1. OUTLINE Definitions Examples of Landfills in the Valley
Construction on Landfills
Materials Placement in Landfills
Developments on Landfills – why develop landfills ??
Concerns Associated with Development on Landfills
Landfill Materials Investigation
Remediation of Construction and Demolition (C&D) Landfills
Example Projects

2. DEFINITIONS
MSW Landfill
C&D Materials
Inert Debris Landfill

3. EXAMPLES OF LANDFILLS IN THE VALLEY
C&D Landfills
Mostly Along the Salt River, Aqua Fria, Gila River & Santa Cruz River
Created Generally by Mining of Aggregates for Concrete, Asphalt, and Base Course Materials
Pits Left Behind are Backfilled with MSW or C&D
24th St Vulcan Materials, 28th St ( Dean Thomas Property), Salt River Pima Maricopa Dobson Plant
Tempe Market Place

4. EXAMPLES OF LANDFILLS IN THE VALLEY
MSW Landfills
Queen Creek Landfill
27th Ave Landfill
Tempe Municipal Landfill
Northwest Regional Landfill, and Others
Inert Debris Landfills
Salt River Materials Group Dobson Plant
28th Street Landfill
24th Street Landfill
Cotton Lane Landfill
Estrella Pit

5. MATERILAS PLACEMENT IN LANDFILLS
No Compaction During C&D Disposals
No Processing is Completed
Creates Nesting of Large Particles
Blind Spots around Odd Shaped Particles
Organics
MSW Decomposes, Develops Settlement, LFG & Leachate

6. MATERILAS PLACEMENT IN LANDFILLS

7. DEVELOPMENTS ON THE LANDFILLS
Install Recreational Facilities
Low Load Bearing Structures on Compacted MSW, e.g. Distribution Center
Heavier Structures on MSW should be on Deep Foundations
Industrial and Commercial Developments on C&D

8. CONCERNS ASSOCIATED WITH LANDFILL MATERIALS
Large Settlement
Uneven/Differential Settlements
Unpredictable – No Model Available on Stability
Compaction by Itself
Biodegradation
Piping, Internal Erosion and Raveling
Gas (LFG) and Leachate Production, Accumulation & Contamination of Air and Ground Water
Organics in C&D Takes Too Long to Decompose

9. LANDFILL MATERIAL INVESTIGATION

10. SOLUTIONS TO PROBLEMS FOR C&D LANDFILLS
Deep Dynamic Compaction (DDC) for Inert Debris Landfills
Compaction Grout
Vibrofloatation (Not Common)
Remove and Reconstruct w/ Engineered Fill/Debris

11. Deep Dynamic
Compaction (DDC)
Tempe Market Place

12. SOLUTIONS TO PROBLEMS FOR C&D LANDFILLS
Deep Dynamic Compaction (DDC):
Effective up to 30’-35’
30-ton Load Drop from feet Height, Multiple Times
Imparts approx. 150 ton-ft/sq.ft. Equivalent to 150% of Standard Proctor Compaction up to 25 Foot Depth
Evaluate Performance
Can’t Take Care of all Piping and Raveling

13. 2000
4000

14. Deep Dynamic Compaction

16. 24th Street and Salt River– Vibration Monitoring

17. Performance Evaluation with Plate Load Test

18. SOLUTIONS TO PROBLEMS FOR C&D
Debris Fill Specifications
Anything as long as Inert Debris
2 to 3 feet Lift Thickness
Compaction with 10 to 15 ton Equipment
3 to 4 Passes with 20 to 30 hertz vibration
30 to 60 Gallons/Cu.Yd. Water

19. Debris Fill Specifications

20. 28th Street and Salt River 24th Street and Salt River
EXAMPLE PROJECTS
Tempe Market Place
28th Street and Salt River
24th Street and Salt River
14th Street and River View Drive

21. Tempe Market Place – Before Development

22. Tempe Market Place – During Stabilization

23. Tempe Market Place – After Development

24. 24th Street & Salt River

25. CONCLUDING REMARKS Environmental Benefits Aesthetic Improvement
Monetary Value Added
Land Use
Positive Economic Impact
Catalyst
Stops Illegal Dumping