Wednesday, December 24, 2008

Doyo Lujeng Dwiarso, Geogrid in Flexible Pavement


Geogrid technology has developed steadily since the products werefirst introduced in the early 1980’s. The initial geogrid products rapidlygained popularity within the civil engineering industry, principallydue to their ability to provide simple, cost-effective solutions in variousroadway and grade separation applications.They have gained widespread acceptance over the last 25 yearsas a solution to problems associated with roads constructed on softor problematic subgrades, but their use with roads on competentsubgrades has been less common. Clear, well-established, design methodology from the AmericanAssociation of State Highway and Transportation Officials (AASHTO)is now available that allows the design engineer to quantify the benefitsof using geogrids to extend pavement design life. This approach canbe applied for the design of major highways or light duty pavementsassociated with local housing or retail store developments.


Geogrid Composition


A geogrid is a regular grid structure of polymeric material used toreinforce soil or other geotechnical engineering related materials.Products are generally classified as either Uniaxial Geogrids orBiaxial Geogrids, depending on whether their strength is predomi-nantly in one or two directions. Uniaxial Geogrids are principally used in grade separation appli-cations for retaining walls and steep slopes. Biaxial Geogrids areused mainly in roadway applications to either stabilize a soft subgrade, or to provide reinforcement to the unbound base coursematerials (referred to as base reinforcement). Benefits of usingBiaxial Geogrids for base reinforcement are typically a reduction ofrequired base course material thickness and/or a significant extension in service life of the pavement structure. In base reinforcement applications, the existing subgrade is of afirm nature or has been rendered such through the use of a subgradeimprovement technique. One of the principal failure mechanisms ofa pavement under these firm subsoil conditions is rutting–resultingfrom progressive lateral movement of the aggregate base courseduring traffic loading. The amount of lateral movement can be reduced greatly byincluding a Biaxial Geogrid within or at the bottom of the basecourse layer. Partial penetration of coarse aggregate particlesthrough the geogrid apertures and subsequent compaction, resultsin “mechanical interlock” or “confinement” of the aggregate particles.


Application Benefits


The principal benefit of using a geogrid within the unbound aggregatecomponent of a flexible pavement is less rutting at the surface. Thisis due to reduced lateral spreading of the unbound aggregate. However, an additional feature of the reinforcement is that thegeogrid confined aggregate results in a much stiffer base courselayer and a lower dynamic deflection of the pavement structureduring traffic loading. Fatigue cracking of the asphalt is thereforealso reduced due to the presence of the geogrid reinforcement.In order for geogrids to work successfully in base reinforcementapplications, they must have the capacity to facilitate efficient loadtransfer between the aggregate and the geogrid. Webster (1992) reported a large-scale research program undertakenby the U.S. Army Corps of Engineers to investigate and determinethe key physical properties of a geogrid required to create optimalinteraction and load transfer. A summary of the key material propertiesdetermined in the study are presented in the table below.Key geogrid properties as determined by the U.S. Army Corps of Engineers.


Expanded Use


As the population of our towns and cities continues to expand rapidly,new or recently constructed housing in the form of sub-division devel-opments are becoming increasingly commonplace. One of the morefrequent problems associated with the roads in these developmentsis adirect result of their method of construction.Phased construction has become an extremely common practice,particularly in residential developments. In order to build a roadwayto gain site access, contractors will initially placethe aggregate component of the pavement and,usually, a thin asphalt layer on top. This techniqueis particularlyuseful when local trenches arerequired for installation of utilitypipes and cables. Pavement distress in the form of asphalt crackingat the surface is common on phased roads withinsub-divisions. In many cases, these “alligatorcracks” start to appear within a very short periodof time following construction – perhaps as little asone or two years. The simple solution to this problem is a layer ofBiaxial Geogrid installed at the bottom or withinthe base course during initial construction. Forrelatively little additional expense at the start of construction, thelifetime of their road is extended enormously, while expensive anddisruptive rehabilitation or reconstruction activities are avoided.Another use of geogrid technology can be found in the developmentof pavements around retail stores. Typically, thicker heavy-duty pavements are adopted in the loading areas around suchstores, while thinner lighter duty pavements are used for the carparking areas.One of the main problems associated with this approach is thepotential for a “bath tub” effect – this is where the subgrade is at alower level in the areas of the heavy duty pavements. These areas areprone to water ingress and build up resulting in a reduction in thelong-term strength of the pavement. In colder regions, these areas are also more susceptible to theeffects of freeze-thaw activity. Both of these situations result in areduction in the design life of the pavement but there are additionalpractical problems for the contractor associated with this more complicated method of construction.In addition to offering protection against the “bath tub” problemsdescribed above, the reinforced sections offer significant material cost savings. Additional benefits result from increased speed of construction – fewer stake out procedures, less undercut/disposal offill, simpler construction, etc.


A Glimpse Into The FutureCurrently, AASHTO provides guidelines for the design of flexible pave-ments in their current design guide (AASHTO,1993) and in InterimStandard PP46-01 (AASHTO, 2001). New pavement design approaches,based on advanced mechanistic-empirical (M-E) principles, are beingdeveloped and refined by AASHTO and other entities. A few DOT’s have already made the leap to improved M-E designmethods, but most are still awaiting official publication of AASHTO’snew design guide which will advocate adoption of this approach topavement design. Official publication of the new AASHTO designguide may still be several years out, but the availability of a M-E baseddesign method incorporatinggeogrids within the pavement structureis currently being finalized by The University of Illinois atChampaign-Urbana.


Source :


R.D. Holtz, Ph.D., P.E., Geosynthetics Soil Reinforcement, Department of Civil & Environmental Engineering, University of Washington

