真三轴加载条件下混凝土的力学特性

发布时间：2018-04-24 00:10

  本文选题：土木建筑工程 + 复合材料　； 参考：《吉林大学学报(工学版)》2017年03期

【摘要】：采用真三轴设备对100mm×100mm×100mm的立方体混凝土试块进行静态加载。首先,保持三个轴向的应力相同,施加应力到设计值p。然后,在保持最小主应力(Z轴)恒定并且X轴应变速率与Y轴应变速率之比也恒定的条件下,单调地增加Y轴应变。通过这种复杂加载试验,研究了混凝土的强度和体积特征。结果表明:在应力-应变混合路径加载的真三轴试验下,混凝土的抗压强度随着最小主应力的增大而增大,随着加载应变速率比的增大而线性递减,都大于单轴抗压强度,最高可达单轴抗压强度的3.4倍;混凝土试块在只经历静水压的加载历史时,初始剪切模量不受影响,不同组剪应力-剪应变关系曲线初始段都存在重合现象。峰值体积应变随着最小主应力和应变速率比的增大而增大,体积先减小后增大,出现扩容现象;当最小主应力为10MPa时,混凝土的峰值强度和峰值体积压应变几乎同时出现,并随着最小主应力的增大,两者出现的时间间隔增大,峰值体应变滞后。
[Abstract]:The cubic concrete specimen of 100mm 脳 100mm 脳 100mm is loaded statically by true triaxial equipment. First, keep the three axial stresses the same and apply the stress to the design value p. Then, under the condition that the minimum principal stress is kept constant and the ratio of X axis strain rate to Y axis strain rate is also constant, the Y axis strain is monotonously increased. The strength and volume characteristics of concrete are studied through this complex loading test. The results show that the compressive strength of concrete increases with the increase of the minimum principal stress and decreases linearly with the increase of the strain rate ratio, and is higher than that of the uniaxial compressive strength under the true triaxial test under the stress-strain mixed path loading. The maximum uniaxial compressive strength is 3.4 times, and the initial shear modulus is not affected when the concrete specimen only experiences the loading history of hydrostatic pressure, and the initial section of the different groups of shear stress-strain relationship curves is overlapped. The peak volume strain increases with the increase of the minimum principal stress and strain rate ratio, and the volume decreases first and then increases, and then increases, and when the minimum principal stress is 10MPa, the peak strength and the peak volume compressive strain of concrete almost appear at the same time. With the increase of the minimum principal stress, the time interval between the two increases and the peak strain lags behind.
【作者单位】： 北京交通大学土木建筑工程学院;
【基金】：国家自然科学基金项目(51279003)
【分类号】：TU528
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本文编号：1794253