Table of Contents
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The Giesa FL2 Frame and blade component of the Automated Vane Shear (AVS) equipment.
Introduction
The AVS test is used for in situ determination of the undrained strength of intact, fully saturated clays (undrained strengths < 100 kN/m2); the test is not suitable for other types of soil or if the clay contains sand or silt laminations.
A four-bladed vane is inserted into the split core and rotated at a constant rate to determine the torque required to cause a cylindrical surface (with a diameter equal to the overall width of the vane) to be sheared by the vane. This destructive measurement is done in the working half, with the rotation axis parallel to the bedding plane. The torque required to shear the sediment along the vertical and horizontal edges of the vane is a relatively direct measure of the shear strength. Typical sampling rates are one section per core until the sediment becomes too firm for insertion of the vane.
The rate of rotation of the vane should be within the range of 6°–12°/min.
The GeoLab software that controls the AVS calculates shear stress as:
Stress (kN/m2) = torque (Nm) × Vane constant (1/m3) × 1/1000
Procedures
Preparing the Instrument
1. Click on the GeoLab Icon on the Desktop to start the GeoLAB application (Figure 1).
Figure 1. GeoLab Icon.
2. Start a new project for each site: Project > new > project > Expedition_SiteHole (Figure 2).
3. Start a new test in the project folder: Project > new > test > CoreTypeSection_Offset or TextID_Offset.
4. Keep the subdirectory highlighted, and click on EXCEL from within the application (Figure 2).
Figure 2. New Project.
5. Select the Excel template (e.g., AVS_master_XXXX.xls) (Figure 3). The PP technician will select and save a master file for each particular expedition.
Figure 3. Excel Templates.
6. Check the rotation speed (1–1.5) and vane type (A, drop-down list) (Figure 4).
Figure 4. Rotation Speed and Vane Type.
Making a Measurement
1. Insert the vane into the sediment, by turning the black handle clockwise, until the top of the wings are even with the sediment surface. Avoid obviously disturbed areas (cracks, gaps, bioturbation, etc.) and note that the test is not suitable for sand or gravel-sized material or for clay that contains sand or silt laminations.
IMPORTANT! If the brass fitting (Figure 5) pushes out of the support beam below the hand crank, the sediment is too hard for this test. Do not attempt to force the vane into the sediment as you may damage the instrument!
Figure 5. Brass fitting
2. Open the Excel spreadsheet from within GeoLAB by clicking on the Excel icon (Figure 2) (Points 3 to 6 on the previous paragraph).
3. Use the barcode gun to scan the section information into the yellow cell below the graph. Be sure to cut everything past the textID (e.g., TEST-U341PA…) and paste into an adjacent cell (Figure 7).
Figure 6. Monitor Acquisition.
4. Measure and enter the offset from top of section (blue cap) into the top interval field (light blue box), then click Enter.
Figure 7. Paste Barcode TEXT_ID (make sure to segregate the TEXT_ID and Label_ID so it will upload properly).
5. Modify this information for each core measured.
6. With GeoLAB already open, Click on init; set sample-time to 1 to 3 readings/sec (i.e., sampling rate), depending have often a measurement will be taken (Ex: 1 sec. means that a measurement each second.; and click the traffic light icon to start the measurement (Figure 8a). Set Input Speed to 1. Monitor the test curve on the Excel screen (Figure 6). When the maximum shear strength of the sediment (highest point of the curve) has been reached, stop the test by clicking the STOP sign icon in the GeoLAB application (Figure 8b).
Figure 8a. Set Acquisition Parameters. Figure 8b (click stop sign after the measurement).
7.Copy the Text_ID from the Excel page.
8. Save the Excel template with its data as a .CSV (comma delimited) file usingSave As…CSV UTF-8 (Comma delimited) (*.csv) : Path = C:\data\gantry\in; Filename = TextID_offset_AVS.csv
9. Click OK pn the pop-up window.
9. Close the EXCEL application, without saving it again, (LIMS will not upload the file if it is in use). Click DON'T SAVE in the pop-up window.
Uploading Data to LIMS
1. Launch MegaUploadaTron (MUT, Applications Folder: IODP) if it is not already running.
2. Check to see if the AVS file(s) are present on the screen. If not, select the proper Upload Directory in the MUT application under File.
3. Click on the directory of choice (e.g., C:/gantry/IN) and check the MUT dialog window. The files to be uploaded should be present in this window.
4. Select the files to be uploaded, or use the Select All checkbox in the lower left corner of MUT.
5. Click the Upload button to load the data into LIMS. Note: MUT will automatically search the .CSV data file and select the peak shear value.
