Geokon 6300, Instruction Manual, Page: 18 / 24

12
4.3 Deflection Calculation
Now, the change in reading must be converted to a lateral deflection. The lateral
deflection is defined as Lsin ∆θ where L is the gauge length between pivot points
and ∆θ is the change in inclination (corrected for temperature) determined from
Equation 3.
The length L
1
, L
2
, L
3
,…. etc., can be calculated by adding 311 mm , (uniaxial
systems) or 524 mm , (biaxial system), to the individual lengths of tubing. This will
give the correct distance between pivot points.
The horizontal displacement profile can be constructed by using the cumulative sum
of the displacement starting with the bottom segment. Subsequent readings over
time will reveal changes in deflection, possible shear zones, etc. For example,
referring to Figure 10 and Equation 4.
D
1
= L
1
∆ sin θ
1
D
2
= L
1
∆ sin θ
1
+ L
2
∆ sin θ
2
D
3
= L
1
∆ sin θ
1
+ L
2
∆ sin θ
2
+ L
3
∆ sin θ
3
D
4
= L
1
∆
sin
θ
1
+ L
2
∆
sin
θ
2
+ L
3
∆
sin
θ
3
+ L
4
∆
sin
θ
4
D
5
= L
1
∆
sin
θ
1
+ L
2
∆
sin
θ
2
+ L
3
∆
sin
θ
3
+ L
4
∆
sin
θ
4
+L
5
∆
sin
θ
5
Where, for small angles:
∆ sin θ = (R
1
−
R
0
) G
Equation 4 - Horizontal Displacement Calculation
Although the system is designed for use with continuous segments and pivots, the
sensors can be installed without interconnecting tubing in standard, round tubing or
pipe using special friction anchoring. In those systems, the assumption is made that
the measured deflection occurs over the segment length and that L is the distance
between sensors.
4.4 Environmental Factors
Since the purpose of the inclinometer installation is to monitor site conditions,
factors that may affect these conditions should be observed and recorded. Seemingly
minor effects may have a real influence on the behavior of the structure being
monitored and may give an early indication of potential problems. Some of these
factors include, but are not limited to: blasting, rainfall, tidal or reservoir levels,
excavation and fill levels and sequences, traffic, temperature and barometric
changes, changes in personnel, nearby construction activities, seasonal changes, etc.
L
1
L
4
L
3
L
5
L
2
D
5
Figure 10 -
Deflection Intervals