不同失水速率下膨胀土的开裂特性研究

Study on the Cracking Characteristics of Expansive Clay at Different Water Loss Rates

含水率变化是导致膨胀土开裂的重要因素,其变化快慢影响了土体的裂隙发展。以某边坡膨胀土作为研究对象,自制了一套无干扰气候箱设备开展土体开裂试验,分析环境温度、相对湿度以及光照强度与薄层膨胀土失水速率之间的关系,通过数字图像技术对裂隙几何特征进行统计分析,定量研究了薄层膨胀土失水速率与蒸发及开裂特征参数的关系。结果表明:在裂隙发育时期,相同含水率下失水速率低的土体裂隙率与裂隙总长更大,节点数目与裂隙条数也更多,失水速率低的土样在裂隙发育达到相对稳定状态时的含水率也更高,土样分块面积也更小。

The change of moisture content is an important factor leading to the cracking of expansive clay, and the speed of its change affects the development of clay cracks.A set of undisturbed climate chamber was developed to conduct soil cracking test, and the relationship between ambient temperature, relative humidity and light intensity and water loss rate of thin expansive soil was analyzed.Statistical analysis was carried out on the geometric characteristics of cracks by image technology, and the relationship between the water loss rate of thin expansive clay and the characteristic parameters of evaporation and cracking was quantitatively studied.The results show that in the period of fissure development, the samples with low water loss rate under the same water content have larger fissure ratio and total fissure length, and more nodes and fissures.Clay samples with low water loss rate develop in fissures.The moisture content when reaching a relatively steady state is also higher, and the clay sample block area is also smaller.