粗粒料三轴湿化颗粒破碎试验研究

颗粒破碎是引起粗粒料湿化变形的重要因素，有必要对其进行深入研究。利用改进的应力控制三轴仪，对坝的粗粒料进行不同围压和湿化应力水平下保持应力水平不变的三轴湿化变形试验，同时对湿化前后的试样进行颗粒分析试验。依据试验结果，分析湿化颗粒破碎的原因，得到湿化变形最及Hardin的颗粒破碎指标表示的颗粒破碎量。对粗粒料湿化变形和湿化颗粒破碎试验结果的分析表明：湿化变形与围压及湿化应力水平有关；湿化引起颗粒破碎，对颗粒级配曲线有较大的影响，湿化前后级配曲线的颗粒累积百分比的差值随粒径呈驼峰状分布，驼峰位于25％含量粒径左右；湿化引起的颗粒破碎使得级配曲线的曲率系数、不均匀系数和60％含量粒径减小；湿化颗粒破碎随着围压和湿化应力水平的增加而增加；湿化变形与湿化颗粒破碎之间有很好的相关性，湿化轴变与湿化颗粒破碎近似成线性关系；湿化变形的基本规律可以根据湿化颗粒破碎规律加以解释。

STUDY ON WETTING BREAKAGE OF COARSE-GRAINED MATERIALS IN TRIAXIAL TEST

Breakage is an important factor to influence wetting deformation of coarse-grained materials;and farther study is necessary.The wetting triaxial tests under various confining pressures and wetting stress levels are carried out on a coarse-grained material with a new stress-control triaxial apparatus;and the grain grading test is done with the samples before and after wetting.According to the tests,the cause of grain breakage due to wetting is explained;and the wetting deformation and grain breakage value expressed by Hardin index are obtained.The test results indicate that the wetting deformation is related to confining pressures and wetting stress levels;the wetting induces the grain breakage;and the wetting grain breakage has obvious influence upon the grain size distribution curve.The difference of grain size distribution curve before and after wetting is like a hump;and the maximum value is located at about the grain diameter of 25% of the grain size distribution curve.The grain breakage caused by the wetting reduce the coefficient of curvature;the coefficient of uniformity and the special grain diameter of 60% of the grain size distribution curve and the grain breakage value becomes greater with the increase of confining pressure and wetting stress level.The wetting deformation has close correlation with the wetting grain breakage;and the axial wetting deformation is linear to the grain breakage approximately.It is found that the wetting deformation behaviour can be explained from the viewpoint of the wetting grain breakage.