Laterite has high void ratio, low density, high moisture content, high plasticity, but it does not match with their physical nature, which has the relatively high strength and low compressibility. In order to improve the strength of laterite and increase its compactness, we usually use the method of dynamic compaction in some large engineering projects. Its easy to find that soil compaction degree increased with the moisture content When the content of moisture is low, but soil compaction decreased after reaching the highest. Multiple compaction can effectively improve the maximum dry density and reduce optimum moisture content, but after compaction number is too much that optimum moisture content dont increase obviously.

Air pollution is one of the most serious environment pollution. 8 typical landscape plants, in Suzhou City, were selected to quantitative study their dust-capturing capacities, and the morphological traits of their leaves were observed under a SEM (scanning electron microscope). The paper showed that there were great differences in the dust-capturing capability of garden trees, and the dust-capturing capacities of garden trees in different seasons were in the order of May > August > November; the leaves of Cinnamomum camphora (L.) Pres, Camellia japonica L. and Euonymus japonicus Thunb. var. Ovatus Aureus had smooth surfaces or tubercles, whose dust-capturing capacities were poor, while the leaf of Loropetalum chinense(R.Br.) Oliv.Var. rubrum Yieh had many wrinkled form of cuticle, deep grooves, trichomes and high stomata desity which were favor of dust-retained, thus its dust- capturing capacity was stronger. The results can be seen as a possibility of select suitable species for urban environment.