砂岩破坏特性与能量耗散的试验研究1)
EXPERIMENTAL RESEARCH ON FAILURE AND ENERGY DISSIPATION CHRACTERISTICS OF THE SANDSTONE1)
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摘要: 通过三轴卸荷试验,探究了不同路径下卸荷速率对砂岩力学特性及破坏过程中的能量耗散的影响。试验结果表明在全过程应力-应变曲线的弹性阶段,轴向变形起主导作用,弹塑性阶段,环向应变的增加值大于轴向应变增加值。在围压卸荷阶段,卸荷速率越小,卸荷阶段的应变折合柔度越大,此时岩样的变形不充分,呈现明显的脆性破坏。恒主应力差路径下的耗散能大于恒轴压路径下的耗散能的35%,卸荷速率越大,岩样的弹性应变能越小。Abstract: The effects of unloading rate under different paths on the mechanical properties of sandstone and the energy dissipation in the failure process have been analyzed by the triaxial unloading test The results are as follows: the axial deformation plays a leading role in the elastic phase of the whole process stress-strain curve. And in the elastoplastic stage, the increase of the hoop strain is greater than the axial strain’s In the confining pressure unloading stage, the smaller the unloading rate, the greater the flexibility of the strain. At the same time, the deformation of the rock sample is insufficient, which is an obvious brittle failure characteristic. The dissipative energy under the constant principal stress difference path is 1.35 times than it is under the constant axial pressure path The larger the unloading rate, the smaller the elastic strain energy of the rock sample.