本文選題：巖石力學(xué) + 軟巖��； 參考：《水利水電技術(shù)》2017年11期

【摘要】：為建立一種描述等幅周期荷載下軟巖應(yīng)變特性的本構(gòu)模型,將Bingham模型中的常值黏壺元件替換成與循環(huán)次數(shù)相關(guān)的變系數(shù)黏壺元件,常值彈性元件替換為隨周期荷載循環(huán)次數(shù)的增大而衰減的非定值彈性元件,即可得到反映周期荷載下軟巖各種應(yīng)變規(guī)律的Bingham本構(gòu)模型。當(dāng)循環(huán)荷載應(yīng)力上限值σmax大于巖石的臨界強(qiáng)度σs時(shí),模型為可反映軟巖3個(gè)應(yīng)變階段的改進(jìn)4參數(shù)Bingam模型;反之則為反映軟巖前兩個(gè)應(yīng)變階段的非常值2參數(shù)Hook模型。將周期荷載分解為一個(gè)定值荷載和一個(gè)平均應(yīng)力值為零的周期荷載,基于流變力學(xué)理論給出了定值荷載作用下基于該模型的本構(gòu)方程式,再根據(jù)黏彈性力學(xué)理論,給出了平均應(yīng)力值為零的周期荷載下基于該模型的本構(gòu)方程式,最后將已獲得的本構(gòu)方程式疊加即得到周期荷載下軟巖本構(gòu)方程式。結(jié)果表明:所建立的本構(gòu)方程式可較好描述周期荷載下不同軟巖各類應(yīng)變特征,對(duì)各類軟巖的應(yīng)變曲線擬合的相關(guān)系數(shù)均在0.868以上,且同一種巖石模型中彈性元件系數(shù)初始值隨周期荷載的動(dòng)應(yīng)力幅值的增大而減小,巖石加速應(yīng)變速率參數(shù)隨動(dòng)應(yīng)力幅值的增大而增大。
[Abstract]:In order to establish a constitutive model to describe the strain characteristics of soft rock under constant amplitude cyclic loading, the constant viscosity pot element in the Bingham model is replaced by a variable coefficient viscosity pot element related to the number of cycles. The constant elastic element is replaced by the non-constant value elastic element which attenuates with the increase of the cyclic number of cyclic loads, and the Bingham constitutive model reflecting the various strain laws of soft rock under periodic load can be obtained. When the upper limit value of cyclic load stress 蟽 max is greater than the critical strength 蟽 s of rock, the model is an improved four-parameter Bingam model which can reflect the three strain stages of soft rock, and the non-constant value 2-parameter Hook model which reflects the first two strain stages of soft rock. The periodic load is decomposed into a constant load and a periodic load with zero mean stress. Based on the rheological theory, the constitutive equation based on the model is given, and then the viscoelastic mechanics theory is used. The constitutive equation based on this model is given under the periodic load with zero mean stress. Finally, the constitutive equation of soft rock under periodic load is obtained by superposing the obtained constitutive equation. The results show that the constitutive equations can well describe the strain characteristics of different soft rocks under cyclic loading, and the correlation coefficients of the fitting of strain curves for each kind of soft rock are above 0.868. In the same rock model, the initial value of elastic element coefficient decreases with the increase of dynamic stress amplitude of periodic load, and the acceleration strain rate parameter of rock increases with the increase of dynamic stress amplitude.
【作者單位】： 貴州大學(xué)國(guó)土資源部喀斯特環(huán)境與地質(zhì)災(zāi)害重點(diǎn)實(shí)驗(yàn)室;貴州大學(xué)土木工程學(xué)院;中國(guó)水利水電科學(xué)研究院;
【基金】：國(guó)家自然科學(xué)基金項(xiàng)目(51168009)
【分類號(hào)】：TU45

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本文編號(hào)：1842922