Study On Salt-Frost Heave Deformation Characteristics Of Saline Soil Subgrade In Southern Xinjiang

There are large areas of distribution of saline soil in southern Xinjiang, mainly saline soil with sulfuric acid and chlorine-based saline soil. In seasonal frozen soil areas in southern Xinjiang, the expansion of sulfate salts and chloride salts dissolved collapsible caused deformation and damage of the road. How to effective repair and reconstruction the roads of deformation and damage is a very important issue, it is also a problem, it is an important part which of To carry out research work of saline soil subgrade salt-frost heave deformation properties in southern Xinjiang. The main research work and results are as follows:By adopting the comparative method of the use of On-site investigation and trial, to study the distribution,formation and engineering characteristics of saline soil in different parts of the southern Xinjiang ,and the results showed that: There are clear regional differences in the distribution, formation, type and composition of the salt saline soil in different parts of the southern Xinjiang by the impact of geographical location, the region's topography, geomorphology and water distribution and geological differences.Through carry out salt-frost heave deformation monitoring test about the section of deformation and damage of Road S207 and Alar urban road. The results showed that: road surface salt-frost heave deformation and the average daily temperature and different depths of the roadbed soil temperature and change the water table have obvious relevance; the maximum salt-frost heave deformation in time lags behind the minimum temperature of daily average and at different depths to the minimum temperature value of roadbed.Through tested the road surface deformation, the roadbed ground temperature at different depths, the temperature of measurement area and the water table on-site testing and monitoring indoor salt- frost heave deformation of in Alaer City line and S207-line .The results show that: S207-line's deformation failure is mainly because of the sodium chloride and the salt expansion deformation of the salt solution collapse deformation interaction. Salt from its high salinity of the water by capillary action will be deep roadbed soil in the soluble sulfate, chloride salts migrate to the accumulation of separation layer structure. At the turn of temperature changes in the process of repeated expansion of salt, the melting depression change.The form of frost damage to the road in Alaer City belongs to the expansion of salt and deformation failure. The sodium salt resulting expansion of cement road salt so that the stability of the expansion of the damage to the grass-roots level, have a surface crack deformation; surface water through surface cracks and infiltration side of the road embankment, in the U-shaped cut off impermeable layer on the formation of the upper stagnant water and Alar City in November of a high water table for the winter low temperature environment road frost heave deformation of the soil to provide sufficient water to freeze and accelerated the deformation of the surface damage.According to the Southern Xinjiang saline soil and salt nature of the project - the evaluation of frost heave deformation test results, the sum put forward "a Strengthen ,two Strict , three Attention " ----the principle of Salt saline soil subgrade - integrated control of frost heave deformation; for Southern Xinjiang road salt saline soil - frost heave engineering disaster, "five steps" comprehensive prevention and control methods and measures, saline soil in Southern Xinjiang of the road reconstruction works has been applied to obtain a clear effect.