含水量及冻融循环对阳曲黄土压缩特性的影响分析

压缩特性是黄土的重要力学特性,是季节性冻土区黄土工程设计的重要依据。为研究冻融循环和含水量变化对黄土压缩特性的影响,以山西阳曲1号隧道为背景,对不同含水量的黄土进行冻融循环后的系列试验。结果表明:冻融循环通过强风化作用于土中自由水,使得土中自由水发生了原位的冻胀融沉和迁移,破坏了土颗粒的胶结物质,改变了土样固体颗粒的粒径分布,粗颗粒减小,细颗粒增加。使得土体的孔隙比、干密度、体积均增加,压缩系数的变化与含水量和冻融循环次数正相关,压缩模量的变化与含水量和冻融循环次数反相关,压缩性增强。本文的研究结果可对阳曲甚至山西的黄土工程提供帮助。

Analysis on Influence of Moisture Content and Freeze-Thaw Cycle on Compression Characteristics of Loess in Yangqu Region,Shanxi Province

The compression performance is one of the important mechanical properties of loess, and is the important basis for the engineering design of loess in seasonal frozen regions. In order to study the influence of freeze-thaw cycles and moisture content changes on the compressive strength of loess, taking the loess of Yangqu No. 1 tunnel face in Shanxi Province as the research object, a series of tests on the loess with different moisture content has been conducted after freeze-thaw cycles. The results show that: the free water in the soil is affected by strong weathering action from freeze-thaw cycles, so the in-place heaving and settlement and migration occurred for the free water in soil, the cementation material for soil particles is destructed, changing particle size distribution of solid particles in the soil, coarse particles decreases with an increase of fine particles. So that the void ratio, dry density and volume of the soil are increased, the compression factor changes are positively correlated with moisture content and freeze-thaw cycles, the compression modulus changes are inversely related to moisture content and freeze-thaw cycles, the compressibility is enhanced. It is a hope that this paper can provide construction reference for loess distributed area of Yangqu even those in Shanxi Province.