6. Users may also check the Automatic Upload checkbox for future uploads without any user intervention required.
Retrieve Data from LIMS
1. Go to LIMS Reports at http://web.ship.iodp.tamu.edu/LORE/.
2. Under Select Report, choose Physical Properties > Shear Strength Automated Vane (AVS).
3. Under Select Sample Range, specify Expedition, Site, Hole, and Section data to retrieve.
4. Click View data or Download data file to view data on screen or download a CSV file.
LIMS Component Table
| ANALYSIS | TABLE | NAME (expanded report) | NAME (standard report) | ABOUT TEXT |
| AVS | SAMPLE | Exp | Exp | Exp: expedition number |
| AVS | SAMPLE | Site | Site | Site: site number |
| AVS | SAMPLE | Hole | Hole | Hole: hole number |
| AVS | SAMPLE | Core | Core | Core: core number |
| AVS | SAMPLE | Type | Type | Type: type indicates the coring tool used to recover the core (typical types are F, H, R, X). |
| AVS | SAMPLE | Sect | Sect | Sect: section number |
| AVS | SAMPLE | A/W | A/W | A/W: archive (A) or working (W) section half. |
| AVS | SAMPLE | text_id | Text ID | Text_ID: automatically generated database identifier for a sample, also carried on the printed labels. This identifier is guaranteed to be unique across all samples. |
| AVS | SAMPLE | sample_number | N/A | Sample Number: automatically generated database identifier for a sample. This is the primary key of the SAMPLE table. |
| AVS | SAMPLE | label_id | N/A | Label identifier: automatically generated, human readable name for a sample that is printed on labels. This name is not guaranteed unique across all samples. |
| AVS | SAMPLE | sample_name | N/A | Sample name: short name that may be specified for a sample. You can use an advanced filter to narrow your search by this parameter. |
| AVS | SAMPLE | x_sample_state | N/A | Sample state: Single-character identifier always set to "W" for samples; standards can vary. |
| AVS | SAMPLE | x_project | N/A | Project: similar in scope to the expedition number, the difference being that the project is the current cruise, whereas expedition could refer to material/results obtained on previous cruises |
| AVS | SAMPLE | x_capt_loc | N/A | Captured location: "captured location," this field is usually null and is unnecessary because any sample captured on the JR has a sample_number ending in 1, and GCR ending in 2 |
| AVS | SAMPLE | location | N/A | Location: location that sample was taken; this field is usually null and is unnecessary because any sample captured on the JR has a sample_number ending in 1, and GCR ending in 2 |
| AVS | SAMPLE | x_sampling_tool | N/A | Sampling tool: sampling tool used to take the sample (e.g., syringe, spatula) |
| AVS | SAMPLE | changed_by | N/A | Changed by: username of account used to make a change to a sample record |
| AVS | SAMPLE | changed_on | N/A | Changed on: date/time stamp for change made to a sample record |
| AVS | SAMPLE | sample_type | N/A | Sample type: type of sample from a predefined list (e.g., HOLE, CORE, LIQ) |
| AVS | SAMPLE | x_offset | N/A | Offset (m): top offset of sample from top of parent sample, expressed in meters. |
| AVS | SAMPLE | x_offset_cm | N/A | Offset (cm): top offset of sample from top of parent sample, expressed in centimeters. This is a calculated field (offset, converted to cm) |
| AVS | SAMPLE | x_bottom_offset_cm | N/A | Bottom offset (cm): bottom offset of sample from top of parent sample, expressed in centimeters. This is a calculated field (offset + length, converted to cm) |
| AVS | SAMPLE | x_diameter | N/A | Diameter (cm): diameter of sample, usually applied only to CORE, SECT, SHLF, and WRND samples; however this field is null on both Exp. 390 and 393, so it is no longer populated by Sample Master |
| AVS | SAMPLE | x_idmp | ||
| AVS | SAMPLE | x_orig_len | N/A | Original length (m): field for the original length of a sample; not always (or reliably) populated |
| AVS | SAMPLE | x_length | N/A | Length (m): field for the length of a sample [as entered upon creation] |
| AVS | SAMPLE | x_length_cm | N/A | Length (cm): field for the length of a sample. This is a calculated field (length, converted to cm). |
| AVS | SAMPLE | status | N/A | Status: single-character code for the current status of a sample (e.g., active, canceled) |
| AVS | SAMPLE | old_status | N/A | Old status: single-character code for the previous status of a sample; used by the LIME program to restore a canceled sample |
| AVS | SAMPLE | original_sample | N/A | Original sample: field tying a sample below the CORE level to its parent HOLE sample |
