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利用WDT-1500多功能材料试验机,对砂岩、砾岩和砂砾岩进行了分级循环荷载试验,研究了岩石的动弹性模量对应力幅值和应力水平的响应特性,得到了动弹性模量和耗散能随应力幅值、应力水平及含水率的变化规律。试验结果表明,分级循环荷载下岩石的能量耗散越多,动弹性模量越小;应力水平越高,动弹性模量和耗散能越大;含水率和应力幅值越大,动弹性模量越小,耗散能越大。讨论了邓肯-张模型能够描述分级循环荷载作用下岩石的应力-应变关系,构建了动弹性模量随应力水平、应力幅值及含水率变化的演化模型,探讨了模型参数的确定方法。根据能量耗散的经验法则,建立了耗散能演化模型,结果表明,该模型能够描述分级循环荷载过程中能量耗散行为。
The cyclic loading tests of sandstone, conglomerate and conglomerate with WDT-1500 multifunctional material testing machine were carried out. The response characteristics of dynamic elastic modulus of rock to stress amplitude and stress level were studied. The dynamic elastic modulus And dissipated energy with stress amplitude, stress level and moisture content of the law of change. The experimental results show that the more the energy dissipation of the rock under graded cyclic loading, the smaller the dynamic elastic modulus; the higher the stress level, the greater the dynamic elastic modulus and dissipation energy; the greater the water content and stress amplitude, the dynamic elastic The smaller the modulus, the greater the dissipation. The Duncan - Zhang model is used to describe the stress - strain relationship of rock under the cyclic loading. The evolution model of dynamic elastic modulus with stress level, stress amplitude and moisture content is established, and the method to determine the model parameters is discussed. According to the rule of energy dissipation, the evolution model of dissipative energy is established. The results show that this model can describe the energy dissipation behavior during the cyclic loading.