Tuesday, December 23, 2008

Doyo Lujeng Dwiarso, Perihal Geosintetik atau Geotekstil


Geosintetik adalah material yang saat ini populer dalam proyek konstruksi di Indonesia terutama dalam pembangunan jalan di atas tanah lunak seperti di pulau Sumatera dan Kalimantan yang banyak terdapat tanah gambut. Selain itugeosintetik juga diaplikasikan sebagai filter pada konstruksi penahan gelombang baik di tepian pantai maupun lepas pantai . Istilah geosintetik mengacu pada material sintetik yang digunakan dalam permasalahan geoteknik. Material sintetik merupakan hasil polimerisasi dari industri-industri kimia atau minyak bumi. . Penggunaan bahan sintetik ini berkaitan dengan sifat ketahanan (durabilitity) material sintetik terhadap senyawa-senyawa kimia, pelapukan, keausan, sinar ultra violet dan mikroorganisme. Polimer utama yang digunakan untuk pembuatan geosintetik adalah Polyester (PET), Polyamide (PM), Polypropylene (PP), dan Polyethylene (PE).Geosintetik yang ada terdiri dari berbagai jenis dan diklasifikasikan dalam beberapa bentuk sebagai berikut :
1. Geotekstil, bahan lulus air dari anyaman (woven) atau tanpa anyaman (non woven) dari benang-benang atau serat- serat sintetik yang digunakan dalampekerjaan tanah.
2. Geogrid, produk geotekstil yang berupa lubang-lubang berbentuk segi empat (geotextile grid) atau lubang berbentuk jaring (geotextile net) , biasanya terbuat dari bahan Polyester (PET) atau High Density Polyethylene (HDPE)
3. Geofabric, semua produk geosintetik yang berbentuk lembaran
4. Geocoposite, kombinasi dua atau lebih tipe geosintetik
5. Geomembrane, geosintetik yang bersifat impermeable atau tidak tembus air, biasanya dibuat dari bahan high density polyethylene (HDPE).
6. Geocell, berbentuk sel-sel sebagai bahan penahan erosi atau perkuatan , terbuat dari bahan High Density Polyethylene (HDPE)7. Geotube, berbentuk tabung memanjang yang digunakan di daerah pantai
8. Geobag, berbentuk karung sebagai perkuatan di aliran sungai atau pantai .
9. Geocontainer, sebagai bahan pembuat pulau atau konstruksi ditengah laut dan diturunkan dari kapal .
10. Vertical drain, sebagai bahan pemercepat aliran disipasi air pori sehingga mempercepat proses settlement.
11. Concrete matras, berbentuk matras atau kasur yang diisi dengan beton untuk penahan dinding sungai pencegah erosi
12. Geojute, terbuat dari jaring-jaring atau bahan serat alami seperti dari serat kelapa sawit untuk penahan erosi .Produk ini mempunyai aplikasi yang sangat luas di bidang geoteknik & teknik sipil dari mulai konstruksi jalan raya, embankmen, perkuatan tanah lunak, jalan kereta api, jembatan, perkuatan lereng dan dinding, waduk, reklamasi pantai dan lainnya.
Geotekstil
Meliputi woven (tenun) dan non woven (tanpa tenun). Tenun dihasilkan dari 'interlaying' antara benang-benang melalui proses tenun, sedangkan non woven dihasilkan dari beberapa proses seperti : heat bonded (dengan panas), needle punched (dengan jarum), dan chemical bonded (enggunakan bahan kimia). Baik woven maupun non woven dihasilkan dari benang dan serat polimer terutama : polypropelene, poliester, polyethilene dan polyamide.Sebenarnya geotekstil pada awalnya dibuat dari berbagai bahan seperti serat-asli (kertas, filter, papan kayu, bambu) , misalnya penggunaan jute untuk percepatan konsolidasi sebagi pengganti pasir sebagai bahan drainase (vertical drain) yang banyak dilakukan di India atau dilakukan di Belanda dengan menggunakan serat filter. Perkuatan tanah lunak juga menggunakan papan-papan kayu atau anyaman bambu yang ditempatkan di atas di atas tanah lunak (jaman Romawi kuno dan juga di Kalimantan Indonesia). Hanya bahan organik tersebut mudah lapuk sehingga umur konstruksi tidak dapat lama kecuali bahan dari bambu atau kayu yang apabila berada dalam air secara terus menerus akan bersifat permanen.
Penanganan Longsoran
Salah satu aplikasi geotekstil adalah untuk penanganan longsoran, beberapa penelitian menunjukkan bahwa penanggulangan longsoran dengan bahan geosintetik atau geotekstil pada ruas jalan sebagai perkuatan timbunan jalan mempunyai fungsi sebagai berikut :
1. Geosintetik atau geotekstil sebagai separator, yaitu mencegah bercampurnya agregat pilihan dengan lapisan asli tanah lunak .
2. Geosintetik atau geotekstil sebagai perkuatan tanah dasar, yang mana material geosintetik atau geotekstil memiliki properties kekuatan tarik yang melawan pergerakan tanah dasar baik mengembang ataupun menyusut.
3. Geosintetik atau geotekstil sebagai perkuatan lereng jalan sementara atau permanen
4. Geomembrane sebagai perkuatan pada bahu jalan, yang berfungsi untuk mencegah perubahan kadar air pada tanah dasar karena geomembran mempunyai sifat kedap air, tahan pelapukan terhadap zat kimia tanah, dan organisme pembusukan dalam tanah, selain itu mempunyai tahanan terhadap kekuatan tarik terhadap longsoran , daya tahan terhadap sobek, dan daya tahan coblos yang tinggi.
5. Geotekstil non woven atau tanpa tenunan yang terbuat dari serat polyprophylene melalui proses needle punched adalah cocok untuk apliaksi pada tanah dasar yang banyak mengandung sisa-sisa tanaman karena mempunayi daya tahan coblos yang lebih tinggi dibandingkan dengan bahan lainnya. Disamping itu geotekstil non woven memiliki sifat hidrolik propertis yang lebih bagus shingga bisa sekaligus berfunsi sebagai filter yang hanya melarutkan air tanpa membawa agregat tanah .
Langkah-langkah perhitungan adalah :
1. Penentuan beban yang bekerja di ruas jalan
2. Analisa stabilitas internal dengan menghitung : tebal lapis perkuatan tanah, panjang geotekstil di depan dan di belakang bidang longsor, panjang total geotekstil bidang longsor, panjang overlap bahan perkuatan, panjang overlap bahan perkuatan, analisis stabilitas lereng, stabilitas terhadap kuat dukung tanah.
Diposkan oleh GEOSYNTHETICS INDONESIA (KNOWLEDGE CENTER) di

Doyo Lujeng Dwiarso, Right Application of Geosynthetics

Base reinforcement
In base reinforcement applications geosynthetics (geotextile) are used as tensile element at the bottom of a (sub)base or within a base course. This improves the service life of a road and/or an equivalent performance is obtained with a reduced base course thickness. Typical base reinforcement applications are roads and parking areas and stock yards.
Subgrade stabilisation
Geosynthetics (geotextile) allow construction over weak subgrades by uniformly distributing the load, improving bearing capacity, and providing reinforcement to weak or low strength subgrades. The use of TenCate geosynthetics as reinforcement, separation and filtration layer offers a simple, quick and cost effective alternative for this "classic" application of geotextiles.
Drainage
Each drainage body must be protected from the penetration of fine soil particles which would otherwise block or clog the system, resulting in a diminishing of the drainage function. Under optimum conditions, this is guaranteed with the filtration geotextiles of TenCate. High water permeability and optimum filtration opening size are the decisive parameters for this application.
Retaining structures
Transportation structures often require retaining walls or steep slopes to save expensive space, to minimize land acquisition or to provide a noise barrier. TenCate geosynthetics are used as integral components in reinforced soil structures such as retaining walls and slopes. TenCate Geosynthetics provide tensile resistance to the soil, enhancing its shear strength characteristics. This enables walls, slopes and embankments to be constructed cost-effectively and quickly. For more details on reinforced earth structures, please see the Retaining Structures section.
NATM tunnels
The main goal of geotextiles used in conventional tunnel construction (e.g. acc. NATM) is the protection of the sealing membrane. Furthermore, the drainage function and the long-term resistance to alkaline media have to be considered. TenCate products fulfil all high technical requirements of modern tunnel construction.
Cut-and-cover tunnels, Galleries
Cut-and-cover tunnels require special multi-layer lining systems which have to fulfil various requirements. A permanent protection of the sealing membrane is provided by high-quality nonwoven geotextiles. Very often, drainage geocomposites are used which can be easily installed, providing an effective drainage of seepage water even under high surcharge loads.
Subgrade stabilisation
TenCate geosynthetics allow construction over weak subgrades by uniformly distributing the load, improving bearing capacity, and providing reinforcement to weak or low strength subgrades. The use of TenCate geosynthetics as reinforcement, separation and filtration layer offers a simple, quick and cost effective alternative for this "classic" application of geotextiles.
Retaining structures
Transportation structures often require retaining walls or steep slopes to save expensive space, to minimize land acquisition or to provide a noise barrier. TenCate geosynthetics are used as integral components in reinforced soil structures such as retaining walls and slopes. TenCate Geosynthetics provide tensile resistance to the soil, enhancing its shear strength characteristics. This enables walls, slopes and embankments to be constructed cost-effectively and quickly. For more details on reinforced earth structures, please see the Retaining Structures section.

