Technology Settlement Investigation
using FutureScan
Lindsay Ivey Burden
Overview
• Purpose of Study
• Background
• Scope of Project / Project Setup
• Results
• Broader Impacts
Purpose
• This study was conducted to evaluate the
suitability of FutureScan to be used as a postconstruction evaluation method by VDOT during
trenchless technology applications.
Poll Question
How familiar are you with Horizontal Directional Drilling?
A.) Not at all familiar
B.) Somewhat familiar
C.) Very familiar
Background
• What is HDD (Horizontal Directional Drilling)?
Problems Associated with HDD
Construction:
• Diameter of
annular space of
most HDD
boreholes is 1.5
times the
diameter of the
pipe itself.
Problems Associated with HDD
Construction
1. Settlement/Subsidence
2. Basal Upheave
3. Hydrofracture
Scope of Project
Goal: Test FutureScan as a means of non-destructive
evaluation for HDD construction
• Reliability of scanning devices (GPR vs. FutureScan)
• Pursuing remediation tactics at time of evaluation to save
existing infrastructure
What is FutureScan?
• A pipe inspection robot operated by CUES, Inc. with the
following capability:
1.
2.
3.
4.
5.
6.
7.
Real-time radar scanning
Void Detection
30° antenna beam width
360° antenna mobility
Frontal Camera View
27-picosecond sampling rate
1st and 2nd tier analysis
(CUES, Inc., 2013)
Poll Question
Have you used Ground Penetrating Radar (GPR)?
A.) Yes, in the field
B.) Yes, in a controlled study
C.) No
What is GPR?
• Ground-Penetrating Radar (GPR) is a wheel-mounted scanning
system with an antenna that lies parallel to the ground
surface.
• The GPR system, U.S. RADAR Seeker SPR, has 0.9 nanosecond
antenna pulse duration and real-time scanning capability.
Project Site
Burnt Chimney, VA – set up a series of “target voids” around a
freshly installed pipe. Monitored roadway elevations over
time.
Soil Analysis for Burnt
Chimney
• ASTM Standard D422 – Hydrometer
• ASTM Standard D4318 – Atterberg Limits
• ASTM Standard D6913 – Sieve Analysis
120
100
Percent Finer (%)
80
60
40
• Silty-Clayey SAND
20
0
10
1
0.1
Grain Diameter (mm)
0.01
0.001
Step 1: Install Target
Anomalies
Target Anomalies at the Burnt
Chimney Site
FutureScan Results for Target
Region
(Yestrebsky & Winiewicz, 2013)
Target
Target Length
(in.)
Target
Thickness (in.)
12
CUES Target
Length
(in.)
10
¼
CUES Target
Thickness
(in.)
¼
1
2
6
8
¼
.32
3
6
6
¼
.29
4
3
4
½
.24
GPR Results for Target Region
During Reaming
Heaves, ranging from 0.33-inches to 1.0-inch, were observed.
Maximum heave of approximately 1-inch.
During Reaming
Slurry seeping from concrete curb gutter and asphalt.
Indicative of a hydrofracture failure.
The Day After Reaming ….
4-months Later …
Maximum settlement: 0.78-inches
Maximum heave: 1.62-inches
Range of settlements in the mid-section:
0.06-inches - 0.78-inches.
Range of upheaval on the ends of the pipe:
0.06-inches - 1.62-inches.
FutureScan Overall Results
Anomalous region detected in the mid-section of the pipe,
between 65-feet and 115-feet south of north outlet.
FutureScan Overall Results
Clock
Angle
10
Anomaly location
from OPW
(inches)
04.65
Anomaly
Thickness
(inches)
4.65
12
02.03
2.03
2
01.33
1.33
6
1.543.63
2.09
8
1.564.65
3.09
Conclusion and Discussion FutureScan
Target Thickness (in.)
CUES Target
Thickness
(in.)
¼
¼
¼
.32
¼
.29
½
.24
Detection of void thickness (average) accurate to +/- 0.10-inches
Limitations:
1. Ferrous Piping Systems
2. Wet Piping Systems
3. Piping Systems less than 15-inch in inner diameter
Broader Implications
• FutureScan used to evaluate compaction (relative
density)
• FutureScan used to evaluate grouting of annular
space (voids in grout itself)
• FutureScan used to evaluate other trenchless
methods (Jack & Bore, Pipe Jacking, Pipe Ramming,
Micro-tunneling).
• FutureScan used for QA/QC purposes on projects.
• FutureScan used to evaluate “kinks” in reamed
boreholes (Can the pipe fit through the borehole
safely?)
Acknowledgements
This research would not be possible with out the following
people:
•
•
•
•
•
•
Frank Morris (UVA)
Ed Hoppe (VCTIR)
Tony Winiewicz (CUES, Inc.)
Tom Yesterbsky (CUES, Inc.)
Dean Grindstaff (Grindstaff Underground)
Mike Igo (Grindstaff Underground)
Poll Question
FutureScan seems like a promising technology
A.) Yes
B.) No
C.) Maybe
D.) Not Enough Information