Bentonite swelling force experiment device and test method

Abstract

The invention discloses a bentonite swelling force experiment device and test method. The device comprises a sealed pressure chamber; a closed sample container is arranged in the middle position in the pressure chamber; the side wall of the sample container is successively provided with a rigid sleeve and a rubber sheath from inside to outside; the sample container is fixed on the pressure chamber through the rubber sheath; a plurality of strain gages are distributed between the rigid sleeve and the rubber sheath; the strain gages are fixed on the outer wall of the rigid sleeve and on the middle height position of the outer wall; the strain gages are connected to a strainmeter; a gas pressure system and a hydraulic pressure system entering into the sample container are arranged on the top of the pressure chamber and below the pressure chamber respectively; an oil hydraulic system communicated to the inner part of the pressure chamber is also provided. The bentonite swelling force experiment device and test method are simple and feasible, accurate measurement for a swelling force in a triaxial pressure experiment process is realized, and meanwhile, the swelling force can be distinguished from other forces.

Description

technical field [0001] The invention relates to an indoor test device and method for expansive soil, in particular to a test device and method for expansibility of bentonite. Background technique [0002] Expansive soils are widely distributed in my country, such as Guangxi, Yunnan, Henan, Hubei, Sichuan, Shaanxi, Hebei, Anhui, Jiangsu and other places. The clay component of expansive soil is mainly composed of strong hydrophilic minerals, and it is a cohesive soil with significant expansion and contraction properties. [0003] In the underground storage of nuclear waste, a special expansive soil (bentonite) is usually selected as the buffer / backfill material of the nuclear waste repository. How to test its expansion force is crucial to its sealing performance; in the process of landfilling waste, In order to more effectively prevent the soil and groundwater around the landfill from being polluted, unsaturated bentonite is usually selected as the anti-seepage isolation laye...

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Problems solved by technology

[0005] However, when conducting triaxial pressure tests, it is necessary to simulate the surrounding rock environment through confining pressure. At this time, because the surface of the sample is covered with a rubber sheath, and there is no place to place a pressure sensor in the space, it cannot be used. The pressure sensor is used to measure the expansion force; if the expansion force is measured by installing a circumferential displacement gauge outside the rubber sheath, a small amount of deformation will occur due to the rubber sheath, resulting in inaccurate measurement

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