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FOUNDATION INVESTIGATION MANUAL
ii
Preface
The preparation of the Saskatchewan Ministry of Highways and Infrastructure Foundation Investigation
Manual (FIM) was initiated in 2013 and has been developed in accordance with local geological
conditions and guidance from the Canadian Foundation Engineering Manual (CFEM) 4th Edition. The
CFEM along with the FIM is intended to become the basis for performance of the Ministry’s
geotechnical works including but not limited to site investigation, interpretation, design, monitoring,
data requirements, reporting, risk mitigation and geohazard risk management.
The FIM contains geotechnical design and construction information that is specific to the local
geological setting and is also based on the experiences gained from the past geotechnical and geo-
environmental projects in Saskatchewan.
iii
Dedication
The Foundation Investigation Manual is dedicated to the past geotechnical field and laboratory testing
staff and engineers. The historical contributions made by the Ministry’s geotechnical and laboratory
staff has provided a significant geotechnical archive that will help with our understanding of current and
future projects in the Province of Saskatchewan.
iv
Table of Contents
Preface......................................................................................................................................................... ii
Dedication .................................................................................................................................................. iii
Table of Contents ....................................................................................................................................... iv
List of Tables ............................................................................................................................................. vi
List of Figures and Illustrations ................................................................................................................ vii
List of Symbols, Abbreviations and Nomenclature ................................................................................. viii
FIM 100 INTRODUCTION ......................................................................................................................1
100.10 Use of this Manual .......................................................................................................................1
100.10.1 Use within the Ministry .......................................................................................................1
100.10.2 Use outside the Ministry ......................................................................................................2
100.20 Use of Other Publications ............................................................................................................3
100.20.1 Approval Requirements .......................................................................................................3
100.30 Design Exceptions .......................................................................................................................4
100.30.1 Design Exception Process Guidelines .................................................................................4
100.30.2 Design Exception Report Guidelines ..................................................................................5
100.30.3 Approval ..............................................................................................................................5
FIM 200 SITE INVESTIGATIONS .........................................................................................................6
FIM 300 LABORATORY TESTING ......................................................................................................6
FIM 400 INSTRUMENTATION OPTIONS ..........................................................................................6
FIM 500 INSTRUMENTATION INSTALLATION ..............................................................................6
FIM 600 INSTRUMENTATION MONITORING .................................................................................7
600.10 Standpipe Piezometer ..................................................................................................................7
600.10.1 Background ..........................................................................................................................7
600.10.2 Required Equipment ............................................................................................................8
600.10.3 Measurement .......................................................................................................................8
600.10.4 Reporting Results ................................................................................................................9
600.20 Pneumatic Piezometer ................................................................................................................11
600.20.1 Background ........................................................................................................................11
600.20.2 Required Equipment ..........................................................................................................12
v
600.20.3 Measurement .....................................................................................................................13
600.20.4 Reporting Results ..............................................................................................................14
600.30 Vibrating Wire Piezometer ........................................................................................................16
600.30.1 Background ........................................................................................................................16
600.30.2 Required Equipment ..........................................................................................................16
600.30.3 Measurement .....................................................................................................................17
600.30.4 Reporting Results ..............................................................................................................20
600.40 Slope Inclinometer .....................................................................................................................23
600.40.1 Background ........................................................................................................................23
600.40.2 Required Equipment ..........................................................................................................25
600.40.3 Measurement .....................................................................................................................26
600.40.4 Reporting Results ..............................................................................................................29
FIM 700 GEOTECHNICAL DESIGN ..................................................................................................36
FIM 800 REPORTING............................................................................................................................36
FIM 900 GEOHAZARD RISK MANAGEMENT................................................................................36
FIM 1000 REFERENCES .......................................................................................................................37
1000.10 References used in this document ............................................................................................37
FIM 1100 INDEX .....................................................................................................................................38
1100.10 Specific Information in this document .....................................................................................38
vi
List of Tables
Table 1 – Design Exception Process ........................................................................................................... 4
Table 1 – Recommended Abbreviations for Geotechnical Instrumentations ............................................. 7
Table 2 – Binding Posts and Vibrating Wire Colour Coding ................................................................... 19
vii
List of Figures and Illustrations
Figure 1 – Water Level Depth Meter. ......................................................................................................... 8
Figure 2 – Standpipe Piezometer Plot Example. ...................................................................................... 10
Figure 3 – Schematic of Pneumatic Piezometer. ...................................................................................... 12
Figure 4 – RST Petur C-108 Pneumatic Readout. .................................................................................... 13
Figure 5 – Pneumatic Piezometer(s) Plot Example. ................................................................................. 15
Figure 6 – Portable Vibrating Wire Data Recorder. ................................................................................. 17
Figure 7 – Vibrating Wire Piezometer(s) Total Head Plot Example. ....................................................... 21
Figure 8 – Vibrating Wire Piezometer(s) Temperature Plot Example. .................................................... 22
Figure 9 – Illustration of SI Casing A-axis Grooves aligned with North. ................................................ 23
Figure 10 – Digitilt Datamate, Inclinometer Probe and Control Cable. ................................................... 25
Figure 11 – Pulley Assembly (Model #51104606). .................................................................................. 26
Figure 12 – Aluminium and PVC Extension Casings (500 mm long) along with Union Coupler........... 26
Figure 13 – Illustration of Pulley Assembly for Depth Control. .............................................................. 28
Figure 14 – Cumulative Displacement Plot Example. .............................................................................. 31
Figure 15 – Incremental Displacement Plot Example. ............................................................................. 32
Figure 16 – Resultant Displacement vs. Time Plot Example. .................................................................. 33
Figure 17 – Direction of Movement Plot Example. .................................................................................. 35
viii
List of Symbols, Abbreviations and Nomenclature
Symbol Definition ABC Factors Factors on the Vibrating Wire Calibration Sheet
atm Standard Atmosphere Unit
A0 Positive A-axis reading (Slope Inclinometer)
A180 Negative A-axis Reading (Slope Inclinometer)
B0 Positive B-axis reading (Slope Inclinometer)
B180 Negative B-axis Reading (Slope Inclinometer)
ARGUS Web-Based Remote Monitoring Software
“B” Unit Hz2/1000
CFEM Canadian Foundation Engineering Manual
DAR Design Authorization Report
FIM Ministry’s Foundation Investigation Manual
ft Foot
Hz Hertz
ID Identification
kPa Kilo Pascals
m Meter
masl Meters Above Sea Level
MHI Saskatchewan Ministry of Highways and Infrastructure
Ministry Saskatchewan Ministry of Highways and Infrastructure
mm Millimeter
N North
psi Pounds per Square Inch
SP Standpipe Piezometer
SI Slope Inclinometer
Tk Temperature Correction Factor (Vibrating Wire)
Tc Current Temperature (Vibrating Wire)
Ti Initial Temperature (Vibrating Wire)
TSB Technical Standards Branch
PN Pneumatic Piezometer
VW Vibrating Wire Piezometer
FIM 100
FOUNDATION INVESTIGATION MANUAL
Section: INTRODUCTION
Subject: Use of this Manual
Date Updated Page 08 October 2013 1 of 38
Date Updated: 08 October 2013
FIM 100 Introduction 100.10 Use of this Manual The Canadian Foundation Engineering Manual (CFEM) and the Foundation Investigation Manual
(FIM), when used together, form the collection of geotechnical design and construction guidelines for
roads, runways, highways and bridges under the jurisdiction or care of the Saskatchewan Ministry of
Highways and Infrastructure (Ministry).
