固结比对饱和砂土液化的影响研究
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摘要
在影响砂土液化的众多因素中 ,固结比的作用已经引起了广大科研工作者的注意 ,研究表明这是影响饱和砂土液化的一个重要因素 ,本文通过动三轴实验 ,研究了在不同固结比下砂土的液化全过程 ,分析表明 ,固结比影响了砂土液化过程中的应力状态 ,从而造成在不同固结比情况下 ,砂土的应变、液化强度和孔隙水压力发展出现明显不同。固结比的不同会影响到砂土的液化应力状态 ,从而造成应变发展的不同 ,固结比为 1的实验受拉破坏先于受压破坏 ,对于其它的固结比 ,拉压破坏先后顺序与土的特性和孔隙水压力的发展有关。并且 ,由于固结比大的砂土在动荷载作用下易于达到剪胀 ,从而应力 应变曲线迅速向稳定形状过渡 ;随着固结比的增加 ,导致影响反向剪应力出现所需要的动应力也愈大 ,从而砂土液化强度会有所提高 ,但是 ,因固结比增加引起砂土强度的增加的趋势会受到动摩擦强度的限制 ;大固结比情况下的砂土进入剪胀较早 ,因而抑制了砂土残余孔隙压力的积累 ,影响了极限孔隙水压力的发展 ,研究表明 ,固结比愈大 ,砂土的极限孔隙水压力呈线性下降趋势
In all elements that effect sand liquidation, the effect of consolidation ratio receives the attention of many scientists and researchers. According to the study, consolidation ratio is an important element in the effect on saturated sand liquidation. In the paper, the effect of the consolidation ratio of saturated sand liquidation was studied based on the dynamic triaxial test. According to the data, the paper analyzes the relation between the different consolidation ratio and the development of the sand liquidation. Basing on this, the authors find the consolidation ratio is an important factor that influences the sand liquidation strength. The difference of consolidation ratio can influence the sand liquidation stress status, resulting in the difference of the strain development. When the consolidation ratio is 1, the drawing destruction occurs before the pressing destruction. As to the others, the order of drawing-pressing destruction is related to the sand characters and pore press. Because the sand with bigger consolidation ratio is subject to reaching shear contraction, the stress strain curve rapidly develops to a steady value. With the increment of consolidation ratio, the required dynamic stress resulting in the presence of retro shear stress is also bigger, resulting in the promotion of sand liquidation strength. But this direction is limited by the dynamic fraction strength. The sand with bigger consolidation ratio reach shear contraction earlier, thus it restrains the collection of sand pore pressure, effects on the development of limited pore pressure. It is testified that big consolidation ratio generates a sand limited pore pressure that takes a downward curve linearly.
In all elements that effect sand liquidation, the effect of consolidation ratio receives the attention of many scientists and researchers. According to the study, consolidation ratio is an important element in the effect on saturated sand liquidation. In the paper, the effect of the consolidation ratio of saturated sand liquidation was studied based on the dynamic triaxial test. According to the data, the paper analyzes the relation between the different consolidation ratio and the development of the sand liquidation. Basing on this, the authors find the consolidation ratio is an important factor that influences the sand liquidation strength. The difference of consolidation ratio can influence the sand liquidation stress status, resulting in the difference of the strain development. When the consolidation ratio is 1, the drawing destruction occurs before the pressing destruction. As to the others, the order of drawing-pressing destruction is related to the sand characters and pore press. Because the sand with bigger consolidation ratio is subject to reaching shear contraction, the stress strain curve rapidly develops to a steady value. With the increment of consolidation ratio, the required dynamic stress resulting in the presence of retro shear stress is also bigger, resulting in the promotion of sand liquidation strength. But this direction is limited by the dynamic fraction strength. The sand with bigger consolidation ratio reach shear contraction earlier, thus it restrains the collection of sand pore pressure, effects on the development of limited pore pressure. It is testified that big consolidation ratio generates a sand limited pore pressure that takes a downward curve linearly.
引文
[1] 聂守智.在动荷载作用下饱和砂土的液化及其强度[J].岩土工程学报,1980,(3).
[2] 张克绪.饱和砂土的液化应力条件[J].地震工程与工程震动,1984,(3).
[3] 汪闻韶.饱和砂土振动孔隙压力实验研究[J].水利学报,1962,(2).
[4] SeedHBandLeeKL .LiquefactionofSaturatedSandsDuringCylicLoading.J .SMFDn,Proc.ASCE ,1961,92(6).
[2] 张克绪.饱和砂土的液化应力条件[J].地震工程与工程震动,1984,(3).
[3] 汪闻韶.饱和砂土振动孔隙压力实验研究[J].水利学报,1962,(2).
[4] SeedHBandLeeKL .LiquefactionofSaturatedSandsDuringCylicLoading.J .SMFDn,Proc.ASCE ,1961,92(6).
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