膨胀土裂隙生成特征研究

Study on Cracking Development of Expansive Soil

以南京绕城高速公路路基弱膨胀土为研究对象,通过改变膨胀土的含水率,在实验室内对降雨蒸发交替作用下膨胀土裂隙开裂过程进行模拟,观测并统计分析裂隙特征的关键因素,研究不同含水率及不同循环次数对裂隙的长度、宽度、数量的影响。研究结果表明:在一次干湿循环过程中,裂隙生成速度随时间变化先快后慢,最终达到稳定;在整个干湿循环过程中,每次循环结束时裂隙数量呈逐渐增多的趋势,在第五次干湿循环之后裂隙发育最终达到稳定。

This paper takes Nanjing Ring Expressway roadbed of weak expansive soil as the research object. By changing the moisture content of expansive soil in the laboratory,this paper made expansive soil fissure cracking in the correct simulation under the action of the rainfall evaporation alternating. Then observed and statistic analyzed the key factors of fracture characteristics to research the cracks rate under different moisture content of different cycle times,such as the length of the fracture,width and quantity. The research results showed that in a dry-wet cycle process,cracks generated quickly before they are slow over time and eventually achieve stability; in the whole dry-wet cycle process,the quantity of cracks appear increasing trend along with the end of each cycle stability at fifth dry-wet circulation.