The CFEM along with the FIM is intended to become the basis for the Ministry’s geotechnical works
including but not limited to site investigation, interpretation, design, monitoring, data requirements,
reporting, risk mitigation and geohazard risk management.
100.10.1 Use within the Ministry Because of the nature of this manual, design information may be contained in a CFEM section, a FIM
section, or a combination of both. Geotechnical design engineers must take care to ensure they are
aware of the Ministry standards that apply to a given design topic.
The following are guidelines for the use of these publications:
• If a design topic is addressed in both the CFEM and the FIM, the Ministry standard procedure
shall be to apply information from both documents in combination, unless;
o If a design topic is addressed in both the CFEM and the FIM, but the FIM contains
information that differs from the CFEM, the information in the FIM shall be taken as the
Ministry standard.
• If a design topic is addressed in the CFEM but is not addressed in the FIM, the information in the
CFEM shall be used for guidance. The normal approval authority applies. A Design Exception
Report is not required; however, the choice of values within the design domain must be justified
by the Design Engineer.
FIM 100
FOUNDATION INVESTIGATION MANUAL
Section: INTRODUCTION
Subject: Use of this Manual
Date Updated Page 08 October 2013 2 of 38
• If a design topic is not addressed in the CFEM or the FIM, but is addressed in another
publication, refer to section 100.20.
100.10.2 Use outside the Ministry The Ministry of Highways and Infrastructure recognizes that others may use the Foundation
Investigation Manual (FIM). The FIM is a consolidation of Ministry policies, standards and practices
specific to the local geological setting. Therefore it is not suitable for adoption by others as design code
or a set of minimum specifications.
FIM users must accept responsibility for each design produced and all associated risk of liability.
FIM 100
FOUNDATION INVESTIGATION MANUAL
Section: INTRODUCTION
Subject: Use of Other Publications
Date Updated Page 08 October 2013 3 of 38
100.20 Use of Other Publications Geotechnical design engineers may wish to consider information in publications other than the CFEM
and the FIM. For example, design engineers must also consult other relevant Ministry publications.
Design engineers may also consult other sources for design guidance. This is especially beneficial when
a particular design topic is not addressed in a Ministry publication or the CFEM, or when the particular
conditions warrant additional research.
100.20.1 Approval Requirements
When considering a design element based on information from another publication, the following
approval requirements apply:
• If information in one Ministry publication is contrary to information in another, the most recently
approved shall be the governing standard. Technical Standards Branch (TSB) must be informed
of any discrepancies or ambiguities.
• If a design topic is not addressed in the CFEM or the FIM, but is addressed in another
publication produced by the Ministry, the normal approval authority applies. A Design
Exception Report is not required; however, the choice of selected values must be justified by the
design engineer.
If a design topic is not addressed in the CFEM or the FIM, and is also not addressed in another
publication produced by the Ministry, any proposed design element based on that information shall be
approved by the same authority as a design exception. See section 100.30 for more information.
FIM 100
FOUNDATION INVESTIGATION MANUAL
Section: INTRODUCTION
Subject: Design Exceptions
Date Updated Page 08 October 2013 4 of 38
100.30 Design Exceptions A design exception is defined as any design element differing from the approved Ministry standard. See
section 100.10 for more information on approved Ministry standards.
When in the professional judgement of the design engineer a design exception is deemed warranted, the
design engineer must obtain proper approval for the recommended exception. The process outlined in
section 100.30.1 provides design engineers with guidelines for obtaining such approval. The purpose of
this process is to ensure design exceptions are formally documented, appropriately evaluated and
properly approved, as well as providing consistency throughout the Ministry and ensuring standards are
kept current.
100.30.1 Design Exception Process Guidelines The following process outlined in Table 1 should be followed for design exception evaluation and
submission.
Table 1 – Design Exception Process
Step Process Detail
1 Identify the Key Issue(s) What are the circumstances that require a geotechnical element to differ from the current standard?
2 Assess various options outside the standard
Identify options that are being considered to address the design exception.
Identify the implications associated with each option.
3 Provide Recommendations Identify the option that is being recommended.
Why was the option selected?
Consider short-term implications, long-term implications and risk management issues.
4 Assess the need for changes to existing standards
Each design exception should be evaluated by the appropriate TSB Section to assess whether current standards should be changed.
5 Submit a report for approval See section 100.30.2
FIM 100
FOUNDATION INVESTIGATION MANUAL
Section: INTRODUCTION
Subject: Design Exceptions
Date Updated Page 08 October 2013 5 of 38
100.30.2 Design Exception Report Guidelines Each design exception must be submitted in a Design Exception Summary Sheet. A design exception
may apply at any phase of the project; however, approved Design Exception Summary Sheets are to be
filed with the Design Authorization Report (DAR). Design Exception Summary Sheet submitted after
approval of the DAR shall be appended to the DAR upon approval. The original DAR is to be placed in
the Region files and a copy is to be sent to TSB.
100.30.3 Approval The approval of Design Exception Summary Sheet is subject to the requirements listed in the Ministry’s
Non-Financial Signing Authority Delegation document. Further to the approval requirements in that
document, all non-minor design exceptions shall be reviewed and recommended by the Executive
Director of TSB.
