07/15/2004 Env Bd Packet - Laserfiche WebLink

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• STS Standard Boring Log Procedures In the process of obtaining and testing samples and preparing this report, common procedures are followed regarding field logs, laboratory data sheets and samples. Field Togs are prepared during performance of the drilling and sampling operations and are intended to document field test data, subsurface observations, sampling depths and exploration procedures. Samples obtained in the field are generally subjected to additional testing and reclassification in the laboratory by more experienced soil technicians, engineers or geologists. The engineer preparing the report reviews the field boring logs and laboratory sample descriptions, classifications and test data. The engineer then uses judgment and experience in interpreting this data and compiling it into the final boring logs. As a result, differences between the field and final boring logs may exist described in the text of the report, as appropriate. The descriptive terms and symbols used on the logs are described on the attached sheet, entitled: "General Boring Log Notes ". We follow a common practice of the geotechnical engineering profession by generally not including field logs and laboratory data sheets in our engineering reports. We do this because the field logs do not represent the engineer's final opinions on appropriateness of field descriptions of conditions encountered in the exploration and testing work. On the other hand, we are aware that certain contractors and subcontractors submitting bids or proposals on work might have an interest in studying these documents before submitting a bid or proposal_ For -this reason, the field logs are retained in our office for review after authorization by our client. We welcome interpretation questions and an opportunity to explain how the information was obtained and why any boring log changes were made in the preparation of our final logs and report. Samples taken in the field, some of which are later subjected to laboratory tests, are retained in our laboratory for sixty days and then are eventually disposed unless special disposition is requested by our client. Samples retained over a long period of time, even in sealed jars, are subject to moisture loss which changes the density and strength of cohesive soil - generally increasing soil strength from that which was originally encountered in the field. Since these samples are then no longer representative of the moisture, density and strength conditions initially encountered, potential observers of these samples should recognize this factor if considering sample re- examination weeks or months after samples were retained.