926 mm, penurunan dengan analisis PVD mempertimbangkan efek smear sebesar 42,926 mm, dan terakhir nilai penurunan dengan analisis Asaoka sebesar 61,448 mm. Disamping itu, besar penurunan akhir benchmark dengan analisis Terzaghi setelah 5 hari pembebanan adalah sebesar 6,824 mm, dimana waktu penurunan yang dibutuhkan untuk mencapai nilai penurunan akhir benchmark pada variasi kedalaman PVD 40 cm berpola segitiga hanya selama 3,945 jam. Kata kunci : Tanah lunak, Prefabricated Vertical Drain (PVD), Terzaghi, smear zone , Asaoka
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perbaikan tanah lunak dengan Prefabricated Vertical Drain pvd dengan pola segitiga dengan variasi kedalaman pada jalan tol pasuruan probolinggo
Jurnal Mahasiswa Jurusan Teknik Sipil, 2020Co-Authors: Fritz Risty, Yulvi ZaikaAbstract:Tanah yang terdapat pada jalan Tol Pasuruan-Probolinggo memiliki ketebalan tanah lempung lunak yang bervariasi. Hal ini dapat menyebabkan daya dukung tanah dasar yang rendah dan perbedaan penurunan tanah dasar, yang akan berdampak pada kerusakan pengerasan jalan. Metode yang digunakan penulis untuk perbaikan pada tanah yang bersifat lunak ini yaitu dengan perlakuan pra-pembebanan dan dipadukan dengan PVD ( Pre - fabricated Vertical Drain ) pola segitiga . PVD adalah Drainase buatan berbentuk pita (potongan melintang segiempat) yang terdiri atas material penyaring geotekstil yang membungkus inti plastik.Pengujian konsolidasi jarak PVD adalah 20 cm, variasi kedalaman 25 cm, 30 cm, dan 40 cm. Uji konsolidasi pada sampel dilakukan dengan menggunakan PVD dan tanpa menggunakan PVD untuk membandingkan parameter tanah. Uji ini dilakukan dalam 5 hari dengan membebani tanah secara bertahap, kemudian tegangan yang diberikan sebesar 232,35 , 276,31 , 376,38 , 433,33 dan 511,87 .
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perubahan karakteristik tanah lunak yang diperbaiki dengan Prefabricated Vertical Drain pvd dengan pola segitiga dengan variasi jarak pada tanah lunak di jalan tol pasuruan probolinggo
Jurnal Mahasiswa Jurusan Teknik Sipil, 2020Co-Authors: Willy Anggi Abadi, Asad Munawir, Yulvi ZaikaAbstract:Pembangunan Infrastruktur di indonesia saat ini sedang berkembang sangat pesat, salah satunya adalah pembangunan jalan tol. Permasalahan yang sering terjadi adalah karakteristik tanah yang kurang stabil pada daerah yang akan dibangun. Salah satu infrastruktur yang mengalami permasalahan ini adalah pembangunan jalan Tol Pasuruan-Probolinggo. Tanah yang berada pada daerah ini mempunyai karakteristik tanah yang tidak stabil akibat kandungan air tanah yang berlebih sehingga tanah menjadi lunak. Oleh karena itu, dibutuhkan usaha perbaikan tanah agar tidak mengalami kerusakan pada saat pembangunan. Metode yang digunakan untuk perbaikan tanah yang bersifat lunak adalah dengan perlakuan pra-pembebanan dan dipadukan dengan PVD ( Pre - fabricated Vertical Drain ) pola segitiga yang divariasikan dengan variabel jarak antar PVD. Pengujian konsolidasi dilakukan dengan memberikan beban secara bertahap dalam kurun waktu 24 jam selama 5 hari dengan variasi jarak 20cm, 25cm, 30cm dan kedalaman sebesar 30cm. Dari hasil analisis konsolidasi, terdapat perbedaan antara