FIM 200
FOUNDATION INVESTIGATION MANUAL
Section: SITE INVESTIGATIONS
Subject: Design Exceptions
Date Updated Page 18 November 2013 6 of 38
Date Updated: 18 November 2013
FIM 200 Site Investigations
FIM 300 Laboratory Testing
FIM 400 Instrumentation Options
FIM 500 Instrumentation Installation
FIM 600
FOUNDATION INVESTIGATION MANUAL
Section: INSTRUMENTATION MONITORING
Subject: Standpipe Piezometer
Date Updated Page 24 January 2014 7 of 38
Date Updated: 24 January 2014
FIM 600 Instrumentation Monitoring This chapter is intended to provide guidance for monitoring the Ministry’s various geotechnical
instrumentation types (e.g. standpipe piezometers, pneumatic piezometers, vibrating wire piezometers
and slope inclinometers). The standard abbreviations for the Ministry’s geotechnical instrumentation
are provided in Table 1.
Table 2 – Recommended Abbreviations for Geotechnical Instrumentations
SP Standpipe Piezometer
PN Pneumatic Piezometer
VW Vibrating Wire Piezometer
SI Slope Inclinometer
The digital outputs, results and recommendations from instrumentation monitoring shall be forwarded to
the Project Manager, Regional Materials Engineer and Sr. Geotechnical Engineer, Technical Standards
Branch (TSB).
600.10 Standpipe Piezometer The Ministry’s standard for installation of standpipe piezometers can be found under Section 500.10.
600.10.1 Background Standpipe piezometers are normally used for long term monitoring of ground water elevations in
proposed cut and fill areas. Standpipe piezometers are also useful for slope stability investigations,
establishing the vertical gradient of water, ground water flow direction, permeability measurements,
monitoring the effectiveness of dewatering, water sampling and environmental monitoring.
FIM 600
FOUNDATION INVESTIGATION MANUAL
Section: INSTRUMENTATION MONITORING
Subject: Standpipe Piezometer
Date Updated Page 24 January 2014 8 of 38
Standpipe piezometers provide information on ground water levels by measuring the water level in the
pipe. The water level in the pipe represents the pore-water pressure in the soil around the filter screen
and intake zone.
600.10.2 Required Equipment The following equipment is required to record the standpipe piezometer readings:
- 50 m water level depth meter (see Figure 1) - Pocket tape measure - Keys to unlock protective caps - Screw Driver or wrenches if the protective cover is a manhole - Field book or data sheet to record readings
The operator needs to be familiar with the safe working procedures of the above equipment. The
operator must ensure equipment is in good working condition and calibrated in advance of mobilizing to
site.
Figure 1 – Water Level Depth Meter.
600.10.3 Measurement Standpipe piezometer readings are recorded in meters from ground surface. In the case of installations
in artesian conditions, the readings are taken directly from the pressure gauge.
Readings in an open piezometer pipe are taken using a water level meter. The probe is lowered down
the tube until it contacts the water, completing an electric circuit as indicated on the gauge (LED
(Reproduced from the
following DGSI Website -
www.slopeindicator.com)
FIM 600
FOUNDATION INVESTIGATION MANUAL
Section: INSTRUMENTATION MONITORING
Subject: Standpipe Piezometer
Date Updated Page 24 January 2014 9 of 38
illuminates and the beeper sounds). Hold the cable at the point at which it touches the top of the
piezometer stickup, then pull the cable out and extend it along the outside of the pipe to ground level.
The water level depth reading is then recorded by subtracting the piezometer stickup height
measurement from the reading obtained at the top of the piezometer stickup. This results in water
depths that are recorded from ground elevation and not the top of the piezometer stickup.
Note: Drilling a borehole and backfilling it temporarily changes the pore-water pressure in the ground,
so readings that are taken immediately after installation will not be good baseline readings. Recovery
of the natural pore-water pressure may take a few hours to a few weeks, depending on the permeability
of the soil. Recovery is signalled by stable readings over a period of a few days. A baseline reading can
then be obtained.
600.10.4 Reporting Results The standpipe piezometer readings shall be plotted as Total Head (meters above sea level (masl)) vs.
Time (Reading Date) as shown in Figure 2. The title of the plot shall identify the control section, project
name and borehole name. The legend shall identify the instrument ID and other relevant descriptors.
This plot could also be utilized to report the results from nested standpipe piezometers.
The plot shall also identify the elevation of the tip of the standpipe piezometer, intake zone (comprising
of piezometer screen and granular backfill) and ground elevation. Total daily precipitation (mm) data
from the closest weather station shall also be plotted on the secondary vertical axis vs. Time (see Figure
2). Excel template to create the XYY plot (as shown in Figure 2) can be downloaded from the
Geotechnical Section under MHI’s knowledge warehouse webpage
http://www.highways.gov.sk.ca/business.
The reported results will allow geotechnical engineers to see the change in total head value with time
and evaluate the impact of various factors (such as pore-water pressure, precipitation, seasonal changes,
depth of influence) on ground strength and stability.
FIM 600
FOUNDATION INVESTIGATION MANUAL
Section: INSTRUMENTATION MONITORING
Subject: Standpipe Piezometer
Date Updated Page 24 January 2014 10 of 38
Figure 2 – Standpipe Piezometer Plot Example.
Ground Elevation
SP1 Tip, 436.37
Intake Zone
0
10
20
30
40
50
60
430
432
434
436
438
440
442
444
446
448
450
10-Aug-11 9-Oct-11 8-Dec-11 6-Feb-12 6-Apr-12 5-Jun-12 4-Aug-12 3-Oct-12
Tota
l Dai
ly P
reci
pita
tion
(mm
)
Ele
vatio
n \T
otal
Hea
d (m
asl)
Time (Reading Date)
008-06-40 Tantallon Access Slide BH-6
SP1Precipitation@Rocanville
LEGEND(STANDPIPE PIEZOMETER PLOT)
FIM 600
FOUNDATION INVESTIGATION MANUAL
Section: INSTRUMENTATION MONITORING
Subject: Pneumatic Piezometer
Date Updated Page 24 January 2014 11 of 38
600.20 Pneumatic Piezometer The Ministry’s standard for installation of pneumatic piezometers can be found under Section 500.20.
600.20.1 Background Pneumatic piezometers are normally used for monitoring pore-water pressures prior to construction,
during construction and post construction. Pneumatic piezometers are also useful for slope stability
investigations, establishing the vertical gradient of water and monitoring the effectiveness of dewatering.
