Study On Water Migration Law Of Remolded Loess Under The Influence Of Temperature

Water content has a significant effect on loess physical and mechanical properties, the loess is sensitive to water, the loess moisture migration will happen under the influence of temperature, which will cause complex soil and water conservation effect like the change of soil humidifying-dehumidification cycle and freezing and thawing cycle complex soil and water conservation role, and results in that cohesive action between soil particles is weakened,and destroys the soil structure stability itself and reduces the soil strength, even will trigger a engineering accident or geological disasters and cause huge economic losses. Therefore, the loess moisture migration under the influence of the temperature test is carried out, and to explore the shallow loess moisture migration with temperature change rule, to understand the effect of temperature on the groundwater environment and the influence of groundwater environmental change on the engineering properties of soil, which can ensure the smooth operation of the project construction and has a vital significance in realizing sustainable development of urban and so on many aspects.This paper takes the loess in Xi'an metro line 3 Ji Xiangcun subway station foundation pit as the research object, firstly, the basic physical properties of loess are analyzed, then loess moisture migration tests under the condition of temperature and frost action are carried out by using frozen soil temperature moisture tester respectively, Based on the analysis of the temperature field and moisture field test results, the influence law of temperature on the loess moisture migration are explored, finally, take loess moisture migration as an example under the frost action, the loess water thermal coupling model for xi 'an region is established.In this paper, the main research conclusions include:(1)Under the condition of sample axis of each point temperature change with depth, characterized by three stages,the temperature rapidly changing phases, and temperature stable phase.(2)Under the condition of temperature and freezing test sample process middle axis under the action of each point temperature distribution with depth is nearly linear, slope absolute value decreases over time,until the stable phase distribution curve.(3)Under the condition of temperature the smaller the initial water content of the faster the temperature change; Dry density on the influence of the temperature field distribution has certain limitation, when the dry density of soil sample is big enough, it is significant for the influence of the temperature field distribution; Soil samples at both ends of the faster the temperature gradient, the greater the temperature changes; Under the same temperature gradient different temperature levels of the soil sample, the lower the temperature of the cold end temperature change more quickly.(4)The greater the temperature gradient under the condition of temperature and dry density,the smaller the more soil moisture migration; To exert the same temperature gradient in different temperature levels of the soil sample, cold plate temperature, the lower the moisture migration, the more significant.(5)Under the action of freezing the greater the initial water content of soil sample the faster the temperature change; The greater the dry density of soil samples the faster the temperature change; Applying the greater the temperature gradient at both ends of soil samples the faster the temperature change; Under the same temperature gradient different temperature levels on both ends of soil samples, cold plate temperature low temperature changes faster and faster.(6)Under the action of applying the greater the temperature gradient at both ends of steady-state frozen soil sample front the farther from the top, the early stage of the water content of the smaller increment, the late water content increment, the greater the steady-state frozen water content near the front of the maximum, the minimum value is smaller, the greater the amount of moisture migration and the greater the; Under the same temperature gradient different temperature levels on both ends of soil samples, steady-state freezing cold plate temperature, the lower front the farther from the top, when the cold plate temperature within a certain range moisture migration is remarkable.(7)Cruelly by comparison with test results and the numerical results prove the applicability of the hydrothermal model in xi 'an region of the loess.