Foundation Improvement Evaluation

Foundation Improvement

EvaluationKentucky River Lock and Dam No.

8A Major Qualifying Project

for Stantec Consulting Services Inc.

Michael Kendall Karyn Sutter

Major Qualifying Project Stantec Project Center

◦ Project Advisors Professor Suzanne LePage Professor Frederick Hart

◦ Stantec Consulting Service Inc. Mentors Daniel Gilbert April Welshans Adam Hacker

Worcester Polytechnic Institute

Civil and Environmental Engineering

LD 8 Foundation Improvement

◦ Karst Features◦ Water Quantity and Quality Concerns◦ Foundation Stability

Problem Statement

Evaluate Existing Dam Conditions Develop Design Options Apply Evaluation Criteria to Design Options Create a Preliminary Design of Best

Foundation Improvement Option

Project Scope

Kentucky River Lock and Dam No. 8

Boring Layout Water Pressure Tests

Site Geology

Exploratory Borings by Geological Region

Materials ◦ Portland Cement◦ Admixtures

Design Techniques◦ Grout Curtain◦ Grout Cap

Background: Grouting

Background: Cut-off Walls

Secant Walls Diaphragm Walls

Design Selection◦ Evaluated Existing Conditions◦ Developed Three Design Options

Methodology

Design Description

Design 1 Grouting in all regions

Design 2 Grouting in all regions, secant wall in region 2

Design 3 Grouting in all regions, secant wall in region 2, 3 and 4

Design Options

Application of Evaluation Criteria◦ Cost◦ Environmental

Permitting◦ Risks

Reduction in Seepage Foundation Damage

◦ Constructability Dewatering Site Access

Design Creation

Methodology

Results: Curtain and Cut-off DepthGrouting Cut-off Walls

Region Recommended Grout Curtain Depth

  Elevation (NAVD88)

Approx. Length@ 15° Inclination

(ft.)Region 1 430 72.5

Region 2 425 78.0

Region 3 453 52.5

Region 4 443 77.5

Region Recommended Cutoff Depths

  Elevation (NAVD88)

Length (Ft.)

Region 2 465 35

Region 3 455 45

Region 4 475 35

Each Secant Shaft Designed with a 4 Ft. Diameter with a 1 Ft. Overlap on Each Side

Two Row Curtain with 16 Ft. Space Between Rows and Injection Holes every 6 Ft.

Cost

Results: Evaluation Criteria

Design Total Cost

Design 1: Grout Curtain Throughout

$2,506,804

Design 2: Grout Curtain Throughout, Secant Wall in Region 2

$2,948,554

Design 3: Grout Curtain Throughout, Secant Wall Regions 2, 3 and 4

$5,024,554

Design Option Costs

Environmental◦ Identical Permitting Requirements

Risks◦ Mostly Dependant on Grouting◦ Seepage Reduction Crucial

Constructability◦ All Designs Practical◦ Verifiability of Technique

Results: Evaluation Criteria

Selected Design 2: Grout Curtain Throughout with a Secant Wall in Region 2

Capstone Design Project

Design of Proposed Foundation Improvement

Highest Water Loss Observed through Region Two

Favorable Cost to Permeability Reduction Ratio

Practical Design

Conclusions

Questions?