Pneumatic piezometers provide immediate response to very slight changes in pore pressure. Pneumatic
piezometers measure pore-water pressures by means of a hydrostatic pressure cell in a plastic or
stainless steel case with a porous (ceramic, metal or plastic) disk to allow the pore water to reach the cell
diaphragm. A supply bottle of compressed gas is used to apply pressure to the cell diaphragm. When the
air/gas pressure equals the pore water pressure the diaphragm relaxes and allows the excess gas to
release. When the gas supply is shut off the pressure in the supply line is equal to the water pressure. A
schematic diagram of a pneumatic piezometer is shown in Figure 3.
FIM 600
FOUNDATION INVESTIGATION MANUAL
Section: INSTRUMENTATION MONITORING
Subject: Pneumatic Piezometer
Date Updated Page 24 January 2014 12 of 38
Figure 3 – Schematic of Pneumatic Piezometer.
600.20.2 Required Equipment The following equipment is required to record the pneumatic piezometer readings:
- A pneumatic readout box compatible with the model of piezometer installed. The recommended readout for all Ministry installations is the RST Petur C-106 or C-108 (see Figure 4).
- Keys to unlock protective caps - Screw Driver or wrenches if the protective cover is a manhole - Field book or data sheet to record readings - Compressed Gas
The operator needs to be familiar with the safe working procedures of the above equipment. The
operator must ensure equipment is in good working condition and calibrated before mobilizing to site.
(Reproduced from the
following DGSI Website -
www.slopeindicator.com)
FIM 600
FOUNDATION INVESTIGATION MANUAL
Section: INSTRUMENTATION MONITORING
Subject: Pneumatic Piezometer
Date Updated Page 24 January 2014 13 of 38
Figure 4 – RST Petur C-108 Pneumatic Readout.
600.20.3 Measurement Pneumatic piezometer readings are recorded in kPa or psi. Readings are taken using a pneumatic
readout box compatible with the sensor used. Turn on the supply tank containing compressed gas
(nitrogen or CO2). Connect the black tubing from the transducer with the quick connect couplers
provided with the equipment. Open the by-pass valve, and observe the data gauge. Once the pressure
ascent decreases or stops, close the by-pass valve and allow the gauge to stabilize. Record the pressure
reading. Bleed out the line after taking the reading. Disconnect the coupler and close the supply tank
valve. The gauge is read directly in kPa or p.s.i. The gauge reading can be converted into pressure head
by using the following conversion:
Height of Head (m) = kPa x 0.10 (Results shall be reported in m) Height of Head (ft) = psi x 2.307
(Reproduced from the
following RST Website -
www.rstinstruments.com)
FIM 600
FOUNDATION INVESTIGATION MANUAL
Section: INSTRUMENTATION MONITORING
Subject: Pneumatic Piezometer
Date Updated Page 24 January 2014 14 of 38
Note: Drilling a borehole and backfilling it temporarily changes the pore-water pressure in the ground,
so readings that are taken immediately after installation will not be good baseline readings. Recovery
of the natural pore-water pressure may take a few hours to a few weeks, depending on the permeability
of the soil. Recovery is signalled by stable readings over a period of a few days. A baseline reading can
then be obtained.
600.20.4 Reporting Results The pneumatic piezometer readings shall be plotted as Total Head (masl) vs. Time (Reading Date) as
shown in Figure 5. The title of the plot shall include the control section, project name and borehole
name. The legend shall identify the instrument ID’s and other relevant descriptors. This plot could also
be utilized to report the results from stacked pneumatic piezometers.
The plot shall identify the elevation of the tip of the pneumatic piezometer and ground elevation. Total
daily precipitation (mm) data from the closest weather station shall be plotted on the secondary vertical
axis vs. Time (see Figure 5). An Excel template to create the XYY plot (as shown in Figure 5) can be
downloaded from the Geotechnical Section under MHI’s knowledge warehouse webpage
http://www.highways.gov.sk.ca/business.
The reported results will allow geotechnical engineers to see the change in total head value with time
and evaluate the impact of various factors (such as pore-water pressures, precipitation, seasonal changes,
depth of influence) on ground strength and stability.
FIM 600
FOUNDATION INVESTIGATION MANUAL
Section: INSTRUMENTATION MONITORING
Subject: Pneumatic Piezometer
Date Updated Page 24 January 2014 15 of 38
Figure 5 – Pneumatic Piezometer(s) Plot Example.
Ground Elevation
PN403A Tip, 587.026
PN403B Tip, 600.426
0
10
20
30
40
50
60
585
590
595
600
605
610
615
7-Apr-08 24-Oct-08 12-May-09 28-Nov-09 16-Jun-10 2-Jan-11 21-Jul-11
Tota
l Dai
ly P
reci
pita
tion
(mm
)
Ele
vatio
n \T
otal
Hea
d (m
asl)
Time (Reading Date)
001-04 Broadview RR Overpass BH403
PN403APN403BPrecipitation@Broadview
LEGEND(PNEUMATIC PIEZOMETER PLOT)
FIM 600
FOUNDATION INVESTIGATION MANUAL
Section: INSTRUMENTATION MONITORING
Subject: Vibrating Wire Piezometer
Date Updated Page 24 January 2014 16 of 38
600.30 Vibrating Wire Piezometer The Ministry’s standard for installation of vibrating wire piezometers can be found under
Section 500.30.
600.30.1 Background Vibrating wire piezometers are normally used for monitoring pore-water pressures prior to construction,
during construction and post construction. Vibrating wire piezometers are also useful for slope stability
investigations, establishing the vertical gradient of water, understanding the impact of dynamic loading
ground improvement and monitoring the effectiveness of dewatering.
Vibrating wire piezometers measure pore-water pressures by converting water pressure to a frequency
signal via a diaphragm, a tensioned steel wire, and an electromagnetic coil. The vibrating wire
piezometer is designed so that a change in pressure on the diaphragm causes a change in tension of the
wire. An electro-magnetic coil is used to excite the wire, which then vibrates at its natural frequency.
The vibration of the wire in the proximity of the coil generates a frequency signal that is transmitted to
the readout device. The readout or data logger stores the reading in Hz. Calibration factors are then
applied to the reading to arrive at a pressure head in meters.
Each vibrating wire piezometer has a serial number and a unique calibration record. Use the sensor
serial number to match the sensor with its calibration record.