Erosion protection
In order to guarantee a quick and lasting vegetation, slopes have to be protected from surface erosion. Erosion-control mats from TenCate not only protect slopes effectively from erosion, but also support the vegetation during the growing phase by storing water and providing protection against attacks by wind and precipitation.
Retaining walls
The installation of high-strength TenCate geosynthetics in layers considerably increases the stability of earth structures and controls the deformation. Geosynthetic reinforced retaining walls allow a variety of facing options including treated timbers, segmental concrete blocks, wrap-around and vegetated facings, gabions, pre-fabricated concrete elements, wire baskets and natural stone to provide superior aesthetics versus conventional cast-in-place concrete walls.
In case of critical deformation restrictions or in applications where survey is required, TenCate Polyfelt Geodetect can be installed in order to monitor the reinforced structure. Geodetect measures and follows the strain in soil and enables transmission of a warning signal as soon as its elongation reaches a preset limit.
Vegetated steep slopes
The installation of high-strength TenCate geosynthetics in layers considerably increases the stability of earth structures and controls the deformation. The inclusion of TenCate geosynthetics enable the use of locally available, often poor quality soil. To combine both engineering and landscaping aspects TenCate offers systems for vegetated steep slopes.
In case of critical deformation restrictions or in applications where survey is required, TenCate Polyfelt Geodetect can be installed in order to monitor the reinforced structure. Geodetect measures and follows the strain in soil and enables transmission of a warning signal as soon as its elongation reaches a preset limit.
Landfill covers
In landfill cover systems, the synthetic geomembrane must be protected from mechanical damage, which can be easily provided by TenCate Polyfelt P. Along slopes, additional requirements must be considered: TenCate Polyfelt Rock reinforcement geosynthetics are used to avoid a transfer of tensile forces into the membrane. Seepage and precipitation water is drained off by drainage geocomposites. Finally, erosion-protection mats guarantee a quick and effective vegetation on the slope surface.
Base lining systems
In landfill base lining systems, the synthetic geomembrane must be protected from mechanical damage, which can be provided by TenCate Polyfelt P. Furthermore, the penetration of fines into the drainage layer resulting in its clogging must be prevented. TenCate Polyfelt TS filter geotextiles fulfil this function permanently.Along slopes, additional requirements must be considered: TenCate Polyfelt Rock reinforcement geosynthetics are used to avoid a transfer of tensile forces into the membrane. Seepage water can be drained off to avoid any pressure underneath the membrane by using drainage geocomposites.
Flood protection dikes
Geosynthetics guarantee the stability of flood protection dikes, due to their special drainage and filtration properties. Geotextile wrapped drainage cores or special filtration mats under rip-rap prevent erosion and a consequent dike fracture. Geotextile reinforced earth structures allow the use of low-quality on-site fill material, thereby providing a reliable and cost effective construction method. TenCate erosion-protection mats prevent surface erosion and thereby contribute to a high slope stability.
Coastal and river bank protection
Geotextiles are used as filter blankets underneath revetments. Their purpose is to prevent erosion caused by the energy of waves and currents and to allow free two-way flow between the water body and the ground without the build up of hydraulic pressure. Geotextiles replace partly, or completely, expensive mineral filter layers. Geosynthetics from TenCate provide both, optimized filtration behaviour for fine or coarse grained soils and high resistance to damage. Geotube® containers are geotextile encapsulated soils that may be used to replacerock as conventional building blocks in marine and hydraulic engineering structures
Canals and reservoirs
In canal and reservoir construction, lining systems using geosynthetics are widely used. The effective long-term protection of synthetic geomembranes can be guaranteed by using the high-quality production geotextile TenCate Polyfelt P. Additionally, drainage geocomposites are often used to drain off seeping ground water and percolating surface water underneath the sealing membrane.
Pipe foundation and mechanical protection
In order to guarantee that a sub-surface pipeline permanently fulfils its function, it must be protected from damage and from settlements of low-bearing-capacity subgrades. Optimum solution in this respect can be provided by TenCate reinforcement products to minimize settlements and TenCate nonwovens for protection purposes.
Buoyancy protection
In order to guarantee that a pipeline remains stable under buoyancy, it must be secured against such forces and against damage during installation. Optimum solution in this respect can be provided by TenCate Polyfelt Rock to take up tensile forces, combined with TenCate Polyfelt nonwovens to protect the pipeline from damage.
Installation under water
In order to guarantee that a pipeline remains stable under buoyancy and under settlements of the subgrade, it must be secured against any harmful forces occurring in the subgrade. Optimum solution in this respect can be provided by TenCate Polyfelt Rock to stabilise
Pillow foundation
The settlement of pipeline foundations should be limited to a minimum. TenCate reinforcement products are successfully used for pillow foundations over low-bearing-capacity subgrades.
Foundation over cavities
In order to minimise the potential of sudden settlements which would be a danger for the public traffic, preventive measures using high-strength TenCate geosynthetics are recommended. In the case of a sudden damage of the subsurface, the geosynthetic acts as a membrane keeping the road or railway structure intact until further repair measures can be undertaken.
In case of critical deformation restrictions or in applications where survey is required, TenCate Polyfelt Geodetect can be installed in order to monitor the reinforced structure. Geodetect measures and follows the strain in soil and enables transmission of a warning signal as soon as its elongation reaches a preset limit.
Pile foundation
In order to guarantee the stability of embankments over weak subgrade, piles are very often used. Geosynthetic reinforced base courses transfer the loads from the embankment to the piles, helping to reduce the required number of piles, thus reducing costs.
In case of critical deformation restrictions or in applications where survey is required, TenCate Polyfelt Geodetect can be installed in order to monitor the reinforced structure. Geodetect measures and follows the strain in soil and enables transmission of a warning signal as soon as its elongation reaches a preset limit.
Embankments on weak subgrade
TenCate geosynthetics are placed at the base of embankments to provide short and long term stability and limit differential settlement. The geosynthetic is placed directly on the soft foundation, prior to the placement of the embankment fill.TenCate Geosynthetics facilitate the construction of a working platform and allow construction of higher embankments and steeper embankment side slopes.
Building drainage
Phreatic and seepage water can cause damage to building structures. Such water can easily and effectively be removed by drainage systems. These systems usually consist of drainage pipes, surrounded by drainage gravel and filter geotextiles. This filter protects the gravel from the penetration of fine soil particles which would otherwise block or clog the system. Alternatively, easy to install drainage mats can be used, replacing the drainage gravel.
Flat roofs
In the case of flat roof gardens, it must be assured that the top soil does not penetrate in to the drainage system, reducing its drainage function. This requirement is guaranteed by using TenCate Polyfelt TS filter geotextiles. Alternatively precipitation water can be drained off by TenCate drainage geocomposites, replacing the drainage gravel. This reduces the weight on the roof and the required construction height.
Parking decks
Generally, maintenance intervals in building structures should be as long as possible. In parking decks, an effective drainage by means of compression resistant drainage mats can considerably contribute to this goal by draining off any water seeping into the structure.
Foundation
When buildings are constructed on subgrade with low bearing capacity, special measures are necessary to guarantee an adequate stability. A simple and cost effective alternative to soil replacement and soil improvement methods is the installation of Geosynthetics to separate, filter and reinforce the soft subgrade.
Basement drainage
Phreatic and seepage water can cause damage to building structures. Such water can easily and effectively be removed by drainage systems. They usually consist of drainage pipes, surrounded by drainage gravel and filter geotextiles. This filter protects the gravel from the penetration of fine soil particles which would otherwise block or clog the system.
Swimming pools, Paddling ponds, Sand pits
Due to the mechanical properties of geotextiles, expensive material such as swimming pool or paddling pond membranes are protected from damage by sharp-edged stones or roots. Furthermore, TS prevents the mixing of different materials, such as sand and soil in a children's sand pit.
Ponds, Biotopes
Due to the mechanical properties of geotextiles, expensive material such as membranes of ponds or biotopes are protected from damage by sharp-edged stones or roots. The sealing function is therefore guaranteed permanently.
Patios, Garage drives, Pathways
Sand and base course under terraces and garden pathways remain clean and permanently separated. Slabs remain even and do not wobble. Frost damage and subsurface erosion are prevented, the function is guaranteed over a long period of time.
Road maintenance
Sooner or later, all roads require cost consuming maintenance. In order to extend the maintenance intervals, paving fabrics are successfully used. They level stresses within the upper structure, and reduce frost damage within the base course. TenCate Polyfelt PGM can be used both in the maintenance of old roads as well as in the construction of new roads.
Please see detail : http://www.tencate.com/

