延吉膨胀岩膨胀力的水-力路径效应与应用适宜性分析

Effect of hydro-mechanical path on swelling pressure of Yanji swelling rock and its application suitability analysis

膨胀力是膨胀岩土地区工程设计和施工中的重要参数,目前常用的膨胀力试验方法主要有膨胀反压法、平衡加压法和加压膨胀法3种。膨胀力大小容易受试验方法的影响。为了研究试验方法对膨胀力的影响,以延吉膨胀岩为研究对象,采用上述3种方法开展了不同初始含水率试样的膨胀力试验,分析比较了3种试验方法的特点和适用范围。结果表明,膨胀力具有强烈的水-力路径效应,3种方法确定的膨胀力存在较大差异,膨胀反压法测得的膨胀力最大,加压膨胀法最小;3种方法确定的膨胀力与初始含水率之间存在明显的线性负相关关系,随着试样初始含水率的增加,不同方法得到的膨胀力与初始含水率的关系曲线逐渐靠拢,水-力路径对膨胀力试验结果的影响逐渐减弱,每一种方法有其自身的特点和特定的适用范围,膨胀力测试应该根据实际工况选择合适的试验方法。

Swelling pressure is an important parameter for the design and construction of geotechnical engineering in swelling rock and soil regions. The swell and load method, the no-swell method, and the load-swell method are the three most commonly used methods for determining swelling pressure. Swelling pressure depends significantly on test method. To explore the effect of testing method on swelling pressure, swelling pressure tests of Yanji swelling rock specimens with different initial water contents were carried out using the above-mentioned three methods; and characteristics of three methods and their application scopes were analyzed and compared. The results indicate that three methods show different values in swelling pressure; and there is a clear effect of hydro-mechanical path on swelling pressure. The swell and load method provides the highest value of swelling pressure; while the load-swell method provides the lowest. There is a significant negative linear relationship between the swelling pressure and the initial water content. Relationships between the swelling pressure and the initial water content obtained by three methods tend to be close to each other with the increasing initial water content, which illustrates that the effect of hydro-mechanical path on swelling pressure is weakened. Every method has its respective characteristic and specific application scope; so testing method of swelling pressure should be determined by practical engineering conditions.