PHYSICAL AND MECHANICAL PROPERTIES OF TYPICAL MORAINE SOIL ON THE QINGHAI-TIBET PLATEAU

There were many times of glacial actions during the pleistocene global ice ages in the Qinghai-Tibet Plateau that is well-known as the roof of the world, leaved a lot of glacial traces. The moraine soil belongs to the special engineering soils, which has complicated composition, mixed structure and changeable physical and mechanical properties. The moraine soil is usually confused with diluvium and eluvium. The site of constructing Yading airport is located at Daocheng Haizi Mountain. Its foundation soil is a typical Qinghai-Tibet Plateau moraine soil, and stacked up after the Daocheng ice cap melt. In order to master the moraine's special physical and mechanical properties, and reveal the relationship between moraine's properties and the glacier evolution, the composition analysis, physical and mechanical properties testing, and ESR dating were carried out during the Yading airport foundation survey. Research shows that the moraine soil of Yading airport, stacked up during 375ka BP and compacted by the glacier, has the characteristics of higher density, lower void ratio, higher foundation deformation modulus and bearing capacity. Moraine soil belongs to the over-consolidated soils(average preconsolidation pressure is about 290kPa) and can be used as a good natural foundation of major engineering in the Qinghai-Tibet Plateau.