Doyo Lujeng Dwiarso, Ecowall

Ecowall adalah geosintetik penguat sistem permukaan batu alami

Ecowall geosintetik penguat sistem permukaan batu alami

Ecowall geosintetik perkuat batu adalah permanen, praktis, ekonomis dan tahan lama sebagai alternatif dari beton konvensional atau struktur blok modular yang mudah dibangun dari material yang sudah tersedia.

Ecowall tersusun dari lapisan, batuan kering, ditahan jaring kawat galvanis, dan diperkuat dengan geosintetik dari TenCate. Ukuran bentuk dapat disesuaikan dengan kebutuhan arsitektur. Ecowall sesuai untuk struktur sampai dengan kemiringan 85°. Hasilnya adalah estetis, bebas perawatan, stabil, struktur curam dengan kapasitas menahan daya beban yang tinggi.

Ecowall menggunakan jaring dengan pengait baja dimana bersama-sama bergabung untuk membentuk unit permukaan yang saling mengunci. Lapisan dari batu atau kerikil sebagai material pengisi digunakan secara langsung dibelakangnya didepan jaring. Beban dipindahkan ke geosintetik penguat melalui gesekan diantaranya dan jaring baja. Perkuatan Polyfelt PEC dapat digunakan apabila tanah dibelakangnya mengandung butiran halus dengan prosentase yang tinggi. Miragrid GX grid seharusnya digunakan apabila lebih banyak butiran yang kasar. Kesluruhannya sistem kemudian menjadi urugan tanah yang memiliki kapasitas daya beban yang memadai.

Kelebihan:
+ Tahan lama
+ Stabilitas lereng yang terjamin
+ Pilihan desain yang fleksibel
+ Mudah untuk dipasang

Kekurangan:
- Perawatan
- Biaya pembangunan

Reference : www.tencate.com

Doyo Lujeng Dwiarso, Polyslope B

Polyslope B adalah gesintetik vegetasi perkuat lereng tanah dan dinding

Konstruksi lereng dengan perkuatan vegetasi menggunakan rangka kerja kantong (geobag) berisi humus yang diperkuat Miragrid geogrids

Polyslope B adalah teknik dengan menggunakan rangka kerja kantong berisi humus dengan Miragrid geogrids sebagai penguat untuk konstruksi lereng curam dan dinding . Hasilnya adalah stabil, permanen, biaya yang efektif, struktur yang ramah lingkungan dengan tanaman alami dan dapat dikerjakan dengan menggunakan pekerja dan material setempat.

Teknik polyslope B adalah sangat sesuai untuk konstruksi dinding dan lereng di daerah pedesaan terpencil, yang mana tenaga kerja setempat dapat digunakan tanpa harus mengeluarkan biaya tinggi. Penggunaan kantong-kantong sebagai pembentuk profil permukaan akan membuat konstruksi dengan struktur permukaan yang kompleks menjadi pekerjaan yang relatif mudah.

Humus yang diisi kedalam kantong memungkinkan tanaman dan rumput setempat bergabung ke dalam sistem dan membantu merangsang pertumbuhan tanaman yang cepat.

Miragrid geogrid diselubungkan ke kantong-kantong dan diikatkan kedalam tanah urugan memastikan struktur yang stabil dan tahan lama.

Teknik polyslope B cocok untuk lereng dan dinding dengan sudut kemiringan sampai 80° dan ketinggian 2m hingga 50m. Rembesan air lapisan bawah tanah yang masuk kedalam struktur dikendalikan oleh pemasangan geosintetik atau geotekstil yang diselubungkan lapisan batu sebagai drainase yang dibangun dibelakang struktur. Air dikeluarkan melalui pipa drainase ke saluran permukaan .

