湘南红砂岩崩解机理研究

Research on the Mechanics of the Swelling and Collapse of the Red Stratum Rock Mass in South Hunan

在红砂岩室内崩解试验和大气条件模拟的渐进崩解试验中,对崩解过程碎屑物的颗粒级别质量变化进行了跟踪.采用分形方法对颗粒级别的质量变化进行了处理,发现红砂岩膨胀崩解过程是一个分数维不断变化的过程.在崩解达到一定程度后,崩解碎屑物的颗粒级别不再发生变化,红砂岩类的吸水膨胀崩解也停止,此时崩解物的分数维亦达到一个不再变化的临界值.该临界值可用来定量表征其崩解的机理,解决了红砂岩的崩解过程一直无法采用定量指标进行刻画的难题.

Red stratum rock mass is a familiar rock mass in rock engineering. It always contains clay mine, for example, kaolinite, montmorilonite and illite. One main character of red stratum rock mass is the rock mass swelling and collapse after clay mine absorbs water. For the fractal mechanics of red stratum rock mass, its collapse is multi-fractal. Through the grain-size analysis of scraps of the rock mass that was produced in the test of collapse in laboratory and in the test of gradual collapse in field atmospheric condition, it was found that the process of absorbing water and collapse of the rock mass was also a process in which the fractal dimension of soft rock scrap changed constantly. When the collapse of the rock mass got to some extent, the grade of scraps of soft rock changed no more, the water absorption and collapsing stopped, and the fractal dimension of scraps that had collapsed inclined to a critical value. The critical value revealed the fractal mechanics of the rock mass when it swelled and collapsed after water was absorbed. The above-mentioned conclusion will present considerable significance to actual engineering practice.