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  本文選題：黃土 + 抗拉試驗(yàn)　； 參考：《鐵道標(biāo)準(zhǔn)設(shè)計》2016年09期

【摘要】：針對現(xiàn)有土工抗拉儀存在的缺陷與不足,設(shè)計改良出一套簡易軸向拉伸試驗(yàn)儀。通過四角調(diào)節(jié)螺栓和夾具設(shè)計,消除摩擦阻力和端部應(yīng)力集中,通過軸心線的控制避免試樣偏心受拉�？梢酝瓿刹煌�尺寸長方體試樣的抗拉試驗(yàn)。由于目前試樣尺寸沒有統(tǒng)一標(biāo)準(zhǔn),為了得到試樣的規(guī)范尺寸并分析試樣尺寸對抗拉特性的影響,利用設(shè)計的拉伸裝置,對不同截面和長細(xì)比試樣進(jìn)行試驗(yàn)。得到的試驗(yàn)結(jié)果有:ω=18.0%,ρd=1.30 g/cm3時,不同截面試樣平均抗拉強(qiáng)度值在14.2~14.6 k Pa,平均極限位移值在8×10-2~9×10-2mm;ω=22.0%,ρd=1.45 g/cm3時,不同長細(xì)比試樣平均抗拉強(qiáng)度值在14.4~14.9 k Pa,平均極限位移值與長細(xì)比的關(guān)系式可表示為b=9.706 7×(l/a)-6.97。分析表明:只要試樣的物理狀態(tài)(含水率ω和干密度ρd)相同,不論含水率ω是否小于或大于塑限值,抗拉強(qiáng)度值均不受截面和長細(xì)比的影響;含水率ω低于塑限值時,極限拉伸位移不隨試樣的截面變化;含水率高于塑限值時,極限拉伸位移與長細(xì)比呈遞增的線性關(guān)系。計算每組試樣抗拉強(qiáng)度值的極差和標(biāo)準(zhǔn)差并分析數(shù)據(jù)的離散性,結(jié)合制樣難易程度和用土量等方面綜合考慮,提出截面邊長2.5 cm,長細(xì)比3的試樣尺寸較為合理,為今后開展土體抗拉強(qiáng)度研究提供可靠依據(jù)。
[Abstract]:In view of the defects and shortcomings of the existing geotechnical tensile tester, a set of simple axial tensile tester was designed and improved. The friction resistance and stress concentration at the end are eliminated by adjusting the bolts and clamps in four angles, and the eccentric tension of the specimen is avoided by the control of the axis line. The tensile tests of cuboid specimens with different sizes can be completed. Because there is no uniform standard for specimen size at present, in order to obtain the standard size of the specimen and analyze the influence of the specimen size on the tensile properties, the different cross-section and aspect ratio samples are tested by the designed tensile device. The experimental results are as follows: the average tensile strength of specimens with different sections is 14.2N14.6 KPA, the average limit displacement is 9 脳 10-2mm at 蠅 _ (18.0) and 蟻 _ d _ (1.30) g/cm3, and the average limit displacement is 8 脳 10 ~ (-2) ~ 9 脳 10 ~ (-2) mm, 蠅 _ (22) and 蟻 _ d ~ (1.45) g/cm3, respectively. The average tensile strength of specimens with different slenderness ratios is 14.4 ~ 14.9 KPA, and the relationship between the average ultimate displacement value and the aspect ratio can be expressed as b _ (9.7067) 脳 l / a ~ (-1) / a ~ (-6.97). The analysis shows that as long as the physical state of the sample (moisture content 蠅 and dry density 蟻 d) is the same, whether or not the moisture content 蠅 is less than or greater than the plastic limit value, the tensile strength value will not be affected by the cross section and the aspect ratio, and when the moisture content 蠅 is lower than the plastic limit value, The ultimate tensile displacement does not change with the cross section of the specimen, and when the moisture content is higher than the plastic limit, the linear relationship between the ultimate tensile displacement and the aspect ratio is increasing. By calculating the range and standard deviation of tensile strength of each group of specimens and analyzing the discreteness of the data, considering the difficulty of sample preparation and the amount of soil used, it is proposed that the sample size with a cross section length of 2.5 cm and a slenderness ratio of 3 is more reasonable. It provides a reliable basis for the study of soil tensile strength in the future.
【作者單位】： 石家莊鐵道大學(xué)土木工程學(xué)院;南京水利科學(xué)研究院;
【基金】：國家自然基金項目(50978172) 鐵道部科技研究開發(fā)計劃項目(2010G018-B-4) 國家大學(xué)生創(chuàng)新創(chuàng)業(yè)訓(xùn)練計劃(201410107018)
【分類號】：TU415

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本文編號：1949956