Research officer, National Research Council of Canada, Ottawa, Ontario
A completely portable computer-controlled servo-mechanism designed for use with the Cambridge self-boring pressuremeter consists of a computer, a data acquisition system (DAS), and an electric-to-pneumatic (E/P) transducer. The computer obtains information on the current state of a test through the DAS and determines the next step in accordance with prescribed test conditions. An appropriate voltage is then sent to the E/P transducer, which regulates in proportion to the voltage received the pressure for expanding the pressuremeter. At present, four test conditions are programmed: a controlled stress increment test, a controlled strain rate test, a controlled strain test, and a cyclic test. Experience with different soils shows that the mechanism operates to design specifications.
Paper ID: GTJ10599J