坝料动力变形特性试验研究

Experimental study on dynamic deformation behaviors of dam materials

在大型动力三轴仪上进行了坝料的动力变形特性试验研究,分析了围压和固结比对最大动模量、动模量衰减规律和阻尼比的影响。试验研究表明:随围压和固结应力比的提高,最大动模量增大;随应变的增大,动模量逐渐衰减;固结比对最大阻尼比影响不大,随固结比的提高最大阻尼比略有降低。基于沈珠江动力变形特性模型,提出了可以将固结比影响归一化的最大动模量和模量衰减的修正公式,该公式能很好地消除围压和固结比对模量衰减规律的影响。结合其它工程试验成果,通过小于5 mm粒径颗粒含量初步探讨了尺寸效应对动力变形特性的影响,研究表明室内试验得出的最大动模量较工程原位土体的要低,而最大阻尼比要略高。

Dynamic deformation behavior tests on dam materials are conducted using a large scale triaxial test apparatus. The effect of confining pressure and consolidated stress ratio on the maximum dynamic modulus, reduction of dynamic modulus and damping ratio is analyzed. It is shown that the maximum dynamic modulus increases with the increase of the confining pressure and consolidated stress ratio, and that the dynamic modulus decreases with the increase of the dynamic strain. The consolidated stress ratio has little effect on the maximum damping ratio. The modified formula of the maximum dynamic modulus and reduction of dynamic modulus with normalized dynamic strain is developed on the basis of the test results. This formula can describe the effect of the confining pressure and consolidated stress ratio on the dynamic modulus. The effect on dynamic deformation of reduced scale is discussed using particles finer than 5 mm. Compared with the field soil, the maximum dynamic modulus of the soil from laboratory tests is smaller, and the maximum damping ratio of the soil from laboratory tests is larger.