600.30.2 Required Equipment The following equipment is required to record the vibrating wire piezometer readings:
Manual System - Vibrating Wire Data Recorder - Keys to unlock protective covers - Screw Driver or wrenches if the protective cover is a manhole - Field book or data sheet to record readings
FIM 600
FOUNDATION INVESTIGATION MANUAL
Section: INSTRUMENTATION MONITORING
Subject: Vibrating Wire Piezometer
Date Updated Page 24 January 2014 17 of 38
Semi-Automatic System - Appropriate Software for downloading data from Vibrating Wire Minilogger (if each individual
vibrating wire sensor is connected to individual Minilogger) - Appropriate Software for downloading data from Multichannel Datalogger (if multiple vibrating
wire sensors are connected to multichannel dataloggers)
Fully-Automatic System - Initial setup is required to remotely link field instruments to remote web application via a cellular
modem. Currently MHI uses ARGUS web-based remote monitoring software.
The operator needs to be familiar with the safe working procedures of the above equipment. The operator must ensure equipment is in good working condition and calibrated before mobilizing to site.
Figure 6 – Portable Vibrating Wire Data Recorder.
600.30.3 Measurement The vibrating wire piezometer provides pressure and temperature data. Be sure to record both if you
want to correct readings for temperature effects. Readings are typically in Hz or B units (Hz2/1000),
rather than units of pressure. Calibration factors must be applied to convert to units of pressure. There
is also the capability of correcting for temperature and barometric pressure.
Calculating the resultant pore water pressure recorded by the vibrating wire piezometer varies depending
on how the instrument is calibrated. For example, RST piezometer calculations are based on the “B”
unit (Hz2/1000) whereas DGSI piezometer calculations are based on Hz.
(Reproduced from the
following DGSI Website
www.slopeindicator.com)
FIM 600
FOUNDATION INVESTIGATION MANUAL
Section: INSTRUMENTATION MONITORING
Subject: Vibrating Wire Piezometer
Date Updated Page 24 January 2014 18 of 38
To convert the Hz/B unit reading to units of pressure, you must apply ABC Calibration Factors listed on
the sensor calibration record. When calculating pressure always follow the instructions on the
calibration sheet provided by the equipment manufacturer.
The ABC factors are used by the Ministry to calculate pressure from vibrating wire piezometers. When
calibration factors are given in either units of psi or kPa, choose the factors for kPa.
The following equation shall be used to calculate the pressure:
Pressure = (A × U2) + (B × U) + C + Tk(Tc – Ti) Where: U is the reading in Hz or B unit (Hz2/1000); A, B, and C are ABC Factors on the sensor calibration record; and Tk is the Temperature Correction Factor; and Tc and Ti are the current and initial temperature. Note: If the vibrating wire piezometer is sealed in a borehole or buried in a fill, there is usually little
variation in temperature, so temperature effects will be small and corrections will be less important. If
the piezometer is suspended in a shallow standpipe or well, it is likely to be affected by day to day
changes and also seasonal changes in temperature. In this case, temperature corrections will be more
important.
Note: If the vibrating wire piezometer is sealed in a borehole or buried in a fill, the only pressure acting
on the piezometer’s diaphragm should be the water pressure at that depth, so a barometric correction is
not required. If you are measuring the water level in a standpipe/ well or lake/ river that is open to the
atmosphere then the pressure recorded by the vibrating wire piezometer is equal to the pressure of
water and the air above the surface of water. An additional vibrating wire piezometer could be utilized
on site to calculate barometric correction. Install another vibrating wire piezometer out in the open and
calculate barometric correction as follows:
Barometric Correction = atm – (atm+ piezometer reading*) => Barometric Correction = - piezometer reading* => Corrected Pressure = Pressure Reading + Barometric Correction
where * is the piezometer reading obtained from vibrating wire piezometer out in the open.
FIM 600
FOUNDATION INVESTIGATION MANUAL
Section: INSTRUMENTATION MONITORING
Subject: Vibrating Wire Piezometer
Date Updated Page 24 January 2014 19 of 38
The following steps provide methodology to collect the readings in the field for different systems -
Manual System
For exposed vibrating wires taped to a post, or vibrating wires in an enclosure, remove the electrical tape
protecting the lead ends and connect wires to the data recorder (as per Table 2).
Table 3 – Binding Posts and Vibrating Wire Colour Coding Binding Posts Wire Colours VW Orange Red VW White & Orange Black TEMP Blue White TEMP White & Blue Green SHIELD Shield Shield
• Switch on the Recorder and press Enter. • At the Type prompt, choose the appropriate frequency and temperature settings. “Hz +
Thermistor” or “B Units + Thermistor” as this data is easily manipulated. • Select the 1400 – 3500 Hz range. • Record the reading in your field logbook along with units and the serial number of the vibrating
wire piezometer.
Semi-Automatic System
For vibrating wires in a protective enclosure and connected to a permanent logger box, open the
enclosure, remove the protective cap on the data port and connect the appropriate cable from the laptop
PC. Open the software LogViewer for single-channel loggers, or Multichannel Logger Software for
multi-channel loggers. Hit “connect”. Once connected, hit “download data” and when prompted to erase
existing data or append to data, always choose “Append to data”.
Fully-Automatic System
Follow instructions provided in ARGUS remote monitoring software manual to setup a new site.
Note: Drilling a borehole and backfilling it temporarily changes the pore-water pressure in the ground,
so readings that are taken immediately after installation will not be good baseline readings. Recovery
FIM 600
FOUNDATION INVESTIGATION MANUAL
Section: INSTRUMENTATION MONITORING
Subject: Vibrating Wire Piezometer
Date Updated Page 24 January 2014 20 of 38
of the natural pore-water pressure may take a few hours to a few weeks, depending on the permeability
of the soil. Recovery is signalled by stable readings over a period of a few days. A baseline reading can
then be obtained.
600.30.4 Reporting Results The vibrating wire piezometer readings shall be plotted as Total Head (masl) vs. Time (Reading Date) as
shown in Figure 7. The title of the plot shall include the control section, project name and borehole
name. The legend shall identify the instrument ID’s and other relevant descriptors. This plot could also
be utilized to report the results from stacked pneumatic piezometers.
The plot shall identify the elevation of the tip of the vibrating wire piezometer and ground elevation.
Total daily precipitation (mm) data from the closest weather station shall be plotted on the secondary
vertical axis vs. Time (see Figure 7). In another plot measured temperature (degree Celsius) from each
instrument shall be plotted on the secondary vertical axis vs. Time (see Figure 8). An Excel template to
create the XYY plots (as shown in Figure 7 and Figure 8) can be downloaded from the Geotechnical
Section under MHI’s knowledge warehouse webpage http://www.highways.gov.sk.ca/business.
