温度变化条件下重塑黄土水分迁移试验

Test of water migration of remolded loess under temperature variation

土体内部由于所处环境差异会造成水分场的不均匀分布,为了探究不同影响因素下重塑黄土水分迁移的规律,配置不同干密度、初始含水率水平的重塑土样,在不同温度梯度、不同温度水平下进行重塑黄土水分迁移室内试验,分析在4种不同因素变化下黄土体内部水分场的变化规律及机理。结果表明:土样两端施加的温度梯度越大,水分迁移速率就越快,温度势是引起土体内部水分迁移的主要驱动力;土样的干密度越大,基质势越大,同时渗透系数越小,阻碍了水分的迁移,故水分迁移速率越慢;当土样含有较大的含水率时,由于渗透系数较小,造成迁移速率较小,当土样初始含水率较小时,由于总土水势较小,造成迁移速率较小,当初始含水率在一定范围内时,其迁移速率较快;在土样两端施加的温度水平越低,导致总土水势越大,故水分迁移速率越快。

Due to the difference of the environment,the uneven distribution of water fields will occur in the soil. In order to explore the effect of different factors on the water migration of remolded loess, laboratory tests of the wa-ter migration of remolded loess, considering dry density and initial water content for the effects of different tem-perature gradients and temperature levels, were carried out. The change law of moisture fields of remolded loess was analyzed. The conclusions show that the greater the temperature gradient, the faster the water migration rate is. Temperature potential is the main factor in the change of water migration. The greater the dry density of soil sam- ples,the greater matric potential,and the smaller the permeability coefficient is,causing the slower migration rate. When the water content of soil samples is larger, the permeability coefficient is smaller and the migration rate is smaller. When the initial water content is smaller, the total soil water potential is smaller, and the migration rate is smaller. When the initial water content is in a certain range, the migration rate is faster. The lower of the tempera-ture level, the greater of the total soil water potential, the faster of the water transport rate is.