advanced drainage system - Polypipe
advanced drainage system - Polypipe
advanced drainage system - Polypipe
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General Structural Design 3.2<br />
Table 3.2.5 Modulus of Soil Reaction<br />
Embedment Compaction Mp Modulus Deflection Strain factor Df for various pipe stiffness (1)<br />
Class as table of Soil Lag factor<br />
NA.8 and reaction DL (2)<br />
deflection coefficient E’2<br />
Kx % MN/m 2 kN/m 2<br />
1.25 2.5 5.0 10 15 30 or more<br />
Class S1 Uncompacted 5 1.5 4.7 4.5 4.3 4.0 3.75 3.0<br />
Kx = 0.083 80 7 1.25 4.7 4.5 4.3 4.0 3.75 3.0<br />
85 7 1.0 4.7 4.5 4.3 4.0 3.75 3.25<br />
90 10 1.0 4.7 4.5 4.3 4.0 3.75 3.5<br />
95 14 1.0 - - - - 3.75 3.5<br />
Class S2 Uncompacted 3 1.5 4.7 4.5 4.3 4.0 3.75 3.0<br />
Kx = 0.083 80 5 1.25 4.7 4.5 4.3 4.0 3.75 3.0<br />
85 7 1.0 4.7 4.5 4.3 4.0 3.75 3.25<br />
90 10 1.0 4.7 4.5 4.3 4.0 3.75 3.5<br />
95 20 1.0 - - - - 3.75 3.5<br />
Class S3 85 5 1.5 6.2 5.5 4.75 4.25 4.0 3.25<br />
Kx = 0.100 90 7 1.25 7.75 6.6 5.5 4.7 4.25 3.5<br />
95 14 1.0 - - - - 4.75 3.5<br />
Class S4 85 3 1.5 6.2 5.5 4.75 4.25 4.0 3.5<br />
Kx = 0.100 90 5 1.25 7.75 6.6 5.5 4.7 4.25 3.5<br />
95 10 1.0 - - - - 4.75 3.5<br />
Class S5 85 1 3.0 - - - - 4.0 3.5<br />
Kx = 0.100 90 3 2.0 - - - - 4.25 3.5<br />
95 7 1.25 - - - - 4.5 3.5<br />
Class B1 85 5 1.5 - - - 5.0 4.0 3.5<br />
Kx = 0.083 90 7 1.25 - - - 5.5 4.25 3.5<br />
Class B2 85 3 2.0 - - - 5.5 4.25 3.5<br />
Kx = 0.083 90 5 1.75 - - - 6.0 5.0 3.5<br />
(1) Pipe stiffness referred to in this table are initial values.<br />
(2) Where the designer can be certain that intial pressurisation will take place within one year of backfilling, a value of 1.0 may<br />
be taken for the deflection lag factor.<br />
Note 1. For construction details of embedment classes see table NA8.<br />
Note 2. Quoted values of E’ 2<br />
assume pipe line will be installed below ground water.<br />
Note 3. Mp indicates modified proctor density and corresponds to the heavy compaction test in BS 1377.<br />
Reference (BS EN 1295-1)<br />
Table 3.2.6 Modulus of Soil Reaction for Native Soils in Various Conditions E’<br />
Soil Type Modulus of soil reaction (kNm -2 x10<br />
3<br />
)<br />
Very Dense Dense Medium Dense Loose Very Loose<br />
Gravel Over 40 15 - 40 9 - 15 5 - 9 3 -5<br />
Sand 15 - 20 9 - 15 4 - 9 2 - 4 1 - 2<br />
Clay, silty sand 10 - 15 6 - 10 2.5 - 6 1.5 - 2.5 0.5 - 1.5<br />
Clay Very hard 11 - 14<br />
Hard 10 - 11<br />
Very stiff 6 - 10<br />
Stiff 4 - 6<br />
Firm 3 - 4<br />
Soft 1.5 - 3<br />
Very soft 0 - 1.5<br />
57
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