Ground Stabilization Methods for a Coal Combustion Product Landfill

1. Ground Stabilization Methods for a Coal Combustion Product Landfill By Victoria Howland and Scott Turgeon

2. Worcester Polytechnic InstituteCivil and Environmental Engineering • Major Qualifying Project • Stantec Project Center • Center Director: Fred Hart • Faculty Co-Advisor: Suzanne LePage • On-Site Stantec Advisor: Tom Pace

3. Problem Statement • Byproducts of coal combustion plants can cause water and soil contamination if not disposed of properly in a landfill. Given an earthquake, the landfill would be subject to various modes of failure, releasing byproducts into the surrounding environment.

4. Problem Statement Solutions • Identify applicable stabilization methods • Deep Soil Mixing • Mixing slurry with in-situ soil • Jet Grouting • Spraying grout into the ground • Slurry Trenching • Creating a slurry wall • Stone Columns • Creating columns from stone • Decision analysis for most suitable stabilization method

5. Gathering Data

6. Area Replacement Ratio • Compare methods according to area replaced • Ideally 20-30% • ARR=

7. Initial Results

8. Address Discrepancies Cost Production Rate

9. Decision Matrix

10. Cost • Given cost per volume • Equipment, materials, labor

11. Schedule • Given production rates • Total time dependent on quantity

12. Safety • Construction can be a dangerous industry • Considered construction methods, machines, and processes for installing each stabilization technique • Same levels of safety

13. Proven Technology • When it was invented • Previous successes and failures • Established stabilization practice

14. Constructability • Ease of installing the technique into the surrounding area • Proper soil conditions, space limitations, or landmark restrictions

15. Client Meeting • Met with client to discuss matrix weighting • Cost = 20% • Schedule = 20% • Safety = 15% • Proven Technology = 25% • Constructability= 20%

16. Decision Matrix with Data

17. Questions?