Research On The Strength And Drainage Condition Evaluation Of Highway Subgrade In Seasonal Frozen Region

With the early construction of the highway have been entering the conservation period, detection of these roads, conservation efforts are also being promoted to an unprecedented level. Highway roadbed and sub-grade strength with inadequate, poor drainage of the sub-grade on the objective itself is causing one of the important causes of lack of strength and stability of sub-grade. Therefore, it is necessary to testing the strength of sub-grade and the drainage performance timely and effectively, give an evaluation and make it being a good technical condition. It has a very important significanc for improving the seasonal frost region highway level of service, extend the life of the road.In order to study the moisture, intensity and drainage conditions of the highway sub-grade in seasonally frozen zone, and to evaluable them. And5road in Heilongjiang province were selected as test road. At the same time, artificial drilling method, PANDA2penetrometer and field investigation have been selected respectively as humidity, intensity of Highway subgrade and drainage conditions of test programmes. In order to obtain a direct correlation between the test results of PANDA2with CBR, aticle had done a comparative test; Analysising the test results of the humidity, intensity of the sub-grade and the drainage conditions, and had done a related research of the method of evaluation for those indexes. Results shown that:there exist a good relationship between the penetration resistance with the CBR, and the formula is y=2.1434x+0.442. After the highway was opened for a period of time, the humidity of Highway sub-grade in seasonally frozen zone gradually keep at the balance humidity and balancing humidity range:20%-24%. Soil humidity and soil types do a do a significantly effect to sub-grade strength; CBR of the up road bed strength gradually stabilized at6%～8%, about most of the down road bed is5%by, the majority of sub-grade strength does not meet regulatory requirements. Defines the concept of the overall strength of sub-grade and use it as the sub-grade strength index; Meantime, raise three indicators:DI, AP, MI, and determined macroeconomic indicators be the method to evaluable the of Highway sub-grade drainage.