Update of Correlations Between Cone Penetration and Boring Log Data

Details

• Creators:
  Alshibli, Khalid ; Okeil, Ayman M. ; Alramahi, Bashar
• Corporate Creators:
  Louisiana State University (Baton Rouge, La.). Department of Civil and Environmental Engineering
• Corporate Contributors:
  Louisiana Transportation Research Center ; United States. Federal Highway Administration
• Subject/TRT Terms:
  • Cone penetrometers
  • Soil penetration test
  • Shear strength
  • Soil mechanics Soil penetration test
  • Shear strength of soils--Testing
  • Soil mechanics--Louisiana
• Publication/ Report Number:
  FHWA/LA.08/439
• Resource Type:
  Tech Report
• Geographical Coverage:
  Louisiana
• Edition:
  Final report; Feb. 2007-March 2008.
• Corporate Publisher:
  Louisiana Transportation Research Center
• Abstract:
  The cone penetration test (CPT) has been widely used in Louisiana in the last two decades as an in situ tool to characterize engineering ; properties of soils. In addition, conventional drilling and sample retrieval using Shelby tube followed by laboratory testing is still the ; acceptable practice in identifying soils engineering properties. The main objective of this project is to update the correlations that are ; currently used by Louisiana Department of Transportation and Development (LADOTD) to interpret CPT data for engineering design ; purposes and to assess the reliability of using CPT data to predict soil shear strength in both the magnitude and spatial variations in the ; field with respect to the Load and Resistance Factor Design (LRFD) methodology. The results of laboratory soil testing were retrieved ; from borehole logs and were used as reference measurements in this study. ; The research team collected project data files in paper printout format from LADOTD and soil testing engineers. Most project files did ; not have spatial coordinates; therefore, aerial images were used to identify latitude and longitude coordinates of CPT and borehole ; locations. The borehole data was not available for all the located CPT soundings. Efforts were made to obtain any available data from ; LADOTD electronic archive as well as paper project documents. A total of 752 CPT tests were documented in which 503 were matched ; with adjacent boreholes and 249 did not have adjacent borehole data available. The CPT data was used to predict soil undrained shear ; strength, bulk density and classification according to Robertson and Zhang and Tumay methods 1, 2. ; The CPT data was then used to develop a database of undrained shear strength estimates with corresponding results from boreholes. The ; results in the database were preprocessed to apply some constraints on data points included in the calibration study, such as setting a ; maximum threshold on the distance between CPT and borehole locations; a minimum and maximum threshold on undrained shear ; strength values were used to represent realistic soil properties. The resulting database included results from 251 CPT soundings with ; borehole results in their vicinity that meet the aforementioned constraints. From these CPT soundings, 862 unique undrained shear ; strength data points were obtained at various depths. The dataset was analyzed for general as well as specific trends in order to identify ; appropriate parameters to be included in the study. Soil classification was clearly the most plausible parameter based on which the CPT ; undrained shear strength estimates should be calibrated. ; The calibration of the CPT expression for undrained shear strength was conducted using two approaches. The first approach is a direct ; correlation based of the transformation model currently used by LADOTD for estimating the shear strength. The First Order Reliability ; Method (FORM) forms the basis for the second approach, which is more detailed and accounts for all sources of uncertainty. Optimum ; CPT coefficient values were computed for various target reliability values. The results were summarized and implementation procedures ; were recommended for future research.
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• Format:
  PDF
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/5699/dot_5699_DS1.pdf
• File Type:
  [PDF - 7.85 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:d6afa5f6c17cf1552ca205535f7ae6762a0adf8538c2a9680936bca1e417d366c97b6d997e7feebd2bebbdd82313ef9a9f6521c84f391f67cc3a6cbdbdb999a7