Relationship Between Erodibility and Properties of Soils (2019)

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117 One of the major problems with analyzing erodibility parameters is that these parameters are derived from different types of tests and are not consistent with one another. While bringing some uniformity to tests results is important, as discussed in Chapter 6, it is equally important to collect existing erodibility data obtained from each test. The first step in collecting such data was to establish an acceptable and consistent fashion for organizing the erosion data collected. To achieve this goal, a global erosion spread sheet called the NCHRP-Erosion spreadsheet was developed. The entire NCHRP-Erosion spreadsheet in .xlsm format can be downloaded from the TRB website (trb.org); search for “NCHRP Research Report 915”. Section 5.1 of this chapter presents how NCHRP-Erosion was organized and developed. Section 5.2 introduces the entries of each column in NCHRP-Erosion. Section 5.3 provides the reader with a manual on how to probe and use NCHRP-Erosion. 5.1 Development and Organization of NCHRP-Erosion During the first phase of this project, nearly 750 erosion tests were collected from the literature review as well as by contacting researchers and organizations working on erosion around the world. Table 26 shows the 34 organizations and people contacted in the first phase of this project. Erosion data were extracted from technical reports, lab test results, field test results, and well-known journal and conference papers. In parallel with the erosion tests, the geotechnical properties of each tested sample, along with any information on the latitude and longitude or origin of the sample, were compiled. The data collected include the results of commercially used erosion tests such as the erosion function apparatus (EFA) test, the jet erosion test (JET), the hole erosion test (HET), the slot erosion test (SET), the ex situ scour testing device (ESTD), the borehole erosion test (BET), the rotating erosion testing apparatus (RETA), the Sediment Erosion Rate Flume (SERF), the in situ erosion evaluation probe (ISEEP), and some large-scale flume tests. In addition to the aforementioned erosion tests, around 250 erosion tests were performed during this project. These tests included the EFA, the JET, the HET, the PET, and the BET (see Chapter 4). Tests of all major geotechnical properties were also conducted on each sample that was tested with any erosion device (see Chapter 4, Section 4.4, and Appendix 2), and a soil properties spreadsheet was generated for each sample. The collected erosion tests and tests performed during this project were gathered in a global spreadsheet consisting of 975 erosion tests. This spreadsheet is called the NCHRP-Erosion spreadsheet. Table 27 is a summary of the number of test results obtained for each erosion C H A P T E R 5 Organization and Interpretation of the Data

118 Relationship Between Erodibility and Properties of Soils No. Contact Person Organization No. Contact Person Organization 1 Stephane Bonelli IRSTEA, France 18 J. Beard North Carolina DOT, USA 2 Sherry Hunt USDA, USA 19 M. Haeri North Carolina DOT, USA 3 Johannes Wibowo USACE, USA 20 Kaye Brubaker University of Maryland, USA 4 Axel Montalvo USACE, USA 21 Timothy Straub USGS, USA 5 Anna Shidlovskaya University of Mines, Russia 22 Tom Over USGS, USA 6 Tony Wahl U.S. Bureau of Reclamation 23 Derrick Dasenbrock Minnesota DOT, USA 7 Maurice Morvant Fugro, USA 24 Abdelkrim ESTP, France 8 John Delphia Texas DOT, USA 25 Marie-Jo Goedert ESTP, France 9 Jeff Locke Fugro, USA 26 Michael Heibaum BAW, Germany 10 M. A. Gabr NCSU, USA 27 Chenzuyu (Tsinghua) Beijing, China 11 Beatrice Hunt AECOM, USA 28 Gijs Hoffmans Deltares, Netherlands 12 Richard Whitehouse HR Wallingford, UK 29 Stephen Benedict USGS, USA 13 Kiseok Kwak KICT, Korea 30 Christophe Chevalier IFSTTAR, France 14 Brian Anderson Auburn, USA 31 Garey Fox NCSU, USA 15 Robbin Fell UNSW, Australia 32 Peter Allen Baylor University, USA 16 Kornel Kerenyi FHWA, USA 33 Lin Wang China Institute of Water Resources 17 D. Henderson North Carolina DOT, USA 34 Mike C. Lin and Scott Shewbridge USACE, USA Note: IRSTEA = Institut National de Recherche en Sciences et Technologies pour l'Environnement et l'Agriculture [National Research Institute of Science and Technology for Environment and Agriculture]; USDA = U.S. Department of Agriculture; USACE = U.S. Army Corps of Engineers; NCSU = North Carolina State University; KICT = Korea Institute of Construction Technology; UNSW = University of New South Wales; FHWA = Federal Highway Administration; ESTP = École Spéciale des Travaux Publics; BAW = Bundesanstalt für Wasserbau (Federal Waterways Engineering and Research Institute); USGS = U.S. Geological Survey; IFSTTAR = Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (Institute of Science and Technology for Transport, Development and Networks). Table 26. Selected list of contact people and organizations around the world. Erosion Test Type Number of Test Result Data Collected EFA 346 HET 233 SET 84 ESTD 17 ISEEP 6 SERF 13 JET 147 BET 17 RETA 14 PET 95 Large-scale widening test 3 Total 975 Table 27. Summary of erosion test data in NCHRP-Erosion.

