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针对单轴拉伸试验中试样形式与拉伸段长度对试验结果影响程度较大,以及目前在该试验中所采用试样形式与拉伸段长度均存在较大差异的问题,研制一组可以制备不同拉伸段长度哑铃状单轴拉伸试样的制样模具;在此基础上,对黏性土试样进行单轴拉伸试验,探讨了黏性土的抗拉特性,以及试样形式与拉伸段长度对其破坏形式、抗拉强度与峰值位移的影响情况。研究结果表明:哑铃状试样可避免拉伸过程中出现的端部松弛与应力集中问题,拉伸断裂面发生在有效拉伸长度范围内;黏性土的破坏形式不是纯脆性破坏,而是在抗拉强度后存在一个软化阶段;抗拉强度随拉伸段长度的增大而减小,峰值位移随拉伸段长度的增大而增大,二者均与拉伸段长度呈对数关系。
For the uniaxial tensile test specimen form and the length of the tensile test section of the greater impact on the test results, and the current test used in the sample form and the length of the tensile section there is a big difference between the problem, the development of a group It is possible to prepare sample preparation molds for dumbbell shaped uniaxial tensile specimens with different stretch lengths. On the basis of this, uniaxial tensile tests on clay specimens are carried out to investigate the tensile properties of clay, The impact of the sample form and the length of the tensile section on its failure mode, tensile strength and peak displacement. The results show that the dumbbell-shaped specimen can avoid the end relaxation and stress concentration problems during the tensile process. The tensile fracture surface occurs within the range of the effective tensile length. The failure mode of the clay soil is not purely brittle failure. After the tensile strength there is a softening stage; the tensile strength decreases with the increase of the length of the tensile section, the peak displacement increases with the length of the tensile section, both of them have a logarithm of the length of the tensile section relationship.