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Indexed by:期刊论文

Date of Publication:2011-11-01

Journal:INSTRUMENTATION SCIENCE & TECHNOLOGY

Included Journals:SCIE、EI、Scopus

Volume:39

Issue:6

Page Number:495-509

ISSN No.:1073-9149

Key Words:fluid power; steady flow; stepping motor; unsaturated soils; water pressure

Abstract:This study is concerned with the development of a novel, high-precision, steady-flow instrument applicable to common unsaturated soils such as clay, silt, sand, gravel soil, and soft soil. The instrument consists of three parts: a high-precision water pressure control system, a high-precision air pressure control system, and a high-precision measurement system. A stepping motor was chosen as the source of water pressure power because it had a high divided driver, reliable operation, simple structure, low cost, and easy maintenance. An electro-pneumatic pressure regulator was used to produce the demanded air pressure. High-precision measurement was archived by a high-resolution grating interferometer, a high-precision balance, and a high-speed 16-bit A/D converter. The device can fully meet the precision requirement of the water pressure, air pressure, and the measurement during the steady flow test for unsaturated soils, which is a very automatic instrument (automatic testing and recording). In this study, volumes of inlet water and outlet water, which are usually difficult to gauge in traditional modes, were gauged by a high-resolution grating interferometer (0.001 mm) and a high-precision balance (0.001 g), and the related experimental study was successfully accomplished.