REAL-TIME SLOPE AND WALL MONITORING AND REPORTING USING 3-D MEMS-BASED, IN-PLACE INCLINOMETER SYSTEM

Transcription

1 REAL-TIME SLOPE AND WALL MONITORING AND REPORTING USING 3-D MEMS-BASED, IN-PLACE INCLINOMETER SYSTEM Aaron J. Muck, P.E., M.ASCE Swaminathan Srinivasan (Vasan), P.E., M.ASCE H.C. Nutting/Terracon

2 Monitored Project Locations in OH, IN, KY I-74 Landslide Stratford Tower Argosy Casino Queen City Square Tower HCN Landslide Owensboro, KY (250 Miles) Ashland, KY (150 Miles)

3 REAL-TIME SLOPE AND WALL MONITORING AND REPORTING USING 3-D MEMS-BASED, IN-PLACE INCLINOMETER SYSTEM MEMS Inclinometer Overview - Instrumentation System & Technology REAL-TIME Wireless Monitoring Platform and Webbased Publishing Three Case Reviews using both MEMS and Conventional Inclinometer Systems - I-74 Highway Embankment Instability MEMS IPID - Hillside Revitalization using Drilled Shafts MEMS IPID - Open Cell Harbor Wall Construction Monitoring - Analog Measurements & Results Summary & Lessons Learned

4 MEMS Inclinometer Overview Inclinometer Applications and IPID Features Monitoring landslide and provide early warning of slope failure. Monitoring ground movements of construction excavation. Monitoring deformations of retaining walls. Confirming/establishing better design assumption. Inclinometer sensor with built-in DAQ (IPID Feature) RS-485 Interface Dual axis silicon 3D MEMS sensor Measuring ranges ±15 Digital output 12 bit resolution(<0.009 ) Long term stability < Inclination and temperature output Shock resistance >20000g Operating temperature range -20 to +70 C

5 Diff.Delta (cm) Tilt angle(degree) Change degree Inclinometer Comparison IPID Stability IPID-15 Linearity IPID-15 v.s Standard Angle X-Axis Y-Axis X-Axis Y-Axis Tilt Angle(degree) IPID v.s SINCO inclinometer system Diff. Delta Tilt Angle (degree)

6 IPID Operation (similar installation with conventional inclinometer) Consist of inclinometer casing and IPID IPID Positioned inside the casing Install Multiple IPID Sensors inside the casing 3 Axis Accelerometers- Applications: Inclinometer, Air Bag, Wii Controller, iphone, etc. The key is resolution.

7 IPID System Digital Cable 22 AWG 4 Conductor New IPID Single Cable Installation Conventional Inclinometereach sensor requires its own cable (analog)

8 IPID System Resolution One IPID per 5 ft, 90 ft depth 5ft per IPID,90 ft depth 90/5=18 IPID Resolution=0.009 deg 5*12*Sin 0.009*1=+/ in(max) 5*12*Sin 0.009*18=+/-0.17in(max)

9 REAL-TIME WIRELESS MONITORING PLATFORM I-1 I-2

10 Example of Real-time Web-based Data Publishing for Inclinometer

11 Real-time Web-Based Publishing Field measurements are much less useful if not readily available for interpretation in real-time. Autonomous operation frees engineers from time-consuming tasks associated with manually collecting, downloading, parsing, calculating, and plotting new data from the field.

12 Web-Based Publishing Program can autonomously: Enter the data into database for archiving Calculate field data using preprogrammed equations Produce plots for distribution. Password-protected website allows users to: View the latest data Search and plot historical data Set alarm thresholds Text Message

13 IPID Case History I-74 Embankment Instability IPID System - Installation Connecting rod IPID

14 IPID System - Solar Power Solar Panel Battery Enclosure

15 IPID System - GPRS Long-Range GPRS Cellular Modem Only 4 Connections Required On-Site (2 Data + 2 Power)

16 An IPID Setup for INDOT Interstate 74 Embankment Monitoring Project (Powered by a 60W Solar Panel) IPID System

17 Example of Real-time Web-based Data Publishing for Inclinometer

18 Example of Real-time Data X-axis one month data (5 min scan, 10 min record)

19 Example of Real-time Data Y-axis one month data (5 min scan, 10 min record)

20 IPID Case History New Hillside Revitalization Stratford Development at Kenwood Undergoing $75 million+ Hillside Redevelopment Developments highlighted by an 18-story residential tower, a 3- story healthcare building, and a 4- story luxury condominium Offering approximate 580,000 square feet of living space Developments also include: 3-story Below-grade Parking Garage Significant Cut/Fill to accommodate Surface Parking & Roadways Four Allan Block Segmental Retaining Walls A Solider Pile Drilled Pier Retaining Wall Without a properly designed retention system, more than 5 ft. fill within existing steep topography underlain by a sloping bedrock surface is not recommended beyond the upper plateau

