Visual-model testing apparatus and testing method for seepage-stress-coupled internal piping penetration

Abstract

The invention discloses a visual-model testing apparatus and testing method for seepage-stress-coupled internal piping penetration. The testing apparatus is composed of four parts, i.e., a variable-head control and liquid circulation system, a vertical loading and penetration system, a laser control system and an image acquisition system and can carry out experimental study on internal piping penetration of non-steady seepage under the conditions of different stresses, different contents of fines, different grading and the like and research on the characteristics of particle loss and deformation and fracture in the process of seepage. The invention also provides a visual testing method for seepage-stress-coupled simulated erosion-type internal piping. According to the method, head difference is applied to a piping soil sample in a stress field in the vertical loading and penetration system in virtue of the variable-head control and liquid circulation system, so a seepage-erosion-stress three-field coupled internal piping test is realized. The visual-model testing apparatus and testing method provided by the invention are simple in procedure, easy in fabrication, capable of realizing direct and in-depth observation, economic and good in operability, so the meso-scopic mechanism of seepage-stress-coupled internal piping is revealed preliminarily, and a testing foundation is provided for subsequent research.

Description

technical field [0001] The invention relates to a seepage model test device and a test method, in particular to a visual test device and a test method for seepage stress coupling simulation of erosion-type internal piping, and belongs to the field of geotechnical engineering seepage tests. Background technique [0002] The deep overburden has the characteristics of loose structure, discontinuous lithology, complex genetic types, and uneven physical and mechanical properties. With the rapid development of my country's hydropower construction in recent years, the construction of high dams and super high dams on deep overburden with poor geological conditions has become an inevitable problem for hydropower construction in Southwest my country, and has attracted widespread attention. Seepage stability of deep overburden is a key scientific issue affecting dam safety. However, the statistics of engineering practice show that under the long-term effect of high seepage strength, e...

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Problems solved by technology

[0005] 1. It is generally based on a scaled-down model, supplemented by relevant monitoring methods. However, the information obtained is often the boundary surface (apparent) or a small number of discrete points inside the model, and it is impossible to dynamically analyze the essential characteristics of internal piping - the migration and loss of fine particles. , holographic acquisition;

[0006] 2. Most of them are carried out under stable seepage conditions, which is far from the actual situation of the project;

[0007] 3. The influencing factors considered are relatively single;

[0008] 4. The measurement of pore water pressure is mostly done by external pore pressure tubes, the measurement process is cumbersome and the readings are unavoidably inaccurate

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