随着承载比有关试验方法和规范的引进,目前用通过承载比试验得到的CBR值作为土体特别是道路施工中路基填土的强度参考标准值逐渐成为普遍的方法.具有特殊工程性质的粉土,其压实后的强度和稳定性直接关系到上层建筑的工程质量和正常使用.对具有轻微膨胀性质的粉土在不同的击实能和初始含水量下压实,进行不浸水和浸水承载比试验,分析不浸水和浸水CBR值随初始含水量和击实能的关系,以及各因素对不浸水和浸水CBR差值的影响.试验结果表明,浸水膨胀软化对压实粉土浸水后的CBR强度有较大影响.不浸水CBR值随初始含水量增大而减小,大多试样的浸水CBR值随初始含水量变化出现峰值.膨胀量、不浸水和浸水CBR差值随初始含水量增加线性减小,不浸水和浸水CBR差值随膨胀量增加线性增大.低含水量下的压实粉土试样不浸水和浸水CBR差值随击实能增加而增大.
With the introduction of the test methods and specifications of California Bearing Ratio (CBR), the CBR value form the bearing ratio test becomes a reference for the soils, especially those used in the construction of road embankment fillings. The compaction strength and stability of silt with special engineering properties is directly related to the quality of construction and regular service of the top buildings. Silt with light swelling properties was compacted under different compaction energy and initial water contents. A series of soaking and un-soaking bearing ratio tests were conducted. The test results show that swelling and softening have greater effects on the CBR strength of compacted silt after immersion in water. The un-soaking CBR values decrease with the increasing of initial water content. There is a peak value on the curves of soaking CBR values and initial water contents for the majority of samples. The swelling amount and the difference between soaking and un-soaking CBR values decrease linearly with the increasing initial water content. The difference between soaking and un-soaking CBR values increase linearly with the increasing swelling amount and the compaction energy of under low water content.