Pada akhirnya struktur vegetasi dengan cepat berbaur dengan lingkungan disekelilingnya. Polyslope B adalah biaya yang efektif, alternatif yang stabil untuk struktur beton konvensional dan alternatif teknik geosintetik penguat tanah untuk dinding dan lereng.

Referensi : www.tencate.com

Doyo Lujeng Dwiarso, Polyslope T

Polyslope T adalah penggunaan geosintetik dan ban mobil bekas untuk konstruksi struktur penahan beban dan penahan lereng dan dinding yang ramah lingkungan.

Polyslope T adalah teknik yang menggunakan ban mobil bekas, diperkuat dengan geosynthetics untuk membangun struktur penahan tanah. Inovasi ini, metode yang ramah lingkungan dari pembuangan ban mobil bekas untuk mendukung penggunaan bahan sisa yang siap tersedia untuk diisi tanah yang diperkuat dengan geosynthetics untuk membangun struktur penahan beban yang stabil.

Pembuangan ban mobil bekas adalah masalah yang besar diseluruh dunia. Teknik Polyslope T dalam menggunakan ban mobil bekas untuk membangun struktur penahan beban yang stabil adalah metode yang positif dalam mendaur ulang ban sebagai cara yang ramah lingkungan. Metode Polyslope T juga mendukung penggunaan sisa pengisi tanah yang tersedia, lebih lanjut lagi mengurangi biaya dan pemanfaatan material yang tersedia. Struktur ban diperkuat dengan geosynthetics untuk menjamin stabilitas dan keamanan.

Ban dipersiapkan untuk digunakan dengan menghilangkan salah satu bibir lingkaran, menjadikan lubang karet yang terbuka. Ban secara mudah terkunci dengan kabel pengikat. Kemudian diletakan diatas geosynthetic penguat dan diisi dengan tanah atau sekumpulan batu. Untuk menghilangkan resiko tanah yang terlepas dari ban, filter Polyfelt geotextile dilapisi dibelakang ban. Tanah kemudian ditempatkan dibelakang ban dan dipadatkan sampai kepadatan yang optimum.

System Polyslope T ideal untuk pembangunan struktur tanah seperti dinding palang rintangan, lereng tanggul, dan perbaikan dari kerusakan lereng dan selokan curam yang akan longsor.

Referensi : www.tencate.com

Doyo Lujeng Dwiarso, Polyslope - S


Polyslope – S adalah geosintetik vegetasi perkuat lereng tanah dan dinding
Kosntruksi lereng dengan perkuatan vegetasi dengan menggunakan perkuatan tanah geosintetik dan rangka kerja berupa jaring kawat baja (wire mesh).
Polyslope S adalah suatu teknik yang menggabungkan antara perkuatan dengan tanah yang ada yang ditahan dibelakangnya oleh jaring kawat baja dan diperkuat dengan geosintetik dari TenCate untuk stabilitas bentuk, permanen, biaya yang efektif, struktur penahan yang ramah lingkungan dengan tumbuhan disekelilingnya. Teknik polyslope sesuai untuk struktur sampai dengan ketinggian 20m.

Para insinyur tiada henti berhadapan dengan kebutuhan untuk membangun secara permanen, struktur tanah yang aman dengan menggunakan tanah yang tersedia di tempat. Polyslope S adalah suatu teknik yang memfasilitasi penggunaan material urugan yang sudah tersedia, diperkuat dengan geosintetik dari TecCate untuk membentuk lereng dan dinding dengan tanaman yang alami.

Polyslope sesuai untuk lereng dan dinding dengan sudut kemiringan hingga 70° dan ketinggian dinding dari 2m hingga 20m. Tanaman setempat serta rerumputan menyatu dengan permukaan untuk membentuk struktur akhir yang bercampur dengan arsitektur disekitarnya.

Polyslope memanfaatkan jaring kawat baja galvanis yang distabilkan dengan kait penahan untuk membentuk sistem permukaan yang stabil untuk geosintetik penguat tanah. Biodegradable geotextiles dimasukan dibelakang jaring untuk mencegah kehilangan tanah dan mendorong pertumbuhan tanaman .

Keuntungan utama dari teknik polyslope adalah bahwa tanah terpencil dapat digunakan sebagai urugan . Perkuatan komposit Polyfelt PEC sering digunakan untuk memperkuat tanah prosentasi partikel halus yang tinggi. Kekuatan tarik PEC diarahkan hingga pergeseran permukaan, sementara itu juga menyediakan saluran pembuangan air untuk memperbanyak pori-pori air. Miragrid GX geogrids secara khusus digunakan untuk memperkuat jenis tanah dengan isi butiran halus.
Manfaat

Kelebihan:
+ Lereng menjadi hijau dengan tumbuhan setempat.
+ Berguna bagi saluran yang kurang baik karena pengisian tanah
+ Cocok untuk daerah perkotaan maupun pedesaan.