sampel yang menggunakan PVD dengan sampel yang tidak menggunakan PVD. Perbedaan yang terjadi yaitu penurunan pada sampel tanah yang menggunakan PVD dengan jarak 20 cm mengalami kenaikan sebesar 1135,6% dan kuat geser tanah pada sampel tanah yang menggunakan PVD dengan jarak 20 cm mengalami kenaikan sebesar 316,66%. Perbedaan ini terjadi karena PVD memberikan lintasan Drainase yang memungkinkan aliran air pori lebih pendek pada saat terjadi konsolidasi, sehingga semakin pendek jarak PVD, maka lintasan aliran air dengan arah vertikal dan horizontal akan lebih pendek. Kata kunci : PVD (Pre-fabricated Vertical Drain), Penurunan tanah, kuat geser, Jarak
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evaluasi perbaikan tanah lunak menggunakan Prefabricated Vertical Drain pvd dengan pola segiempat
Jurnal Mahasiswa Jurusan Teknik Sipil, 2020Co-Authors: Audia Maknolia Wahyunita, Yulvi ZaikaAbstract:Karakteristik tanah pada jalan Tol Gempol - Pasuruan memiliki konsistensi tanah yang tidak stabil yang sering disebut tanah lunak. Tanah lunak adalah tanah yang kurang bisa mendukung kekuatan konstruksi. Disebabkan rendahnya daya dukung tanah dan tingginya kandungan air menyebabkan sulit terdranasi karena tanah memiliki permeabilitas relatif rendah dan memiliki kompresibilitas yang besar mengakibatkan tanah mengalami penurunan yang besar dengan waktu yang sangat lama sehingga menyebabkan kerusakan pada konstruksi. Untuk menangani permasalahan tersebut maka diperlukan perbaikan tanah. Salah satu metode perbaikan tanah lunak yang akan dilakukan yaitu dengan cara mempercepat konsolidasi menggunakan Prefabricated Vertical Drain (PVD) dengan pola segiempat. Pada analisis penelitian ini digunakan aplikasi yaitu aplikasi elemen hingga 2D untuk menganalisa kasus lapangan dan uji skala kecil di laboratorium. Pada kondisi lapangan memiliki kedalaman tanah sedalam 24,5 m memiliki 6 lapisan tanah dengan tinggi timbunan sebesar 10,2 m, traffic load sebesar 30kN/m 2 dan diberikan PVD pola segiempat pada kedalaman hingga 13 m, jarak antar PVD sebesar 1 m. Pada kondisi laboratorium digunakan kasus yang diselidiki oleh peneliti lain yang digunakan sebagai pembanding hasil analisa menggunakan aplikasi elemen hingga 2D. Pemodelan tanah untuk skala lapangan mengguanakan model Mohr-coulumb dan pemodelan skala kecil dilaboratorium menggunakan model Soft-soil . Dengan mesh generation yaitu coarse agar hasil yang didapatkan memiliki nilai yang optimum. Pada skala lapangan diberikan calculation type yaitu degree of consolidation 90%. Hasil akhir pada penelitian ini yaitu jumlah penurunan yang terjadi akibat pemasangan PVD dan tanpa PVD, tegangan-regangan yang terjadi, dan safety factor . Hasil analisis menggunakan aplikasi elemen hingga pemberian Prefabricated Vertical Drain (PVD) dengan Pola Segiempat , mampu meningkatkan konsolidasi yang lebih besar serta mempercepat waktu konsolidasi 4 kali lebih cepat dari pemodelan tanah tanpa PVD pada skala lapangan yaitu sebesar 1,377 m dengan waktu kurang lebih 1 tahun. Pada skala kecil di laboratorium memiliki penurunan terbesar pada variable C dengan penurunan sebesar 0,578 cm. Kata kunci: Tanah lunak, FEM 2D, PVD, segiempat, skema, konsolidasi.
