Study On The Influence Of Fine Grained Soil To Filler Of High Railway Freeze-thaw Strength And The Frost Heave Amount

In seasonal frozen cold injury problems has always been an important problem of road traffic safety in north China, due to seasonal freezing ablation of moisture in the soil of freezing and thawing, strength loss and subgrade frozen heaving and cause of subgrade deformation and damage, brings to the road construction and maintenance of many difficulties.In this paper, including test and analysis:(1)Freeze-thaw strength test, here is chosen than CBR value as a measure of the strength of the indicators. Will have been equipped with good 1# to 5# sample into the freezing and thawing test experiment contents, experiment box within 2 ℃ in fluctuation of temperature fluctuations. And to control the conditions of different freezing and thawing experiment, these conditions include moisture content, saturation and dry density, degree of compaction, etc. Test container, operation process steps such as sample preparation method according to the actual situation to do the corresponding change, not completely the same as the traditional CBR test, penetration test with specification are consistent. Will be frozen before frozen after comparing the CBR value, to determine the influence of different factors on the freezing and thawing strength value, and analyze the cause of this phenomenon.(2)Amount of frost heaving test, and the specification USES the frost heave rate as its attribute values, the same will be equipped with good 1# to 5# sample test in constant temperature box, box temperature fluctuations in the up and down within 0.1 ℃. Because it is to study the influence of the moisture content of frost heaving ratio, so can’t set the filling water device, soil sample tube and also because the maximum particle size of sample to take the corresponding change, using one-way to freeze, cold end temperature is controlled by a cold bath, sample on the end face of freedom. Through the analysis of the test results of the influence of different factors on the rate of frost heave.Finally through the experimental study has found that the moisture content is sample CBR value and the amount of frost heaving is the most important influence factors, the addition of fine grained soil, can mild reduced the compaction of subgrade filling. Within a certain range can also increase the CBR value, after packing frozen before frozen in condition such as moisture content of certain cases, the rate of frost heave also has certain decrease. The grain size composition of smaller than silty clay silt subgrade filling for CBR value of increasing and decreasing of frost heaving ratio is more obvious. And the reasons for this phenomenon are analyzed. Finally it is concluded that fine grained soil improvement of subgrade, make it meet the requirements of frost heave level, improve the compaction degree and intensity is feasible.