循环荷载下岩石临界强度的测定

Determination of Critical Strength of Rocks Subjected to Cycle Loading

通过对花岗岩、白砂岩和大理岩进行单轴压缩、疲劳特性试验,提出了一种测定循环荷载下岩石临界强度和疲劳强度的新方法。该方法以全应力-应变曲线试验为基础,进行不同高、低应力水平的疲劳试特性验。试验结果表明,岩石的临界强度不仅受岩石固有性质影响,而且受控于应力水平,特别是应力振幅。变幅应力与常幅应力相比,其临界强度降低21.6%～28.8%。试验求得的方程和参数对岩石基础工程的设计和运行安全评估具有实际应用价值。

A new method of determining the critical strength and fatigue strength of rock subjecting to cycle loading was put forward through the tests of uniaxial compression,fatigue property of granite ,white sandstone and marble. Based on the tests of the complete stress-strain curve, the fatigue tests on different high,low stress level were carried out in this method. The results showed that the critical strength was not only affected by rock＇s nature,but also was controlled by the stress level, especially stress amplitude. Comparing with the constants stress, the critical strength of the variable stress was lowered by 21.6% -28.8%. The test parameters and the equations acquired form this test would have practical value for the assessment of the design and safe operation in the rocks base engineering.