Development and primary application of apparatuses for anisotropic soil specimen preparation and suffusion test
ZHANG Liangliang1, 2, 3, YANG Biao1, CHEN Rui1, 2, ZHANG Hongyan3, WANG Zhiqiang3, 4#br#
(1. School of Intelligent Civil and Ocean Engineering, Harbin Institute of Technology(Shenzhen), Shenzhen, Guangdong 518055, China; 2. Guangdong Provincial Key Laboratory of Intelligent and Resilient Structures for Civil Engineering, Shenzhen,
Guangdong 518055, China; 3. Center for Environmental Monitoring of Geology, Shenzhen, Guangdong
518000, China; 4. School of Civil Engineering, Chongqing University, Chongqing 400044, China)
Abstract：To investigate the suffusion characteristics of soil with anisotropic initial fabric and the localized characterization of suffusion, two apparatuses were developed in this study. The first apparatus is designed for soil specimen preparation, taking into account initial fabric anisotropy and allowing for controllable sampling directions. The second apparatus is intended for suffusion testing and measures local pore water pressure in soil under triaxial stress conditions. The preparation apparatus enables precise control over the inclination angle of the compaction direction relative to the sampling direction. This inclination angle corresponds to the complementary angle of , where represents the angle of the principal axis direction of the initial fabric relative to the seepage direction. The suffusion apparatus captures various information, including local pore water pressure, deformation, and fine particle loss, under triaxial stress conditions from both global and local perspectives. Suffusion tests were conducted on the anisotropic soil specimens under conditions of = 0°, = 30°, = 45°, and = 90°, thereby verifying the reliability of the developed apparatuses. The results indicate that, globally, the suffusion process can be divided into three stages: initial, development, and failure. Locally, the migration of fine particles exhibits significant localized characteristics and spatial heterogeneity. The local hydraulic gradients are uniformly distributed during the initial stage but become non-uniform during the development stage, characterizing the initiation of suffusion. Furthermore, a smaller results in greater heterogeneity of the soil pore structure induced by suffusion, leading to reduced internal stability of the soil. This weakening effect is directly reflected in the reduction of the initiation and failure hydraulic gradients as decreases (90°→45°→30°→0°). This phenomenon is closely related to the increased migration resistance of fine particles caused by the horizontal arrangement of soil particles induced by compaction. The apparatuses developed in this study provide reliable and effective tools for investigating suffusion anisotropy.
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2025, Vol. 44 
