红砂岩单轴压缩试验的率效应研究

利用MTS 322试验机对均质红砂岩进行了低加载（应变）率范围内不同量级的单轴压缩试验,考察了加载率对压缩强度、切线弹模和破坏应变的率效应影响规律。试验过程中采用位移控制加载,对应的加载量级分别为0.12,1.2,12,120 mm/min。研究结果表明：位移控制加载率与试样实际加载率、应变率之间均存在良好的线性关系。不同加载速率下岩石材料的单轴压缩强度、切线弹模随着加载率的增加呈现增加趋势,单轴压缩强度增加了11%,切线弹模增加了13%,率效应显著。通过试验数据发现,破坏应变与应变率（加载率）之间无相关性,不具有率效应规律,故强度准则应该是应力准则而不是应变准则。

Study On Rate Effect of Uniaxial Compression Test for Red Sandstone

The uniaxial compression tests of homogeneous red sandstone under low loading （strain） rate range with different order of magnitude were carried out using hydraulic servo test machine.The effects of loading （strain） rate on the compressive strength,tangent elastic modulus and failure strain were investigated.The displacement control loading was adopted in the process of testing,and the loading rate were 0.12,1.2,12,120 mm/min respectively.The results show that there are good linear relationship among displacement control loading rate,actual loading rate and strain rate of specimen.The uniaxial compressive strength and tangent elastic modulus of rock materials increase with the loading rate under different loading rates,the uniaxial compressive strength increases by 11%,the tangent elastic modulus increases by 13%,and the rate effect is remarkable. It is also found that the failure strain is no associated with strain rate （loading rate） by experimental data,and there is no law of rate effect,so the strength criterion should be stress criterion instead of strain criterion.