Organization and Interpretation of the Data 119 device. Figure 79 is a summary chart of the data compiled for NCHRP-Erosion since the start of the project. The important characteristic of NCHRP-Erosion is its ability to bring a wide range of erodibility parameters together and compare them in a consistent fashion, as proposed by Briaud (2008). The following erodibility parameters were selected to represent the erosion characteristics of a soil: • Critical shear stress, tc; • Critical velocity, vc; • Initial slope, Ev, of the z . versus v curve; and • Initial slope, Et, of the z . versus t curve. In addition, the erosion category (EC) in the Briaud erosion chart (2013) was considered as an additional parameter for describing the erosion characteristics of a soil and was added as a parameter for the erosion correlations study. Figure 3 in Chapter 1 shows the erosion categories based on velocity and shear stress, respectively. In NCHRP-Erosion, all the erosion data are analyzed according to the procedures described below for the five erodibility parameters: vc , tc , Ev , Et , and EC. 1. Critical velocity, vc. All the data points of the velocity erosion curve are plotted on the erosion chart (Chapter 1, Figure 3). This plot is on a logarithmic scale for both the x-axis and the y-axis. The zero on the y-axis (logarithmic scale) is set at an arbitrarily low erosion rate of 0.1 mm/hour. The reasons for choosing an arbitrarily low erosion rate of 0.1 mm/h are that (1) a log-log scale plot cannot take a zero value and (2) 0.1 mm/h is practically the same as 0 mm/h. If the erosion curve intercepts the horizontal axis at any point, that point is the critical velocity. If there is no data point on that axis, the line between the first two points of the erosion curve is extrapolated linearly and the point at which this extrapolated line crosses the horizontal axis is selected as the critical velocity value. 2. Critical shear stress, sc. All the data points of the shear stress erosion curve are plotted on the erosion chart (Chapter 1, Figure 3). This plot is on logarithmic scale for both the x- and the y-axes. The zero on the y-axis (logarithmic scale) is set at an arbitrarily low erosion rate of 0.1 mm/hour. If the erosion curve intercepts the horizontal axis at any point, that point is the critical shear stress. If there is no data point on that axis, the line between the first two Figure 79. Summary chart of data compiled for NCHRP-Erosion since the start of the project.