21 New Site Grading & Developments Grading Hillside Fill & Cut 70,000+ and 50,000 cubic yards of cut and fill 70,000+ Cubic Yard CUT Fill Stabilized by Shear Key Fill Stabilized by Soldier Pile Wall Fill Stabilized by Drilled Pier 3-level Basement Excavation, as deep as 45+ ft below grade up to about 16 ft of new building fill on upslope side of stabilization piers for a flatter developed area.

22 Subsurface Profile Existing Fill Glacial Till Residual Clay Weathered Shale Gray Shale Material 38 Test Borings drilled, generally consists of: - New Fill (up to 16 feet in height) - Topsoil/Pre-Existing Fill (i.e., fat clay up to 26 ft.) - Weathered Till and Glacial Till - Residual Clay (including fat clay) - Ordovician Bedrock N-Value Range bpf Existing Fill Most 10- Glacial Till 4-30 Most 10+ Residual Clay Bedrock Moisture Content % Most Average at Most 20- Average Thickness ft. 10 Highly weathered shale moisture contents ranged from 13% to 31%; unconfined compressive strengths ranged from 5.3 to 13.7 tsf, underlain by Gray Shale 6

23 Slope Stabilization Design Using Slope Stabilization Pier Important Design Steps Load Distribution along Length of Pier Deflection Criteria at Pier Top Overall Stability of Corrected Slope

24 Wireless Network

25 Instrumentation Results (IPID-Inclinometer)

26 IPID Case History Open Cell River Wall Instrumentation Station Layout 6: Below MSE Wall 3: Behind preexisting sheet pile wall and new OPEN CELL wall & 2: Between new back-to-back OPEN CELL walls 4, 5, & 7: Behind new OPEN CELL wall

27 Instrumentation Setup at Each Station Each Location Typically Contained: 4 Piezometers 1 In-Place Inclinometer String Settlement Monitor Location 5 Also Had: 12 Strain Gauges 4 Strain Gauges Were Added to Location 4 to Monitor Wall Repair

28 Wireless Network at Argosy Harbor

29 Wall/Soil Lateral Movement (IN) Instrumentation Results (Inclinometer) Location 49 5 (Cell 40) Monitoring Enclosure Inclinometer Data (Direction Facing New Boat Slip) /26/2007 9/15/ /5/ /25/ /14/ /4/ /24/2007 1/13/2008 2/2/ Wall Backfill to Elev Boat Slip 21 Excavation 19 Complete at Elev Wall Backfill to Elev /26/2007 9/15/ /5/ /25/ /14/ /4/ /24/2007 1/13/2008 2/2/2008 2/22/2008 Date 7-9 (40%) (60%) Behind Wall Backfill Elevation (Height) New Boat Slip Excavation (Invert) Soil Lateral Movement at Elev. 460 Soil Lateral Movement at Elev. 450 Soil Lateral Movement at Elev. 430 Wall Wye Pile Deflection at Elev. 480

30 Safe or Not?

31 Summary & Lessons Learned Wireless networks along with the use of relay/timer system allowed monitoring without the inconvenience and cost associated with running wires throughout extensive project areas. The use of MEMS based IPID with a built-in data acquisition module greatly reduces the time and cost to setup an in-place inclinometer system. The use of digital RS-485 protocol and single cable IPID system allows many more sensors (up to 32 sensors per cable) to be installed in a standard inclinometer casing (only conventional sensors). The built-in RS-485 based data acquisition provides an easy method for long distance transmission and remote monitoring, and is compatible with other industrial RS-485 interfaced modules. Dual axis silicon 3-D MEMS inclinometer sensors can be modified to true 3-D and measure vertical movements, if more flexible wires/rods are used between sensors. The use of automated geotechnical instrumentation and customized software allowed the designer, contractor, and owner to make critical, time sensitive decisions through data from the website.

32 Acknowledgments INDOT, Office of Geotechnical Engineering, Indianapolis, Indiana The Stratford Companies, Indianapolis, Indiana; Paric/Ruscilli a JV, Cincinnati, Ohio Argosy Casino/Penn National Gaming, Lawrenceburg, Indiana; Messer/Harmon Construction, Cincinnati, Ohio; PND Engineers, Seattle, Washington AGI, San Francisco, California Kenkul Corporation, Taipei, Taiwan

33 Thank you for your attention. QUESTIONS?