干湿循环作用下膨胀土裂隙开展室内试验研究

Research on the fissure development indoor test of expansive soil cracks under the action of dry-wet circulation

为了解裂隙开展演化规律,以合肥黑色中膨胀土为研究对象,对模型试样进行一系列干湿循环试验,研究降雨蒸发作用下膨胀土裂隙演化规律。利用图像识别程序对面积裂隙率等进行定量分析并观测土样侧面裂隙开展形态以及深度。结果表明:单次脱湿情况下,土体的面积裂隙率、裂隙分形维数等形态参数和裂隙深度随时间逐渐增加,且土体表面形态参数存在极限值;干湿循环作用表现为裂隙的反复开裂、愈合使得土体结构趋于松散,裂隙率、裂隙分维趋于稳定;由侧向剖面观测得到边坡失稳是横向裂隙发展贯通而引起的。

In order to know the regulation of crack evolution,dry w et cycling test taking hefei expansive soil as the research object is carried out to study the expansive soil crack evolution under rainfall evaporation.The image recognition program is used to quantitatively analyze the crack rate of the area and observe the shape and depth of the lateral fissure.The results show that in the case of single dehum idification,the area crack ra te,fracture fractal dimension and other morphological parameters and fissure depths gradually increase with dehumidification tim e,and the soil surface morphological param eters have the lim it value.The w et cycle is characterized by repeated cracking and healing of fissures,which tend to loosen the soil structure,and the crack rate and fissure fractal dimension tend to be stable.The lateral slope instability is caused by lateral fracture development through lateral profile observation.