120 Relationship Between Erodibility and Properties of Soils points of the erosion curve is extrapolated linearly and the point at which this extrapolated line crosses the horizontal axis is selected as the critical shear stress value. Figure 80 shows an example of how the critical shear stress is calculated for a case where the line has to be extended to cross the horizontal axis. 3. Initial slope, Ev, of the z . versus v plot. Ev is obtained by fitting a straight line through the initial points of the curve. 4. Initial slope, Es, of the z . versus s plot. Et is obtained by fitting a straight line through the initial points of the curve. 5. Erosion category, EC. The median point in the erosion curve is considered as the repre- sentative point for EC. Therefore, EC depends on the location of the median point on the erosion curve. The number of points on the erosion function can therefore have an impact on the choice of EC; it is recommended that many points be obtained to define EC. As mentioned earlier, the erosion function is not a single number but a curve. EC translates this curve into a single number that gives useful information about the range of erosion rate for a sample at a given water velocity or hydraulic shear stress. Figure 81 illustrates 100,000 10,000 1,000 100 10 1 0.1 100,00010,0001,0001001010.1 Er os io n R at e (m m /h r) Figure 80. Example showing how critical shear stress is obtained when erosion curve itself does not cross the horizontal axis. 100,000 10,000 1,000 100 10 1 0.1 100,00010,0001,0001001010.1 Er os io n R at e (m m /h r) Figure 81. Example showing how EC is obtained for a sample erosion curve; the EC for this example is 2.25.

Organization and Interpretation of the Data 121 how EC is determined. EC for this particular example was obtained as 2.25. Note that the dashed lines on Figure 81 represent the EC values corresponding to 1.25, 1.75, 2.25, 2.75, and so on. 5.2 Column Contents in NCHRP-Erosion As discussed in the previous section, NCHRP-Erosion includes 975 erosion tests, that is, 975 rows. Each row in NCHRP-Erosion consists of 49 columns. The entries for the columns are listed in Table 28. All test results are presented in the same format of erosion rate versus velocity or versus shear stress, or both. Furthermore, they are all plotted on the erosion categories proposed by Briaud (2013). In several cases, the data collected had to be digitized. Now, all plots of erosion functions in the erosion function column have embedded spread sheets of their own. That way the user can click on the plot and obtain the point-by-point data. A manual on how to use NCHRP-Erosion is presented in Section 5.3. A comments column for each erosion test gives pertinent details about any special treatment or condition during the erosion test or in Part 1 Part 3, Section 1 (continued) 1. Record numbers 25. Pocket penetrometer strength (kPa) 2. Contact/credit 26. Tensile strength (kPa) 3. Data conducted/sampled 27. UCS (kPa) 4. Project title/sponsor 28. Vane shear strength, Su (kPa) 5. Sample name 29. Percentage of fines (%) 6. Sample depth 30. SPT N-value 7. Soil type 31. D50 (mm) 8. USCS classification 32. D10 (mm) 9. AASHTO classification 33. D30 (mm) 10. Natural/man-made 34. D60 (mm) Part 2 35. Cc 11. Erosion test type 36. Cu 12. Erosion function curve Part 3, Section 2 13. Erosion category 37. Void ratio, e (%) 14. Slope of velocity curve (Ev) 38. Degree of saturation, Sr (%) 15. Slope of shear stress curve (E ) 39. Percentage of compaction (%) 16. Critical velocity (Vc) 40. Specific gravity (Gs) 17. Critical shear stress ( ) 41. Dispersion ratio (%) 18. Remarks on erosion test 42. pH Part 3, Section 1 43. Electrical conductivity (microsiemens) 19. General comments 44. Fluid temperature ( C) 20. Liquid limit, LL (%) 45. Salinity (ppm) 21. Plastic limit, PL (%) 46. Percentage of clay (%) 22. Plasticity index, PI (%) 47. Percentage of silt (%) 23. Wet unit weight, (kN/m3) 48. Organic content (%) 24. Water content (%) 49. Soil activity Note: USCS = Unified Soil Classification System; UCS = unconfined compressive strength; SPT = standard penetration test. τ Table 28. List of entries in NCHRP-Erosion.