Kekurangan:
- Waktu pembangunan
- Biaya pembangunan
- Perubahan bentuk permukaan

Monday, December 22, 2008

Doyo Lujeng Dwiarso, Reinforced Retaining Wall


Concept Retaining walls are required where a soil slope is uneconomical or not technicallyfeasible. When compared with conventional retaining structures, walls with reinforcedbackfills offer significant advantages. They are very cost effective, especially for higher walls. Furthermore, these systems are more flexible than conventional earth retaining walls such as reinforced concrete cantilever or gravity walls. Therefore, they are very suitable for sites with poor foundations and for seismically active areas.
Modern reinforced soil technology was developed in France by H. Vidal in the mid 1960s. His system is called Reinforced Earth and is shown in Fig. 4. Steel strips are used to reduce the earth pressure against the wall face. The design and construction of Vidaltype reinforced earth walls are now well established, and many thousands have been successfully built throughout the world in the last 25 years. Other similar proprietary reinforcing systems have also been deve loped using steel bar mats, grids, and gabions.
The use of geotextiles as reinforcing elements started in the early 1970’s because ofconcern over possible corrosion of metallic reinforcement. Systems using sheets ofgeosynthetics rather than steel strips are shown in Figure / The maximum heights of geosynthetic reinforced walls constructed to date are lessthan 20 m, whereas steel reinforced walls over 40 m high have been built. A significant benefit of using geosynthetics is the wide variety of wall facings available, resulting in greater aesthetic and economic options. Metallic reinforcement is typically used with articulated precast concrete panels or gabion-type facing systems.Design ConsiderationsReinforced wall design is very similar to conventional retaining wall design, but with the added consideration of internal stability of the reinforced section. External stability is calculated in the conventional way--the bearing capacity must be adequate, the reinforced section may not slide or overturn, and overall slope stability must be adequate. Surcharges (live and dead loads; distributed and point loads) are considered in the conventional manner. Settlement of the reinforced section also should be checked if the foundation is compressible.
A number of different approaches to internal design of geotextile reinforcedretaining walls have been proposed (Christopher et al., 1990; Allen and Holtz; 1991; Holtz,1995), but the oldest and most common--and most conservative--method is the tieback wedge analysis. It utilizes classical earth pressure theory combined with tensile resisting “tiebacks” that extend back of the assumed failure plane (Fig. 6). The KA (or Ko) is assumed, depending on the stiffness of the fa cing and the amount of yielding likely to occur during construction, and the earth pressure at each vertical section of the wall is calculated. This earth pressure must be resisted by the geosynthetic reinforcement at that section.
To design against failure of the reinforcement, there are two possible limiting or failure cond itions: rupture of the geosynthetic and pullout of the geosynthetic. The corresponding reinforcement properties are the tensile strength of the geosynthetic and its pullout resistance. In the latter case, the geosynthetic reinforcement must extend some distance behind the assumed failure wedge so that it will not pull out of the backfill.
Typically, sliding of the entire reinforced mass controls the length of the reinforcing elements. For a detailed description of the tieback wedge method, see Christopher and Holtz (1985), Bonaparte et al. (1987), Allen and Holtz (1991), and Holtz et al. (1997). Recent research (e.g., Lee et al., 1999; Lee, 2000; Bathurst et al.,2000) has indicated that the tieback wedge approach is overly conservative and uneconomical, and modifications and deformation-based designs are rapidly being deve loped. Other important design considerations include drainage and potential seismic loading.
Material PropertiesGeosynthetic properties required for reinforced walls are similar to those listed in Table 1, Section 8.3 and discussed in Section 9.3 for reinforced slopes. Properties are required for design (stability), constructability, and durability. Allowable tensile strength and soil- geosynthetic friction are required for stability design, and similar to reinforced slopes, a partial factor or reduction factor approach is common. The ultimate wide width strength is reduced to account for uncertainties in creep strength, chemical and biological degradation effects, installation damage, and joints and connections. Berg (1993), Holtz et al.(1997), and Koerner and Hsuan (2001) give details about the determination of the allowable geosynthetic tensile strength. They also describe how soil- geosynthetic friction is measured or estimated.Backfill for geosynthetic reinforced walls should be free draining if at all possible. If not, then adequate drainage of infiltrating surface or groundwater must be provided. This is important for stability considerations because drainage outward through the wall face may not be adequate. Soil properties required include gradation, percent fines,chemical composition, compaction, unit weight, and shear strength. To insure stability,appropriate consideration of the foundation and overall slope stability at the site is also important (Holtz et al., 2001b).Wall Facing ConsiderationsA significant advantage of geosynthetic reinforced walls over conventional retaining structures is the variety of facings that can be used and the resulting aesthetic options that can be provided. Aesthetic requirements often determine the type of facing systems. Anticipated deflection of the wall face, both laterally and downward, may place further limitations on the type of facing system selected. Tight construction specifications and quality inspection are necessary to insure that the wall face is constructed properly; otherwise an unattractive wall face, or a wall face failure, could result.
Facing systems can be installed (1) as the wall is constructed or (2) after the wall is built. Facings installed as the wall is constructed include segmental and full height precast concrete panels, interlocking precast concrete blocks, welded wire panels, gabion baskets, treated timber facings, and geosynthetic face wraps. In these cases, the geosynthetic reinforcement is attached directly to the facing element. Systems installed after construction include shotcrete, cast-in-place concrete facia, and precast concrete or timber panels; the panels are attached to brackets placed between the layers of the geosynthetic wrapped wall face at the end of wall construction or after wall movements are complete. Facings constructed as the wall is constructed must either allow the geosynthetic to deform freely during construction without any buildup of stress on the face, or the facing connection must be designed to take the stress. Although most wall design methods assume that the stress at the face is equal to the maximum horizontal stress in the reinforced backfill, measurements show that considerable stress reduction occurs near the face, depending on the flexibility of the face. See Allen and Holtz (1991) and Holtz et al. (1997) for a detailed discussion of wall facing systems.ConstuctionConstruction procedures for geosynthetic reinforced walls and abutments are givenby Christopher and Holtz (1985) and Holtz et al. (1997). Procedures are relatively simple and straightforward, but failures are surprisingly common, especially with proprietary precast segmental concrete block-faced wall systems. It appears that most of these failures are due to (1) inadequate design, particularly of the foundation and back slope of the wall, and/or (2) problems in construction. The latter include poor inspection and quality control, poor compaction, use of inappropriate backfill materials, lack of attention to facing connections, and lack of clear lines of responsibility between designers, material suppliers, and contractors.
Reinforced Steep Slope (with geosynthetics)
Concept The first use of geosynthetics for the stabilization of steep slopes was for the reinstatement of failed slopes. Cost savings resulted because the slide debris could be reused in the repaired slope (together with geosynthetic reinforcement), rather than importing select materials to reconstruct the slope. Even if foundation conditions are satisfactory, costs of fill and right-of-way plus other considerations may require a steeper slope than is stable in compacted embankment soils without reinforcement. As shown in Fig.3, multiple layers of geogrids or geotextiles may be placed in a fill slope during construction or reconstruction to reinforce the soil and provide increased slope stability. Most steep slope reinforcement projects are for the construction of new embankments, alternatives to retaining walls, widening of existing embankments, and repair of failed slopes. Another use of geosynthetics in slopes is for compaction aids (Fig. 3). In this application, narrow geosynthetic strips, 1 to 2 m wide, are placed at the edge of the fill slope to provide increased lateral confinement at the slope face, and therefore increased compacted density over that normally achieved. Even modest amounts of reinforcement in compacted slopes have been found to prevent sloughing and reduce slope erosion. In some cases, thick nonwoven geotextiles with in-plane drainage capabilities allow for rapid pore pressure dissipation in compacted cohesive fill soils.Design Considerations The overall design requirements for reinforced slopes are similar to those for unreinforced slopes--the factor of safety must be adequate for both the short- and long-term conditions and for all possible modes of failure. These include: (1) internal--where the failure plane passes through the reinforcing elements; (2) external--where the failure surface passes behind and underneath the reinforced mass; and (3) compound--where the failure surface passes behind and through the reinforced soil mass. Reinforced slopes are analyzed using modified versions of classical limit equilibrium slope stability methods (e.g., Terzaghi et al., 1996). Potential circular or wedge-type failure surfaces are assumed, and the relationship between driving and resisting forces or moments determines the factor of safety. Based on their tensile capacity and orientation, reinforcement layers intersecting the potential failure surface increase the resisting moment or force. The tensile capacity of a reinforcement layer is the minimum of its allowable pullout resistance behind, or in front of, the potential failure surface and/or its long-term design tensile strength, whichever is smaller. A variety of potential failure surfaces must be considered, including deep-seated surfaces through or behind the reinforced zone, and the critical surface requiring the maximum amount reinforcement determines the slope factor of safety. The reinforcement layout and spacing may be varied to achieve an optimum design. Computer programs are available for reinforced slope design which include searching routines to help locate critical surfaces and appropriate consideration of reinforcement strength and pullout capacity. Additional information on reinforced slope design is available in Christopher et al. (1990), Christopher and Leshchinsky (1991), Berg (1993), Holtz et al.