The reported results will allow geotechnical engineers to see the change in total head value with time
and evaluate the impact of various factors (such as pore-water pressures, precipitation, seasonal changes,
ground temperature, depth of influence) on ground strength and stability. Ground temperature can play
a vital role in understanding the ground instability and structural issues in areas with potential for
permafrost degradation.
FIM 600
FOUNDATION INVESTIGATION MANUAL
Section: INSTRUMENTATION MONITORING
Subject: Vibrating Wire Piezometer
Date Updated Page 24 January 2014 21 of 38
Figure 7 – Vibrating Wire Piezometer(s) Total Head Plot Example.
Ground Elevation Ground Elevation
VW-3C Tip, 459.51VW-3C Tip, 459.51
VW-3B Tip, 453.11VW-3B Tip, 453.11
VW-3A Tip, 446.41VW-3A Tip, 446.410
10
20
30
40
50
60
445
450
455
460
465
470
12-Oct-10 30-Apr-11 16-Nov-11 3-Jun-12 20-Dec-12 8-Jul-13
Tota
l Dai
ly P
reci
pita
tion
(mm
)
Ele
vatio
n \T
otal
Hea
d (m
asl)
Time (Reading Date)
008-06-40 Tantallon Access Slide BH-3
VW-3C (SN 12631)VW-3B (SN 12624)VW-3A (SN 12618)Precipitation@Rocanville
LEGEND(VIBRATING WIRE PIEZOMETER PLOT)
FIM 600
FOUNDATION INVESTIGATION MANUAL
Section: INSTRUMENTATION MONITORING
Subject: Vibrating Wire Piezometer
Date Updated Page 24 January 2014 22 of 38
Figure 8 – Vibrating Wire Piezometer(s) Temperature Plot Example.
Ground Elevation
VW-3C Tip, 459.51VW-3C Tip, 459.51
VW-3B Tip, 453.11VW-3B Tip, 453.11
VW-3A Tip, 446.41VW-3A Tip, 446.414
5
6
7
8
9
10
445
450
455
460
465
470
12-Oct-10 30-Apr-11 16-Nov-11 3-Jun-12 20-Dec-12 8-Jul-13
Mea
sure
d Te
mpe
ratu
re (
Deg
ree
Cel
cius
)
Ele
vatio
n \T
otal
Hea
d (m
asl)
Time (Reading Date)
008-06-40 Tantallon Access Slide BH-3
VW-3C (SN 12631)VW-3B (SN 12624)VW-3A (SN 12618)VW-3C TempVW-3B TempVW-3A Temp
LEGEND(VIBRATING WIRE PIEZOMETER PLOT)
FIM 600
FOUNDATION INVESTIGATION MANUAL
Section: INSTRUMENTATION MONITORING
Subject: Slope Inclinometer
Date Updated Page 24 January 2014 23 of 38
600.40 Slope Inclinometer The Ministry’s standard for installation of slope inclinometer casing can be found under Section 500.40.
600.40.1 Background A slope inclinometer (SI) is used to monitor subsurface ground movement and displacement. It can be
used to monitor movement in slopes and embankments, provide warning of developing instabilities, and
monitor settlement of embankments and roadway subgrades.
SI casing is typically installed in a borehole but can also be embedded in a fill or cast into concrete.
Note: The inclinometer casing shall be installed so that one set of grooves is aligned in the North
direction, which shall be labelled “N” for NORTH. This shall be the A0 axis as shown in Figure 9. (See
Section 500.40 for further information).
Figure 9 – Illustration of SI Casing A-axis Grooves aligned with North.
The SI probe consists of a stainless steel body, a connector for control cable, and two pivoting wheel
assemblies. The probe uses two force-balanced accelerometers to measure tilt along two axes; the “A”
and “B” axis. The positive direction is referred to the as the “0” axis and the negative axis is the “180”
axis. The control cable is marked with yellow bands at half meter intervals and red bands at one meter
intervals. The cable has numeric labels every five meters.
B0 B180
A0
A180
FIM 600
FOUNDATION INVESTIGATION MANUAL
Section: INSTRUMENTATION MONITORING
Subject: Slope Inclinometer
Date Updated Page 24 January 2014 24 of 38
Slope inclinometer measures progressive changes in angle of inclination of a guide casing resulting from
the movement of geohazards such as earth masses, structural deformations due to landslides and
subsidence due to construction.
Actual slope inclinometer readings are taken in arbitrary “reading units” rather than angles or deviation.
Reading units are defined as:
Displayed Reading = sinθ × Instrument Constant Reading Metric = sinθ × 25,000
The standard two-pass survey provides two readings per axis for each interval. The probe is oriented in
the “0” direction for the first reading and in the “180” direction for the second reading. During data
reduction, the algebraic difference of the two readings is found and divided by 2, since there were two
readings. Use of the algebraic difference preserves the direction of the tilt, as indicated with a positive
or negative sign and serves to counteract any offsets in the probe’s accelerometers. Observe the
equation and example values below:
A0 Reading = 359
A180 Reading = -339
Combined Reading = = 349
To calculate lateral deviation, the algebraic difference of the two readings is divided by 2, divided by the
instrument constant, and multiplied by the measurement interval (probe length.)
Lateral Deviation = Measurement Interval × sin θ
Lateral Deviation =
Lateral Deviationmetric =
The displacement is simply defined as the difference in current deviation from initial deviation.
FIM 600
FOUNDATION INVESTIGATION MANUAL
Section: INSTRUMENTATION MONITORING
Subject: Slope Inclinometer
Date Updated Page 24 January 2014 25 of 38
600.40.2 Required Equipment The following equipment is required to record the slope inclinometer readings:
- Keys to unlock protective covers - Screw Driver or wrenches if the protective cover is a manhole - Digitilt Datamate Model #50310900 Portable Digital Indicator (see Figure 10) - Digitilt Inclinometer Probe Model # 50302510 - Slope Indicator 100 m control cable, graduated with yellow 0.5 m marks and red 1m marks. - Large pulley assembly Model #51104606 which fits 70 mm and 85 mm diameter casing (see
Figure 11) - Silicone spray or light oil - Aluminum or PVC guide casing permanently installed in the structure to be surveyed - Aluminium or PVC extension casing (500 mm long) along with union coupler (Figure 12) which
needs to be used if the on-site SI installation is flush to ground or below ground and covered with a cap.
