The Geotechnical Report must consist of a summary and conclusion section in the main body of the report with any supporting data attached separately. The licensed engineer shall determine the sub-surface investigations required. These investigations should include but are not limited to continuous soil borings and test pits. Cone Penetrometer tests may also be included to supplement the physical samples and lab testing provided.
Investigations shall be spaced according to the geotechnical engineer’s sub-surface evaluation and be representative of the entire proposed source. The licensed engineer’s test plan must provide a comprehensive sampling to at least 5 feet below the bottom of the proposed excavation.
All soil samples must be classified in accordance with the Unified Soil Classification system. See below for required soil testing. The supporting data attached to the geotechnical report shall be comprehensive and include as a minimum all field logs, soil sampling and testing results, and a detailed investigation location map with the location of the potential borrow source and all investigation locations superimposed. The soil investigation locations must include latitudes and longitudes for plotting purposes.
1. Soil classification shall be performed in accordance with the Unified Soil Classification System and ASTM D 2487.
2. Atterberg Limits Test shall be performed in accordance with ASTM D 4318.
3. Determination of moisture content shall be performed in accordance with ASTM D 2216 or ASTM D 4643.
4. Determination of organic content shall be performed in accordance with ASTM D 2974, Method C.
5. Control compaction curves shall be established in accordance with ASTM D 698 (Standard Proctor Compaction Tests). A control compaction curve is required for each soil type from each source. Where material is blended and stockpiled, a control compaction curves will be required for each resulting blend of material and will be utilized in lieu of those required for the "unblended materials".
6. Sand Content shall be determined by- 200 wash in accordance with ASTM D-1140.
Test Procedures for Borings
1. A moisture content determination shall be made and recorded on all samples classified as (CH), (CL), and (ML) at no less than 2 foot intervals.
2. For (CH), (CL), and (ML) soils, Atterberg Limits and Organic Content Testing (ASTM D 2974, Method C), is required every 5 feet (minimum).
3. Samples with moisture contents at 70% or higher or having a Liquid Limit of 70 or higher must be tested for organic content for that sample as well as for a sample 2 feet above and 2 feet below that sample.
4. Sand content tests will be required for samples that classify as CL (with a PI greater than 10) and for all clay samples (CH and CL) with greater than 10% coarse grain materials estimated by visual classification for 2 or more consecutive feet.
5. Sand content tests shall be limited to one test every 5 feet of sampling and shall conform to ASTM D1140-00 (#200 sieve required).
6. Sand content tests will be required for samples that classify as a ML, but limited to one test every 5 feet of sampling.