Advancements in Use of Geophysical Methods for Transportation Projects (2020)

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A-1 A P P E N D I X A Survey Questionnaire Dear Geotechnical Engineer, The Transportation Research Board (TRB) is preparing a synthesis on the use of geophysical methods for transportation projects. This is being done for NCHRP, under the sponsorship of the American Association of State Highway and Transportation Officials, in cooperation with the Federal Highway Administration. Your cooperation in completing the questionnaire will ensure the success of this effort. If there is someone else at your agency who is more familiar with agency use of geophysical methods, please forward the survey request to that person. You may also share the survey response effort with a colleague by following the instructions included below, although only one response per question per agency is allowed. Please complete the survey by February 22. We estimate the survey will take approximately 20 minutes to complete. If you have questions, please contact the co-investigator, Andy Boeckmann, at 573-884-7613 or boeckmanna@missouri.edu. Any supporting materials or additional documents that might be useful for this study would be much appreciated and can be sent directly to Andy by email. Thank you for participating in the survey! The remaining sections before the page break appear on the first page of the survey. MOTIVATION Effective and economical characterization of subsurface site conditions is a critical component of transportation projects. Geophysical methods provide a nondestructive means to rapidly and economically characterize subsurface conditions over a spatial extent that is not possible with conventional methods. Despite these benefits, challenges and obstacles remain that must be overcome if routine implementation of geophysical methods for transportation projects is to be realized. The goal of the study is to document current practices and guidelines used by transportation agencies for the application of geophysical methods to transportation projects. This survey is the most critical component of the project effort. NOTES ON COMPLETING THE QUESTIONNAIRE 1. A PDF of the survey was included in the distribution email. Please use the PDF to preview questions, share with colleagues, or print a hardcopy of the questionnaire.

A-2 Advancements in Use of Geophysical Methods for Transportation Projects 4. To forward a partially completed response to a colleague, use the forward buttons at the bottom of each screen to progress to the final page of the survey. The final page asks if you would like to share the response with a colleague. If so, please check the checkbox associated with the question, enter your colleague’s email address, and click the forward button. Scroll to the bottom of the response summary page and click the forward button one more time and Qualtrics will send your colleague a new link to finish the questionnaire. QUESTIONNAIRE DEFINITION OF GEOPHYSICAL METHODS The term “geophysical methods” here is defined as measurement techniques that apply physical principles to define geology and study earth materials. This definition does not include methods that are used to characterize the condition or properties of man-made materials and structures. While some methods can be applied to both geological and man-made materials (e.g., surface wave methods), this survey only considers the application of these methods for geotechnical site characterization. CONTACT INFORMATION Contact information will be collected for the agency’s point of contact for the survey using the survey software. 2. Responses will automatically save each time you click on the forward or back buttons found on the bottom of each page. Your responses will repopulate if you click on the link sent with the original distribution. You must be on the same computer and using the same browser for your responses to repopulate. 3. You will have a chance to preview your responses prior to submitting.

Survey Questionnaire A-3 SURVEY 1) Has your agency used geophysical methods for geotechnical site investigation? (For the purposes of this survey, geophysical methods refer to measurement techniques that apply physical principles to define geology and study earth materials.) Yes No I’m not sure. If “No” or “I’m not sure” is selected: Is there someone in your agency who is more familiar with agency experience regarding geophysical methods? Yes No If yes, the respondent will be asked to forward the survey to a colleague. Question 2 will be presented to respondents who indicate in Question 1 that their agency has not used geophysical methods. After responding to Question 2, these respondents will be presented with Questions 17 through 21 (skipping Questions 3 through 16). 2) Please indicate the reasons your agency has not used geophysical methods by selecting all responses below that apply. Cost of geophysical methods is too great. Practical limitations regarding site access prevent effective implementation. It takes too long to implement geophysical methods (from planning to reporting of results). Results from geophysical methods are too uncertain (i.e., imprecise). Results from geophysical methods are too unreliable (i.e., inaccurate). Agency engineers do not know where or when to apply geophysical methods because of unfamiliarity with the capabilities and limitations of the methods. Agency engineers do not have a good understanding of how to interpret the results or evaluate their reliability. Our agency is reluctant to apply any new methods for geotechnical site characterization, geophysical or otherwise (i.e., agency inertia). There are no local contractors or in-house expertise available for performing geophysical methods. Contracting Other, please specify: _____________________________

