藏东南地区砂卵石抗剪强度试验研究

Experimental Study on Shearing Strength of Sand Pebble in Southeast Tibet

为了研究藏东南地区砂卵石土的抗剪强度特性,本文以拉林高等级公路高路堤砂卵石填料为研究对象,对砂卵石土进行颗粒分析试验。在天然级配的基础上对砂卵石土进行级配改良,本文对原状砂卵石土和级配改良后的砂卵石土进行不同垂直压力下的直剪试验。通过试验得出:砂卵石土的应力应变关系大多呈应变软化型。砂卵石土先发生剪缩,后发生剪胀,整体呈现明显的剪胀性。天然砂卵石土都存在缺粒现象,通过级配改良,砂卵石土抗剪强度得到提高。随着粒径为20 mm~60 mm土颗粒质量百分数的增加,砂卵石土的抗剪强度随之增加。本文分析了砂卵石土的物理力学特性,为藏东南地区高路堤填方工程提供技术参考。

In order to study the shearing strength characteristics of sandy pebble soil in southeast Tibet,this paper took the sandy pebble packing on the high road embankment of Lalin high grade highway as the research object,and particle analysis test were conducted on sandy pebble soil.On the basis of natural cascade,the cascade of sand pebble soil was gradated and improved.In this paper,the undisturbed sand pebble soil and sand pebble soil with improved cascade were tested by direct shear tests under different vertical pressures.The results showed that the stress-strain relationship of sandy pebble soil was mostly strain softening.The sandy pebble soil clipped first,dilation occurred later,and the overall presented obvious dilation.All the natural sandy pebble soil had the phenomenon of grain deficiency,and the shear strength of natural sandy pebble soil was improved by the improvement of cascade.With the increase of the percentage of soil particle mass with a particle size of 20 mm-60 mm,the shear strength of sandy pebble soil increased accordingly.The mechanical properties of sandy pebble soil were analyzed in this paper,which can provide technical reference for the high embankment filling project in southeast Tibet.