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膨胀土在含水量降低时发生干缩开裂,给工程带来了极大的危害,其中降雨条件下裂隙膨胀土渗流问题是一个典型的膨胀土工程问题。制备6个相同的南阳重塑膨胀土样,在相同的环境下分别脱湿96,79,63,48,39,30 h,通过数码拍照得到不同时刻试样表面裂隙图片,通过分析得到试样表面裂隙率;为了衡量裂隙在深部方向的发育情况,使用煤油进行渗透实验,得到煤油入渗系数与脱湿时间、平均含水率、表面裂隙率的关系曲线;在油渗实验结束后进行室内模拟降雨入渗实验,得到裂隙膨胀土入渗率的变化规律。通过对实验数据整理分析发现试样脱湿时间、试样平均含水率、试样表面裂隙率、煤油入渗系数、降雨入渗实验径流开始时间、试样入渗率之间有良好的相互关系,降雨入渗实验初期入渗率较大,入渗率随时间衰减很快,在15 min内降低了两个数量级,脱湿时间越长的样初期入渗率越高,衰减的也越快;入渗率在较短的时间内就开始趋于稳定,稳定后的入渗率随试样表面裂隙率线性增长,增长到一个峰值后迅速降低。
When the moisture content decreases, the expansive soil shrinks and cracks, which brings great harm to the project. The seepage problem of the expansive soil under the condition of rainfall is a typical expansive soil engineering problem. Six identical Nanyang remodeled expansive soil samples were prepared and desiccated for 96, 79, 63, 48, 39 and 30 h under the same environment respectively. The pictures of fissures on the surface of the sample at different times were obtained by digital photography. Samples were obtained by analysis In order to measure the development of fractures in the deep direction, kerosene was used to carry out infiltration experiments to get the curves of kerosene infiltration coefficient and desorption time, average moisture content and surface fracture rate. After the oil infiltration experiment was finished, indoor simulation Rainfall infiltration experiment to get the infiltration rate of expansive soil crack variation. Through the analysis of the experimental data, it is found that there is a good correlation between the desorption time of the sample, the average moisture content of the sample, the sample surface fracture rate, the kerosene infiltration coefficient, the start time of the rainfall infiltration experiment runoff, and the sample infiltration rate The infiltration rate of the infiltration experiment was higher in the initial stage of the rainfall infiltration, and the infiltration rate decayed rapidly with time, decreasing by two orders of magnitude within 15 min. The longer the dehumidification time, the higher the initial infiltration rate and the faster the decay rate The infiltration rate began to stabilize in a relatively short period of time. The steady infiltration rate increased linearly with the fracture rate of the sample surface and rapidly decreased after reaching a peak value.