1. June 21, 20061 NEES 4 th Annual Meeting Instrumentation for the NEESR Sand Aging Field Experiment David A. Saftner University of Michigan PhD Student

2. June 21, 20062 Co-Authors Mr Thaweesak Jirathanathaworn, UM PhD Student Dr Russell Green, UM Assistant Professor SAND AGING Ms Jennifer Ngai, UM Undergraduate Student Dr Jerome Lynch, UM Assistant Professor

3. June 21, 20063 Special Thanks Dr Richard Woods, UM Professor Emeritus Mulzer Crushed Stone, Inc. Nicholson Construction SAND AGING Dr Kyle Rollins, BYU Professor Mr Jan Pantolin, UM Lab Technician

4. June 21, 20064 Outline Sand Aging Overview Project Overview Parameters and Instrumentation Data Acquisition Systems (DAS) DAS and Instrumentation Comparison Summary SAND AGING

5. June 21, 20065 Sand Aging Overview Time dependent strength gain without measurable increase in settlement First extensive study during Jebba Dam construction on Niger River in Nigeria (1984) Increase in soil improvement projects increases importance of sand aging SAND AGING

6. June 21, 20066 Sand Aging Overview SAND AGING Explanations Mechanical changes – particle reorientation, particle shearing (Mesri et al, 1990) Aging measured after tens of minutes (figure from Bowman, 2002)

7. June 21, 20067 Sand Aging Overview Explanations (Continued) Chemical changes – creation of cementation through silica gel (Mitchell and Solymar, 1984) Denisov & Reltov experiment Aging without fabric disruption Reduced strength under blast areas General theories – pore pressure dissipation, blast gas dissipation, and cold welding SAND AGING

8. June 21, 20068 Project Overview Site requirements = loose, clean, saturated sand SAND AGING

9. June 21, 20069 Project Overview Liquefaction induction methods Explosive compaction Vibro-compaction Vibro-seis SAND AGING

10. June 21, 200610 Parameters and Instrumentation Acceleration Micro-electro-mechanical system (MEMS) accelerometers Piezoelectric accelerometers Geophones (velocity) Allow for calculation of energy dissipation in the soil and its effect on aging SAND AGING

11. June 21, 200611 Parameters and Instrumentation Settlement Sondex settlement tubes Determine settlement as a function of depth and time SAND AGING Sondex readout w/ probe Inclinometer casing inside Sondex corrugated pipe Sensing ring (magnet) Inclinometer and sensing ring installed at stable ground

12. June 21, 200612 Parameters and Instrumentation Pore Water Pressure Pore pressure transducers Will ensure that liquefaction is induced Multiple sensors will monitor spatial generation and dissipation of excess pore pressure SAND AGING

13. June 21, 200613 Parameters and Instrumentation Sampling Rate Acceleration – based on testing method Settlement – weekly Pore Pressure – 1 Hz Sampling Duration Acceleration – based on testing method Settlement – UTC Pore Pressure – until conditions return to hydrostatic (we expect hours) SAND AGING

14. June 21, 200614 Data Acquisition Systems Olson Instruments, Inc. Freedom Data PC 16 channels User defined sampling rate 20 GB hard drive SAND AGING

15. June 21, 200615 Data Acquisition Systems Wireless Data Acquisition System (DAS) 128 kB RAM Transmits data up to 300m at 38.4 KB/s Sampling rates: 50, 70, 100, 200, 400, & 500 Hz SAND AGING

16. June 21, 200616 SAND AGING Shaker moving at 10 Hz Manifold holds pressure up to 1000 psi DAS Comparison

17. June 21, 200617 DAS Comparison SAND AGING Geophones output 7 V per in/sec Correct frequency measured in both systems Impedance of wireless DAS distorts amplitude

18. June 21, 200618 DAS Comparison SAND AGING Pressure transducers output 5 V per ksi Cable based DAS does not recognize DC input without being reconfigured Wireless systems reports correct output Volts Time (seconds) Cable-based Wireless

19. June 21, 200619 Instrumentation Comparison SAND AGING Emplacing Instrumentation Geophones MEMS & Piezoelectric Accelerometers

20. June 21, 200620 Summary Sand aging = time-dependent strength gain Measure acceleration, settlement, and pore pressure dissipation caused by three liquefaction methods Different DAS appropriate for different instruments Emplacement methods next step in determining which instruments will be used SAND AGING

21. June 21, 200621 Questions? http://www-personal.umich.edu/~rugreen/NEES/