A-4 Advancements in Use of Geophysical Methods for Transportation Projects All remaining questions will be presented to respondents who indicate in Question 1 that their agency has applied geophysical methods. 3) Please indicate the reasons your agency has used geophysical methods by selecting all responses below that apply. For the responses below, “conventional subsurface investigation methods” refer to drilling, sampling, and laboratory testing, the standard penetration test, and the cone penetration test. Geophysical methods are cost-effective. Because of site access, geophysical methods have been applied where conventional subsurface investigation methods were not feasible. Because of environmental constraints, geophysical methods have been applied where conventional subsurface investigation methods were not feasible. Geophysical methods can be implemented quickly (from planning to reporting of results). Geophysical methods provide a direct measure of certain engineering parameters (e.g., shear wave velocity) to be used in analysis. Geophysical methods produce subsurface imaging of a large mass of materials in two or three dimensions. Other, please specify: _____________________________ 4) In the past five years, about how frequently has your agency applied geophysical methods on average? One time per year or less Two times per year Three to five times per year Six to ten times per year More than ten times per year I don’t know. 5) Who performs geophysical investigations? Agency personnel perform all geophysical investigations (i.e., all investigations are in- house). Contractors perform all geophysical investigations. Some investigations are performed in-house; others are performed by contractors. I don’t know. If “Some investigations are performed in-house…” is selected, respondents will be asked to indicate which methods are performed in-house.

Survey Questionnaire A-5 6) How does your agency’s current use of geophysical methods compare with its use of geophysical methods five years ago? o Geophysical methods are used less frequently now than five years ago. o Geophysical methods are used with about the same frequency now as five years ago. o Geophysical methods are used more frequently now than five years ago. o Geophysical methods were not used five years ago. o I don’t know. 7) Which geophysical methods has your agency used? Please select all that apply. Seismic methods: □ Seismic refraction □ Seismic reflection □ Seismic tomography □ H/V spectral ratio □ Full Waveform Inversion □ Active source surface wave techniques (e.g., SASW, MASW) □ Passive surface wave techniques (e.g., ReMi) □ Seismic methods, but I don’t know which ones specifically. Electrical methods: □ 1D resistivity soundings (e.g., VES) □ 2D resistivity profiling (e.g., Dipole/Dipole, Wenner, etc.) □ 2D resistivity imaging (e.g., pole-Dipole, electrical resistivity tomography [ERT], etc.) □ Induced polarization (IP) □ Self-potential (SP) □ Electrical methods, but I don’t know which ones specifically. Electromagnetic (EM) methods: □ Ground-penetrating radar (GPR) □ Time-domain EM □ Frequency-domain EM (terrain conductivity) □ Very low frequency (VLF) □ Seismoelectric □ Electromagnetic methods, but I don’t know which ones specifically. Magnetic methods: □ Total-field □ Gradiometer □ Magnetic methods, but I don’t know which ones specifically. Gravity methods: □ Microgravity □ Standard gravity □ Gravity methods, but I don’t know which ones specifically.

A-6 Advancements in Use of Geophysical Methods for Transportation Projects Borehole logging methods: Downhole seismic Crosshole seismic Electrical (SP, Resistivity, E-logs) Electromagnetic induction Nuclear (e.g., gamma-gamma, natural gamma, neutron, etc.) Optical televiewer Acoustic televiewer Suspension logging (e.g., PS Logger) Hydrophysical Borehole deviation Other responses: Other, please specify: _____________________________ Geophysical methods, but I don’t know which ones specifically. 8) For which applications has your agency applied geophysical methods? Please select all that apply. Routine design of bridge foundations Routine design of embankments or cut slopes Routine design of retaining walls Seismic site effects Liquefaction Landslide evaluation Utility location Evaluation of roadway subsidence Evaluation of scour (extent of existing scour, potential for future scour) Evaluation and QC of construction (e.g., fill placement, excavation of unsuitable material) Forensic investigation of failed infrastructure Other, please specify: _____________________________

Survey Questionnaire A-7 9) For which geologic investigation objectives has your agency applied geophysical methods? Please select all that apply. Evaluation of rock: Depth to bedrock Topography of bedrock Faulting in bedrock Fractures in bedrock Mapping bedrock strength (i.e., rippability) Mapping weak zones in bedrock (e.g., shear zones or weathered areas) Mapping lithology in bedrock Estimating rock mass stiffness (e.g., elastic modulus, shear modulus, etc.) Estimating rock mass density Evaluation of soil: Mapping lithology in overburden soils Mapping sand and/or gravel deposits (i.e., borrow investigations) Mapping clay (i.e., excavation issues for expansive or swelling clays) Mapping unsuitable materials (e.g., rubble, organics, etc.) Estimating soil stiffness (e.g., elastic modulus, shear modulus, etc.) Estimating soil density Estimating clay content Evaluation of groundwater: Mapping groundwater table Mapping groundwater flow Mapping groundwater salinity Landslide evaluation: Mapping landslide extents (laterally) Slip surface identification and definition Evaluation of deformations Evaluation of sinkholes, voids or erosion features: Karst or other dissolution features Failed culverts/sewers Abandoned mines Scour features Other, please specify: _____________________________