122 Relationship Between Erodibility and Properties of Soils interpretation of the results. Also, a column for general comments about the sample provides related special information about the sample, if applicable. Figure 82 shows a general view of NCHRP-Erosion, including its three parts: • Part 1: Record Information, • Part 2: Erosion Information, and • Part 3: Soil Properties Information – Section 1: Most-common geotechnical soil properties, and – Section 2: Less-common properties. The entries of each aforementioned part are described in the following sections. It is very important to note that many cells in NCHRP-Erosion are empty because of the lack of infor- mation for each sample. 5.2.1 Part 1: Record Information Part 1 of NCHRP-Erosion presents the general record information of the soil sample. Figure 83 shows this information for one sample in NCHRP-Erosion as an illustration. There are 10 columns: 1. Record Number: the row number associated with the sample in NCHRP-Erosion. 2. Contact/Credit: information about the person or entity that owns the data associated with this sample. 3. Date Conducted/Sampled: the date the test was conducted or, in the case of natural samples, the date the sample was obtained from the field. 4. Project Title/Sponsor: the title of the project or, when applicable, the sponsor, that led to the measurement of this sample’s test results. 5. Sample Name: the name associated with the sample. 6. Sample Depth: the depth of a natural sample in either meters or feet, depending on the original data. 7. Soil Type. 8. USCS Classification. 9. AASHTO Classification. 10. Natural/Man-made. Identifies whether the sample is remolded (man-made) or natural (intact). 5.2.2 Part 2: Erosion Information Part 2 of NCHRP-Erosion presents the erosion test results for the sample. Figure 84 shows these data for the sample presented in Figure 83. The first column, “Erosion Test Type,” identifies the type of erosion test conducted on the sample. In this example, the sample was tested in the EFA. In NCHRP-Erosion, each erosion test type is designated with a specific color. The colors used to designate each erosion test are shown in Table 29. These colors help the user identify each test more easily in a big-picture view of the spreadsheet. The second column, “Erosion Function,” plots the erosion test results on the erosion category chart proposed by Briaud (2008). As mentioned earlier, all plots of erosion functions in the erosion function column have embedded spreadsheets of their own. That way the user can click on the plot and obtain the point-by-point data. A manual on how to use NCHRP-Erosion is presented later in Section 5.3. The next five columns—Erosion Category, Ev, Et, Vc, and tc— present the five erodibility parameters obtained after each erosion test. It should be noted that not all erosion tests can produce all five erodibility parameters. For instance, the JET and the HET can report only three of these five erodibility parameters (Erosion Category, Et, and tc),

Part 1: Record Info. Part 2: Erosion Info. Part 3: Soil Properties Info. Section I Section II Figure 82. General view of NCHRP-Erosion.

124 Relationship Between Erodibility and Properties of Soils Record Number Contact / Credit Date Conducted / Sampled Project Title / Sponsor Sample Name Sample Depth Soil Type USCS Classifi- cation AASHTO Classification Natural / Man-made 786 Jean Louis Briaud / TAMU, US 1/17/2017 NCHRP 24-43 B-12-16 (18'-20.5') @18.95' 18.95' Clay CL A-7-6 (23.6) Natural Figure 83. Example of record information recorded in Part 1 in NCHRP-Erosion. Erosion Test Type Erosion Function Erosion Category Ev (mm/hr- m/s) Eτ (mm/hr- pa) τc (Pa) Vc(m/s) Remarks on Erosion Test EFA 2.5 4.66 1.22 0.57 0.92 E R O S I O N P A R A M E T E R S 0.1 1 10 100 1000 10000 100000 0.1 1 10 100 Er os io n Ra te (m m /h r) Velocity (m/s) Very High Erodibility I High Erodibility II Medium Erodibility III Low Erodibility IV Very Low Erodibility V Non-Erosive VI 0.1 1 10 100 1000 10000 100000 0.1 1 10 100 1000 10000 100000 Er os io n Ra te (m m /h r) Shear Stress (Pa) Very High Erodibility I High Erodibility II Medium Erodibility III Low Erodibility IV Very Low Erodibility V Non-Erosive VI Figure 84. Erosion information (Part 2) recorded in NCHRP-Erosion.

