均匀单轴压应力场下岩石的力学性质

为了研究在均匀压应力场下岩石的力学性质,制作了中等壁厚的环形岩石试件,该试件在承受均布外压时,其内壁处于均匀单轴压应力状态,且内壁的应变可直接量测。控制试件的壁厚,内壁的应力可在一定的误差范围内由静力平衡条件求得。试验在自行研制的中壁圆环抗压试验机上进行,结果表明:在均匀压应力场下,岩石的应力——应变曲线无明显的峰后段,且其强度高于常规单轴抗压强度并具有较小的变异系数。

The mechanical property of rock in the uniform uniaxial stress state

Medium-walled circular ring rock specimens are made in order to study the mectanical property of rock. The inner wall specimen is subject to uniform uniaxial stress while the outer wall specimen is subject to the uniform outer pressure. The stress of the inner wall can be computered directly with some tolerable errors by static equilibrium equation without the need for elastic or plastic hypothesis. The error can be controled by setting the ratio of the iner radius to the outer radius . The test is carried out in the medium-walled circular ring testing machine made by the authors. According to the result of the experiments, conclusion is reached that the uniaxial compres-sive stress-strain curve does not present the falling regin, but has higher compressive strength and more minute variance coefficient than with traditional rock compressive testing.