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perbaikan sifat mekanik tanah lunak yang diperbaiki dengan Prefabricated Vertical Drain pvd pola segiempat dengan perubahan kedalaman pemasangan studi kasus jalan tol pasuruan probolinggo
Jurnal Mahasiswa Jurusan Teknik Sipil, 2020Co-Authors: Iffat Shafwan Haristama, Arief Rachmansyah, Yulvi ZaikaAbstract:Masalah yang sering dijumpai pada infrastruktur jalan tol di pulau jawa ialah tanah lunak karena nilai daya dukung tanah dan kuat geser rendah sehingga menyebabkan penurunan pada pondasi jalan tol tersebut. Alternatif perbaikan tanah yang digunakan ialah dengan melakukan prakompresi pada tanah yang dibantu dengan Prefabricated Vertical Drain (PVD). Perbaikan tanah menggunakan beberapa variasi kedalaman pvd dalam pemasangannya, yaitu kedalaman 25cm, 30cm, dan 40cm sedangkan untuk jarak antar PVD sama yaitu sebesar 20cm. Pengujian dilaksanakan selama 5 hari dengan pemberian beban secara bertahap sebanyak 5 (lima) variasi pembebanan serta nilai tegangan yang diratakan setiap 1 variasi beban yang diberikan yaitu sebesar 232,35 kg/m 2 , 276,31 kg/m 2 , 376,38 kg/m 2 . 433,33 kg/m 2 , dan 511,87 kg/m 2 . Hasil pengujian menunjukkan ada perbedaan penurunan pada sampel, kenaikan penurunan pengunaan pvd kedalaman 25cm sebesar 31%, untuk pvd kedalaman 30cm sebesar 94% dan untuk pvd kedalaman 40cm sebesar 97% dibanding dengan sampel yang tidak menggunakan pvd. Perbedaan kuat geser juga terlihat, untuk kedalaman pvd 25cm nilai kenaikannya sebesar 65%, untuk kedalaman pvd 30cm sebesar 81% dan untuk kedalaman pvd 40cm sebesar 90%. Berdasarkan hasil yang didapatkan semakin dalam kedalamanan pemasangan PVD maka akan semakin besar penurunan yang akan terjadi diwaktu yang sama dan nilai kuat geser akan meningkat. Semakin besar kedalaman PVD maka nilai tegangan air pori turun sampai nilai nol akan semakin cepat, sehingga kecepatan konsolidasi meningkat. Kata Kunci : Tanah Lunak, PVD, Persegi, Kedalaman, Kekuatan.
Suksun Horpibulsuk - One of the best experts on this subject based on the ideXlab platform.
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consolidation behavior of dredged ultra soft soil improved with Prefabricated Vertical Drain at the mae moh mine thailand
Geotextiles and Geomembranes, 2020Co-Authors: Suksun Horpibulsuk, Apichat Suddeepong, Artit Udomchai, Prajueb Doncommul, Runglawan Rachan, Arul ArulrajahAbstract:Abstract The effectiveness of the Prefabricated Vertical Drains (PVDs) in the consolidation of ultra-soft dredged soil with various soil water contents (W) in Mae Moh mine, Lampang, Thailand was researched via a series of large-scale model tests and numerical analysis. Large settlements with the delay of excess pore pressures is a distinct behavior of ultra-soft soil. The PVD dimensions were found to have a significant effect on the rate of consolidation and the delay of excess pore pressure at low total Vertical stress (σv). The smaller PVD dimension resulted in the smaller rate of consolidation and longer delay of excess pore pressure. The unDrained shear strength (Su) of ultra-soft clay at various degrees of consolidation could be approximated by the Vertical effective stress (σ′v) based on the SHANSEP where the σ′v was determined from the Asaoka's observational method. The finite element analysis with axisymmetric and plane strain models showed that the axisymmetric model produced an excellent settlement prediction. However, the excess pore pressures were not well predicted by the axisymmetric model, due to the delay of excess pore pressures at the early stages of consolidation. In practice, the plane strain models proposed by Chai et al. and Indraratna and Redana's methods are suggested to predict the consolidation settlement of the Mae Moh dredged soil improved with PVD. The outcome of this research will facilitate the geotechnical design of reclamation of ultra-soft dredged soil in Mae Moh mine and other similar soils.
