tailieunhanh - SOIL ENGINEERING: TESTING, DESIGN, AND REMEDIATION phần 2

Sau khi chấp nhận sự phân công điều tra cơ sở tư vấn địa kỹ thuật nên soạn thảo một chương trình điều tra lĩnh vực cho các kỹ sư lĩnh vực để làm theo. Các hướng dẫn nên bao gồm các tần số và khoảng cách giữa các lỗ kiểm tra, độ sâu của các lỗ kiểm tra, kiểm tra các trường bắt buộc, | After accepting the foundation investigation assignment the geotechnical consultant should draft a program of field investigation for the field engineer to follow. The instruction should consist of the frequency and spacing of the test holes the depth of the test holes the field test required etc. The field engineer should use his or her own judgment to determine whether the instruction should be modified. It is important that the field engineer not leave the site until all the information is gathered. The consultant cannot usually afford to investigate the site twice. Unlike some government projects where cost overruns can be tolerated the consulting business is highly competitive undue expense generally results in financial loss. Disturbed Samples Disturbed samples can be collected during the drilling process. Sometimes they can be collected without interrupting the operation. Samples can be collected from the auger cuttings at intervals. The field engineer should be sure that soils from different strata will not become mixed during drilling. Samples collected must represent soils from each different stratum. Disturbed samples can be stored in fruit jars. They should be sealed to retain the in situ moisture content and properly labeled. In test pit excavation large samples will sometimes be required in order to fulfill the laboratory testing requirements. Such samples should be at least 12 X 12 in. in size wrapped in wax paper and carefully transported to the laboratory. After it is carefully trimmed to the desired size such a sample can be considered as undisturbed. Representative samples can usually be obtained by driving into the ground an open-ended cylinder known as Split Spoon. Spoons with an inside diameter of about 2 in. consist of 4 parts a cutting shoe at the bottom a barrel consisting of a length of pipe split into one half and a coupling at the top for connection to the drill rod. Undisturbed Samples A very simple sampler consists of a .