循环热力作用下压气储能洞室钢衬的疲劳耐久性

Fatigue Durability of Steel Lining in Compressed Air Energy Storage Caverns Under Cyclic Thermomechanical Effects

以大同云冈矿拟建的压气储能电站为例,构建压气储能洞室热力耦合计算模型,通过应力疲劳、应变疲劳、裂纹扩展疲劳3种疲劳分析方法对长期运行条件下钢衬的耐久性进行研究。结果表明:钢衬疲劳寿命计算中必须考虑裂纹扩展的影响,应力疲劳法和应变疲劳法由于没有考虑裂纹扩展的影响,会使疲劳寿命计算结果偏大;钢衬疲劳寿命主要受围岩弹性模量、洞室运营压力和初始裂纹尺寸影响,围岩弹性模量越大、洞室运营压力及初始裂纹尺寸越小,相应的钢衬疲劳寿命就越大;此外,钢衬疲劳寿命随着钢衬厚度的增加而增加,但存在一个最佳厚度,当钢衬厚度大于该厚度时,钢衬的疲劳寿命将不会有明显变化。

Based on a proposed compressed air energy storge power station project in Yungang Mine,Datong,China,the thermodynamic coupling calculation model of compressed air energy storge caverns was established,and the durability of steel lining under long-term operation conditions was studied by using three fatigue analysis methods:stress fatigue method,strain fatigue method and crack propagation fatigue method.Results show that the stress fatigue method and strain fatigue method overestimated the fatigue life of steel lining.Thus,the crack propagation must be taken into consideration in calculation.The fatigue life of lining is mainly affected by the elastic modulus of surrounding rock,the operating pressure of carven and the initial crack size.The fatigue life will be much longer if higher elastic modulus of surrounding rock,lower operating pressure and smaller initial crack size are adapted.The fatigue life of steel lining increases nonlinearly with the lining thickness.However,a critical value of lining thickness can be found,exceeding which the fatigue life will not change significantly.