(1997), and Bathurst and Jones (2001). For slide repair applications, it is very important that the cause of original failure is addressed in order to insure that the new reinforced soil slope will not have the same problems. Particular attention must be paid to drainage. In natural soil slopes, it is also necessary to identify any weak seams that could affect stability.Material Properties Geosynthetic properties required for reinforced slopes are similar to those listed in Table 1. in the previous post Properties are required for design (stability), constructability, and durability. Allowable tensile strength and soil-geosynthetic friction are most important for stability design. Because of uncertainties in creep strength, chemical and biological degradation effects, installation damage, and joints and connections, a partial factor or reduction factor concept is recommended. The ultimate wide width strength is reduced for these various factors, and the reduction depends on how much information is available about the geosynthetics at the time of design and selection. Berg (1993), Holtz et al. (1997), and Koerner and Hsuan (2001) give details about the determination of the allowable geosynthetic tensile strength. They also describe how soil-geosynthetic friction is measured or estimated. An inherent advantage of geosynthetic reinforcement is their longevity, especially in normal soil environments. Recent studies have indicated that the anticipated half-life of reinforfcement geosynthetics in between 500 and 5000 years, although strength characteristics may have to be adjusted to account for potential degradation in the specific environmental conditions. Any soil suitable for embankment construction can be used in a reinforced slope system. From a reinforcement point of view alone, even lower-quality soil than conventionally used in unreinforced slope construction may be used. However, higher-quality materials offer less durability concerns, are easier to place and compact, which tends to speed up construction, and they have fewer problems with drainage. See Berg (1993) and Holtz et al. (1997) for discussion of soil gradation, compaction, unit weight, shear strength, and chemical composition.Construction Similarly to reinforced embankments, proper construction is very important to insure adequate performance of a reinforced slope. Considerations of site preparation, reinforcement and fill placement, compaction control, face construction, and field inspection are given by Berg (1993) and Holtz et al. (1997).Reference :R.D. Holtz, Ph.D., P.E., Geosynthetics Soil Reinforcement, Department of Civil & Environmental Engineering, University of Washington
Bituminous geomembrane : see Geomembrane, bituminous.Bonded geogrid : see Geogrid, bonded.Drainage composite : see Geocomposite drain.Elastomeric geomembrane : see Geomembrane, elastomeric.Electrokinetic geosynthetic : A composite material which may provide filtration, drainage, reinforcement in addition to electrical conduction.Extruded geogrid : see Geogrid, extruded.Geoarmour : A permeable geosynthetic material placed over the surface of the soil, in conjunction with pattern-placed block armour units, to prevent erosion.Geobar : A polymeric material in the form of a bar, used in contact with soil/rock and/or any other geotechnical material in civil engineering applications.Geoblanket : A permeable, biodegradable (synthetic or natural) structure placed over the soil for temporary erosion control applications, usually while vegetation is being established.Geocell : A three-dimensional, permeable, polymeric (synthetic or natural) honeycomb or web structure, made of strips of geotextiles, geogrids or geomembranes linked alternatingly and used in contact with soil/rock and/or any other geotechnical material in civil engineering applications.Geocomposite : A manufactured or assembled material using at least one geosynthetic product among the components, used in contact with soil/rock and/or any other geotechnical material in civil engineering applications.Geocomposite clay liner : An assembled structure of geosynthetic materials and low hydraulic conductivity earth materials (clay or bentonite), in the form of a manufactured sheet, used in contact with soil/rock and/or any other geotechnical material in civil engineering applications.Geocomposite drain : A prefabricated subsurface drainage product which consists of a geotextile filter skin supported by a geonet or a geospacer.Geocomposite reinforcement : An assembled structure of dissimilar geosynthetic materials used for soil reinforcement.Geofoam : A polymeric material which has been formed by the application of the polymer in semi-liquid form, through the use of a foaming agent, and results in a lightweight material with high void content, used in contact with soil/rock and/or any other geotechnical material in civil engineering applications.Geoform : A three-dimensional, permeable geosynthetic structure, filled with soil or sediment waste such that the fill takes the shape of the inflated geoform.Geogrid : A planar, polymeric structure consisting of a regular open network of integrally connected tensile elements, which may be linked by extrusion, bonding or interlacing, whose openings are larger than the constituents, used in contact with soil/rock and/or any other geotechnical material in civil engineering applications.Geogrid, bonded : A geogrid manufactured by bonding, usually at right angles, two or more sets of strands or elements.Geogrid, extruded : A geogrid manufactured by extruding polymers and drawing in a sheet form.Geogrid, knitted : A geogrid manufactured by knitting together yarns or elements, usually at right angles to each other.Geogrid, woven : A geogrid manufactured by weaving yarns or elements, usually at right angles to each other.Geomat : A three-dimensional, permeable, polymeric structure, made of bonded filaments, used to reinforce roots of grass and small plants and extend the erosion-control limits of vegetation for permanent erosion control applications.Geomattress : A three-dimensional, permeable geosynthetic structure, placed over the surface of a soil, and then filled with concrete mortar or soil, to prevent erosion.Geomembrane : A planar, relatively impermeable, polymeric (synthetic or natural) sheet used in contact with soil/rock and/or any other geotechnical material in civil engineering applications.Geomembrane, bituminous : A planar, relatively impermeable sheet manufactured from natural bituminous materials.Geomembrane, elastomeric : A planar, relatively impermeable sheet manufactured from elastomeric polymers. Geomembrane, plastomeric: A planar, relatively impermeable sheet manufactured from plastomeric polymers.Geonet : A planar, polymeric structure consisting of a regular dense network, whose constituent elements are linked by knots or extrusions and whose openings are much larger than the constituents, used in contact with soil/rock and/or any other geotechnical material in civil engineering applications.Geospacer : A three-dimensional polymeric structure with large void spaces, used in contact with soil/rock and/or any other geotechnical material in civil engineering applications.Geostrip : A polymeric material in the form of a strip, used in contact with soil/rock and/or any other geotechnical material in civil engineering applications.Geosynthetic : A planar, polymeric (synthetic or natural) material used in contact with soil/rock and/or any other geotechnical material in civil engineering applications.Geotextile : A planar, permeable, polymeric (synthetic or natural) textile material, which may be nonwoven, knitted or woven, used in contact with soil/rock and/or any other geotechnical material in civil engineering applications.Geotextile, knitted : A geotextile produced by interlooping one or more yarns, fibres, filaments or other elements.Geotextile, nonwoven : A geotextile in the form of a manufactured sheet, web or batt of directionally or randomly orientated fibres, filaments or other elements, mechanically and/or thermally and/or chemically bonded.Geotextile, woven : A geotextile produced by interlacing, usually at right angles, two or more sets of yarns, fibres, filaments, tapes or other elements.Knitted geogrid : see Geogrid, knitted.Knitted geotextile : see Geotextile, knitted.Nonwoven geotextile : see Geotextile, nonwoven.Plastomeric geomembrane : see Geomembrane, plastomeric.Woven geogrid : see Geogrid, woven.Woven geotextile : see Geotextile, woven.
Source :R.D. Holtz, Ph.D., P.E., Geosynthetics Soil Reinforcement, Department of Civil & Environmental Engineering, University of Washington