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laboratory measurements of factors affecting discharge capacity of Prefabricated Vertical Drain materials
Soils and Foundations, 2016Co-Authors: Myint Win Bo, Arul Arulrajah, Suksun Horpibulsuk, Avirut Chinkulkijniwat, Melvyn LeongAbstract:Abstract The discharge capacity is a critical parameter controlling the performance of Prefabricated Vertical Drains (PVDs). The laboratory measurement of the discharge capacity is of the upmost importance when it comes to assessing the performance of proposed PVDs prior to their usage in the field, and hence, the significance of this paper. However, the laboratory measurement of the discharge capacity required to obtain the optimal performance of PVDs by laboratory testing methods is still uncertain. This is because there are various apparatus for discharge capacity testing currently in use by various commercial and research organizations, all of which provide widely varying values of discharge capacity for the same type of PVD under the same hydraulic conditions. The measured discharge capacity of PVDs in the laboratory, with and without surrounding soils, is affected by factors such as the dimensions of the apparatus, the test duration, the hydraulic gradient, the type of surrounding materials, the applied confining pressure and the deformation configuration of the Vertical Drains. The effects of these factors are investigated, reviewed and discussed in this paper. The relevant equations for obtaining the required discharge capacity of PVDs by laboratory methods are also presented and discussed in this paper. The test results indicate that a small tester results in the underestimation of the discharge capacity particularly for PVDs with a high discharge capacity. A reduction in PVD thickness, the clogging of the filter, the deformation of the PVDs, due to an increase in the duration of the tests (creep), and Vertical pressure all cause a reduction in the discharge capacity for a particular hydraulic gradient. Softer surrounding soils and lower PVD stiffness cause a large deformation of the soils surrounding the PVDs. For a particular PVD, the creep effect on the decrease in discharge capacity is significant with a short duration, but becomes insignificant after a long duration. The deformation of PVDs under folded conditions is found to be the most critical factor in the resulting decrease in discharge capacity.
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quality management of Prefabricated Vertical Drain materials in mega land reclamation projects a case study
Soils and Foundations, 2015Co-Authors: Myint Win Bo, Arul Arulrajah, Suksun Horpibulsuk, Melvyn LeongAbstract:Abstract The quality management of Prefabricated Vertical Drain (PVD) material installation in ground improvement works in land reclamation projects is a critical task for designers, contractors and clients alike. Only if a good quality management system is established, can the expected performance of the PVD improvement works in the field be ensured. A case study of quality management of PVD materials in the mega Changi East land reclamation Project in the Republic of Singapore is presented in this technical report. The quality management of PVD works consisted of several processes, starting from selection of the type of PVD, properties of the PVD materials and ultimate performance verification in the field. This paper describes selection of PVDs against the comprehensive specification adopted in this project. The paper also describes the selection of the PVD installation rig and accessories based on the in-situ ground conditions. Test results from quality control test laboratories such as tension, permeability and discharge capacity are also presented and discussed. This paper seeks to set a benchmark for material quality management of PVD works in large-scale PVD ground improvement projects.
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EVALUATION OF GROUND IMPROVEMENT AND RECHARGE USING Prefabricated Vertical Drain (PVD) FOR THE SECOND BANGKOK INTERNATIONAL AIRPORT (SBIA) PROJECT
2002Co-Authors: Suksun Horpibulsuk, Dennes T. Bergado, W BunthaiAbstract:The improvement of the inherent properties of soft Bangkok clay by preloading with Prefabricated Vertical Drain (PVD) is extensively and presently applied. However, the issues related to analysis and design have not been widely available to geotechnical engineers. This paper attempts to illustrate the consolidation parameters for design and to introduce a method to capture the settlement characteristics of the soft ground improved by PVD. The method is the one-dimensional (1-D) finite element analysis, which can handle the case of the multi-layered soil deposits with different soil properties. The analysis of the settlement for the soil improved by PVD at the Second Bangkok International Airport (SBIA), Thailand with the different consolidation parameters at each soil layer is done by the PVD-SD software Version 2.3. It is found that the predicted curves were in agreement with the measured ones. Furthermore, based on the measurements at the SIBA site and the full-scale recharge test at the campus of Asian Institute of Technology, it was demonstrated that the PVD was also effective in recharging the ground and erased the piezometric level drawndown down to the depth of PVD installation. The piezometric drawdown is due to the excessive withdrawal of groundwater leading to the ground subsidence. For the covering abstract see ITRD E117244.
