不同含水率下黄土冻融循环对湿陷性影响探讨

黄土通常可作为公路路基主要的填筑材料,湿陷性黄土经压实后,很大程度消除了湿陷性,能够满足路基整体强度和稳定性的要求,但在季节冻土区,黄土路基运营几年后仍发生大量的不均匀沉降、塌陷等病害。为分析冻融循环作用下各级含水率对黄土湿陷性的影响,采用室内试验的方法,对湿陷性黄土进行不同的冻融次数,探究其在冻融循环过程中变形及冻融循环后湿陷情况。实验结果表明:冻融循环之后的各级含水率重塑黄土仍具有二次湿陷性;冻融循环作用下高含水率的土体结构比低含水率的土体结构破坏的较早;干密度一定时,低含水率的土体冻融循环之后的净变形量越大,湿陷系数越小,冻融循环之后的净变形量越小,湿陷系数越大。

Effect of freeze-thaw cycles on collapsibility of loess under different moisture contents

Loess is usually used as the main building materials for road subgrade. The collapsibility can be greatly eliminated after compaction of collapsible loess, and it can satisfy the requirements of whole intensity and stability of road subgrade. However, a lot of disasters such as differential settlement and collapse occur after the road subgrade of loess has been used for several years in seasonally frozen soil zone. In order to analyze the influence of various levels of moisture contents on collapsibility of loess under freeze-thaw cycles, deformation and collapsibility of collapsible loess are studied under different freeze-thaw cycles in laboratory. The test results indicate that the remolded loess at every level of moisture content still has secondary collapsibility after freeze-thaw cycles. The soil structure with higher moisture content is damaged earlier than that with lower moisture content under freeze-thaw cycles. When the dry density is certain, the larger the net amount of deformation with low soil moisture content after freeze-thaw cycles is, the smaller the collapsible coefficient is, and vice versa.