研究黄土湿陷性的新方法

为了研究吸力对黄土湿陷变形的影响,研制了一套可以控制吸力的非饱和土湿陷三轴仪。该三轴仪底座为二元结构,既能控制吸力又能浸水。将该三轴仪和GDS压力/体积控制器相结合,实现了浸水过程中量测浸水体积的功能,并可施加浸水压力。该设备能精确量测试样体变;控制偏应力;精确量测浸水量。利用该仪器探讨了原状湿陷性黄土控制吸力三轴湿陷试验的方法,并进行了净围压相同吸力不同和吸力相同净围压不同的双线法三轴湿陷试验。结果表明:吸力越大湿陷变形越大,净围压对湿陷变形有显著影响。非饱和土湿陷三轴仪为研究黄土的湿陷特性提供了有力的工具。

A new method of studying collapsibility of loess

A new triaxial testing system which could control suction in wetting-induced collapsible tests was successfully developed to study suction effects on wetting-induced collapsible deformation.The pedestal of the triaxial cell was made up of two major parts,and the equipment not only could control suction but also could make water accessible to soil.A pressure / volume controlled equipment was combined with the triaxial system to measure the water volume absorbed by samples accurately and to add pressure on water to filtrate into the samples.The apparatus could measure volume change precisely and keep deviator stress unvaried as well as measure the volume of water filtrating into the samples exactly.A triaxial collapsible testing procedure was described using the new apparatus for undistrubed collapsible loess with controlled suction.Furthermore,a series of double triaxial collapsible tests were conducted under different suctions and the same net cell pressure,and tests under different net cell pressures and the same suction were also done.It was indicated that the collapsible deformation increased with the increasing suction,and the effect of the net cell pressure on collapsible deformation was remarkable.The new triaxial system was a useful facility to study wetting-induced collapsible behavior of loess.