PRS Neoloy® Tough Cells Reinforced Base for Container Yard

Neoloy Tough Cells add tensile stiffness and strength for durable pavements subject to heavy-duty dynamic and static loading.

THE CHALLENGE

A large container terminal operator was expanding storage yard capacity to deal with facility growth at one of its port in Europe. Pavement loading of intermodal container yard operations is extreme – dynamic loading of Reach Stackers lifting containers reaches 1000 kN per axle when lifting containers and stacking 5-high. Strong pavement structural and stable subgrade are required.
The site soil conditions were heterogeneous, saturated sand pocketed with numerous 300m deep holes caused by local gemstone mining operations. Subgrade modulus was 40 MPa. To achieve a basic working layer, the deep holes were first filled with local sand and then dynamic compaction was used to increase soil density.
While geocells were considered for to improve the subgrade strength, only Neoloy Tough Cells had the required modulus improvement factor – due to their unique engineering properties:

• High dynamic (elastic) stiffness (>525 MPa @ 60°C) – for heavy
  dynamic loading with low rutting
• High tensile strength (>19 kN/m perforated) – for reliable load
  distribution under static loading without settlements
• Low permanent deformation (<3% at 75 years) – for long-term
  performance

CONVENTIONAL SOLUTION

Chemical stabilizers were deemed insufficient for subgrade stabilization. In addition to high costs, and complicated application, they have limited long-term reliability and may leach into local soil or water-tables.

NEOLOY TOUGH CELLS SOLUTION

Neoloy Tough Cells were chosen for the subgrade/subbase improvement. Neoloy created a stiff homogenous layer over the damaged native soil. Locally dredged sand from port deepening works and hydrotechnical constructions was used for infill. The Neoloy Subgrade Improvement Factor (SIF) improved the subgrade modulus by more than 6x, and was verified by static plate testing. The Neoloy composite system forms a semi-rigid
mattress, which acts like a slab. The slab effect reduces vertical pressure and neutralizes differential settlement for reliable container yard pavement performance. The Neoloy subbase also serves as a self-draining system.
The high Neoloy SIF enabled a 33% reduction in the concrete layer, which was replaced by a local sand overfill above the Neoloy layer. The surface course was 10 cm concrete paving blocks over 4 cm cement stabilized sand levelling bed.

BENEFITS

• Subgrade bearing capacity improved by 6x – while significantly improving the modulus of structural layers above the Neoloy
• Sustainable benefits – reduce site construction and carbon footprints, by using locally dredged sand for infill, instead of imported aggregate
• 30% cost savings – in construction and total life cycle costs
• Simple logistics, rapid installation – 2000 sqm/day
• Improved pavement lifespan – low maintenance

PROJECT AT A GLANCE

Application
Container Yard
Subgrade/Soil
Unconsolidated saturated soil
Region
Eastern Europe
Installation
2019

ABOUT PRS
PRS is the world’s leading supplier of cost effective soil stabilization solutions. With a global network of fully owned subsidiaries and independent local distributors, PRS provides a full range of end-to-end support services. Since its establishment in 1996, PRS has implemented thousands of successful projects in over 80 countries.