Full-automatic unsaturated soil consolidometer

Abstract

The invention discloses a full-automatic unsaturated soil consolidometer, which comprises a control cabinet (1), a consolidometer body (2) connected with the control cabinet (1), and a diffused bubble scouring device (3) connected with the consolidometer body (2), wherein the consolidometer body (2) comprises a pressure chamber (12), a pressure loading device, a suction control device, an information detection device and a data acquisition device. The full-automatic unsaturated soil consolidometer has the advantages of reasonable structural design, simple operation and high degree of automation, can be applied to the study of unsaturated soil consolidation tests for controlling matric suction or vertical net stress, can be used for studying soil-water characteristic curves and hysteresis phenomena thereof during the unsaturated soil moisture absorption and dehumidification processes in different stress states, can replace the traditional soil-water characteristic curve pressure plate extractor, can realize precise, permanent and efficient control over matric suction, can greatly improve the precision of unsaturated soil experiments, and has wide application range.

Description

technical field [0001] The present invention relates to a full-automatic unsaturated soil consolidation instrument, in particular to a soil-water characteristic curve and hysteresis phenomenon of studying moisture absorption or dehumidification process in different stress states under the condition of controlling matrix suction or net vertical stress fully automatic testing equipment. Background technique [0002] The automatic unsaturated soil consolidation instrument is used to detect the soil-water characteristics of unsaturated soil, that is, the soil-water characteristic curve of unsaturated soil, and the soil-water characteristic curve can reflect the strength and water holding capacity of unsaturated soil , permeability coefficient and hysteresis of the shrink film and other physical properties. For the soil with the same characteristics, the moisture absorption and dehydration processes of the soil under different stress states show different soil-water characterist...

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Problems solved by technology

[0003] At present, the experimental instruments for studying the hydraulic and mechanical properties of unsaturated soils mainly include pressure plate instruments, unsaturated soil triaxial instruments, and unsaturated soil consolidation instruments. There are some disadvantages at least. For example, the unsaturated soil triaxial instrument can only simulate simple stress state due to its loading mode and automation degree; while the existing pressure plate instrument and unsaturated soil consolidation instrument In terms of defects, the vertical loading rod is easily affected by the added air pressure, which will affect the accuracy of vertical stress loading, and in the test process, the pressure plate instrument usually uses a measuring tube to measure the water content of the sample, and the water content in the measuring tube It will evaporate with the increase of temperature, which will lead to errors in the measured water content and reduce the reliability of the test

At the same time, most instruments do not consider the influence of unsaturated test time. When the time is long, closed air bubbles may be generated in the cavity under the clay plate, and the generation of these air bubbles will affect the control and accuracy of the suction in the unsaturated soil test. sex

[0004] After searching the patent literature, some beneficial explorations and improvements have been made to the unsaturated soil consolidation instrument in the prior art in terms of stress state and test automation, for example: a multifunctional unsaturated soil consolidation instrument (Chinese patent application number is 201420655972 .X), the loading device of the instrument is improved to realize the one-dimensional (K0 state) consolidation test, but it does not consider the influence of air pressure on the loading rod during the process of applying air pressure, which will reduce the vertical stress exerted by the loading rod, Moreover, the air pressure loading system does not form a closed loop, and the system cannot achieve effective servo loop control, which will affect the reliability of the test

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