关键词: 物理力学性质, 沙漠砂, 试验, 古尔班通古特沙漠

Abstract: The field survey and a great deal of experimental studies for physical and mechanical characters indicate that the sand thickness of Gurbantonggut desert generally is less than 200 m, sand grains are uniform and their dominant diameter(d₆₀) vary between 0.12 and 0.25, the grain size is decreased toward the south and from surface to deep. In natural environment, the moisture of dune sands is 1%~2%, the dry'sand density is 1.55~1.62 g·cm^-3, it belongs to middle density and low compressibility. The infiltration coefficient is 2.0×10^-2~4.0×10^-3 cm·s^-1, the critical breakage ratio is 0.9~1.7 in earth flow form. The shearing strength is indexed as c=5.0~14.0 kPa and φ=29°~34°. The characterized bearing capacity is 100 kPa. Based on the degree of frost heaving, dune sands can be classified as no-frost heaving sands in natural environment, no or weak frost heaving sands in less than 18% of moisture, and frost heaving sands in water saturated condition. The mechanics of dune sands is affected by dry density and moisture. The higher the dry density is, the less the moisture is, and the better its mechanics is. For engineering in desert, the key measures for ensuring the safety and operation of engineering facilities are to increase dry density and enhance seepage so as to avoid the high moisture content.

Key words: physical and mechanical characteristics, dune sands, experiment, Gurbantonggut desert