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利用室内大型循环直剪仪进行了一系列筋土界面循环剪切试验,筋材采用土工编织布和无纺土工布,土体采用中国ISO标准砂,在竖向应力分别为30、60、90kPa,剪切位移幅值分别为1、3、5mm,砂土密实度分别为22%、52%、75%时,研究了竖向应力、剪切位移幅值、砂土密实度对筋土界面循环剪切特性的影响,分析了循环剪切过程中2种土工布与砂土界面的剪切应力峰值和剪切应力-剪切位移的变化规律。研究结果表明:2种土工布与砂土界面均会发生循环剪切软化现象,但软化规律不同;竖向应力从30kPa增大到90kPa时,土工编织布与砂土界面循环剪切应力峰值增大了72.9%,无纺土工布与砂土界面循环剪切应力峰值增加了167.5%,表明竖向应力对土工编织布与砂土界面的循环剪切特性影响明显;剪切位移幅值分别为1、3、5mm时,土工编织布与砂土界面剪切应力峰值分别为25.9、27.9、29.8kPa,无纺土工布与砂土界面剪切应力峰值分别为21.8、23.8、22.6kPa,表明随着剪切位移幅值增大,土工编织布与砂土界面剪切应力峰值随之增大,而无纺土工布与砂土界面剪切应力峰值先增大后减小;在3种砂土密实度下,土工编织布与砂土界面剪切应力峰值之间的最大差值不超过2kPa,无纺土工布与砂土界面剪切应力峰值之间的最大差值不超过3kPa,表明砂土密实度对2种土工布与砂土界面的循环剪切特性影响不明显。
A series of cyclic shear tests were carried out by using the large-scale indoor circular shear tester. The geotextile was made of geotextile and non-woven geotextile. The soil was made of China ISO standard sand. The vertical stress was 30,60 and 90 kPa , The shear displacement amplitude is 1, 3, 5mm respectively, the density of sand and soil is 22%, 52% and 75% respectively. The influence of vertical stress, shear displacement amplitude, The influence of cyclic shear characteristics on the shear stress and shear stress-shear displacement at the interface between two geotextiles and sand was analyzed. The results show that the cyclic shear softening occurs at the interface between the two kinds of geotextiles and sand, but the softening rules are different. When the vertical stress increases from 30 kPa to 90 kPa, the cyclic shear stress at the interface between geotextile and sand increases A large increase of 72.9%, the cyclic shear stress peak value of non-woven geotextile and sand increased 167.5%, indicating that the vertical stress had an obvious effect on the cyclic shear properties at the interfaces of geotextile and sand; the amplitude of shear displacement was The shear stress peak value of the interface between geotextile and sand was 25.9, 27.9 and 29.8 kPa respectively at 1, 3, 5 mm. The interfacial shear stress peak value of non-woven geotextile and sand was 21.8, 23.8 and 22.6.6 kPa, respectively, The amplitude of shear displacement increases with the increase of the shear stress at the interface between geotextile and sand, while the peak value of shear stress at the interface between geotextile and sand increases first and then decreases. Density, geotextile cloth and sand interface shear stress peak value of the maximum difference between no more than 2kPa, non-woven geotextile sand and sand interface shear stress peak value of the maximum difference between not more than 3kPa, indicating that the sand Density of two kinds of geotextiles and sand interface cycle shear special Little effect.