北疆渠道基土盐-冻胀特性的试验研究

干旱缺水已逐渐成为制约我国农业发展的主要因素,西北寒冷地区输水渠道由于渠基土的盐胀和冻胀造成了严重的渠水渗漏损失。为研究渠基土的盐-冻胀变形特性,本文选取北疆输水灌渠典型土体进行了不同干密度、不同Na_2SO_4含量和不同含水率条件下的盐-冻胀变形试验。结果表明:随着干密度的升高,土体盐-冻胀率先增大后减小,在某一干密度下盐-冻胀率最大。随着土体Na_2SO_4含量和含水率的升高,土体盐-冻胀率逐渐增大,土体盐-冻胀率与Na_2SO_4含量之间呈现二次多项式关系,与含水率之间呈现线性关系。与干密度相比,Na_2SO_4含量和含水率对土体盐-冻胀率的影响较大。

Salt-frost heave properties of channel bed soil in the Northern Xinjiang

Water shortage has been the main constraint on agricultural development, and salt-frost heave of conveyance channel bed soil in winter has caused severe leakage in the northwest region of China. A typical frost heaving susceptible channel bed soil was chosen from the Northern Xinjiang and a series of salt-frost heave experiments were conducted to study the heaving property of this soil. The test results show that:(1)the salt-frost heaving rate increases firstly and then decreases as dry density of the soil increases, and it reaches its peak at one particular dry density;(2)with the increase of Na₂SO₄ and water content in the soil, the salt-frost heaving rate increases rapidly, and the relationship of salt-frost heaving rate with these two variations are correlated as quadratic polynomial and linear respectively;(3)compared with the dry density, Na₂SO₄ and water content has more influence on salt-frost heaving rate of this Low-Liquid limit clay. This research provides basic data to solve the freezing injury problem of conveyance channels in North Xinjiang cold and arid area.