Testing Device for Soil-Water Characteristic Curve of Coarse-grained Soil with Double Inlet Value

Abstract

The invention discloses a test device for the soil-water characteristic curve of double air intake value of coarse-grain roadbed filler. A porous clay plate or metal plate is installed on the bottom cover of the sample loading container, and a porous plate sealing "O" ring is laid on the clay plate, and nylon mesh is laid on the bottom surface of the top cover; the water head stabilization device is respectively connected with the water storage container and the water tank, and the water head is stable The water inlet pipe at the lower part of the device is connected from the bottom cover through the first valve and the drain pipe; the outlet of the dropper is connected to the first end of the Y-shaped pipe through the second valve, and the second end of the Y-shaped pipe is connected to the drain pipe through the third valve. Connection, the third end of the Y-shaped tube is connected to one end of the ballast tube, and the other end is connected to the liquid level mark; there is an exhaust port on the bottom cover, and the air pressure source is connected to the top cover through the pressure distribution valve and the intake pipe, and the top cover There is also a drain. The invention can measure the soil-water characteristic curves of dual air intake values ​​corresponding to the large and small pore groups of the coarse particle filler, and provides a measurement means for the research on the hydraulic characteristics of the coarse particle filler.

Description

technical field [0001] The invention relates to a test device, in particular to a test device for a soil-water characteristic curve of double air intake value of coarse-grained roadbed filler. Background technique [0002] As the main structure, the high-speed railway foundation requires a design service life of 100 years. The surface layer of the subgrade bed is graded gravel, and the bottom layer of the subgrade bed is coarse-grained soil, which often contains a certain proportion of fine particles (particle size less than 0.075mm), and the content of fine particles of various specifications of fillers does not exceed 30%. The aggregate structure is formed during subgrade compaction, and the pore size distribution is bimodal (inter-aggregate pore structure and intra-aggregate pore structure), and the large and small pore groups correspond to different air intake values. The soil-water characteristic curve with dual air intake values ​​determines the unsaturated permeabili...

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Problems solved by technology

Since there are many factors affecting the soil-water characteristic curve of unsaturated soil, the soil-water characteristic curve may change greatly due to the influence of one or more factors, resulting in a large error in the deduced results, and the above derivations are mostly concentrated in Single pore group distribution

In terms of indoor test measurement: mainly through triaxial pressure plate instrument and large-diameter permeation cylinder, but the particle size of the sample tested by triaxial pressure plate instrument is small, and it is difficult to prepare samples, and the large-diameter permeation tube without external pressure source cylinder, the measured matrix suction range is narrow, and the test accuracy is not enough

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