干湿循环作用下植被混凝土结构演化

选取植被混凝土生态基材为研究对象，制备6种初始含水率分别为13%、19%、25%、31%、37%、43%的试样。通过烘干法和叠式饱和法分别模拟脱湿和增湿过程，采用土壤收缩仪测量试样宏观胀缩量，Matlab软件提取试样表面裂隙几何特征，探究干湿循环作用下植被混凝土结构演化规律。结果表明:试样在常温下的干缩过程可分为急剧收缩阶段、平缓收缩阶段和稳定阶段3个阶段；干湿循环过程中，试样收缩量与膨胀量近乎等量；裂隙发育过程主要体现在裂隙宽度、总长度及总面积随循环次数增加而增大；初始含水率过低或过高，均易使植被混凝土发生湿胀干缩破坏；初始含水率31%试样的裂隙平均宽度、裂隙总面积、裂隙长度和表面收缩率均最小，31%为生产实践的最佳含水率。

Evolution of vegetation concrete structures under action of drying-wetting cycles

The vegetation concrete ecological base material was selected as the research object, and the samples with six levels of initial water contents of 13%, 19%, 25%, 31%, 37%, 43% were prepared. The dehumidification and humidification processes were simulated by drying method and stacking saturation method respectively. The macroscopic expansion and shrinkage of samples were measured by soil shrinkage meter, and the geometric characteristics of cracks on the surface of samples were extracted by Matlab software. The structural evolution law under the action of drying-wetting cycles was studied. The results show that the drying shrinkage process of the samples at laboratory temperature is manifested as three stages, including sharp shrinkage stage, smooth shrinkage stage and stable stage. During the drying-wetting cycles, the shrinkage and expansion of the samples are almost equal. The crack development process is mainly reflected in the increase of crack width, total length and total area with the increase of cycle times. If the initial water content is too low or too high, the wet expansion and dry shrinkage damage is easily occurred. The average crack width,crack total area, crack length and surface shrinkage of the samples with 31% initial water content are the smallest, which is the optimum water content in production practice.