Organization and Interpretation of the Data 125 while the EFA can generate all five. Finally, the last column in Part 2, “Remarks on Erosion Test,” presents any special treatment or necessary comment regarding the test. 5.2.3 Part 3: Soil Properties Information 5.2.3.1 Section 1: More Typically Obtained Geotechnical Properties Section 1 of Part 3: Soil Properties Information in NCHRP-Erosion presents the geotechnical index properties of the sample that are more typically obtained by engineers. Figure 85 shows the data in Section 1 of Part 3 for the sample presented in Figures 83 and 84. The first column provides general information about the location of the sample, longitude/latitude coordinates, color, and any special treatment of the sample, where applicable. The other columns include mostly the more typically obtained geotechnical properties. 5.2.3.2 Section 2: Less Typically Obtained Geotechnical Properties Section 2 of Part 3: Soil Properties Information in NCHRP-Erosion presents the geotechnical index properties of the sample that are less typically obtained by the engineers. Figure 86 shows the data in Section 2 of Part 3 for the sample presented in Figures 83 and 84. 5.3 NCHRP-Erosion Manual One of the most important features of NCHRP-Erosion is its ability to be filtered with regard to any column entry. In other words, NCHRP-Erosion is a relational spreadsheet that allows the user to perform multiconditional inquiries. Table 28 lists all 49 entries for one test record in NCHRP-Erosion. The remainder of this section describes the embedded sheets in NCHRP- Erosion and presents the manual for sample inquiry operation in the 2016 Windows version of Microsoft Excel. 5.3.1 Description of Embedded Sheets in NCHRP-Erosion The first tab in NCHRP-Erosion, “About” (Figure 87), opens to a sheet that provides all the information about the spreadsheet, including what it is called, when it was developed, who the Erosion Test Type Associated Color EFA Pink JET Light Blue HET Gray PET Orange SET Lavender SERF Yellow ESTD Green ISEEP Dark Blue BET Dark Orange RETA Red Large-scale flume White Table 29. List of colors used to designate erosion tests in NCHRP-Erosion.

126 Relationship Between Erodibility and Properties of Soils authors are, the organization that performed the research, and the organization for which the spreadsheet was developed. This sheet also includes the responses to three basic questions: • What is NCHRP-Erosion? • What does NCHRP-Erosion incorporate? • What does NCHRP-Erosion do? The second tab, “Inquiry Operation Manual,” directs the user to Section 5.3 of this report, which provides instruction on how to filter and search within NCHRP-Erosion. The tab includes a link to a PDF of the report on the TRB website. The instructions presented in Sec- tion 5.3 below are according to Microsoft Excel for Windows 2016. Although the macOS ver- sion of Microsoft Excel might be slightly different in appearance, it is similar to the Windows version in terms of the procedure. The third tab opens to the entire NCHRP-Erosion spreadsheet, which is explained in the pre- vious Sections 5.1 and 5.2 of this chapter. The fourth to the final tabs are sheets that contain the General Comments LL PL PI (kN/m3) Water Content (%) Pocket Penet. (kPa) Tensile Strength (KPa) UCS (KPa) VST Su (KPa) Percent Fines (%) SPT N-value D50 (mm) D10 (mm) D30 (mm) D60 (mm) Cu Cc 1- Alcona Dam 2- Cemented 3-Light Brown 4- Undrained shear strength is predicted from Pocket Penetrometer (=0.3*Compres- sion Strength) 42.1 18.6 23.5 18.2 20.51 354 106.2 95.5 0.0028 0.0040 G E O T E C H N I C A L P R O P E R T I E S Figure 85. Geotechnical properties recorded in Part 3, Section 1 in NCHRP-Erosion. Void Ratio Degree of Saturation Percent Compaction (%) Gs Dispersion Ratio pH Electrical Conductivity (micro siemens) Fluid Temp. (oC) Salinity (ppm) Percent Clay (%) Percent Silt (%) Organic Content (%) Soil Activity Relative Density (%) 2.7017 47.66 47.84 0.492 G E O T E C H N I C A L P R O P E R T I E S Figure 86. Geotechnical properties recorded in Part 3, Section 2 in NCHRP-Erosion.

