本文選題：巖石力學(xué)　切入點：動荷載　出處：《巖土力學(xué)》2017年09期

【摘要】：為了合理地描述巖石的阻尼行為,提出了考慮軸向和環(huán)向阻尼振動的巖石阻尼參數(shù)計算方法;通過動循環(huán)荷載、分級循環(huán)荷載和常幅循環(huán)荷載試驗,對比分析了這3種不同應(yīng)力路徑下砂巖、礫巖及砂礫巖的阻尼特性,得到了阻尼參數(shù)對應(yīng)力幅值、應(yīng)變幅值的響應(yīng)特性,揭示了常幅循環(huán)加載過程中阻尼比和阻尼系數(shù)隨循環(huán)次數(shù)的演化規(guī)律;從熵守恒和能量守恒定律出發(fā),建立了巖石阻尼比隨循環(huán)次數(shù)演化的經(jīng)驗?zāi)Ｐ�。結(jié)果表明:(1)動荷載下巖石的阻尼比與軸向應(yīng)變幅值成線性遞增,而阻尼系數(shù)恰好相反;分級循環(huán)荷載下巖石的阻尼參數(shù)都隨應(yīng)力幅值成線性遞增。(2)疲勞破壞門檻值是巖石耗散能和阻尼比演化規(guī)律發(fā)生變化的分界點,在應(yīng)力上限高于疲勞破壞門檻值時,耗散能、阻尼比及阻尼系數(shù)隨循環(huán)次數(shù)都呈3階段的變化規(guī)律,演化曲線呈半U型;在應(yīng)力上限低于疲勞破壞門檻值時,呈現(xiàn)2階段的發(fā)展規(guī)律,演化曲線呈L型;(3)通過砂巖的阻尼比試驗,驗證了所建模型能夠描述砂巖在常幅循環(huán)荷載過程中阻尼行為。
[Abstract]:In order to describe the damping behavior of rock reasonably, a method for calculating the damping parameters of rock considering axial and toroidal damping vibration is put forward, and the dynamic cyclic load, graded cyclic load and constant cyclic load are tested. The damping characteristics of sandstone, conglomerate and sandy gravel under these three different stress paths are compared and analyzed, and the response characteristics of damping parameters to stress amplitude and strain amplitude are obtained. The evolution law of damping ratio and damping coefficient with the number of cycles in constant amplitude cyclic loading is revealed, and the conservation of entropy and energy is considered. An empirical model for the evolution of rock damping ratio with cyclic times is established. The results show that the damping ratio of rock increases linearly with the amplitude of axial strain under dynamic loading, but the damping coefficient is exactly the opposite. Under graded cyclic loading, the damping parameters of rock increase linearly with the stress amplitude. 2) the fatigue failure threshold is the boundary point of the evolution law of dissipation energy and damping ratio of rock. When the upper stress limit is higher than the fatigue failure threshold, the dissipative energy can be obtained. The damping ratio and damping coefficient change in three stages with the cycle number, and the evolution curve is half U, and when the upper limit of stress is lower than the fatigue failure threshold, it shows the development law of two stages. The model is proved to be able to describe the damping behavior of sandstone under constant cyclic loading.
【作者單位】： 西安理工大學(xué)巖土工程研究所;
【基金】：國家自然科學(xué)基金資助項目(No.11572246,No.51678484) 陜西省自然科學(xué)基礎(chǔ)研究計劃(No.2015JM5175)~~
【分類號】：TU45

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