Manual de carreteras

USER’S MANUAL VIBRATING-WIRE PIEZOMETERS Big Boy: Model 98050 Slim Jim: Model 98051 Conehead: Model Number 98052 Serial No._____________________________

140 Chestnut Street San Francisco, CA 94111 USA Tel (415) 364-3200 Fax (415) 861-1448 info@geomechanics.com www.geomechanics.com

Copyright ©2008 by Applied Geomechanics, All rights reserved. Document No. D0031A

TABLE OF CONTENTS 1.Introduction and Specifications ......................................................................................................................1 2. Operating Principle.........................................................................................................................................2 3. Taking Readings.............................................................................................................................................3 4. Converting Frequency Readings to Pressure..................................................................................................3 5. Temperature Measurement .............................................................................................................................6 6. Temperature Correction ofPressure Readings ...............................................................................................8 7. Barometric Pressure Correction......................................................................................................................8 8. Installation......................................................................................................................................................8 8.1 8.2 8.3 8.4 8.5 8.6 8.7 8.8 Saturating Filters ...............................................................................................................................8 Taking Zero Readings; Acceptance Test ..........................................................................................9 Borehole Installation UsingSand......................................................................................................9 Grouted Borehole Installation .........................................................................................................10 In Situ or Push-In Installation .........................................................................................................10 Embankment Installation................................................................................................................11 Installation in Open Standpipes.......................................................................................................12 Cable Care.......................................................................................................................................12

9.Troubleshooting............................................................................................................................................12 10. Warranty and Limitation of Liability ..................................................................................................13

1. Introduction and Specifications
The Applied Geomechanics family of vibrating-wire piezometersincludes the following models: • • • Big Boy Piezometer (Model 98050) Slim Jim Piezometer (Model 98051) Conehead Push-in Piezometer (Model 98052)

Each of these piezometers is available in a variety of pressure ranges, indicated by the dash number following the model number (Table 1). All are constructed of stainless steel to retard corrosion and enhance long-term performance in fieldinstallations. All use an internal magnetic wire, attached at one end to a moveable diaphragm and anchored at the other end, to measure pore water pressure. Pressure changes move the diaphragm, lengthening or shortening the wire and altering its resonant frequency. Factory calibrations of the piezometers are used to convert the measured frequency to pressure. Key features of the three piezometer types are...