新型土工单轴拉伸试验装置的研制及应用
发布时间：2018-11-01 15:46
【摘要】：针对目前土工单轴拉伸试验水平的不足,研制了一套新型土工单轴拉伸试验装置,该套装置主要由试样制备、加载、控制与数据采集4个部分组成。试验装置通过燕尾槽与双滑动底板的设计,可以制备不同拉伸段长度的试样并分别开展相应的单轴拉伸试验;通过试样形式与所对应拉伸夹具的设计,解决了试样端部在拉伸过程中出现的松弛与应力集中问题;通过双导轨拉伸装置的设计,避免了试样在拉伸过程中出现的应力偏心现象;通过双级变速箱的设计使最小拉伸速率可达到0.001 mm/min,能够准确描述材料单轴拉伸破坏的演化过程,并能准确测试材料的抗拉强度以及全过程的拉应力-位移关系曲线。基于所研制的试验装置开展了黏性土的单轴拉伸试验,试验结果表明:黏性土的单轴拉伸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,此时仍具有一定的承载能力;随着试样拉伸段长度的增大,抗拉强度呈对数减小,峰值位移呈对数增大;随着拉伸速率的增加,抗拉强度呈对数增加,峰值位移呈线性增加;抗拉强度与峰值位移均随压实度的递增呈线性增加;随着含水率的递增,试样的抗拉强度先增大后减小,即存在一个峰值,而峰值位移呈线性增加。
[Abstract]:In view of the deficiency of the present uniaxial tensile test, a new type of geo-uniaxial tensile test device is developed. The device is mainly composed of four parts: sample preparation, loading, control and data acquisition. Through the design of swallowtail groove and double sliding bottom plate, the specimen with different tensile length can be prepared and the corresponding uniaxial tensile test can be carried out respectively. Through the design of specimen form and the corresponding tensile fixture, the problem of relaxation and stress concentration at the end of the specimen during the tensile process is solved. The stress eccentricity of the specimen during the tensile process is avoided by the design of the double guideway drawing device. Through the design of two-stage gearbox, the minimum tensile rate of 0.001 mm/min, can accurately describe the evolution process of uniaxial tensile failure of the material, and the tensile strength of the material as well as the tensile stress-displacement curve of the whole process can be accurately measured. The uniaxial tensile test of clay is carried out based on the experimental device. The results show that the failure mode of clay under uniaxial tension is not pure brittle failure, but a softening stage after tensile strength. At this time, there is still a certain bearing capacity; With the increase of tensile length, the tensile strength decreases logarithmically and the peak displacement increases logarithmically, and with the increase of tensile rate, the tensile strength increases in logarithm, and the peak displacement increases linearly. The tensile strength and the peak displacement increase linearly with the increase of compaction, and the tensile strength increases first and then decreases with the increase of water content, that is, there is a peak value and the peak displacement increases linearly.
【作者单位】： 南昌工程学院土木与建筑工程学院;江西省水利土木特种加固与安全监控工程研究中心;江西省水利土木工程基础设施安全重点实验室;南昌航空大学土木建筑学院;河海大学岩土力学与堤坝工程教育部重点实验室;
【基金】：国家自然科学基金项目(No.51609114) 江西省青年科学基金项目(No.20114BAB216010) 河海大学岩土力学与堤坝工程教育部重点实验室开放基金项目(No.2016001)~~
【分类号】：TU415
[Abstract]:In view of the deficiency of the present uniaxial tensile test, a new type of geo-uniaxial tensile test device is developed. The device is mainly composed of four parts: sample preparation, loading, control and data acquisition. Through the design of swallowtail groove and double sliding bottom plate, the specimen with different tensile length can be prepared and the corresponding uniaxial tensile test can be carried out respectively. Through the design of specimen form and the corresponding tensile fixture, the problem of relaxation and stress concentration at the end of the specimen during the tensile process is solved. The stress eccentricity of the specimen during the tensile process is avoided by the design of the double guideway drawing device. Through the design of two-stage gearbox, the minimum tensile rate of 0.001 mm/min, can accurately describe the evolution process of uniaxial tensile failure of the material, and the tensile strength of the material as well as the tensile stress-displacement curve of the whole process can be accurately measured. The uniaxial tensile test of clay is carried out based on the experimental device. The results show that the failure mode of clay under uniaxial tension is not pure brittle failure, but a softening stage after tensile strength. At this time, there is still a certain bearing capacity; With the increase of tensile length, the tensile strength decreases logarithmically and the peak displacement increases logarithmically, and with the increase of tensile rate, the tensile strength increases in logarithm, and the peak displacement increases linearly. The tensile strength and the peak displacement increase linearly with the increase of compaction, and the tensile strength increases first and then decreases with the increase of water content, that is, there is a peak value and the peak displacement increases linearly.
【作者单位】： 南昌工程学院土木与建筑工程学院;江西省水利土木特种加固与安全监控工程研究中心;江西省水利土木工程基础设施安全重点实验室;南昌航空大学土木建筑学院;河海大学岩土力学与堤坝工程教育部重点实验室;
【基金】：国家自然科学基金项目(No.51609114) 江西省青年科学基金项目(No.20114BAB216010) 河海大学岩土力学与堤坝工程教育部重点实验室开放基金项目(No.2016001)~~
【分类号】：TU415
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