H M Abuelnaga - One of the best experts on this subject based on the ideXlab platform.
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equivalent diameter of a Prefabricated Vertical Drain
Geotextiles and Geomembranes, 2009Co-Authors: H M Abuelnaga, Abdelmalek BouazzaAbstract:The aim of this study is to evaluate numerically the equivalent diameter of a Prefabricated Vertical Drain (PVD) using an equal flow rate approach. This approach requires that the equivalent circular well to be able to yield similar discharge as a PVD well when subjected to similar pressure-controlled pumping condition. Simple equivalent diameter equation was obtained from the numerical study. The proposed equation is discussed in light of the equivalent diameter equations and experimental results currently available in the literature. The outcomes of this study give more insight in this subject and improve the method of calculating the equivalent diameter of a PVD well.
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technical noteequivalent diameter of a Prefabricated Vertical Drain
Geotextiles and Geomembranes, 2009Co-Authors: H M Abuelnaga, Abdelmalek BouazzaAbstract:The aim of this study is to evaluate numerically the equivalent diameter of a Prefabricated Vertical Drain (PVD) using an equal flow rate approach. This approach requires that the equivalent circular well to be able to yield similar discharge as a PVD well when subjected to similar pressure-controlled pumping condition. Simple equivalent diameter equation was obtained from the numerical study. The proposed equation is discussed in light of the equivalent diameter equations and experimental results currently available in the literature. The outcomes of this study give more insight in this subject and improve the method of calculating the equivalent diameter of a PVD well.
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numerical evaluation of Prefabricated Vertical Drain enhanced soil vapour extraction system
Geosynthetics International, 2008Co-Authors: H M Abuelnaga, Abdelmalek Bouazza, John J Bowders, Omaira CollazosAbstract:The aim of this study is to investigate numerically the performance of a Prefabricated Vertical Drain (PVD) as a soil vapour extraction well, and the pattern of the induced air flow. A validated numerical model for a single PVD extraction well is developed based on the result of a well-designed laboratory air-pumping test. The results of the validated numerical model are used to evaluate the flow efficiency of a PVD extraction well. The validity of the simple analytical approach to determine air permeability based on the results of air-pumping tests is also discussed. The output of this study highlights the influence of PVD well resistance on the overall performance of soil vapour extraction systems, and the effect of the PVD's oblong cross-section on the air flow characteristics.
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innovative thermal technique for enhancing the performance of Prefabricated Vertical Drain during the preloading process
Geotextiles and Geomembranes, 2006Co-Authors: H M Abuelnaga, D T Bergado, S ChaiprakaikeowAbstract:Abstract This paper examines the effect of raising the temperature of soft Bangkok clay, up to 90 °C, on the performance of the Prefabricated Vertical Drain (PVD) during the preloading process. The effect of temperature on the engineering behavior of soft Bangkok clay was first investigated using a modified triaxial test apparatus and flexible wall permeameter which can handle temperatures up to 100 °C. The results of the triaxial tests on clay specimens demonstrate that raising the soil temperature increases its shear strength, under Drained heating condition, as well as its hydraulic conductivity. In addition, large oedometer tests were performed to investigate the performance of PVD at elevated temperatures. The response of the soil sample with PVD for the thermal consolidation path which involved increasing the soil temperature at constant Vertical effective stress condition and the thermo-mechanical path which involved increasing simultaneously both the soil temperature and the Vertical effective stress were investigated. The consequent results indicated that the thermo-mechanical path shows promising results regarding the consolidation rate. For both reconstituted and undisturbed specimens, higher consolidation rate was observed for the soil specimen with PVD loaded under elevated temperature. This behavior can be attributed to the increase in the soil hydraulic conductivity as the soil temperature increases. Therefore, raising the soil temperature during the preloading period can enhance the performance of the PVD, particularly, by reducing the Drainage retardation effects due to the smear zone around PVD.
