JOINT TRANSPORTATION RESEARCH PROGRAM INDIANA DEPARTMENT OF TRANSPORTATION AND PURDUE UNIVERSITY Engineering Properties of Marls Alain El Howayek Marika Santagata Antonio Bobet Nayyar Zia Siddiki SPR-3639 • Report Number: FHWA/IN/JTRP-2015/11 • DOI: 10.5703/1288284315533 RECOMMENDED CITATION El Howayek, A., Santagata, M., Bobet, A., & Siddiki, N. Z. (2015). Engineering properties of marls (Joint Transportation Research Program Publication No. FHWA/IN/JTRP-2015/11). West Lafayette, IN: Purdue University. http://dx.doi. org/10.5703/1288284315533 AUTHORS Alain El Howayek Graduate Research Assistant Lyles School of Civil Engineering Purdue University Marika Santagata, PhD Associate Professor of Civil Engineering Lyles School of Civil Engineering Purdue University (765) 494-0697 [email protected] Corresponding Author Antonio Bobet, PhD Professor of Civil Engineering Lyles School of Civil Engineering Purdue University (765) 494-5033 [email protected] Corresponding Author Nayyar Zia Siddiki, PhD Geotechnical Operations Manager Indiana Department of Transportation JOINT TRANSPORTATION RESEARCH PROGRAM The Joint Transportation Research Program serves as a vehicle for INDOT collaboration with higher education institutions and industry in Indiana to facilitate innovation that results in continuous improvement in the planning, https://engineering.purdue.edu/JTRP/index_html design, construction, operation, management and economic efficiency of the Indiana transportation infrastructure. Published reports of the Joint Transportation Research Program are available at http://docs.lib.purdue.edu/jtrp/. NOTICE DepartmentThe contents of of Transportation this report reflect or the the Federal views of Highway the authors, Administration. who are responsible The report for does the not facts constitute and the accuracya standard, of the data presented herein. The contents do not necessarily reflect the official views and policies of the Indiana specification, or regulation. COPYRIGHT Copyright 2015 by Purdue University. All rights reserved. Print ISBN: 978-1-62260-356-5 ePUB ISBN: 978-1-62260-357-2 TECHNICAL REPORT STANDARD TITLE PAGE 1. Report No. 2. Government Accession No. 3. Recipient's Catalog No. FHWA/IN/JTRP‐2015/11 4. Title and Subtitle 5. Report Date Engineering Properties of Marls April 2015 6. Performing Organization Code 7. Author(s) 8. Performing Organization Report No. Alain El Howayek, Maria C. Santagata, Antonio Bobet, Nayyar Zia‐Siddiki FHWA/IN/JTRP‐2015/11 9. Performing Organization Name and Address 10. Work Unit No. Joint Transportation Research Program Purdue University 550 Stadium Mall Drive West Lafayette, IN 47907‐2051 11. Contract or Grant No. SPR‐3639 12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered Indiana Department of Transportation Final Report State Office Building 100 North Senate Avenue Indianapolis, IN 46204 14. Sponsoring Agency Code 15. Supplementary Notes Prepared in cooperation with the Indiana Department of Transportation and Federal Highway Administration. 16. Abstract The term “marl” is used to designate soft, carbonate‐rich, fine‐grained soils, which pose concerns related to both settlement and stability. Despite the prevalence of marls in Indiana and the concerns associated with their behavior, very limited work has been done to study the engineering properties of these soils. This was the motivation for this research project, which involved two primary activities: a) the creation of a map and database of existing information on marl deposits in Indiana; and b) an in‐depth characterization of the properties of a marl deposit in Daviess County, which was considered representative of similar deposits encountered in Indiana. The marl database was generated using ArcGIS 10.0.from information available at the INDOT, and involved mining data from over five thousand boreholes. The second part of the project involved field tests (seismic cone penetration tests, standard penetration tests, field vane shear tests), and laboratory experiments (index tests, incremental and constant rate of strain consolidation tests, and K0‐consolidated undrained triaxial tests) conducted on high quality Shelby tubes samples. Additionally, the mineralogy and the microstructure of the soil were studied in detail. The laboratory tests reveal that the deposit was not homogeneous as was initially anticipated, but was, instead, formed by two types of soils that repeat in horizontal thin layers. These two soils, referred to as ‘soil M’ and ‘soil C’, are both characterized by very high calcium carbonate contents but show distinct index and engineering properties, that may be ascribed to differences in mineralogy and composition. This stratification is not detected by the field tests. The