巴基斯坦塔尔沙漠风积砂土湿陷性特征

Collapsibility Characteristics of Wind-Blown Sand in Thar Desert,Pakistan

依托巴基斯坦塔尔矿区风积砂土湿陷性研究课题,基于前期勘察成果和相关湿陷性试验结果,对塔尔沙漠风积砂土的湿陷性特征及其基本物理指标与湿陷性的相关性进行分析研究。结果表明:风积砂土的湿陷性主要分布在①、②层,湿陷性系数平均值为0.039,湿陷性程度属于轻微-中等;风积砂土的颗粒组成和易溶盐特征是湿陷变形的主要内在基础;风积砂土湿陷性系数与含水率之间离散性较强,与孔隙比基本呈正相关关系,与干密度之间基本呈线性负相关,当孔隙比<0.65或干密度>1.60 g/cm^(3)时,风积砂土不具有湿陷性。

The collapsibility characteristics of wind-blown sand in Thar Desert of Pakistan are investigated based on preliminary survey findings and collapsibility test results.The correlation between basic physical indexes of wind-blown sand and collapsibility are also examined.Results demonstrate that the collapsibility of wind-blown sand is mainly distributed in layer①and layer②,and the average collapsibility coefficient is 0.039,indicating slightly to moderately collapsible.The grain composition and soluble salt characteristics of wind-blown sand are the main internal basis of collapsible deformation.In addition,strong dispersion is found between collapsibility coefficient and water content of the wind-blown sand.Collapsibility coefficient is also positively correlated with porosity and linearly negatively with dry density.When porosity is smaller than 0.65 or dry density exceeds 1.60 g/cm^(3),wind-blown sand is not collapsible.