Freeze-thaw Cycle For Compaction Of Loess Moisture Distribution, The Deformation And The Density Of The Heavy Influence Of Experimental Studies

In north China region distribution of a large domain of loess. In loess accumulation is quaternary soil particles, powder is rich in carbonate, big pore, yellow soil. And in northern tundra season, including the helan shan to a vast area of ailao shan west and north qinling-uptown huaihe river region,. With the implementation of the western development strategy, the loess region high-speed railway, highway construction has achieved great development, has greatly promoted the sustainable development of the local economic construction, because of the loess (including the loess shape soil) distribution range in thickness, therefore, all sorts of buildings, roads are the main bearing soil engineering construction.But in the winter season and, on the other hand, under the influence of the negative temperature and topsoil pore water in the frozen ice, volume expansion (9%) expansion coefficient, On the other hand, is more important role in the negative temperature gradient, the moisture in the permafrost not flowing of freezing area migration, gathered together, and frozen ice lens, appear drastically lung expansion, the frost heave deformation changes in 10-30cm, what can exceed 40cm. So frost heaving deformation, almost no buildings can withstand. It is the season is the main reason for the disaster permafrost. And the loess is a typical kind of unsaturated soil water, its structural special sensitivity collapsible loess generally has made sex, sex is the collapsible loess collapsible loess engineering geological properties of peculiar, it under certain pressure after soaking water changes and structure of significant additional sink phenomenon, the characteristics of loess engineering construction and often threat to the normal operation and use.This paper from the freeze-thaw processes and loess embankment collapsible deformation of the relationship G30 study Angle, highway and freeze-thaw cycle period of ancient collapsible loess embankment of deformation mechanism. Take this section typical loess samples, through the freeze-thaw cycles and compaction effect of moisture distribution density, and the deformation and test, the density of the loess freeze-thaw cycle and migration, deformation, research, and relationships are as follows:1, repeated freeze-thaw cycle function under the condition that the soil water content, from the bottom to increase soil moisture roof gradually, and with the increase of freeze-thaw cycle times, increasing the content.2, the soil after repeated freeze-thaw processes, the soil structure has changed, and more close to the roof, change. The changes in the structure of the soil moisture, mainly because of the heavy soil particles and migration, make the permeability of soil and water, water transport more easily.3, small soil moisture content increase rate density than big density, but with the soil sample frequency increases, freeze-thaw soils tend to be a stable content. This is a stable value depends on natural freeze-thaw cycle changes in temperature and cycle.4 and freeze-thaw cycles that soil porosity density increases, dry density decreases, density of dry density soil samples. Maintain a stable in the end, it also further demonstrates the process of freeze-thaw cycle is to never stable state soil dynamic stability of development process, repeated freeze-thaw cycle changes, the properties of soil was to new dynamic stability of soil balance development.5, and in the frozen soil samples from stable, frozen soil samples of frontal interface, this thawing zone may be of freeze-thaw cycle of critical influence, freeze-thaw interface soil temperature changes slowly near here, mainly because the ice quantity (water), phase interface, so the freezing-thawing is vigorous moisture content, temperature, reaction is frozen water transfer mechanism of ice, the focus of research area.6, in frozen soil samples, the beginning of the frost heave significantly increased dramatically, deformation, melting thaw deformation is lesser, frost heaving and thaw quantity index increased performance for the soil sample, In the number of freeze-thaw eight times to 15 times during freezing expansion, equal to thaw is highly stable; soil samples, Along with the increase of number of freeze-thaw soils, is slightly settlement.7, and freeze-thaw cycles of porosity ratio would increase, with the former frost thawing cycle times, collapsible soil deformation in linear increase, and the density of compacted loess, the smaller dual influences the collapsible deformation is more apparent. Therefore, the seasonal frozen thawing, engineering construction, the roadbed compaction of collapsible loess deformation will become more prominent.