Organization and Interpretation of the Data 127 original test data used to plot the erosion functions for each erosion test. Each of these sheets is named in the format of a three-word title that consists of the abbreviated or summarized project name, the contact organization, and the erosion test type. For example, the embedded sheet named “ALDOT-Auburn-EFA Data” provides the EFA test data corresponding to an Alabama Department of Transportation project, and the contact organization is Auburn University. It should be noted that the detailed information on the title of the project and person to contact are stated in the corresponding row in NCHRP-Erosion. It should be noted that the names of some embedded sheets are in the format of a two-word title consisting of the contact organization and erosion test type. Figure 88 shows an image of a small part of NCHRP-Erosion that focuses on the embedded sheets. 5.3.2 Inquiry Operation Manual The operation manual in this section is presented with an example inquiry within NCHRP- Erosion. The procedure explained here can be used in any other application regardless of the number of the filters that the user desires to incorporate to search the spreadsheet. The list of choices that the user can opt to use to filter each column entry are also described within this example inquiry. PROGRAM NCHRP-Erosion VERSION BETA 1.0 DATE August 2018 AUTHORS Jean-Louis Briaud, Iman Shafii PERFORMING ORGANIZATION Texas A&M Transportation Institute (TTI) SPONSOR National Cooperative Highway Research Program What Is NCHRP-Erosion? NCHRP-Erosion is a relational spreadsheet that allows the user to perform multiconditional inquiries between erodibility parameters and soil geotechnical properties. What Does NCHRP-Erosion Incorporate? NCHRP-Erosion consists of nearly 1,000 erosion tests. Around 750 erosion tests were collected from the literature review as well as by contacting researchers and organizations working on erosion around the entire world. Erosion data were extracted from technical reports, lab test results, field test results, and well-known journal/conference papers. In parallel with the erosion tests, the geotechnical properties of each tested sample, along with any information on the latitude and longitude or origin of the sample were compiled. The data collected include the results of commercially used erosion tests such as the erosion function apparatus test (EFA), the jet erosion test (JET), the hole erosion test (HET), the slot erosion test (SET), the ex-situ scour testing device (ESTD), the borehole erosion test (BET), the rotating erosion testing apparatus (RETA), the Sediment Erosion Rate Flume (SERF), the in-situ erosion evaluation probe (ISEEP), and some large-scale flume tests. In addition to the aforementioned compiled data, around 250 erosion tests were performed during this project (NCHRP Project 24-43). These tests included the EFA, the JET, the HET, the PET, and the BET. Tests of all major geotechnical properties were also conducted on each sample that was tested with any erosion device, and soil properties spreadsheets were generated for each sample.. What Does NCHRP-Erosion Do? The important characteristic of NCHRP-Erosion is its ability to bring a wide range of erodibility parameters together and compare them in a consistent fashion as proposed by Briaud (2008). The erodibility parameters selected to represent the erosion characteristics of a soil are the critical shear stress (τc), the critical velocity (vc), the initial slope (Ev) of the z ̇ versus v curve, the initial slope (Eτ) of the z ̇ versus τ curve, and the erosion category (EC). Figure 87. Image of the first sheet, “About,” in NCHRP-Erosion.

NCHRP-Erosion NCHRP-Erosion NCHRP-Erosion Version Beta 1.0 Figure 88. Image of a small part of NCHRP-Erosion that focuses on the embedded sheets.

