Device and method for monitoring mesostructure change of sandy soil medium under seepage action

Abstract

The invention discloses a device for monitoring micro structure changes of a sand soil medium under a seepage effect. The device comprises a nuclear magnetic resonance analysis and imaging system and a seepage system, wherein the seepage system comprises a water tank, a test fixing device, a sample filling device, piezometric tubes and a measuring cylinder; the sample filling device is fixed in the nuclear magnetic resonance analysis and imaging system, one end is connected with the water tank, and the other end is connected with a collecting device; the water tank is fixed at a high place; and the piezometric tubes are arranged at both ends of the sample filling device. The invention also discloses a monitoring method. The monitoring method comprises the following steps: gradually changing the height of the water tank, applying a CPMG (Carr-Purcell-Meiboom-Gill) signal to a sample, obtaining a sample T2 spectrum according to the nuclear magnetic resonance analytic system, and calculating the initial physical property of the sample according to the T2 spectrum; and scanning the internal cross section of the sample through the nuclear magnetic resonance imaging system to obtain a photo of the internal initial cross section of the sand soil medium. By using the monitoring device, no movement of the sample occurs in the seepage and monitoring processes, and the device does not need to be disassembled repeatedly, thus completely realizing nondestructive real-time detection and achieving the advantages of convenience and reliability.

Description

technical field [0001] The invention belongs to the technical fields of geotechnical engineering and water conservancy engineering, and in particular relates to a monitoring device for the change of the mesoscopic structure of sand medium under the action of seepage, and also relates to a monitoring method thereof. Background technique [0002] Sand medium materials are widely distributed in nature and are widely used as geotechnical engineering materials, such as foundation materials, dam shell materials and slope materials. Studies have shown that the rock-soil structure composed of sandy-soil medium materials often suffers seepage damage (flowing soil, piping, and granular hydraulic erosion, etc.), resulting in geological disasters such as foundation instability and slope slippage. In order to prevent the occurrence of such geological disasters, it is necessary to understand the structural changes of sandy soil media materials under the action of seepage, so as to put for...

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Problems solved by technology

[0005] Another object of the present invention is to provide a monitoring method using the above-mentioned device, which solves the problem that the existing monitoring method cannot perform real-time and non-destructive monitoring of changes in the mesoscopic structure of the sand medium

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