PORE CHARACTERISTICS OF MALAN LOESS UNDER COMPRESSION TEST AT HEIFANG PLATFORM

The frequent occurring landslides and more than 3m subsidence at Hefangtai are caused by long-term irrigation in Linxia city, Gansu province. This paper analyzes the microstructure nature of the loess collected from top and bottom of Heifangtai. The consolidation test with increasing water content and mercury intrusion porosimetry are conducted on the loess samples in this paper. The loess at the top of the platform is characterized by loose particle, packing with bigger porosity. The clay content is lower. The loess at the bottom of the platform, however, processes relatively tight arrangement of the particles with less porosity, and higher clay content. In the consolidation test, the void ratio falls sharply. The microstructure strength of the loess reduces suddenly or loss when 21% water content. This abrupt change in bottom loess does not occur, which indicates relatedly weak water sensitivity. The pore diameter compression interval of the top loess is 100m. The 5～20m. The compression interval of the bottom loess is 100m and 1～10m. However, the volume of the pore,0.1m, increases as the water content increases.