河西寒旱区盐渍土地层温湿度变化模式

盐渍土病害的发生与发展在很大程度上取决于土体内水、热变化状况。笔者以甘肃酒泉瓜州地区戈壁盐渍土为原型，利用硅半导体温度测量方式和时域反射技术（TDR）实时监测了盐渍土地层温度和湿度变化情况，分析了河西寒旱区盐渍土地层温湿度的变化模式。结果表明：研究区地层温度的日变化和年变化分别表现为一定周期的正弦曲线，地表处温度变化最剧烈；随深度增加温度变化幅度呈指数衰减，对环境气温的滞后效应也明显增加，日温度变化影响深度为40~50 cm，年温度变化影响深度为500~600 cm。因强烈的蒸降比和较深的地下水位，研究区地层基本无外界水分补充或损耗，地层湿度在一定时期内基本不发生明显变化，仅降水时期在浅表部有所波动。分析表明，研究区浅部100~150 cm深度范围内温度变化较大的地层中存在发生盐渍土病害的可能性，这也在很大程度上取决于地层的湿度情况，因此工程建设中应做好浅表层的防排水措施。

Variation Pattern of Temperature and Humidity for Saline Soil in Cold and Arid Regions of Hexi Corridor

The occurrence and development of salty soil diseases mainly depends on the temperature and humidity in cold and arid regions. In order to comprehend the variation pattern of temperature and humidity for saline soil of Hexi corridor, Gobi saline soil in Guazhou, Gansu Province was selected to monitor by thermo-sensitive probe and time domain reflectometry (TDR) during winter and summer. Based on the monitoring data, we knew that the soil temperature presented as sinusoid variation by a daliy or annual cycle, and the shallow soil temperature varied greater than the deep soil. With the depth increasing, not only the temperature amplitude decayed exponentially, but also the hysteresis increased proportionally. At a certain depth, soil temperature came to almost constant, the depth for daily was 40-50 cm while the depth for annual was 500-600 cm. Because of the large evaporation precipitation ratio and distant groundwater, there was no water supplied or lost in soil, which brought about an invariable humidity for soil, only a microvariation in shallow by the rainfall. It was considered that there was a probability for the salty soil diseases occurred in depth of 100-150 cm, which depended on the humidity of soil largely, so the waterproof and drainage should be enhanced on ground surface.