Study On Stress Path Tests Of Unsaturated Loess

Loess mainly distributed in China's arid and semi-arid central and western regions, it is a typical example of structural soil, a special structural and the particular sensitivity of the water. The many experiment results show that soil strength and deformation characteristics of the stress not only with the relevant state, but also by such as the formation mode, the Dutch history, as well as factors such as stress path on the Loess. unique pore structure makes overhead loess stress due to the mechanical characteristics of different stress paths there is a big difference.Based on the analysis and summary of the loess predecessors on the basis of mechanical properties, Yangling and Luochuan loess in Shaanxi region for the study of loess samples selected for different humidity, the conditions of the consolidation of different stress path test, comparative analysis various factors affecting the particular conditions of the consolidation, loading methods, the initial water content, and other factors on the mechanical properties of quantitative, qualitative impact of the inter-regional similarities and differences between the mechanical properties of loess were analyzed. Under this stress and the path of the research findings, this paper presents a suitable made by the loading of the constitutive relation.In this paper, the intact soil and the disturbed soil of this two areas of the same conducted under the conditions of the consolidation of different conventional triaxial compression test (CTC), reduced triaxial compression (RTC), triaxial compression (TC ), as well as the loess Luochuan K0 consolidation of the RTC and CTC triaxial compression test study.The results show that: the stress-strain curve of intact soil and disturbed soil showed a strain-hardening, the principal stress difference with the consolidation of all the pressure increases. For various loading, in which the principal stress test CTC is the biggest, followed by the TC, the smallest is RTC. Under the same stress path,various loess curve infulunced by the water content obviously: with the water content changes, their stress-strain relationship will emerg a restructuring process, that is, changed from the low-water content of the strain hardening into a high - water under the strain softening type,and volumetric strain from shrink into dilatancy phenomenon, and the intensity of shear strain decline because the water content of continuous increase . Various regions of the physical nature of the soil differences in different parts made in the soil under same stress state have the different stress-strain curve. Through the experimental conditions under stress path loess analysis of the structural changes,water and the coupling effect the structural impact of structural loess largely. because of different stress path of their loading,unloading different ways, resulting in the structural parameters of loess have great distinction, water content is an important factor of structural changes . Generally speaking, the conventional triaxial compression test can access larger structural parameters. In the same way under the load, the initial water content more lower the structural parameter more larger, with the increase of the initial water content, structure Parameters gradually lower. And the initial consolidation of the confining pressure of 300 kPa,the Yangling loess aquifer and consolidation pressure has a turning point, at this point, whether it is loaded any way, the structural parameters achieve the maximum.Based on the test established by the consolidation pressure in the unconsider under the influence of the constitutive relation, capable of loess structural stress and strain relations between the good fitting, and the reaction water content and stress path for the structural impact.