The operator needs to be familiar with the safe working procedures of the above equipment. The operator must ensure equipment is in good working condition and calibrated before mobilizing to site.
Figure 10 – Digitilt Datamate, Inclinometer Probe and Control Cable.
(Reproduced from the
following DGSI Website -
www.slopeindicator.com)
FIM 600
FOUNDATION INVESTIGATION MANUAL
Section: INSTRUMENTATION MONITORING
Subject: Slope Inclinometer
Date Updated Page 24 January 2014 26 of 38
Figure 11 – Pulley Assembly (Model #51104606).
Figure 12 – Aluminium and PVC Extension Casings (500 mm long) along with Union Coupler.
600.40.3 Measurement Upon arrival at site, lay out a tarp to set the equipment on. The equipment needed is the inclinometer
probe, the DataMate readout box, the control cable, and the pulley assembly. Some people find it is
(Reproduced from the
following DGSI Website -
www.slopeindicator.com)
FIM 600
FOUNDATION INVESTIGATION MANUAL
Section: INSTRUMENTATION MONITORING
Subject: Slope Inclinometer
Date Updated Page 24 January 2014 27 of 38
useful to bring a basket or box to hold the control cable and a rag to wipe off the probe and cable after
readings have been taken.
Unlock and remove the protective cap from the casing. Attach the pulley assembly. Remove protective
caps from probe and control cable.
Align the connector key with the keyway in the probe. Then insert the connector and tighten the nut to
secure the connection. Do not over-tighten the nut, since this will flatten the O-ring and reduce its
effectiveness.
The inclinometer casing shall be installed so that one set of grooves is aligned in the North direction,
which shall be labelled “N”. This is the A0 axis (See Section 500.40 for further information).
The probe shall be drawn from the bottom to the top of the casing two times. The upper wheels of the
probe shall be inserted into the A0 groove for the first pass and the A180 for the second pass.
Note: A pulley assembly shall be used for all SI readings to assist with depth control. The jam cleat on
the pulley assembly holds the cable and the top edge of the chassis provides a convenient reference for
cable depth marks (see Figure 13).
FIM 600
FOUNDATION INVESTIGATION MANUAL
Section: INSTRUMENTATION MONITORING
Subject: Slope Inclinometer
Date Updated Page 24 January 2014 28 of 38
Figure 13 – Illustration of Pulley Assembly for Depth Control.
To reduce likelihood of error handle the control cable consistently and accurately and align the depth
marks on the control cable with the same reference. The Ministry has historically used the cable clamps
as the reference point for measurement of SI data (as shown in Figure 13). The placements for a
particular depth should be within 5 mm of the previous reading.
Turn on the data mate recording unit. This energizes the accelerometers, making them less susceptible
to shock.
Insert the probe into the casing with the upper wheels of both wheel assemblies in the A0 groove.
(Cupping the wheels with a hand to compress the springs will help with insertion). If a pulley assembly
is being used, take out the pulley wheel, insert the probe, and then replace the wheel.
Lower the probe slowly to the bottom. Do not allow it to strike the bottom. Allow the probe to adjust to
the temperature inside the casing for at least five minutes. If this is the initial reading of the SI the
starting depth should be within about 0.5 m of the bottom of the casing.
(Reproduced from the
following DGSI Website -
www.slopeindicator.com)
FIM 600
FOUNDATION INVESTIGATION MANUAL
Section: INSTRUMENTATION MONITORING
Subject: Slope Inclinometer
Date Updated Page 24 January 2014 29 of 38
If the probe is accidentally drawn above the intended depth, lower it down to the previous reading depth
and then draw it up again to the intended depth. This helps to ensure consistent probe placement.
Raise the probe to the starting depth. Wait for the numbers on the readout to stabilize. If readings do
not stabilize, record an average reading. Press the button on the DataMate to record both the A and B
axis readings. Raise the probe to the next depth. Wait for a stable reading, and then record it. Repeat
this process until the probe is at the top of the casing.
Remove the probe and rotate it 180 degrees, so that the lower wheels of both wheel assemblies are
inserted into the A0 groove. When you remove the probe, cup the wheels with your hands to prevent
them from snapping outwards. Also, hold the probe upright when rotating it.
Lower the probe to the bottom, raise it to the starting depth, and continue the survey. Take readings at
each depth until you have reached the top. Remove the probe. At this point, you may want to validate
the data set and make any corrections necessary.
Note: If this is the initialization survey, repeat the above steps to obtain two readings.
For quality assurance, the field operator should check Checksums before leaving the site. A checksum
is the sum of 0 and 180 degree readings at the same depth. For example -
A0 Reading = 359 A180 Reading = -339
Checksum = 359 + (-339) = 20
Ideally, the sum should be close to zero since the readings have opposite signs. In practice, checksums
are rarely zero. In general, the operator should look for consistency in checksums. A checksum that is
significantly different from checksums above and below it may indicate that the probe wasn’t positioned
correctly or the reading was not stable when recorded.
600.40.4 Reporting Results The slope inclinometer data shall be presented utilizing the following four plots – namely cumulative
displacement plot, incremental displacement plot, resultant displacement vs time plot and direction of
FIM 600
FOUNDATION INVESTIGATION MANUAL
Section: INSTRUMENTATION MONITORING
Subject: Slope Inclinometer
Date Updated Page 24 January 2014 30 of 38
movement plot for the critical shear zone(s). The detail for each of these four plots is provided in the
section below.
Magnitude and Zone of Shear Movement
Changes in deviation are called displacements, since the change indicates that the casing has moved
away from its original position. When displacements are summed and plotted, the result is a high
resolution representation of movement.
Cumulative displacement plot shows a displacement profile. Displacements are summed from bottom to
top of the SI casing. As an example, ARGUS web-based monitoring software generated cumulative
displacement plot is shown in Figure 14.
FIM 600
FOUNDATION INVESTIGATION MANUAL
Section: INSTRUMENTATION MONITORING
Subject: Slope Inclinometer
Date Updated Page 24 January 2014 31 of 38
Figure 14 – Cumulative Displacement Plot Example.
Incremental displacement plot shows movement at each measurement interval. The growing “spike”
indicates a shear movement. As an example, ARGUS web-based monitoring software generated
cumulative displacement plot is shown in Figure 15.
