§ 19
How much should I dig, and how much pipe sand and filling should there be?
Answer: A cable trench consists of the cable zone at the bottom (levelling layer, pipe and surrounding fill above pipe top) and backfill on top. DS 475 requires the surrounding fill to go at least 0.10 m above pipe top. The calculator works out the fixed excavation, how much sand or gravel the cable zone takes when the pipe's own volume is deducted, and how much backfill is needed for the rest up to ground level. The trench is calculated with vertical sides, thus at most 1.70 m deep.
Udgravning = længde × bundbredde × dybde
Ledningszone = længde × (bundbredde × (afretningslag + diameter + omkringfyldning) − π × r²), hvor r = diameter ÷ 2
Tilfyld = længde × bundbredde × (dybde − ledningszonens højde)
DS 475: surrounding fill must be at least 0.10 m above pipe top
| Symbol | Meaning | Unit |
|---|---|---|
| laengde | Grave length | m |
| bundbredde | Grave bottom width | m |
| dybde | Depth from ground to bottom of trench | m |
| diameter | Pipe outer diameter | mm |
| under | Levelling layer under the pipe | mm |
| over | Surrounding filling above pipe top | mm |
| = | Sand/gravel for cable trench | m³ |
| = | Excavation (fixed dimension) | m³ |
| = | Fill above cable zone | m³ |
| = | Cable zone height | mm |
| = | Pipe top depth below ground | m |
Does not apply when
The calculator's own default values inserted. The figures are calculated with exactly the formula the tool uses.
Substituted
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Til en ledningsgrav skal du vide, hvor meget der graves, hvor meget rørsand der skal til, og hvor meget tilfyld. Beregneren regner alle tre.
En 20 m stikledning i 110 mm graves 1,2 m ned med 0,6 m bund.
It means: Du graver 14.4 m³, skal bruge 3.53 m³ rørsand og 10.68 m³ tilfyld. Rørtoppen ligger 0.99 m nede.
En 42 m ledning i 160 mm graves 1,6 m ned med 0,8 m bund og 150 mm over røret.
It means: Udgravningen er 53.76 m³, rørsand 12.93 m³ og tilfyld 39.98 m³. Ledningszonen er 410 mm høj.
Ledningszonen er røret plus 20 cm.
Udgravning = sand + tilfyld + rør: 3,53 + 10,68 + 0,19 = 14,4 m³.