Measurand's SAAV is designed to take on a cyclical shape around the inside of the casing as it is installed. To ensure the SAAV is properly seated in the correct cyclical shape, Measurand recommends lifting and pumping it in the casing prior to applying final compression. Measurand also recommends verifying that the SAAV has taken the appropriate cyclical shape by using the SAAV Installation Verification tool in our SAARecorder application.
WARNING: The SAAV Installation Verification diagnostic will change the power mode of a ShapeArray running in low power mode to regular power mode for the duration of the diagnostic. The dialog must be fully closed to return the ShapeArray back to low power mode. Do not disconnect the ShapeArray from the computer running SAARecorder without first closing the dialog.
In SAASuite 3.0 or higher, the SAARecorder application is launched by clicking the Manual Data Collection button.
Figure 1: Launch SAARecorder from SAASuite by clicking the Manual Data Collection button
Step 1 - Launch SAARecorder and Connect to the SAAV
First you must connect your computer to the SAAV with an appropriate interface. More information on properly connecting your computer and the SAARecorder application to a Measurand ShapeArray is available in the following articles in our Support web site.
- Connecting a ShapeArray to a PC using the SAA232
- Connecting ShapeArrays to a PC using the SAA232-5
- Connecting to a PC Using the Portable Diagnostic Unit
- Connecting to a PC using the SAAFPU
- Connecting to a PC using the SAAUSB
NOTE: A pre-recorded raw data sample from SAARecorder (.RSA) or a Campbell Scientific data logger raw data file (.DAT) can be loaded into verification tool for analysis instead of being directly connected to the instrument. This is described in more detail in Step 3 below.
Step 2 - Launch the SAAV Installation Verification Tool
Once your computer and SAARecorder are connected to the SAAV, you need to launch the SAAV Installation Verification tool from the Diagnostics menu in SAARecorder.
Figure 2: The SAAV Installation Verification tool is launched from the Diagnostics menu in SAARecorder
Step 3 - Input the Casing's Inner Diameter
In the SAAV Installation Verification window, if you are directly connected to the SAAV, ensure the Live Data option is selected. Alternatively, if you wish to analyze data saved in a raw data file (.RSA or .DAT), then select the Recorded Data option and click the Browse button to select the raw data file. Once your data source is selected, enter the inner diameter of the casing into which the SAAV is being installed in the Casing Inner Diameter field. For standard inclinometer casings we would expect inner diameter values similar to the following.
- 70 mm outer diameter - 59 mm inner diameter
- 85 mm outer diameter - 73 mm inner diameter
Figure 3: The casing's inner diameter must be entered into the Casing Inner Diameter field
NOTE: The Casing Inner Diameter value will need to be entered in millimetres or inches depending on SAARecorder's units setting. The units setting can be changed by selecting the SAA Setup | Units menu option.
Step 4 - Determine Whether the SAAV Has Achieved the Proper Cyclical Shape
As the SAAV takes on a cyclical shape within the casing, it will compress. The amount of compression in the instrument will determine how close the instrument is to the ideal cyclical shape within the casing. Pumping the SAAV to achieve an appropriate amount of compression will reduce the amount of settlement expected after installation.
The SAAV Installation Verification Tool calculates the compression associated with the ideal cyclical shape of the SAAV within the casing using a theoretical model consisting of perfectly rigid segments and joints. Although the SAAV's joints are flexible, this is a good approximation for installation purposes.
Changing the Casing Inner Diameter value will calculate and display the following compression values for the SAAV.
- Calculated Compression: The compression associated with the theoretical ideal cyclical shape within the specified casing inner diameter. Calculated compression is determined using the target tilt magnitude calculated for a given casing, the length of the SAAV segments, and the overall length of the SAAV.
- Actual Compression: The current amount of compression within the SAAV based on the live reading or the raw data file selected. Actual compression is calculated using the measured tilts and segment lengths. When this value is higher than the expected compression, the SAAV is typically well seated.
- Remaining Required: How much more compression is required to achieve the compression associated with the theoretical ideal cyclical shape.
- Calculated Potential Settlement: The calculated potential settlement is a conservative measure of the settlement that can remain during the pumping process. This value should be used as a general indication and checked against settlement observed using the extension tubes during the pumping process. It is determined by summing the displacement which would be required to make a segment with tilts lower than the target tilt shift to meet the target tilt. Since the physical tilts are dependent on the adjacent segments, segments with higher than expected tilts can cause adjoining segments to have lower than expected tilts. Both segments in this case are well seated against the wall, but the tool will estimate that the segment with lower than expected tilt will shift. This means that the calculated potential settlement is likely to be higher than the settlement which can actually take place.
The dot graph presents the tilt magnitude angle in degrees of each segment in the SAAV relative to the calculated medial axis. The expected average tilt to achieve the Calculated Compression is displayed as a dotted blue line in the graph.
Figure 4: The dot graph provides a quick visualization of the segment's tilt relative to the medial axis
In the dot graph, green dots to the right of the dotted blue line indicate segments that have achieved a desirable tilt. Red dots to the left of the dotted blue line show segments whose tilts are below the expected average.
The Average Tilt Quality indicator in the bottom right corner of the window displays the average tilt value relative to the medial axis in degrees for all segments and a quality indicator showing a Poor (red light) or Good (green light) rating. This rating is determined by the number of segments that have not reached the expected average tilt and their proximity to the expected average tilt. The SAAV should be pumped until the average tilt rating indicates Good (green light) and the Actual Compression is greater than the Calculated Compression.
Figure 5: The Average Tilt Quality indicator indicating that an acceptable cyclical shape has been achieved