Numerical Simulation Study on Compression Characteristics of Gravelly Soil Mixture Based on Soft Servo Method

Abstract

Because of complex mechanical properties and deformation mechanism, gravel soil mixture is an important medium of concern in the field of geotechnical engineering. Based on the continuous-discontinuous coupling algorithm formed by the structure shell elements and the particle discrete element method (PFC3D), the soft servo loading of the sample is realized, and the typical triaxial compression test data are used to calibrate mesoscale parameters. Furthermore, the numerical tests under different rock contents and confining pressure are carried out. The change rule of shear strength of mixed medium is discussed. It shows that the continuous-discontinuous coupling algorithm achieves a good effect in reflecting the deformation process. Under the mechanism of the flexible servo, the failure mode of the sample takes on drum-failure mode, and the internal of the damaged sample forms an obvious asymmetric X-shaped shear band. With the increase of stone content, the internal friction angle and cohesive force distribution of the sample have certain discreteness, but on the whole, the internal friction angle and cohesive force increase with the increase of stone content. The results can provide a reference for the parameter determination of mixed mediums such as gravel soil.

Numerical simulation study on erosion collapse failure mechanism of cemented conglomerate accumulation

“…However, the discrete element method can reflect these characteristics well (Cundall and Strack, 1980). This finding confirms that particle flow code (PFC) can effectively reflect the physicomechanical properties and deformation failure mechanism of gravel media (Ju et al, 2018;Gong and Liu, 2015;Meng et al, 2018;Ning et al, 2021).…”

Numerical Application of a Proposed Material Constant Estimation Method Based on Ideal Mixing Theory

“…Ham et al (2010) [20] employed the two-phase mixture theory suggested by Gutierrez (2005) [21] in an effort to study the influence of gravel content on initial dry density and compression index of D-G-S. In this theory, the overall void ratio e(P) of the mixed material is a function of the gravel content (P) by mass and is related to the void ratio of sand (e s ) and void ratio of gravel (e g ), as shown in Equation (1).…”

“…Gravel-soil mixture is an important medium of concern in the field of geotechnical engineering [1], and several studies in the literature have been conducted to clarify the engineering characteristics of gravel materials including investigations on the effect of gravel content on precompression stress [2][3][4][5][6][7][8][9][10][11][12][13]. However, the mechanical properties and deformation mechanism of gravelly soils are complex because of inhomogeneity, high porosity, and under-compaction [14].…”