A-8 Advancements in Use of Geophysical Methods for Transportation Projects 10) Has your agency established specific policies, guidelines, and/or procedures for application of geophysical methods? Yes No I don’t know. If yes: Please provide a link(s) to an online version of the document(s), or upload the document(s) as an attachment below. Link to documents (Insert text box) Upload documents (Insert upload button) Documents are not available for sharing. 11) Has your agency applied geophysical methods on any especially noteworthy or challenging projects? Yes No I don’t know. If yes: Please briefly describe any noteworthy or challenging applications of geophysical methods. (Text box) 12) Considering the past five years, about how much has your agency spent on geophysical investigations on average each year? 0 to $50,000 $50,001 to $100,000 $100,001 to $150,000 $150,001 to $250,000 $250,001 to $500,000 More than $500,000 I don’t know. 13) How are subsurface investigations generally funded at your agency? Note this question refers to all methods of subsurface investigation, not just geophysical methods. The annual agency budget includes funds allocated for subsurface investigation. Funding for subsurface investigations comes from other agency funds (project design funds, project construction funds, agency maintenance funds, etc.). Other, please specify: ________________________ I don’t know.

Survey Questionnaire A-9 Question 14 will be asked of respondents who indicate the annual agency budget includes funds allocated for subsurface investigation. All other respondents will be asked Question 15. 14) Do the annual agency budget funds allocated for subsurface investigation include specific allocations for geophysical investigations? Yes No I don’t know. 15) Which funding sources have been used to pay for geophysical investigations? Please select all that apply. Project design funds Project construction funds Agency maintenance funds Agency emergency response funds Other, please specify: _____________________________ I don’t know. Question 16 will be asked to all respondents except those who indicate in Question 5 that all geophysical investigations are performed in-house. 16) What types of contracts have been used to procure geophysical investigation services? Please select all that apply. Unit price (i.e., cost per subsurface profile, etc.) Cost-plus (a.k.a. cost reimbursement) Time and materials Lump sum/firm fixed price Indefinite delivery, indefinite quantity (IDIQ) or similar on-call service agreement Other, please specify: _____________________________ I don’t know.

A-10 Advancements in Use of Geophysical Methods for Transportation Projects The remaining questions will be asked to all respondents, including those who indicate in Question 1 that they have not used geophysical methods. 17) Please indicate your familiarity and use of each of the following resources related to geophysical methods by selecting one column per row. Resource I am not familiar with this resource. I have heard of this resource, but have not used it. I have used this resource. FHWA Manual: Application of Geophysical Methods to Highway Related Problems NCHRP Synthesis 357: Use of Geophysics for Transportation Projects EDC-5 Webinar on Advanced Geotechnical Exploration Methods Transportation Research Circular No. E-C130: Geophysical Methods Commonly Employed for Geotechnical Site Characterization ASTM/AASHTO Standards If respondent indicates use of ASTM/AASHTO standards, respondent will be asked to list the standards that have been used. 18) (Optional) Please indicate any other resources or training related to geophysical methods your agency has utilized. (Text box)

Survey Questionnaire A-11 19) Please indicate how likely each of the following resources would be to increase your agency’s use of geophysics by selecting one column per row. Likelihood of increasing agency use of geophysics: Resource Not at all likely Somewhat unlikely Neither likely nor unlikely Somewhat likely Very likely I don’t know. In-person training (e.g., NHI course) Online webinar Guidance manual (e.g., FHWA Geotechnical Engineering Circular) 20) Please indicate how useful each of the following content areas would be for new training or guidance resources: Value of content area: Content area Not useful Somewhat useful Very useful I don’t know. Technical background of specific geophysical methods Use and applications of geophysical methods Procedures for field performance of geophysical methods Interpretation of engineering parameters from results of geophysical methods Case histories documenting projects with effective use of geophysical methods 21) (Optional) Please use the text box below to offer any additional thoughts regarding development of training resources for geophysical methods. (Text box) END OF SURVEY Your responses have been submitted. Thank you for completing the survey. Your responses are very important, and your feedback is welcome. If you have questions or comments, please contact Andrew Boeckmann E2509 Lafferre Hall, University of Missouri, Columbia, MO 65211, 573-884-7613 boeckmanna@missouri.edu the co-investigator: