The research on stable rising height and harmful rising height of capillary water

Freeway subgrade frost damage in seasonally frozen ground region is an important issue plagued northern China and western road construction. With the increasing of highway construction and road traffic load, the traffic safety and comfort have become increasingly demanding, the influence on maintenance costs and project life of frost damage has been growing. Capillary water rising height is widely used in the design and construction of housing, roads, railways and other engineering. This paper has made comprehensive analysis for the test data got by 45 standpipes which are composed of 17 soils for the last 10 years and summarizes the factors that affect the capillary rise height and the law. The empirical formula are induced for coarse soil and fine-grained soil to estimate the stable rising height. It combine the two kinds of soil for analysis for the first time and obtain the integrated parabolic regression equation. According to test data of capillary water distribution along the height and associated test (frost heave test, centrifugal moisture test and plastic test), it has determined the harmful rising height of the standpipe capillary test. The results are comparised with the relevant domestic norms. At last it gets the parabolic regression equation for estimating the harmful rising height of capillary water.