Soft Soil Improvement with Conventional and Geogrid-Encased Stone Piles Under an Embankment

2017 ◽  
pp. 110-125
Author(s):  
Mohamd B. D. Elsawy
Keyword(s):  
Soft Soil ◽  
Soil Improvement

scholarly journals PLANNING OF SOFT SOIL IMPROVEMENT WITH PRELOADING AND PREFABRICATED VERTICAL DRAIN METHOD

2018 ◽  
Vol 2 (01) ◽  
pp. 19
Author(s):  
Ana Crosita Ningsih ◽  
Luthfi Amri Wicaksono ◽  
Mokhamad Farid Ma'ruf
Keyword(s):  
Urban Areas ◽  
Soil Structure ◽  
Soft Soil ◽  
Soil Improvement ◽  
Building Site ◽  
Planning Time ◽  
Coral Sand ◽  
Rapid Construction ◽  
Prefabricated Vertical Drain ◽  
Surrounding Areas

The northern coastal areas of Java such as Gresik and surrounding areas have a soil structure of alluvium consisting of gravel / coral, sand, clay soil and shells. Soil basic conditions are soft enough to cause land subsidence (settlement). The need for rapid construction causes the urban areas to become less and more for development land. This requires the improvement of soft soil to be used as a building site. As for the method to be done in this planning using a combination of preloading and PVD methods to accelerate the process of land degradation. Based on the planning result, the total height of embankment (preloading) is 3.5 m and the planning time lasted 4 months. Soft soil improvement is done up to 25 m depth with PVD design using triangle pattern and space 1.3 m. The 95% consolidation decrease due to the load of embankment caused the soil to fall as deep as 1,928 m. In this planning use modeling Plaxis 8.6 2D and the resulting yield of soil is 1,990 m. Wilayah pesisir pantai utara Jawa seperti daerah Gresik dan sekitarnya mempunyai struktur tanah berupa alluvium yang terdiri dari batu kerikil/koral, pasir, tanah lempung dan pecahan kulit kerang. Kondisi tanah dasar yang cukup lunak menyebabkan terjadinya penurunan tanah (settlement). Adanya kebutuhan konstruksi yang semakin pesat menyebabkan wilayah perkotaan menjadi semakin sedikit untuk dijadikan lahan pembangunan. Hal ini mengharuskan dilakukannya upaya perbaikan tanah lunak agar bisa dijadikan lahan bangunan nantinya. Adapun pada metode yang akan dilakukan pada perencanaan ini menggunakan kombinasi metode preloading dan PVD untuk mempercepat proses penurunan tanah. Berdasarkan hasil perencanaan didapatkan total tinggi timbunan (preloading) adalah 3,5 m dan waktu perencanaan berlangsung 4 bulan. Perbaikan tanah lunak dilakukan sampai dengan kedalaman 25 m dengan desain PVD menggunakan pola segitiga dan spasi 1,3 m. Penurunan konsolidasi 95% akibat beban timbunan menyebabkan tanah turun sedalam 1,928 m. Pada perencanaan ini menggunakan pemodelan Plaxis 8.6 2D dan hasil penurunan tanah yang dihasilkan adalah sedalam 1,990 m.

scholarly journals ANALISIS PENGGUNAAN PREFABRICATED VERTICAL DRAINS (PVD) PADA TANAH LEMPUNG LUNAK YANG TERDAPAT LAPISAN LENSA

2020 ◽  
Vol 3 (1) ◽  
pp. 119
Author(s):  
Andreyan Prasetio ◽  
Aniek Prihatiningsih
Keyword(s):  
Soft Soil ◽  
Soil Improvement ◽  
Cohesive Soils ◽  
Consolidation Process ◽  
Prefabricated Vertical Drains ◽  
Soil Layers ◽  
Vertical Drains ◽  
Vertical Drain ◽  
Installation Depth ◽  
Consolidation Time

Problem that often occurs in soft cohesive soils is settlement caused by consolidation process. If  construction activities doing when the soils has not been consolidated, settlement can occur. To accelerate  the consolidation process, soil improvement are usually do, one method of soil improvement to accelarate the consolidation process is vertical drain using prefabricated vertical drains (PVD). The soft soil layers in the field are not always continuous, sometimes found soft soil layers that have a lens layer. In this study, will discuss about the settlement and consolidation time of soft  soil layers that have a lens layer which has been improved by PVD with 1 meter distance. Infrastructure that stand on a location that is installed by PVD is taxiway and loading by Airbus A380 aircraft of 18,22ton/m2. Analysis using the 1 dimensional consolidation theory of Terzaghi. For PVD installation to a depth of 50 meters, preloading settlement of 234,80 cm with a consolidation time of  2260 days for the square pattern PVD and 1918 days for triangle pattern PVD. Post loading settlement for PVD installation depth of 50 meters by 2,50 cm. AbstrakMasalah yang sering terjadi pada tanah kohesif dan lunak adalah penurunan yang disebabkan proses konsolidasi. Penurunan dapat menyebabkan keretakan pada struktur konstruksi yang berada di atasnya. Jika suatu kegiatan konstruksi dilakukan saat tanah belum terkonsolidasi, maka konstruksi tersebut dapat mengalami penurunan.. Untuk mempercepat proses konsolidasi biasanya dilakukan perbaikan tanah, salah satu metode perbaikan tanah untuk mempercepat proses konsolidasi yaitu vertical drain dengan menggunakan prefabricated vertical drains (PVD). Lapisan tanah lunak yang terdapat di lapangan tidak selalu kontinu, terkadang ditemukan lapisan tanah lunak yang terdapat lapisan lensa. Pada penelitian ini, penulis akan membahas mengenai waktu konsolidasi yang dibutuhkan oleh lapisan tanah kohesif dan lunak yang terdapat lapisan lensa yang telah diperbaiki dengan menggunakan PVD berjarak 1 meter. Infrastruktur yang berdiri di atas lokasi yang dipasang PVD berupa taxiway dengan beban berupa pesawat Airbus A380 sebesar 18,22 ton/m2. Analisis dilakukan menggunakan teori konsolidasi 1 dimensi Terzaghi. Untuk pemasangan PVD hingga kedalaman 50 meter diperoleh penurunan pra pembebanan sebesar 234,80 cm dengan waktu konsolidasi selama 2260 hari untuk pemasangan PVD pola persegi dan selama 1918 hari untuk pola segitiga . Penurunan pasca pembebanan untuk pemasangan PVD hingga kedalaman 50 meter sebesar 2,5 cm.