Doyo Lujeng Dwiarso, Mekanika Tanah dalam Geotekstil


Mekanika tanah adalah bagian dari geoteknik yang merupakan salah satu cabang dari ilmu teknik sipil, dalam bahasa Inggris mekanika tanah berarti soil mechanics atau soil engineering dan Bodenmechanik dalam bahasa Jerman.
Istilah
mekanika tanah diberikan oleh Karl von Terzaghi pada tahun 1925 melalui bukunya "Erdbaumechanik auf bodenphysikalicher Grundlage" (Mekanika Tanah berdasar pada Sifat-Sifat Dasar Fisik Tanah), yang membahas prinsip-prinsip dasar dari ilmu mekanika tanah modern, dan menjadi dasar studi-studi lanjutan ilmu ini, sehingga Terzaghi disebut sebagai "Bapak Mekanika Tanah".

Tanah didefinisikan sebagai material yang terdiri dari:
Agregat (butiran) mineral-mineral padat yang
tidak terikat secara
kimia satu sama lain
Zat Cair
Gas yang mengisi ruang-ruang kosong diantara butiran mineral-
mineral padat tersebut
Tanah berguna sebagai pendukung pondasi
bangunan dan juga tentunya sebagai bahan bangunan itu sendiri (contoh: batu bata).

Percobaan di lapangan
Pengambilan contoh dan benda uji tanah
Pendataan lapisan dengan cara penge
boran
Uji CPT atau Sondir
Uji Tekan Pelat
Uji kepadatan tanah di lapangan
Uji Permeabilitas sumur
Uji SPT (eng: Standard Penetration Test)
Uji DCP
Uji
Kekuatan Geser Tanah di lapangan, dengan menggunakan
Uji Baling-Baling


Percobaan di laboratorium
Distribusi Butiran Tanah,
untuk tanah berbutir besar digunakan
Uji Ayak (eng: Sieve Analysis, de: Siebanalyse),

untuk tanah berbutir halus digunakan Uji Hidrometer (eng: Hydrometer, de: Aräometer/Sedimentationsanalyse).
Berat Jenis Tanah (eng: Specific Grafity, de: Wichte)
Kerapatan Tanah (eng: Bulk Density, de: Dichte) dengan menggunakan Piknometer.
Kadar Air, Angka Pori dan Kejenuhan Tanah
(eng: Water Content, Pore Ratio and Saturation Ratio; de: Wassergehalt, Hohlraumgehalt, Sättigungszahl)
Permeabilitas (eng: Permeability, de: Wasserdurchlässigkeit)
Plastisitas Tanah dengan menggunakan Atterberg Limit Test untuk mencari:
-
Batas Cair dan Plastis,
-
Batas Plastis dan Semi Padat,
-
Batas Semi Padat dan Padat (eng: Liquid Limit, Plastic Limit, Shrinkage Limit; de: Zustandgrenzen und Konsistenzgrenzen)

Konsolidasi (eng: Consolidation Test, de: Konsolidationversuch)
Uji
Kekuatan Geser Tanah, di laboratorium terdapat tiga percobaan untuk menentukan kekuatan geser tanah, yaitu:
- Percobaan Geser Langsung (eng: Direct Shear Test, de: Direktscherversuch),
- Uji Pembebanan Satu Arah (eng: Unconvined Test, de: Einaxialversuch) dan
- Uji Pembebanan Tiga Arah (eng & de: Triaxial)

Uji
Kemampatan dengan menggunakan Uji Proctor
Pada kelanjutannya, ilmu ini digunakan untuk:
- Perencanaan
pondasi
- Perencanaan perkerasan lapisan dasar
jalan (pavement design)
- Perencanaan struktur di bawah tanah (
terowongan, basement) dan dinding penahan tanah)
- Perencanaan
galian
- Perencanaan
bendungan
- Perencanaan
lereng

Sumber : Wikipedia

Doyo Lujeng Dwiarso, Geosynthetics Function


Doyo Lujeng Dwiarso, Among other uses, geosynthetics can be used for Separation, Filtration, Reinforcement, Drainage, Protection and Moisture Barriers[4]. Different geosynthetics are suited for various applications and the diagram to the right illustrates their suitability.
Filtration can significantly enhance the performance of a geotechnical structure, and geosynthetics can be used to produce an effective filtration system[5]. The job of a filter is to allow water to pass through the plane of the filter, whilst retaining particles of the filtered soil. Filtration can improve the performance of a geotechnical structure by controlling the erosion of the structure and reducing the amount of fines that are washed out of the soil matrix. When fines get washed out of a soil it can reduce the cohesion of the matrix and thus the strength of the soil, referred to piping. Mitigating these two problems also improves the durability of a structure. Geosynthetic filters can improve the reliability and performance of traditional graded soil filters and require less work to construct. Geotextiles are well suited to this application.
Drainage required in nearly all geotechnical structures. Whether used to remove surface water from a sports field, or to reduce lateral pressure on a retaining wall, the need for effective drainage cannot be underestimated. Drains of various designs have been used in the past, most based on the use of a high permeability layer built into the ground using aggregates, single layers of Geosynthetics can produce the same results. Drains can be distinguished from filters as such; water travels across the plane of filters and travels with the plane of drains. Geotextiles and geocomposites are well suited to this application.
Protection/Barrier In some geotechnical applications it is necessary to separate or protect one section of the works from another. This could be for a multitude of reasons, including stopping leachate seepage, protecting a structure from moisture and protecting a geotechnical structure from erosion. Geotextiles and Geomembranes are suited to this application.
Separation The geosynthetic acts to separate two layers of soil that have different particle size distributions. For example, geotextiles are used to prevent road base materials from penetrating into soft underlying soils, thus maintaining design thickness and roadway integrity. Separators also help prevent fine-grained subgrade soils from being pumped into permeable granular road bases[6]. Geotextiles and geomembranes are most suited to this application.
Reinforcement Geosynthethics can be used to reinforce a soil mass in, increasing the effective angle of shear and increasing the stability of an earth structure. In the reinforcement function, the geosynthetic is subjected to a sustained tensile force. Soil and rock materials are noted for their ability to withstand compressive forces and their relative low capacity for sustained tensile forces. In much the same way that tensile forces are taken up by steel in a reinforced concrete beam, the geosynthetic supports tensile forces that cannot be carried by the soil in a soil/Geosynthetic system. Geogrid/geonets and geotextiles are best suited to this function.