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Primary Consolidation Settlements under Landfill Lining Systems - Design Calculator
The uneven distribution of these stresses (different waste thickness), creates a differential settlement between different points along the landfill cross section. The potential impact of these settlements on the performance of the leachate collection system and liner system must be evaluated.


where:
Symbol |
Description | Unit |
| SC | primary consolidation settlement | m |
| n | number of clay sublayers | m |
| Cr | recompression index (as shown in Figure 2) | - |
| Hi | thickness of clay sublayer # i | m |
| eo | initial void ratio | - |
| OCR | overconsolidation ratio | - |
| σ'voi | effective normal stress (evaluated at the middle of the sublayer # i) | kPa |
| Cc | compression index (as shown in Figure 2) | - |
| Δσvi | additional normal stress (at the middle of the sublayer # i) | kPa |


where:
Symbol |
Formula |
| Po | = γWASTE * h1 | P1 | = γWASTE * h2 |
| a | = h1/S1 |
| X | = h2/S2 |
| β | = π * [90 + tan-1(X/Z)]/180 |
Finally, the average slope resulted form the differential settlement between Points 1 and 2 is calculated as follows (see Figure 4):
"Designing with Geosynthetics". R.M. Koerner, Prentice Hall
Publishing Co., Englewood Cliffs, NJ, 1998. "Geosynthetic Design Guidance for Hazardous Waste Landfill Cells and
Surface Impoundments", G. N. Richardson and R. M. Koerner, 1987. "Soil Mechanics & Foundations", Muni Budhu, John Wiley & Sons, NY, 2000. Copyright 2001 Advanced Geotech
Systems. All rights reserved.
Figure 4. Average Slope Resulted From Differential Settlement