砂土中部分级配的直剪强度指标变化规律
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摘要
在实际的基础工程中,土的抗剪强度设计参数研究非常重要。为了解决实际工程中大粒径土很难测定剪切强度指标及抗剪强度这个问题,一般采用相似级配或部分级配砂土通过室内直接剪切试验、三轴压缩试验来分析砂土的剪切强度。该研究通过最大粒径40 mm原级配中截取最大粒径分别为2 mm,5 mm和10 mm的部分级配,直接剪切试验。经分析随着最大粒径的增大内摩擦角增大,但增大趋势越来越慢,颗粒之间的咬合力出现减小的趋势。在垂直应力整体较小时,剪切强度先增大再略有减小,垂直应力较大时,剪切强度一直增大。
In practical foundation engineering,it is very important to study the design parameters of soil shear strength. In order to solve the problem that it is difficult to determine the shear strength index and shear strength of large-size soil in practical engineering,the shear strength of sand soil with similar or partially graded grading is generally analyzed by direct shear test and triaxial compression experiment in laboratory. In this study,a direct shear test was carried out by cutting part of the original gradation with the maximum particle size of 40 mm and the maximum particle size of 2 mm,5 mm and 10 mm,respectively. The analysis shows that the internal friction angle increases with the increase of the maximum particle size,but the increasing trend is slower and slower,the bite force between sand particles tends to decrease. When the vertical stress is small,the shear strength first increases and then decreases slightly. When the vertical stress is large,the shear strength increases continuously.
In practical foundation engineering,it is very important to study the design parameters of soil shear strength. In order to solve the problem that it is difficult to determine the shear strength index and shear strength of large-size soil in practical engineering,the shear strength of sand soil with similar or partially graded grading is generally analyzed by direct shear test and triaxial compression experiment in laboratory. In this study,a direct shear test was carried out by cutting part of the original gradation with the maximum particle size of 40 mm and the maximum particle size of 2 mm,5 mm and 10 mm,respectively. The analysis shows that the internal friction angle increases with the increase of the maximum particle size,but the increasing trend is slower and slower,the bite force between sand particles tends to decrease. When the vertical stress is small,the shear strength first increases and then decreases slightly. When the vertical stress is large,the shear strength increases continuously.
引文
[1]杨涛,路明月.土体抗剪强度试验方法及强度指标的物理含义[J].山西建筑,2014,40(29):82-84.
[2]王誉霖.近似级配条件下砂土力学性差异及其PFC分析方法的研究[D].重庆:重庆交通大学专业硕士学位论文,2017.
[3] SL 237—1999,土工试验规程[S].
[4]李振,李鹏.粗粒土直接剪切试验抗剪强度指标变化规律[J].防渗技术,2002,8(1):11-14.
[5]司洪洋.粗颗粒土石料的定名与粗度系数[J].水利水运科学研究,1981(1):73-77.
[6]董云.土石混合料力学特性的试验研究[D].重庆:重庆交通学院,2005.
[7]郭庆国.关于粗砾土工程特性及其分类的探讨[J].水利水电技术,1979(6):53-57.
[8]李振,邢义川.干密度和细粒含量对砂卵石及碎石抗剪强度的影响[J].岩土力学,2006,27(12):2255-2260.
[9]杨健,颜雪,徐新春.粉细砂的抗剪强度试验研究[J].现代公路,2013,7(53):150-151.
[10]禹艳阳,朱豪伟,蒋宇卓,等.粒径大小对粗细粒混合土力学性质的影响[J].四川建材,2018,44(9):88-90.
[2]王誉霖.近似级配条件下砂土力学性差异及其PFC分析方法的研究[D].重庆:重庆交通大学专业硕士学位论文,2017.
[3] SL 237—1999,土工试验规程[S].
[4]李振,李鹏.粗粒土直接剪切试验抗剪强度指标变化规律[J].防渗技术,2002,8(1):11-14.
[5]司洪洋.粗颗粒土石料的定名与粗度系数[J].水利水运科学研究,1981(1):73-77.
[6]董云.土石混合料力学特性的试验研究[D].重庆:重庆交通学院,2005.
[7]郭庆国.关于粗砾土工程特性及其分类的探讨[J].水利水电技术,1979(6):53-57.
[8]李振,邢义川.干密度和细粒含量对砂卵石及碎石抗剪强度的影响[J].岩土力学,2006,27(12):2255-2260.
[9]杨健,颜雪,徐新春.粉细砂的抗剪强度试验研究[J].现代公路,2013,7(53):150-151.
[10]禹艳阳,朱豪伟,蒋宇卓,等.粒径大小对粗细粒混合土力学性质的影响[J].四川建材,2018,44(9):88-90.