干湿循环作用下云南红土裂缝发展研究

发布时间：2018-04-23 16:42

本文选题：云南红土 + 干湿循环　；参考：《水土保持学报》2017年02期

【摘要】：以干湿循环为控制条件,考虑初始干密度、增湿次数和脱湿次数等影响因素,采用室内试验和图像处理相结合的方法,研究云南红土裂缝的产生及其发展演化。控制初始干密度为1.20,1.30,1.40,1.50g/cm~3,通过增湿、脱湿的干湿循环及膨胀率等试验方法,观察红土样裂缝的变化,并应用Matlab图像处理技术提取红土样的裂缝特征参数。结果表明:干湿循环作用下,初始干密度越大,红土样越容易开裂,干密度较小时(1.20g/cm~3)土样始终不开裂,随干密度增大(1.30,1.40g/cm~3),红土样在第3次增湿中开裂,干密度达1.50g/cm~3时,红土样在第2次增湿中开裂,增湿过程对红土样裂缝发展的影响显著大于脱湿过程的影响;红土样的膨胀率随浸泡时间延长逐渐增大,干密度为1.20,1.30,1.40g/cm~3时约8min膨胀基本稳定,干密度为1.50g/cm~3时约36min膨胀趋于稳定;对应红土样的裂缝条数、长度、面积和宽度等特征参数随增湿次数、脱湿次数增大而增大;随干密度增大,红土样的裂缝条数、长度与面积增大,裂缝宽度在干密度约1.30g/cm~3处存在峰值。干湿循环作用引起云南红土开裂的关键因素在于增湿过程中红土样的不均匀膨胀,红土裂缝属于膨胀裂缝,其发展过程包括裂缝孕育期(0~2次)、裂缝形成发展期(2~6次)和裂缝稳定期(6~8次)3个阶段,这3个阶段综合作用的结果,最终影响了红土裂缝的发展演化趋势。
[Abstract]:Taking the dry and wet cycle as the control condition and considering the influence factors such as initial dry density, times of humidification and times of dehumidification, the generation and evolution of the cracks in Yunnan laterite were studied by the combination of laboratory test and image processing. The initial dry density is 1.20 ~ 1.30 ~ 1.40 ~ 1.50 g / cm ~ (-3). By means of humidification, dehumidification, dry-wet cycle and expansion rate, the changes of cracks in laterite samples are observed, and the fracture characteristic parameters of red soil samples are extracted by Matlab image processing technique. The results show that the higher the initial dry density is, the easier it is for the red soil sample to crack, and the dry density of 1.20 g / cm ~ (3) soil sample does not crack. With the increase of dry density of 1.30 ~ 1.40 g / cm ~ (-3), the red soil sample is cracked in the third humidification, the dry density is 1.50 g / cm ~ 3, the dry density is 1.50 g / cm ~ 3, and the dry density is 1.50 g / cm ~ 3, and the dry density is 1.50 g / cm ~ 3. The effect of humidification process on the crack development of red soil sample is obviously greater than that of dehumidification process, and the expansion rate of red soil sample increases gradually with the prolongation of soaking time, and the dry density of 1.20g / cm ~ 3 1.30g / cm ~ 3 is basically stable, and the swelling rate of red soil sample increases gradually with the extension of soaking time, and the dry density of red soil sample is about 1.30g / cm ~ 3. The dry density is 1.50g / cm ~ 3 about 36min expansion tends to be stable, the characteristic parameters such as the number of cracks, length, area and width of the red soil sample increase with the times of humidification, and the number of cracks in the laterite sample increases with the increase of dry density. With the increase of length and area, the crack width has a peak value at the dry density about 1.30g/cm~3. The key factor of the cracking of Yunnan laterite caused by dry and wet circulation is the uneven expansion of the red soil sample in the process of humidification, and the fracture of the red soil belongs to the expansion fracture. The development process includes three stages: the incubation period of fractures is twice, the formation and development of fractures is 6 times), and the stable period of fractures is 6 times). The result of the comprehensive action of these three stages has finally affected the development and evolution trend of the fractures in laterite.
【作者单位】：昆明理工大学电力工程学院;
【基金】：国家自然科学基金项目(51568031)
【分类号】：TU43

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