Quick preparation device and method of saturated soil sample

Abstract

The invention relates to quick preparation device and method of a saturated soil sample. Saturated clay is extruded by utilizing a load-vacuum combined consolidation principle so as to obtain a saturated clay sample with a low water content (the water content is lower than a plastic limit). The device comprises a sleeve, a base, a piston, a vacuum cavity and a fixing sleeve, wherein the sleeve is sequentially and respectively provided with a slide-fit piston, a cylindrical porous stone internally embedded with a horizontal pressure sensor and the fixing sleeve; the piston, the base and the sleeve are respectively provided with upper draining holes, lower draining holes and side draining holes; and a vacuum extraction hole is arranged on the vacuum cavity. The draining process of the saturated clay is accelerated under the extruding effect of the piston through the negative pressure (about 101.325kPa) condition of the vacuum cavity, and meanwhile, horizontal stress and vertical stress applied on the saturated clay are obtained through the horizontal pressure sensor and a vertical pressure sensor so as to further obtain a coefficient k0 of earth pressure at rest (a specific value of the horizontal pressure to the vertical pressure applied to the soil sample under the condition of no lateral deformation).

Description

technical field [0001] The invention relates to a device and method for rapidly preparing a saturated soil sample, which is especially suitable for the research on the basic mechanical properties of deep frozen soil. Background technique [0002] The use of frozen walls (or frozen soil walls) as temporary support structures is widely used in deep topsoil frozen sinking projects and urban underground projects. The purpose is to block water and soil pressure and carry out soil excavation under its protection. Therefore, the mechanical properties of deep soil and deep frozen soil, especially the K 0 The mechanical properties of deep soils and deep frozen soils of consolidation (that is, soil consolidation without lateral deformation) have been extensively studied. The deep permafrost experienced K 0 Consolidation, freezing, unloading and a series of complex working conditions, the indoor test is an important method and means to study the basic mechanical properties of deep fr...

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Problems solved by technology

[0003] At present, the preparation of remolded saturated clay samples is mainly through layering and compaction first, and then using capillary saturation method or suction saturation method. This method can usually only obtain saturated clay with a relatively high water content (water content higher than the plastic limit). The sample is suitable for conventional triaxial tests, but for saturated clay samples with low water content (water content below the plastic limit), it is difficult to apply the method of layering compaction first and then pumping and saturating

[0004] Ensuring the smooth discharge of water in saturated clay under pressure is the key to quickly prepare saturated clay samples with low water content (water content below the plastic limit). There is no effective preparation method

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