seattle, wa - tunneling short course
TRANSCRIPT
Seattle, WA www.soilfreeze.comSHORING * GROUNDWATER CONTROL * ENVIRONMENTAL
Haiku is one of the most important forms of traditional Japanese poetry.
Haiku is:
a 17-syllable verse form
consisting of three metrical units of 5, 7, and 5 syllables.
Haiku’s are easy
But sometimes they don’t make sense
Refrigerator
“While most of the elements of the Brightwater project are on schedule, I am extremely concerned about the construction delays on the remaining two-mile segment of the outflow tunnel”
Dow Constantine – King County Executive
• $1.8 Billion, five year Mega project• 13 miles of 17.5’ diameter tunnel, 114 acre facility• Shaft Freezing, break-in/break-out freezing, TBM rescue
History of Ground Freezing
• Ground freezing techniques were used by German scientist F. Hermann Poetsch, in 1883.
• It was first used in America by Chapin Mine Company in Iron Mountain, where freezing was performed to a depth of 100 feet.
• Over the years, the mining industry refined Ground Freezing techniques to successfully complete thousands of shafts all over the world. Some shafts over 2,000 feet deep.
• In the 1900’s freezing expanded into heavy civil construction helping complete many huge projects including: the Grand Coulee dam, the Chunnel, and Boston’s Big Dig.
• Freezing became know as “the method to use when all other methods failed”.
• Why? Because Freezing nearly always worked but the cost was prohibitive.
How Ground Freezing Works
www.soilfreeze.com
Manifolds and Freeze Pipes
Before Freezedown During Freezedown
- Size ranges from 20 to 500 tons of chilling capacity. Sized to fit each project.
- Brine is chilled as it passes over baffles in specially designed chambers
- Primary Refrigerant is R507
- Highly automated and very reliable
Electric Chiller Units
www.soilfreeze.com
- Brine and ground temperatures at multiple depths are monitored and recorded daily.
- Chillers controlled remotely.
- Remotely monitored via internet connection.
Instrumentation & Monitoring
www.soilfreeze.com
-10-505
10152025303540455055606570
0 1 2 3 4 5 6 7 8 9 10
Te
mp
era
ture
[°F
]
Elapsed Time Since Start of Freezing (2-1-2016) [week]
CP-32, Surface Temperature Pipe: T-6 (Temp vs Time)
T6: 58'bgs
T6: 66'bgs
Frozen Soil Wall Formation
Freeze Pipes
Frozen Soil
Impermeable Soil Layer
Groundwater
How Groundwater Cut-off is achieved
www.soilfreeze.com
Zone Freeze Technology (Patented)
Structural Shoring System
Frozen Soil
FullExcavation
3” Diameter Steel Pipes
Profile View
Cutoff Layer
Ground Freezing Engineering/Analysis
Temp/W
Plaxis 2D & 3D
●All shoring designs are stamped by a licensed engineer
Soils Analysis
I
Bottom Of Excavation 22’ BGS
45’ BGS (Bottom of Freeze)
SAND
GRAVEL
SILTCLAY
Thermal Analysis
Design and Analysis
“Ground Freezing is utilized in extremely difficult conditions where no other excavation support is feasible, and where cost is usually not a factor.” Kennedy/Jenks Consultants
“The freezing method is remarkably versatile and, with ingenuity, it can be adapted to a great many project conditions.” Dr. Kamran M. Nemati, Professor in Construction Management and Civil
Engineering at the University of Washington
U.S. Environmental Protection Agency (EPA) - Frozen soil barriers are “environmentally benign” and have significant advantages over “conventional containment systems using steel, concrete, slurry walls, or grout curtains” and offer “extremely low maintenance costs, allowing continued use for extended periods”. EPA Site Technology Program, (7th edition, p. 202).
Department of Energy (DOE) - “Frozen soil can eliminate groundwater flow paths” and “the potential is great.” (Scientific Ecology Group, Inc. for Martin Marietta Energy Systems, Document STD-R-00-01)
Freezing to provide groundwater control and excavation support for shaft sinking remains the primary application. In fact, for deep shafts, no better method has yet been established. (The Constructor, Civil Engineering Publication)
- Effective in all soil types (sand, gravel, silt, clay and peat or a mix soil condition)
Advantages
* HKIE Civil Division International Conference 2012iCiD: innovation and Creativity of infrastructure Developments for Quality Cities
High Certainty of Uniformity
Advantages
Advantages
Adaptable
Eco-Conscious
Conventional Shoring
• Dewatering System
• Electrical Power
• Water Treatment Cost
• Water Disposal Cost
• Contaminates
Freeze Shoring
Freezing For the Tunneling Industry
Frozen Soil
23 ft
Freezing For the Tunneling Industry
Freezing For the Tunneling Industry
Freezing For the Tunneling Industry
Freezing For the Tunneling Industry
Freezing For the Tunneling Industry
Soil Freezing for Effective Stabilization for TBM Rescues
Case Study:
Brightwater Regional Waste Water Treatment Plant
• $1.8 Billion, five year Mega project• Located in King & Snohomish Counties, Washington• 13 miles of 17.5’ diameter tunnel, 114 acre facility• Four contracts for Tunneling, Three Joint Venture Contractors
“While most of the elements of the Brightwater project are on schedule, I am extremely concerned about the construction delays on the remaining two-mile segment of the outflow tunnel”
Dow Constantine – King County Executive
The Fix
• Modify receiving shaft to become a launch shaft
• Modify and re-launch Elizabeth
• Stabilize Soil in front of and around the stuck Rainier TBM
• Completely “gut” Rainier including cutter face
• Drive Elizabeth over two miles to Intercept Rainier’s tunnel alignment
• Drive Elizabeth into the empty shell of Rainier
BT3 Junction
Obstacles to Overcome• Stuck under residential neighborhood• 330’ deep, 7 Bar pressure• Geometry involved with freezing around TBM• Electrical power (no 480 volt)• Difficult / disturbed soil conditions
Project Location
BT3 Junction FreezingFreezing Around TBM to Remove Cutter
TBM @ 315’
GW @ 120’
Freeze Pipe Installation
In-tunnel Drilling to Install Freeze Pipes
Figure 5. Elevation plot of thermal results near BT3 face with 4 freeze pipes activated below TBM
Main bearing Removal
Cutterhead Dismantling
Frozen Soil
Fingers Crossed
Hole Through
Success