人工冻结深部软岩单轴力学性能试验及蠕变模型

THE UNIAXIAL MECHANICAL PERFORMANCE TEST AND CREEP MODEL OF ARTIFICIAL FROZEN DEEP SOFT ROCK

  • 摘要: 为了了解深部软岩在冻结条件下的单轴力学性能,以东北地区的原状泥砂岩为试验对象,利用自行研制的WDT-100型人工冻土试验仪器,对其进行不同温度下的人工冻土单轴抗压强度试验和单轴蠕变试验,得到泥砂岩单轴压缩应力-应变关系曲线,各温度下试样的单轴抗压强度以及蠕变曲线.单轴压缩试验结果表明:试样在给定温度和加载速率条件下,单轴压缩应力-应变关系曲线都有较为明显的屈服点,并且都在屈服点后,强度有所提高,出现硬化现象.单轴蠕变试验结果表明:单轴压缩蠕变曲线有非线性特征,单轴压缩蠕变的等时应力-应变曲线向应变轴靠拢;单轴压缩时蠕变模量随时间的增长而降低.最后采用遗传算法优化模型参数,得出泥砂岩蠕变经验方程.与试验结果对比,发现拟合情况较好.

     

    Abstract: In order to understand the uniaxial mechanical performance of the deep soft rock under the frozen condition, the undisturbed pelitic sandstone from northeast of China is taken for test. The uniaxial compressive strength test and the uniaxial creep experiment for the artificial frozen pelitic sandstone are performed by using the self-developed artificial soil test instrument of WDT-100 type, and the stress-strain curve of the mud-sandstone, the uniaxial compressive strength at different temperatures, and the creep duration curve are obtained. The uniaxial compressive strength test shows that the stress-strain curve has an obvious yield point, and shows hardening phenomenon. The uniaxial creep experiment shows that the creep duration curve has nonlinear characteristics, the isochronous stress-strain curves are deviated to the strain axis, and the uniaxial compression creep modulus decreases with time, then tends to be stable over time. Finally the empirical formula is obtained by using a genetic algorithm to optimize model parameters. Compared with the results of test, the agreement is good.

     

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