Research Of Moisture And Dry Density In Compacted Loess On Engineering Characteristics

Compacted loess as the main building materials widely used in earth dam, highway, railway and airport runway and other projects in arid and semiarid region along with many engineering disease problem.There are two aspects due to the disease,on one hand, the quality of the construction or human factors, on the other hand,the engineering properties of compacted loess damaged by the change of the moisture. To explore the moisture and dry density of the compacted loess engineering characteristics, Jiu Zhou-tai loess sample adopted in microcosmic test, strength and compression test, try to combine macroscopic strength and micro structure characteristics in this paper. The tests show that:(1) The smaller dry density sample.compression deformation owe to the destruction of the macrovoid condense.Larger dry density sample, the compression deformation due to the result of small and medium pore further consolidation.Maximum dry density sample have the trait of relatively homogeneous microstructure. There is great difference in pore size percentage which one similar dry density samples but in different compaction moisture.(2) The same dry density of compacted loess, which has disparate compression deformation under different moisture states, increasingly obvious with the more close to the optimal moisture. It has strong water sensitivity and the engineering properties susceptible to moisture when the compacted loess in maximum dry density. There is no collapsibility when the sample under the compaction water content,and it will collapse in other water states. All the compacted loess are collapsibility when the moisture more than optimum moisture content.(3) As the same dry density,the compression strength increased with the moisture when the water lower than the optimum water (17%), whereas it reduced with the moisture. The moisture not only impact on the compression strength of compacted loess but also effect the modulus of elasticity and stress path.The influence of moisture on compression strength is not obvious at low dry density, and the it will be evident if the dry density increased.