Organization and Interpretation of the Data 129 As shown in Figure 89, the bottom-right corner of each column’s header shows a small arrow that can be expanded by clicking on it. After clicking on the arrow, the list of choices that the user can select from is shown. Depending on the column entry, the list can include the names of the contact people, project titles, sample names, soil type, USCS, and so forth. For example, Figure 89 shows the list of contact people/organizations that have contributed to NCHRP- Erosion. The user has the option to filter the NCHRP-Erosion data to the data associated with one, two, or a few of the contact people by checking only the box near the desired contact person/ organization and unchecking all other choices. In this example inquiry, the entire data set is filtered to show only erosion test data from “Jean-Louis Briaud/TAMU, USA.” As shown in Figure 89, the user also has the option to enter any name in the small search box instead of scrolling through all the choices to find the desired person. In this example inquiry, the next goal is to filter the Briaud data to show only the data for clay samples. Figure 90 shows the list of choices available to select from in the soil type column. Similarly, all the boxes should be unchecked except for the box for clay. As shown in Figure 90, user has the following options from which to select: cemented sand, clay, gatorock, gravel, lime- stone, sand, silt, and silt-clay. Some data do not have any entries in the soil type column; these are indicated with a dash (-) in the list of choices. In this example inquiry, the next goal is to further filter the clay data into only low plastic clay (CL) soils. Figure 91 shows the list of USCS classifications that the user can select from. As with previous columns, some entries might be missing; these are indicated with a dash (-). The user has the option to select from “USCS classification,” “AASHTO classification,” or both. It is very important to mention that Figure 91 shows all possible choices for the USCS entry, while if the user selects only “clay,” as in the example inquiry, the USCS choices are limited to the clay symbols only (see Figure 92). As shown in Figure 92, after the data have been filtered to show clay soils only, the USCS options are also narrowed down to a list of CH, CH with sand, CL, CL/CH, CL with sand, CL with sand/SC, and OH with sand. It should be noted that at each step, the user can clear the filter by selecting the “Data” tab from the Microsoft Excel toolbar and then clicking on the “Clear” command on the toolbar (i.e., Select: Data → Clear). Figure 93 illustrates this process. The next step in this example inquiry is to further filter the selected data to show only EFA test data. Figure 94 shows the process of checking the EFA box and unchecking all other choices. As shown in Figure 94, the choices adjust themselves and update as the prior filters are applied to the search. In this example, the choices are narrowed down to the list of BET, EFA, ESTD, HET, JET, large-scaled widening test, PET, and SET. The next step in this example inquiry is to filter the data further to show the data that have a liquid limit (LL) between 5% and 30%. Figure 95 shows how the selected data can be filtered with regard to the LL. Note that more filters on each column entry can be applied and added to the search criteria. In this example inquiry, only the filter process with regard to LL is shown. The same procedure can be applied to all other column entries. As shown in Figure 95, Microsoft Excel itself has some predefined boundaries that can be selected, such as “greater than . . .” or “between.” However, the custom filter allows the user to choose any arbitrary boundary for filtering the data. After “Custom Filter . . .” is selected, as shown in Figure 95, the Custom AutoFilter window pops up (Figure 96). This window allows the user to select from a wide range of choices to define a custom boundary to filter the data. As described earlier, the example inquiry in this section narrows the data to those that have a liquid limit between 5% and 30%. Figure 96 shows how this range is define in the Custom AutoFilter window in Microsoft Excel (2016).

NCHRP-Erosion Version Beta 1.0 Figure 89. Filtering the data with regard to contact person/organization. In this example inquiry, Steps 1 and 2 show how to filter data to show only the data from Jean-Louis Briaud.

NCHRP-Erosion Version Beta 1.0 Figure 90. Filtering the data with regard to the soil type.

NCHRP-Erosion Version Beta 1.0 Figure 91. Filtering the data with regard to the USCS.

NCHRP-Erosion Version Beta 1.0 Figure 92. Filtering the data with regard to the USCS. In this example inquiry, Steps 1 and 2 show how to filter data to show only low plastic clay (CL) soils out of all clay data.

NCHRP-Erosion Version Beta 1.0 Figure 93. Clearing the filters.

NCHRP-Erosion Version Beta 1.0 Figure 94. Filtering the data with regard to erosion test type. In this example inquiry, Steps 1 and 2 show how to filter data to show only the EFA data.

Figure 95. Filtering data with regard to the liquid limit.

Organization and Interpretation of the Data 137 Figure 96. Custom AutoFilter window in Microsoft Excel. In this example inquiry, the data are filtered to show only those for which the liquid limit is between 5% and 30%.