Melvyn Leong - One of the best experts on this subject based on the ideXlab platform.
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laboratory measurements of factors affecting discharge capacity of Prefabricated Vertical Drain materials
Soils and Foundations, 2016Co-Authors: Myint Win Bo, Arul Arulrajah, Suksun Horpibulsuk, Avirut Chinkulkijniwat, Melvyn LeongAbstract:Abstract The discharge capacity is a critical parameter controlling the performance of Prefabricated Vertical Drains (PVDs). The laboratory measurement of the discharge capacity is of the upmost importance when it comes to assessing the performance of proposed PVDs prior to their usage in the field, and hence, the significance of this paper. However, the laboratory measurement of the discharge capacity required to obtain the optimal performance of PVDs by laboratory testing methods is still uncertain. This is because there are various apparatus for discharge capacity testing currently in use by various commercial and research organizations, all of which provide widely varying values of discharge capacity for the same type of PVD under the same hydraulic conditions. The measured discharge capacity of PVDs in the laboratory, with and without surrounding soils, is affected by factors such as the dimensions of the apparatus, the test duration, the hydraulic gradient, the type of surrounding materials, the applied confining pressure and the deformation configuration of the Vertical Drains. The effects of these factors are investigated, reviewed and discussed in this paper. The relevant equations for obtaining the required discharge capacity of PVDs by laboratory methods are also presented and discussed in this paper. The test results indicate that a small tester results in the underestimation of the discharge capacity particularly for PVDs with a high discharge capacity. A reduction in PVD thickness, the clogging of the filter, the deformation of the PVDs, due to an increase in the duration of the tests (creep), and Vertical pressure all cause a reduction in the discharge capacity for a particular hydraulic gradient. Softer surrounding soils and lower PVD stiffness cause a large deformation of the soils surrounding the PVDs. For a particular PVD, the creep effect on the decrease in discharge capacity is significant with a short duration, but becomes insignificant after a long duration. The deformation of PVDs under folded conditions is found to be the most critical factor in the resulting decrease in discharge capacity.
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quality management of Prefabricated Vertical Drain materials in mega land reclamation projects a case study
Soils and Foundations, 2015Co-Authors: Myint Win Bo, Arul Arulrajah, Suksun Horpibulsuk, Melvyn LeongAbstract:Abstract The quality management of Prefabricated Vertical Drain (PVD) material installation in ground improvement works in land reclamation projects is a critical task for designers, contractors and clients alike. Only if a good quality management system is established, can the expected performance of the PVD improvement works in the field be ensured. A case study of quality management of PVD materials in the mega Changi East land reclamation Project in the Republic of Singapore is presented in this technical report. The quality management of PVD works consisted of several processes, starting from selection of the type of PVD, properties of the PVD materials and ultimate performance verification in the field. This paper describes selection of PVDs against the comprehensive specification adopted in this project. The paper also describes the selection of the PVD installation rig and accessories based on the in-situ ground conditions. Test results from quality control test laboratories such as tension, permeability and discharge capacity are also presented and discussed. This paper seeks to set a benchmark for material quality management of PVD works in large-scale PVD ground improvement projects.
