扭剪荷载作用下饱和南京砂不排水特性试验研究

发布时间：2018-05-18 23:13

本文选题：单调扭剪 + 循环扭剪　；参考：《岩土力学》2017年01期

【摘要】：通过空心圆柱扭剪仪对不同相对密实度的饱和南京砂分别进行了单调扭剪不排水、排水试验以及循环扭剪不排水试验。试验结果表明:在单调扭剪试验中,试样相转换线的位置与排水条件无关,但相对密实度较大试样的相转换线斜率小于相对密实度较小的试样。在循环扭剪不排水试验中,对于相对密实度较小的试样,当其有效应力路径接近单调扭剪荷载作用下具有相同初始条件试样的相转换线时,孔压急剧增加,扭剪应变迅速增大,试样出现不稳定现象,随后发生初始液化;对于相对密实度较大的试样,当其有效应力路径接近单调扭剪荷载作用下试样的相转换线时,试样出现循环活动现象,随着循环扭剪荷载的继续施加,有效应力路径表现为以破坏线为边界且呈"蝴蝶"形状的一系列重叠的回滞环,此时孔压在某一常值上下波动,累积孔压不再增加。具有相同初始条件的试样在循环和单调扭剪荷载作用下得到的相转换线几乎相同,这一规律不受相对密实度的影响。
[Abstract]:Through the hollow cylindrical torsional shear apparatus, the monotone torsional shear undrained test, the draining test and the cyclic torsional shear undrained test were carried out on the saturated Nanjing sand with different relative compactness. The results show that in the monotone torsional shear test, the position of the phase transition line is independent of the drainage condition, but the slope of the phase conversion line of the sample with the larger relative density is smaller than that of the sample with the lower relative compactness. In the cyclic torsional shear undrained test, when the effective stress path is close to the phase transition line of the specimen with the same initial condition under monotone torsional shear load, the pore pressure increases sharply and the torsional shear strain increases rapidly. When the effective stress path is close to the phase transition line of the specimen under monotone torsional shear load, the sample appears the phenomenon of cyclic activity, and the initial liquefaction occurs when the specimen is unstable, and then the initial liquefaction occurs, and when the effective stress path is close to the phase transition line of the specimen under monotone torsional shear load, With the continuous application of cyclic torsional shear load, the effective stress path is shown as a series of overlapping hysteresis loops with the boundary of failure line as the boundary and the shape of "butterfly". Under this condition, the pore pressure fluctuates up and down at a constant value, and the cumulative pore pressure does not increase. The phase transfer lines of specimens with the same initial conditions are almost the same under cyclic and monotone torsional shear loads, and this rule is not affected by relative compactness.
【作者单位】：浙江大学滨海和城市岩土工程研究中心;温州大学建筑工程学院;温州大学浙江省软弱土地基与海涂围垦工程技术重点实验室;
【基金】：国家自然科学基金项目(No.51508417,No.51238009,No.51278383)~~
【分类号】：TU411

【相似文献】