FIM 600
FOUNDATION INVESTIGATION MANUAL
Section: INSTRUMENTATION MONITORING
Subject: Slope Inclinometer
Date Updated Page 24 January 2014 32 of 38
Figure 15 – Incremental Displacement Plot Example.
Rate of Movement
“Another purpose of inclinometer measurements is to determine the rate of shear movement. Usually,
the shear zone is less than a few metres thick, and thus the sum of change over this zone is
representative of the magnitude and rate of the entire landslide” (Stark and Choi, 2008). The rate of
movement can be evaluated from a plot of resultant displacement versus time data as shown in Figure
16. The title of the plot shall include the control section, project name and borehole name. The legend
FIM 600
FOUNDATION INVESTIGATION MANUAL
Section: INSTRUMENTATION MONITORING
Subject: Slope Inclinometer
Date Updated Page 24 January 2014 33 of 38
shall identify the instrument ID, plotted depth and elevation. An Excel template to create the Resultant
Displacement (mm) vs Time (Reading Date) plot (as shown in Figure 16) can be downloaded from the
Geotechnical Section under MHI’s knowledge warehouse webpage
http://www.highways.gov.sk.ca/business.
Figure 16 – Resultant Displacement vs. Time Plot Example.
The rate of movement is frequently more important than the magnitude of movement because it
determines whether or not the slide is accelerating, decelerating, or continuing at the same rate. This
0
0.5
1
1.5
2
2.5
3
3.5
10-Aug-10 18-Nov-10 26-Feb-11 6-Jun-11 14-Sep-11 23-Dec-11 1-Apr-12 10-Jul-12 18-Oct-12
Res
ulta
nt D
ispl
acem
ent
(mm
)
Time (Reading Date)
008-06-04 Tantallon Access Slide BH-3
SI003(Depth 29 m/ Elev 412.3 masl)
SI003 (Depth 29.5m/ Elev 411.8 masl)
SI003 (Depth 30m/ Elev 411.3 masl)
LEGEND
FIM 600
FOUNDATION INVESTIGATION MANUAL
Section: INSTRUMENTATION MONITORING
Subject: Slope Inclinometer
Date Updated Page 24 January 2014 34 of 38
information can be utilized for geohazard risk management and to inform the public and any third
parties involved.
Whether the slide is accelerating or moving at the same rate is also important to determine shear strength
and potential for strength loss. For example, if the shear zone is not at residual strength, strength loss
will occur with continued movement until the residual condition is reached. This strength loss
phenomenon can result in acceleration of the slide mass and progressive failure of the slope. The rate of
movement is also of importance to investigate the effect of rainfall, slope loading, toe excavation, and
remedial measures on slope stability. (Stark and Choi, 2008)
Direction of Movement
Determining the direction of movement is important to determine the cause of the slide, critical cross-
section (which needs to be parallel to the direction of movement), back calculation of shear strength
parameters, and design of remedial measures. The direction of movement can also be used to determine
if the slide is moving as a single unit or not, which can be helpful in evaluating the effectiveness of
proposed remediation options. (Modified from Stark and Choi, 2008)
As per the Ministry standard the inclinometer casing shall be installed so that one set of grooves is
aligned in the North direction, which shall be labelled “N” for NORTH. This shall be the A0 axis (See
Figure 9). Thus, the actual magnitude and direction of movement can be determined by plotting two
components of movement measured in the A-axes and B-axes as shown in Figure 17. The title of the
plot shall include the control section, project name and borehole name. The legend shall identify the
instrument ID, plotted depth and elevation. An Excel template to create the Direction of Movement plot
(as shown in Figure 17) can be downloaded from the Geotechnical Section under MHI’s knowledge
warehouse webpage http://www.highways.gov.sk.ca/business.
FIM 600
FOUNDATION INVESTIGATION MANUAL
Section: INSTRUMENTATION MONITORING
Subject: Slope Inclinometer
Date Updated Page 24 January 2014 35 of 38
Figure 17 – Direction of Movement Plot Example.
-3
-2
-1
0
1
2
3
-3 -2 -1 0 1 2 3
A -A
xis
Res
ulta
nt D
ispl
acem
ent (
mm
)
B Axis Resultant Displacement (mm)
008-06-04 Tantallon Access Slide BH-3
SI003(Depth 29 m/ Elev 412.3 masl)
SI003 (Depth 29.5m/ Elev 411.8 masl)
SI003 (Depth 30m/ Elev 411.3 masl)
LEGEND
FIM 700
FOUNDATION INVESTIGATION MANUAL
Section: GEOTECHNICAL DESIGN
Subject: Slope Inclinometer
Date Updated Page 18 November 2013 36 of 38
Date Updated: 18 November 2013
FIM 700 Geotechnical Design
FIM 800 Reporting
FIM 900 Geohazard Risk Management
FIM 1000
FOUNDATION INVESTIGATION MANUAL
Section: REFERENCES
Subject: References used in this document
Date Updated Page 18 November 2013 37 of 38
Date Updated: 18 November 2013
FIM 1000 References
1000.10 References used in this document
CFEM 2006. Canadian Foundation Engineering Manual 4th Edition, Canadian Geotechnical Society
DGSI Slope Indicator Website www.slopeindicator.com
Non-Financial Signing Authority Delegation Document (effective 1 April 2013)
RST Instruments Website www.rstinstruments.com
Stark and Choi 2008. Slope Inclinometers for Landslides, Timothy D. Stark and Hangseok Choi,
Landslides 2008.
FIM 1100
FOUNDATION INVESTIGATION MANUAL
Section: INDEX
Subject: Specific Information in this document
Date Updated Page 18 November 2013 38 of 38
Date Updated: 18 November 2013
FIM 1100 Index
1100.10 Specific Information in this document
CFEM ....................................... ii, viii, 1, 2, 3, 37
Design Authorization Report (DAR) ................ 5
Design Exception Summary Sheet.................... 5
Displacement....................................... 31, 32, 33 instrumentation ................................................. 7
monitoring ..................... 7, 11, 16, 17, 19, 30, 31
Movement ..................................... 30, 32, 34, 35
North ................................................... 23, 27, 34
Pneumatic Piezometer ..................... 7, 11, 12, 15
pore water.................................................. 11, 17
precipitation .......................................... 9, 14, 20
Slope Inclinometer ...................................... 7, 23 Standpipe Piezometer.................................. 7, 10
Total Head ....................................... 9, 14, 20, 21
Vibrating Wire Piezometer ............. 7, 16, 21, 22