SOFT SOIL IMPROVEMENT USING CHEMICAL-RUBBER CHIPS MIXTURE

2015 ◽  
Vol 76 (2) ◽  
Author(s):  
Aminaton Marto ◽  
Norazirah Aziz ◽  
Mohammed Ridzuan Jahidin ◽  
Nor Zurairahetty Mohd Yunus ◽  
Fauziah Kasim ◽  
...  
Keyword(s):  
Void Ratio ◽  
Soft Soil ◽  
Soil Improvement ◽  
Soil Test ◽  
Unconfined Compression ◽  
Marine Clay ◽  
Untreated Sample ◽  
Unconfined Compression Test ◽  
Soft Soils ◽  
Clay Particles

Soft soils are widely found in many areas around the world as well as in Malaysia. Marine clay is one of the problematic soft soils. The marine clay should be pretreated before the construction to enhance the usability and serviceability of highway constructed on this type of soil. This paper presents the research results on the usability of chemical (SH-85)-rubber chips mixtures as the stabilizing agent in improving the characteristics of marine clay from two engineering perspectives; the strength and the compressibility. Three types of laboratory tests were conducted; index soil test, unconfined compression test and oedometer test. The results show that the treated samples had higher unconfined compressive strength compared to untreated sample. The strength of marine clay increased when the amount of the SH-85 increased.  The void ratio reduced in value when the chemical-rubber chips mixture was added to the marine clay. It is due to the chemical that acts as a binder that interlocks the rubber chips and the marine clay particles, reducing the compressibility. It has been concluded that the mixture of chemical-rubber chips with 8 % SH-85 plus 1 % of rubber chips is more effectively improved the characteristics of marine clay.  

scholarly journals METODE VACUUM CONSOLIDATION DENGAN PRELOADING UNTUK MEMPERCEPAT KONSOLIDASI TANAH PADA PERUMAHAN DI TANGERANG

2021 ◽  
Vol 4 (1) ◽  
pp. 171
Author(s):  
Jason Sastilaya ◽  
Gregorius Sandjaja Sentosa
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Soil ◽  
Drainage System ◽  
Soil Condition ◽  
Soil Improvement ◽  
Soil Conditions ◽  
Soil Plasticity ◽  
Calculation Results ◽  
Long Time

The expansion of housing in big cities cannot be denied given the rapid population growth in Indonesia. One of the areas that is currently expanding housing is Kosambi City, Tangerang. Soil conditions in Kosambi City are soft soil with high moisture content and soil plasticity, low permeability and soil bearing capacity, and high pore water pressure. This soft soil condition makes the consolidation decline take a very long time. To overcome the problem of the length of time for this consolidation settlement, it is necessary to improve the land. Soil improvement is being carried out, namely the method of vaccum consolidation with preloading. The combination of these methods is carried out by installing a vertical drainage system in the form of prefabricated fabricated drain (PVD) in soft soil, then the initial load is given in the form of preloading on the soil. The calculation results show that the amount of consolidation reduction that occurs when clay soil is loaded with a stockpile of 1.2 m high, a water surcharge of 1.3 m and a vaccum load is 0.3929 m and 0.6968 m for 85 years. The combined method of preloading and PVD is proven to be able to accelerate the time of consolidation, where Preloading and PVD are installed in a triangle pattern between 0.80 m to a depth of 12 m, capable of achieving a consolidation degree of 90% within 8 weeksPerluasan perumahan di kota besar tentu tidak dapat dipungkiri mengingat pesatnya pertumbuhan penduduk di Indonesia. Salah satu daerah yang sedang dilakukan perluasan perumahan yaitu Kosambi City, Tangerang. Kondisi tanah di Kosambi City merupakan tanah lunak dengan kadar air dan plastisitas tanah yang tinggi, permeabilitas dan daya dukung tanah yang rendah, serta tingginya tekanan air pori. Kondisi tanah lunak ini membuat penurunan konsolidasi membutuhkan waktu yang sangat lama. Untuk mengatasi masalah lamanya waktu penurunan konsolidasi ini, perlu dilakukan perbaikan tanah. Perbaikan tanah yang dilakukan yaitu metode vaccum consolidation dengan preloading. Kombinasi pada metode ini dilakukan dengan cara memasang sistem drainase vertikal berupa prefabricated fabricated drain (PVD) di dalam tanah lunak, kemudian diberikan beban awal yaitu berupa timbunan (preloading) pada tanah tersebut. Hasil perhitungan menunjukkan besar penurunan konsolidasi yang terjadi jika tanah lempung dibebani dengan timbunan setinggi 1,2 m, water surcharge setinggi 1,3 m dan beban vaccum  adalah 0,3929 m dan 0,6968 m selama 85 tahun. Metode kombinasi preloading dan PVD terbukti mampu mempercepat waktu konsolidasi, dimana Preloading dan PVD dipasang dengan pola segitiga berjarak 0,80 m hingga kedalaman 12 m, mampu mencapai derajat konsolidasi 90% dalam waktu 8 minggu. 

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