| AVS | SAMPLE | parent_sample | N/A | Parent sample: the sample from which this sample was taken (e.g., for PWDR samples, this might be a SHLF or possibly another PWDR) |
| AVS | SAMPLE | standard | N/A | Standard: T/F field to differentiate between samples (standard=F) and QAQC standards (standard=T) |
| AVS | SAMPLE | login_by | N/A | Login by: username of account used to create the sample (can be the LIMS itself [e.g., SHLFs created when a SECT is created]) |
| AVS | SAMPLE | login_date | N/A | Login date: creation date of the sample |
| AVS | SAMPLE | legacy | Legacy flag: T/F indicator for when a sample is from a previous expedition and is locked/uneditable on this expedition | |
| AVS | TEST | test changed_on | TEST changed on: date/time stamp for a change to a test record. | |
| AVS | TEST | test date_started | ||
| AVS | TEST | test group_name | ||
| AVS | TEST | test status | ||
| AVS | TEST | test old_status | ||
| AVS | TEST | test test_number | ||
| AVS | TEST | test date_received | TEST date received: date/time stamp for the creation of the test record. | |
| AVS | TEST | test instrument | TEST instrument [instrument group]: field that describes the instrument group (most often this applies to loggers with multiple sensors); often obscure (e.g., user_input) | |
| AVS | TEST | test analysis | TEST analysis: analysis code associated with this test (foreign key to the ANALYSIS table) | |
| AVS | TEST | test x_project | TEST project: similar in scope to the expedition number, the difference being that the project is the current cruise, whereas expedition could refer to material/results obtained on previous cruises | |
| AVS | CALCULATED | test version | ||
| AVS | CALCULATED | test order_number | ||
| AVS | RESULT | test replicate_test | ||
| AVS | RESULT | test replicate_count | ||
| AVS | RESULT | test sample_number | TEST sample number: the sample_number of the sample to which this test record is attached; a foreign key to the SAMPLE table | |
| AVS | RESULT | Depth CSF-A (m) | Depth CSF-A (m) | Depth CSF-A (m): position of observation expressed relative to the top of the hole. |
| AVS | RESULT | Depth CSF-B (m) | Depth CSF-B (m) | Depth [other] (m): position of observation expressed relative to the top of the hole. The location is presented in a scale selected by the science party or the report user. |
| AVS | RESULT | giesa_raw_asman_id link | RESULT instrument: name of the instrument used | |
| AVS | RESULT | giesa_raw_filename | RESULT needle name: serial number of the needle used (H#### for half-space; V#### for full-space) | |
| AVS | RESULT | max_torque_angle (deg) | RESULT number of solutions: number of independent valid solutions the SAM method found; the higher this number, the better (and <100 should be carefully checked) | |
| AVS | RESULT | offset (cm) | Offset (cm) | RESULT offset (cm): position of the measurement relative to the top of a sample (generally a section) |
| AVS | RESULT | penetration_direction | RESULT spreadsheet uploader ASMAN_ID: serial number of the ASMAN link for the spreadsheet uploader file | |
| AVS | RESULT | rotation_rate (deg/sec) | RESULT spreadsheet uploader filename: file name of the spreadsheet uploader file | |
| AVS | RESULT | shear_strength (kN/m²) | RESULT start time (s): the starting time of the experiment in seconds from initialization | |
| AVS | RESULT | vane | RESULT average thermal conductivity (W/(m*K), SAM): mean result of successive thermal conductivity observations using the SAM method | |
| AVS | SAMPLE | sample description | Sample comments | SAMPLE comment: contents of the SAMPLE.description field, usually shown on reports as "Sample comments" |
| AVS | TEST | test test_comment | Test comments | TEST comment: contents of the TEST.comment field, usually shown on reports as "Test comments" |
| AVS | RESULT | result comments | Result comments | RESULT comment: contents of a result parameter with name = "comment," usually shown on reports as "Result comments" |
Credits
This document originated from Word document AVS_QSG_372.docx (see Archived Versions below for a file copy) written by T. Cobb (2017-12-18). Credits for subsequent changes to this document are given in the page history.
All improvements to the Quick Start Guides and User Guides are a communal effort, with honorable mention to the group of LOs, ALOs, and technicians who have helped.
Archived Versions
- AVS Quick Start Guide - 27Sept2022
- AVS Quick Start Guide 2020 (*.pdf)
- AVS_QSG_372.docx: Written by T. Cobb (2017-12-18)