Lapisan Tanah Dasar (Subgrade)Lapis

Lapisan Tanah Dasar (Subgrade)
Lapisan tanah dasar adalah lapisan tanah yang berfungsi sebagai tempat perletakan lapis perkerasan dan mendukung konstruksi perkerasan jalan diatasnya. Menurut Spesifikasi, tanah dasar adalah lapisan paling atas dari timbunan badan jalan setebal 30 cm, yang mempunyai persyaratan tertentu sesuai fungsinya, yaitu yang berkenaan dengan kepadatan dan daya dukungnya (CBR).
Lapisan tanah dasar dapat berupa tanah asli yang dipadatkan jika tanah aslinya baik, atau tanah urugan yang didatangkan dari tempat lain atau tanah yang distabilisasi dan lain lain.

Ditinjau dari muka tanah asli, maka lapisan tanah dasar dibedakan atas :

Lapisan tanah dasar, tanah galian.
Lapisan tanah dasar, tanah urugan.
Lapisan tanah dasar, tanah asli.

Kekuatan dan keawetan konstruksi perkerasan jalan sangat tergantung dari sifat-sifat dan daya dukung tanah dasar.
Umumnya persoalan yang menyangkut tanah dasar adalah sebagai berikut :

Perubahan bentuk tetap (deformasi permanen) akibat beban lalu lintas.
Sifat mengembang dan menyusutnya tanah akibat perubahan kadar air.
Daya dukung tanah yang tidak merata akibat adanya perbedaan sifat-sifat tanah pada lokasi yang berdekatan atau akibat kesalahan pelaksanaan misalnya kepadatan yang kurang baik.

Hasil (Inggris) 1:

The Basic Soil Layer (Subgrade)The basic soil layer is a layer of soil that serves as the place they saw layers of roughness and roughness of the road construction support on it. According to the specs, the land base is the topmost layer of the cover of the road approx 30 cm, which has certain requirements according their function, namely with respect to density and power dukungnya (CBR).The basic soil layer can be either the original soil if the soil is compacted to the original, or ground urugan arrive from somewhere else or the ground is stabilized and others.Reviewed from the face of the land, then the land base layers are distinguished: Basic soils, soil minerals. Basic soils, soil urugan. Basic soils, soil.The strength and durability of construction of road roughness greatly depends on the properties and resources support the land base.General issues pertaining to the land base is as follows: Change the form fixed (permanent deformation) due to traffic load. The nature of the expanding and shrinking of land due to changes in moisture content. Power support uneven land due to the difference of soil properties on a nearby location or due to implementation errors such as density.

Hasil (Inggris) 2:

Basic soil layer (subgrade)
layer is a layer of subgrade soil that serves as a placement pavement and pavement construction support thereon. According to the specifications, the subgrade is the uppermost layer of the embankment of the road about 30 cm, which has specific requirements according to its function, namely with regard to density and carrying capacity (CBR).
The soil base can be either native soil compacted if the soil is originally good, or soil urugan brought in from elsewhere or soil, stabilized and others. Judging from the face of the original soil, then a layer of subgrade distinguished by: Layers of land, soil excavation. layer of subgrade, soil urugan. layer of subgrade, the native land. The strength and durability of pavement construction depends on the properties and the carrying capacity of the land base. Generally, issues concerning land base is as follows: Changes in the form of fixed (permanent deformation) due to traffic loads. The nature expands and shrinking of soil due to changes in moisture content. Carrying capacity of the ground is uneven due to differences in soil properties at a nearby location or due to improper implementation of eg unfavorable density.