![]() ![]() Airey conducted conventional and stress path triaxial tests on cemented carbonate soil obtained from the northwest shelf of Australia and found that the dry density and cementation degree of natural calcareous rock samples vary greatly. Chu studied the engineering characteristics of coarse-grained soil, such as strength and deformation. investigated the strength and deformation characteristics of undisturbed unsaturated loess under different moisture content conditions. studied the undisturbed and remolded samples by using the consolidation instrument test. Aiming at the collapse potential of Gorgan loess, Haeri et al. proposed a new method for measuring the preconsolidation pressure of structural loess soil. introduced the coefficient of pore expansion to correct the possible differences in measuring the total pore volume under dry or water-saturated conditions. gave the column test results on large undisturbed samples. ![]() Ovalle and Arenaldi-Perisic introduced the behavior of natural diatomite under compression, shear and cyclic loads, and the new opinion of undisturbed high plastic diatomite sludge in Mejillones Bay, Northern Chile. Burland insisted that, like the initial void ratio and stress history, the structure had a significant impact on the mechanical properties of undisturbed soil. defined the structure of a soil mass as “tectonic” and “joint,” which shows the arrangement of soil particles and interactions between soil particles. Natural soil forms structural deformation due to the influence of soil deposition history and surrounding environmental changes. Therefore, remolded soil samples are mostly used in laboratory tests. For soil samples with less cohesion, the original shape of undisturbed samples cannot be maintained during sampling and sample preparation. The original structure of cohesive soil can be well maintained during sampling and sample preparation, so undisturbed soil samples are used comprehensively. Soil samples are divided into undisturbed soil samples and remolded soil samples. Remarkably, the preparation method of soil sample is an important factor affecting the determination results of soil laboratory test. But by comparison, the boundary conditions of indoor test are relatively clear and easy to control, and the research results of soil indoor test are quite rich. However, its boundary conditions cannot be accurately controlled and cannot reflect the stress-strain relationship of soil in other stress-strain states. In the in-situ test, the stress state of soil is close to its real stress state. The measurement methods of mechanical characteristic parameters of soil are divided into in-situ test and laboratory test. The results show that: (1) the structure has an obvious influence on the stress-strain relationship of the sample, the stress-strain curve of the undisturbed sample is a strain softening curve, and the stress-strain curve of the remolded sample is a weak strain hardening curve (2) under the same loading conditions, the triaxial shear strength of the undisturbed soil is significantly higher than that of the remolded soil (3) the change rule of the consolidation ratio of undisturbed and remolded samples is basically the same, but the final consolidation ratio of remolded soil is greater than that of undisturbed soil. Based on the conventional tests such as particle analysis, specific gravity, critical moisture content, and consolidation test of undisturbed loess from Xi’an, this paper focuses on the static triaxial consolidated drained shear and consolidated undrained shear tests on undisturbed and remolded loess. The difference of sample preparation methods will directly lead to the difference of the structure of the sample, and the mechanical response characteristics under external load will be different. ![]()
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