不同含水率对土体降温速度影响的试验分析

Experimental analysis on influence of different moisture content on soil samples cooling rate

土体含水率的不同会影响人工冻结法施工时的冻结壁交圈时间,而水文条件的不同往往导致现场施工周期预测不准。本文通过配置不同含水率的土体,将其放置在相同的环境温度进行冻结,并布置温度传感器实时采集温度变化数据。结果表明:1)土体未冻水发生相变的时间会随着含水率的增加而增加;2)饱和、未饱和土的温度下降速度不同,其中未饱和土的零上温度下降速度与含水率成反比,而零下温度下降速度在含水率为16%、24%时基本相同,20%时最高;饱和土的零上温度下降速度在含水率为36%时最大,38%时达到低值。饱和土的零下温度下降速度则与含水率呈现反比。

Soil sample with different moisture content has a great influence on the time of freezing wall intersection during artificial freezing construction, and the different hydrological conditions often lead to inaccurate prediction of construction period.The soil sample equipped with different moisture content is placed in a low temperature chamber to freeze at the same ambient temperature.Temperature sensors are arranged in the soil samples to collect real-time temperature change data.The results show that: 1)the time of latent heat evolution from liquid to solid increases with the increase of moisture content;2)the temperature drop rate of saturated soil is different from that of unsaturated soil.The temperature drop rate above zero is inversely proportional to moisture content, while the temperature drop rate below zero is basically the same at 16% and 24% moisture content, and the highest temperature drop rate is at 20%;the temperature drop rate of saturated soil is the highest at 36%,and reaches a low value at 38%.The decreasing rate of temperature below zero of saturated soil is inversely proportional to moisture content.