Grindstone Seepage Mitigation Project Village of Ruidoso Ed Toms 2105 NMWDOC Spring Workshop May 12, 2015
Overview –History –Site Investigations –Construction Contracting –Design –Closing and Questions 2015 NMWDOC Spring WorkshopPage 2
Project History
History –139-foot high gravity Roller Compacted Concrete Dam –1,300-foot long section –Built in 1986 –Water supply to the Village of Ruidoso 2015 NMWDOC Spring WorkshopPage 4
History - Plan View 2015 NMWDOC Spring WorkshopPage 5
History - Sections 2015 NMWDOC Spring WorkshopPage 6
History - Facing Elements 2015 NMWDOC Spring WorkshopPage 7
History - Issues –High seepage issues since first filling in 1988 –Repairs in 1989, 1996, 2002, and 2009 –Seasonal trends Winter higher seepage rates –Interviews with Original construction personnel - Poorly zones of partially cemented aggregates Transverse thermal cracks Page NMWDOC Spring Workshop
History - Issues –High seepage issues since first filling in 1988 –Repairs in 1989, 1996, 2002, and 2009 –Seasonal trends Winter higher seepage rates –Interviews with Original construction personnel - Poorly zones of partially cemented aggregates Transverse thermal cracks Page NMWDOC Spring Workshop
Site Investigations Phase
Site Investigations –Reservoir at El El 6860, where lower seal would be installed, was below water. –Cored 3 vertical rustication joints – Joints 44, 46, & 50. –Excavated a test pit at Joint 49 – confirmed foundation contact likely as indicated on record drawings. –Concrete facing was cracked through at all joint locations cored. –Segregated, poorly consolidated RCC encountered at concrete/RCC interface is a potential seepage pathway behind liner. –Sealant in many of the vertical joints was randomly separated from the sides of the joint NMWDOC Spring WorkshopPage 11
Investigations – Vertical Joints 2015 NMWDOC Spring WorkshopPage 12
Investigations – Vertical Joints 2015 NMWDOC Spring WorkshopPage 13
Investigations – Vertical Joints 2015 NMWDOC Spring WorkshopPage 14
Investigations – Vertical Joints 2015 NMWDOC Spring WorkshopPage 15
Construction Contracting
Construction Contracting Method –Design/Bid/Build –Construction Manager at Risk (C-MAR) –Construction Manager/General Construction (CM/GC) –Design/Build –Project schedule defined delivery method – CM/GC –CARPI Liner and Contractor Worked closely with AECOM during the design Priced the project based on unit measures Issued a Guaranteed Maximum Price (GMP) o $3.5 million Page NMWDOC Spring Workshop
Design Phase
Partial Lining Option –Advantages Lower impact on VOR water operations Less expensive –Disadvantages Lower probability to improve stability and mitigate seepage Sealing facing at 6860 against all pathways may be difficult and costly Remobilization costs if sealing does not mitigate seepage effectively or if stability is in question 2015 NMWDOC Spring WorkshopPage 19
Complete Lining Option –Advantages Higher probability to improve stability and mitigate seepage Double seal and grouted cutoff costs not needed and put towards liner No remobilization costs –Disadvantages Higher impact on VOR water operations More expensive, 27,500 SF more compared to lining to dam bottom above 6860 Requires additional excavation and dewatering 27-foot dead pool below intake invert 2015 NMWDOC Spring WorkshopPage 20
Design Elements 2015 NMWDOC Spring WorkshopPage 21
Design Elements 2015 NMWDOC Spring WorkshopPage 22
Design Elements 2015 NMWDOC Spring WorkshopPage 23
Design Elements 2015 NMWDOC Spring WorkshopPage 24
Design Elements 2015 NMWDOC Spring WorkshopPage 25
Construction Phase
Foundation Excavation 2015 NMWDOC Spring WorkshopPage 27
Dry Pack Mortar 2015 NMWDOC Spring WorkshopPage 28
Liner and Internal Profile Material 2015 NMWDOC Spring WorkshopPage 29
Anchor System 2015 NMWDOC Spring WorkshopPage 30
Curtain Holes Urethane Grout Injection 2015 NMWDOC Spring WorkshopPage 31
Construction Coring of Face Element 2015 NMWDOC Spring WorkshopPage 32
Chemical Grout 2015 NMWDOC Spring WorkshopPage 33
Vertical Joint Low-Modulus Epoxy 2015 NMWDOC Spring WorkshopPage 34
Progress – Water Installation 2015 NMWDOC Spring WorkshopPage 35
Installed Tension Profile Page NMWDOC Spring Workshop
Final Installation Example Page NMWDOC Spring Workshop
Questions? Ed Toms 2015 NMWDOC Spring Workshop