饱和砂土三轴试验中的若干问题

陈春霖; 张惠明

饱和砂土三轴试验中的若干问题 English Version

广东省公路建设公司!广东广州510600；铁道部科学研究院深圳研究设计院!广东深圳518034；

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出版历程
- 发布日期: 2000-11-23

Some problems in triaxial test on saturated sands

1.Guangdong Highway Construction Company Guangzhou 510600 China 2.Shenzhen Research Design Institute China Academy of Railway Sciences Shenzhen 518034 China

摘要

摘要: 砂土的稳态强度是评估砂土液化破坏的重要指标。其特点一是受密度或孔隙比的影响很大 ,二是发生在较大的轴向应变水平 ,受不均匀变形影响较大。研究结果表明 ,砂土试样在饱和过程及不排水剪切过程均产生体积变形 ,对试验结果造成严重影响。借助侧向变形仪HRDT可直接测定或推算上述体变。通过利用润滑试样帽或用低密度试样可减小端部约束对试验结果的影响 ,但润滑试样帽的润滑剂和橡皮模的厚度要适中 ,以免产生较大的孔隙比误差。常规面积修正法在大应变时会明显高估了偏应力。为修正这种误差 ,本文提出了一种新面积修正方法。对于高均匀系数砂土 ,重复使用砂样进行剪切试验可能会导致较大的试验误差 ;进一步的结果表明 ,砂土稳态强度的试验结果的离散性与其均匀系数有相关关系 ,高均匀系数砂土的稳态孔隙比的离散值是低均匀系数的 3倍以上。
- 稳态强度 /
- 试验 /
- 三轴 /
- 砂 /
- 误差 /
- 面积修正 /
- 均匀系数
Abstract: Steady state (SS) strength, an important parameter in evaluating the stability of sand deposits against flow sliding, may be significantly affected by testing details including volume change during saturation and undrained shear, end restraint and non uniform deformation. The error in SS strength due to the volume change can be corrected by using a radial deformation transducer (e.g. HRDT) to measure the radial deformation of a triaxial sample. The effect of end restraint is insignificant for loose sand samples and can be considerably reduced by applying lubricated end platen. The thickness of the lubricant and the membrane should not be too thick to produce additional error in void ratio. A new method is suggested to correct the cross sectional area of a triaxial sample. Reuse of sheared sand material may produce large error in SS strength for sands with high coefficient of uniformity (C u ). The scatter of the void ratio in steady state is about 0.02 for sands with low value of C u , and can be over 0.06 for C u  of 2.0～2.7.
- steady state strength /
- testing /
- triaxial /
- sand /
- error /
- area correction /
- coefficient of uniformity

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