Test method and device for measuring swelling-shrinking deformation in dry-wet cycle of soil sample

Abstract

The invention provides a test method and device for measuring swelling-shrinking deformation in a dry-wet cycle of a soil sample. The device comprises a test mold, a sample ring arranged in the test mold and used for carrying the soil sample for measurement of the swelling-shrinking deformation in the dry-wet cycle, upper permeable stone arranged above the sample ring and used for injecting water into the soil sample for a soil sample swelling test, lower permeable stone arranged below the sample ring and used for discharging redundant water injected into the soil sample, a heating component arranged on the periphery of the test mold and used for heating the swelling soil sample obtained after the swelling test to make the swelling soil sample dried and lose water for a soil sample shrinking test, and a measuring component arranged above the upper permeable stone and used for measuring the swelling deformation of the soil sample subjected to water injection through the upper permeable stone and / or measuring the shrinking deformation of the swelling soil sample heated by the heating component. By the adoption of the device, the water absorbing swelling property and water losing shrinking property of the soil sample can be evaluated more precisely.

Description

technical field [0001] The invention relates to the field of road construction, in particular to a test method and a device for measuring the expansion-shrinkage deformation of soil samples in dry-wet cycles. Background technique [0002] Black cotton soil is a special clay mainly composed of montmorillonite, illite and other clay minerals widely distributed in East Africa. Shrinkage, resulting in cracking and other damage to structures built on black cotton soil, resulting in great safety problems and economic losses. Especially under repeated dry-wet cycle conditions, the black cotton soil foundation or roadbed will produce repeated deformations of severe expansion and contraction, which will cause great additional stress to buildings or structures. When the tensile strength of the material is exceeded, the building or The structure cracks. [0003] Generally, there are two failure modes for buildings or structures built on black cotton soil roadbed. When the atmosphere...

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Problems solved by technology

[0004] In the prior art, existing test methods can only evaluate the expansibility and free shrinkage characteristics of black cotton soil respectively, that is, the expansion and contraction properties of black cotton soil are measured separately, wherein, the unloaded expansion rate or the loaded expansion rate test It is used to measure the expansion of black cotton soil, and the free shrinkage test is used to measure the shrinkage of black cotton soil. Therefore, it cannot reflect the repeated expansion and contraction characteristics of black cotton soil under the action of atmospheric rainfall-evaporation, and it is impossible to judge whether black cotton soil is It can be used as foundation or roadbed filler, and corresponding treatment measures should be formulated

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