| Abstrakt: |
This research mainly focuses on the health condition of the Lima Expressway subgrade soil which encountered certain pavement distresses during 7 years of service. For subgrade soil at different sections and depths, laboratory and field tests were performed to obtain properties such as density, moisture content, specific gravity, particle size distribution, shear modulus, California bearing ratio (CBR), etc. The test results show that the samples of the unhealthy section are usually fractured or loose and obviously differ from those in the healthy section. Filling sections, among the unhealthy sections, contain slightly swollen soil and the free swell ratio reaches about 60%. When the standard for stopping the drop of the hammer is reached, the depth of the healthy section is shallower than that of the unhealthy section, or the number of DCP blows in the healthy section is lower. However, there is no obvious weakness trend in average moisture content, optimum moisture content, and shear modulus range. In addition, the CBR of the subgrade soil in the unhealthy section is less than 30%, but all CBR values are 2–4 times higher than the requirements of national specifications. Accordingly, the CBR values indicate that the bearing capacity of the subgrade soil can still meet the requirements, even if there are some pavement diseases. [ABSTRACT FROM AUTHOR] |
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