Opportune Landing Site CBR and Low-Density Laboratory Database
Abstract
Laboratory CBR (California bearing ratio) tests were performed on soils obtained from Opportune Landing Sites (OLS) in California, Texas, and Indiana. Initial CBR samples were prepared using standard American Society for Testing and Materials (ASTM) methods (i.e., compaction effort). Standard laboratory methods rarely reproduce in-situ density, moisture, and CBR values and therefore do not accurately represent the complete range of these values measured in the field. Because the OLS program focuses on natural unprepared sites for use as landing zones, a repeatable method of reproducing in-situ strength CBR values in the laboratory was necessary. By reducing the compaction effort on the laboratory samples, density and moisture regimes found in field conditions were more closely matched. Various compaction techniques were used to prepare consistent, low-density samples for CBR measurements. A companion study was performed for a detailed analysis on the effect of fine grained soil particles on CBR values. A well-graded (SW) and poorly graded (SP) sand were used as the base material. A clay (CL) and silt (CLCH) were added to the sand in varying proportions. CBR samples were prepared with these blended soils using both standard and low-density compaction methods.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 2008
- Accession Number
- ADB340031
Entities
People
- Larry S. Danyluk
- Rosa T. Affleck
- Sally A. Shoop
- Wendy L. Wieder
Organizations
- Engineer Research and Development Center