consolidation tests show that the deposit has an OCR less than 2 and compressibility parameters markedly dependent on stress level, as typical of sensitive soils. K0‐consolidated undrained compression triaxial tests show that both soils exhibit normalized behavior, and that the relationship between strength and stress history is well described by the SHANSEP equation (although the SHANSEP parameters differ for the two soils). Comparison of the field data and laboratory results provides the means to validate published correlations for interpretation of the geotechnical properties of marls from field results. For the site examined, correlations to estimate shear wave velocity, stress history, and undrained strength from CPT results are identified. Implementation recommendations are provided for soil identification, sampling and specimen preparation, interpretation of filed data, and preliminary design. 17. Key Words 18. Distribution Statement marl, carbonatic soil, mineralogy, consolidation properties, No restrictions. This document is available to the public through the undrained shear strength, SHANSEP National Technical Information Service, Springfield, VA 22161. 19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages 22. Price Unclassified Unclassified 105 Form DOT F 1700.7 (8‐69) EXECUTIVE SUMMARY of marls and explore, in particular, the effect of shells, mineral composition, and carbonate content on both index and engineer- ENGINEERING PROPERTIES OF MARLS ing properties. The consolidation tests showed that the deposit has an OCR less The term marl is used to designate soft, carbonate-rich, low- than 2, approximately constant with depth. The presence of the organic, gray-colored, fine-grained soils typically deposited under shells and/or the higher calcium carbonate content translated into a lakes or swamps, which are commonly encountered in the slightly higher preconsolidation stress in soil M versus soil C. Both midwestern region of the United States. Such layers are typically soils exhibit S-shaped compression curves, with compressibility characterized by low dry density, very high water content, and low parameters markedly dependent on stress level. Soil C is shear strength, and they pose concerns related to excessive characterized by a higher compression index relative to soil M, settlement, slope instability, and increased downdrag on deep although for both soils the data fall within the range typical of soft foundations. Despite the prevalence of marls in Indiana and the clays. K0-consolidated tests performed varying the pre-shear concerns associated with their behavior, very limited work has effective stress showed that both soils exhibit normalized behavior been done to study the engineering properties of these soils. This with the relationship between undrained shear strength, OCR and was the motivation for this research project, which involved two effective stress being well described by the SHANSEP equation: m primary activities: (1) the creation of a map and database of Su/s9vc 5 S(OCR) . However, there was a significant difference in existing information on marl deposits in Indiana; and (2) the in- the SHANSEP parameters measured on the two soils (S 5 0.28 depth characterization of the properties of a marl deposit in and 0.34, and m 5 0.72 and 0.85, for soils C and M, respectively). Daviess County, Indiana, which was considered representative of Consistent with this observation, the maximum obliquity friction similar deposits encountered throughout the state. angle for soil M (j9mo 5 39u [likely affected by the presence of The database used for mapping marl deposits in Indiana was shells]) exceeded that measured on soil C (j9mo 5 30u), and the generated from information available at the Indiana Department value of the normally consolidated K0 was greater for soil C (K0 5 of Transportation (INDOT) and involved mining data from over 0.56) relative to soil M (K0 5 0.49). For both soils the cohesion 5,000 boreholes. Through this effort, 325 borelogs were identified intercept was found to be negligible. as containing marl. The data from these borelogs were compiled Comparison of the field data and laboratory results provides using ArcGIS 10.0. The resulting map preserves information on the means to validate existing correlations for interpretation of the location, project DES number and description, borehole number geotechnical properties of marls from field results. For the site and coordinates, marl layer thickness and depth, and percentage examined it was found that, of the 13 relationships examined, only of CaCO3, and marl classification. It is easily accessible and can be the one developed by Andrus, Monahan, Piratheepan, Ellis, and expanded as more data becomes available.