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 post- construction 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.Real-time radar scanning 2.Void Detection 3.30° antenna beam width 4.360° antenna mobility 5.Frontal Camera View 6.27-picosecond sampling rate 7.1 st and 2 nd 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 Silty-Clayey SAND

Step 1: Install Target Anomalies

Target Anomalies at the Burnt Chimney Site

FutureScan Results for Target Region Target Target Length (in.) CUES Target Length (in.) Target Thickness (in.) CUES Target Thickness (in.) 11210¼¼ 268¼ ¼ ½.24 (Yestrebsky & Winiewicz, 2013)

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 inches. Range of upheaval on the ends of the pipe: 0.06-inches 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 Anomaly location from OPW (inches) Anomaly Thickness (inches) 10 0     

Conclusion and Discussion - FutureScan Target Thickness (in.) CUES Target Thickness (in.) ¼¼ ¼.32 ¼.29 ½.24 Detection of void thickness (average) accurate to +/ 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