分级加载条件下深部灰岩蠕应变特性研究
发布时间：2018-12-12 13:16
【摘要】：为研究深部灰岩蠕应变特性,采用GDS-VIS三轴流变仪对不同深度试样做分级加载单轴蠕变试验。基于试验结果,计算出灰岩长期强度与瞬时强度之比的均值为0.758,且深度越深比值越小;分析不同深度灰岩在各分级应力水平下轴向蠕应变增量与加载级数的变化规律,并将蠕应变增量进行一次累加,得到轴向蠕应变。结果表明:蠕应变增量随级数的增加呈现先减小后剧增的变化规律,且随深度增加,蠕应变增量达到谷底所对应的应力百分比有明显增大趋势;在分级加载过程中,随级数增加,轴向蠕应变先后呈现减速增加、等速增加和加速增加3个发展阶段;当恒载应力百分比为60%~70%时,蠕应变趋于稳定,当超过该范围后,蠕应变加速增加直至发生蠕变破坏。研究得到的这一应力百分比范围可以为识别深部灰岩是否会发生蠕变破坏提供依据。
[Abstract]:In order to study the vermicular strain characteristics of deep limestone, uniaxial creep tests with GDS-VIS triaxial rheometer were performed on specimens with different depths. Based on the experimental results, the average value of the ratio of long-term strength to instantaneous strength of limestone is 0.758, and the ratio of depth to depth is smaller. The variation law of axial vermicular strain increment and loading series of limestone with different depth under various graded stress levels is analyzed. The creep strain increment is accumulated once and the axial vermicular strain is obtained. The results show that the increment of vermicular strain decreases at first and then increases sharply with the increase of series, and with the increase of depth, the percentage of stress corresponding to crease of vermicular strain increases obviously. In the process of step loading, with the increase of series, the axial creep strain increases successively, and increases at equal speed and accelerates at three stages of development. When the percentage of dead load stress is 60 ~ 70, the vermicular strain tends to be stable, and when it exceeds this range, the creep strain accelerates until creep failure occurs. The obtained stress percent range can provide a basis for identifying whether creep failure will occur in deep limestone.
【作者单位】： 江西理工大学资源与环境工程学院;江西理工大学江西省矿业工程重点实验室;
【基金】：国家自然科学基金项目(51564012) 江西省科技支撑计划项目(20141BBE50005)
【分类号】：TU45
本文编号：2374632
[Abstract]:In order to study the vermicular strain characteristics of deep limestone, uniaxial creep tests with GDS-VIS triaxial rheometer were performed on specimens with different depths. Based on the experimental results, the average value of the ratio of long-term strength to instantaneous strength of limestone is 0.758, and the ratio of depth to depth is smaller. The variation law of axial vermicular strain increment and loading series of limestone with different depth under various graded stress levels is analyzed. The creep strain increment is accumulated once and the axial vermicular strain is obtained. The results show that the increment of vermicular strain decreases at first and then increases sharply with the increase of series, and with the increase of depth, the percentage of stress corresponding to crease of vermicular strain increases obviously. In the process of step loading, with the increase of series, the axial creep strain increases successively, and increases at equal speed and accelerates at three stages of development. When the percentage of dead load stress is 60 ~ 70, the vermicular strain tends to be stable, and when it exceeds this range, the creep strain accelerates until creep failure occurs. The obtained stress percent range can provide a basis for identifying whether creep failure will occur in deep limestone.
【作者单位】： 江西理工大学资源与环境工程学院;江西理工大学江西省矿业工程重点实验室;
【基金】：国家自然科学基金项目(51564012) 江西省科技支撑计划项目(20141BBE50005)
【分类号】：TU45
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