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piezometer measurements of Prefabricated Vertical Drain improvement of soft soils under land reclamation fill
Engineering Geology, 2013Co-Authors: Arul Arulrajah, Myint Win Bo, Melvyn Leong, M M DisfaniAbstract:Abstract Piezometers are commonly used for monitoring the dissipation of pore water pressure and therefore the determination of degree of consolidation of soft soils after ground improvement in land reclamation projects. This paper compares the degree of consolidation obtained using pore pressure monitoring data from vibrating wire piezometers and pneumatic piezometers installed in a test site in the Changi East Reclamation project in Singapore. The test site consisted of a Vertical Drain sub-area at which Prefabricated Vertical Drains were installed at 2.0 m × 2.0 m square spacing as well as an adjacent control sub-area where no Prefabricated Vertical Drains were installed. Pneumatic piezometers were installed at the same elevations as the vibrating-wire piezometers in both sub-areas for comparison purposes. During the surcharge period of 32 months, the piezometer monitoring data were analysed at various periods to determine the degree of consolidation of the underlying soft marine clay. The degree of consolidation values interpreted from both types of piezometers were compared with predictions from neighbouring settlement plates to evaluate their performance. The findings of the comparison between pneumatic and electric vibrating-wire piezometers indicate that both types of piezometer are suitable for monitoring the consolidation behaviour of soft soil under land reclamation fills.
Arul Arulrajah - One of the best experts on this subject based on the ideXlab platform.
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Application of Prefabricated Vertical Drains to the Changi Land Reclamation Project, Singapore
Geosynthetics in Civil and Environmental Engineering, 2020Co-Authors: Arul Arulrajah, Myint Win Bo, Hamid NikrazAbstract:The Changi East Reclamation Project in the Republic of Singapore involved the filling of approximately 200 million cubic of sand for the land reclamation of a total area of about 2500 hectares. Land reclamation was carried out using fill materials obtained from dredging granular material from the seabed at the borrow source. The ground improvement technique which involved combination of Prefabricated Vertical Drain (PVD) with preloading was successfully applied in this project to improve the underlying compressible soils. The project comprises the installation of Prefabricated Vertical Drains and the subsequent placement of surcharge to accelerate the consolidation of the underlying marine clay. In order to monitor the performance of ground improvement and to validate the performance of the Prefabricated Vertical Drain system, several geotechnical instruments were installed to monitor the degree of consolidation at both area with PVD and area without PVD as control area. This paper provides a case study of the ground improvement works carried out with Prefabricated Vertical Drains at the Changi East Reclamation Project and their subsequent performance assessment.
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consolidation behavior of dredged ultra soft soil improved with Prefabricated Vertical Drain at the mae moh mine thailand
Geotextiles and Geomembranes, 2020Co-Authors: Suksun Horpibulsuk, Apichat Suddeepong, Artit Udomchai, Prajueb Doncommul, Runglawan Rachan, Arul ArulrajahAbstract:Abstract The effectiveness of the Prefabricated Vertical Drains (PVDs) in the consolidation of ultra-soft dredged soil with various soil water contents (W) in Mae Moh mine, Lampang, Thailand was researched via a series of large-scale model tests and numerical analysis. Large settlements with the delay of excess pore pressures is a distinct behavior of ultra-soft soil. The PVD dimensions were found to have a significant effect on the rate of consolidation and the delay of excess pore pressure at low total Vertical stress (σv). The smaller PVD dimension resulted in the smaller rate of consolidation and longer delay of excess pore pressure. The unDrained shear strength (Su) of ultra-soft clay at various degrees of consolidation could be approximated by the Vertical effective stress (σ′v) based on the SHANSEP where the σ′v was determined from the Asaoka's observational method. The finite element analysis with axisymmetric and plane strain models showed that the axisymmetric model produced an excellent settlement prediction. However, the excess pore pressures were not well predicted by the axisymmetric model, due to the delay of excess pore pressures at the early stages of consolidation. In practice, the plane strain models proposed by Chai et al. and Indraratna and Redana's methods are suggested to predict the consolidation settlement of the Mae Moh dredged soil improved with PVD. The outcome of this research will facilitate the geotechnical design of reclamation of ultra-soft dredged soil in Mae Moh mine and other similar soils.
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laboratory measurements of factors affecting discharge capacity of Prefabricated Vertical Drain materials
Soils and Foundations, 2016Co-Authors: Myint Win Bo, Arul Arulrajah, Suksun Horpibulsuk, Avirut Chinkulkijniwat, Melvyn LeongAbstract:Abstract The discharge capacity is a critical parameter controlling the performance of Prefabricated Vertical Drains (PVDs). The laboratory measurement of the discharge capacity is of the upmost importance when it comes to assessing the performance of proposed PVDs prior to their usage in the field, and hence, the significance of this paper. However, the laboratory measurement of the discharge capacity required to obtain the optimal performance of PVDs by laboratory testing methods is still uncertain. This is because there are various apparatus for discharge capacity testing currently in use by various commercial and research organizations, all of which provide widely varying values of discharge capacity for the same type of PVD under the same hydraulic conditions. The measured discharge capacity of PVDs in the laboratory, with and without surrounding soils, is affected by factors such as the dimensions of the apparatus, the test duration, the hydraulic gradient, the type of surrounding materials, the applied confining pressure and the deformation configuration of the Vertical Drains. The effects of these factors are investigated, reviewed and discussed in this paper. The relevant equations for obtaining the required discharge capacity of PVDs by laboratory methods are also presented and discussed in this paper. The test results indicate that a small tester results in the underestimation of the discharge capacity particularly for PVDs with a high discharge capacity. A reduction in PVD thickness, the clogging of the filter, the deformation of the PVDs, due to an increase in the duration of the tests (creep), and Vertical pressure all cause a reduction in the discharge capacity for a particular hydraulic gradient. Softer surrounding soils and lower PVD stiffness cause a large deformation of the soils surrounding the PVDs. For a particular PVD, the creep effect on the decrease in discharge capacity is significant with a short duration, but becomes insignificant after a long duration. The deformation of PVDs under folded conditions is found to be the most critical factor in the resulting decrease in discharge capacity.
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quality management of Prefabricated Vertical Drain materials in mega land reclamation projects a case study
Soils and Foundations, 2015Co-Authors: Myint Win Bo, Arul Arulrajah, Suksun Horpibulsuk, Melvyn LeongAbstract:Abstract The quality management of Prefabricated Vertical Drain (PVD) material installation in ground improvement works in land reclamation projects is a critical task for designers, contractors and clients alike. Only if a good quality management system is established, can the expected performance of the PVD improvement works in the field be ensured. A case study of quality management of PVD materials in the mega Changi East land reclamation Project in the Republic of Singapore is presented in this technical report. The quality management of PVD works consisted of several processes, starting from selection of the type of PVD, properties of the PVD materials and ultimate performance verification in the field. This paper describes selection of PVDs against the comprehensive specification adopted in this project. The paper also describes the selection of the PVD installation rig and accessories based on the in-situ ground conditions. Test results from quality control test laboratories such as tension, permeability and discharge capacity are also presented and discussed. This paper seeks to set a benchmark for material quality management of PVD works in large-scale PVD ground improvement projects.
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piezometer measurements of Prefabricated Vertical Drain improvement of soft soils under land reclamation fill
Engineering Geology, 2013Co-Authors: Arul Arulrajah, Myint Win Bo, Melvyn Leong, M M DisfaniAbstract:Abstract Piezometers are commonly used for monitoring the dissipation of pore water pressure and therefore the determination of degree of consolidation of soft soils after ground improvement in land reclamation projects. This paper compares the degree of consolidation obtained using pore pressure monitoring data from vibrating wire piezometers and pneumatic piezometers installed in a test site in the Changi East Reclamation project in Singapore. The test site consisted of a Vertical Drain sub-area at which Prefabricated Vertical Drains were installed at 2.0 m × 2.0 m square spacing as well as an adjacent control sub-area where no Prefabricated Vertical Drains were installed. Pneumatic piezometers were installed at the same elevations as the vibrating-wire piezometers in both sub-areas for comparison purposes. During the surcharge period of 32 months, the piezometer monitoring data were analysed at various periods to determine the degree of consolidation of the underlying soft marine clay. The degree of consolidation values interpreted from both types of piezometers were compared with predictions from neighbouring settlement plates to evaluate their performance. The findings of the comparison between pneumatic and electric vibrating-wire piezometers indicate that both types of piezometer are suitable for monitoring the consolidation behaviour of soft soil under land reclamation fills.