發(fā)布時(shí)間：2018-06-02 13:41

  本文選題：深厚覆蓋層 + 地震動(dòng)　； 參考：《巖土工程學(xué)報(bào)》2017年07期

【摘要】：基于美國(guó)加州Caltrans/CDMG的兩個(gè)井下臺(tái)陣加速度記錄,從時(shí)域和頻域分析了百米級(jí)易液化深厚覆蓋層在不同地震下的地震動(dòng)放大效應(yīng),揭示了地震動(dòng)從基巖向覆蓋層傳播的4個(gè)重要特征:(1)加速度放大效應(yīng)受土層深度影響,近地表20~30 m以內(nèi)放大效應(yīng)突出;(2)地震動(dòng)三分量的放大效應(yīng)具有方向性,水平向與豎向地震動(dòng)放大效應(yīng)差異顯著;(3)基巖加速度呈現(xiàn)"小震放大、大震衰減"的規(guī)律;(4)加速度放大規(guī)律與頻率相關(guān),深厚覆蓋層放大頻帶較寬。初步分析了造成上述放大效應(yīng)的可能原因。在此基礎(chǔ)上,基于平面波動(dòng)假設(shè)提出了考慮層間波阻抗比放大和傳播路徑衰減的深厚覆蓋層加速度放大效應(yīng)簡(jiǎn)化函數(shù),改進(jìn)了1/4波長(zhǎng)法的參數(shù)取值,并結(jié)合自由表面效應(yīng),對(duì)前述臺(tái)陣記錄的放大效應(yīng)進(jìn)行了估算,發(fā)現(xiàn)無論時(shí)域還是頻域,預(yù)測(cè)結(jié)果與實(shí)際觀測(cè)都較接近。本文研究成果可為深厚覆蓋層液化判別和抗震設(shè)計(jì)的加速度選取提供理論依據(jù)和簡(jiǎn)化分析方法。
[Abstract]:Based on the acceleration records of two downhole arrays in Caltrans/CDMG, California, the ground motion amplification effect of 100 meters easy liquefaction deep overburden under different earthquakes is analyzed in time domain and frequency domain. It is revealed that four important characteristics of ground motion propagating from bedrock to overburden layer: 1) acceleration amplification effect is affected by the depth of soil layer, and the amplification effect of three components of ground motion is directional within 20 ~ 30 m near the ground surface. There is a significant difference between horizontal and vertical ground motion amplification effects. (3) the acceleration of the bedrock is characterized by "small earthquake amplification, large earthquake attenuation" (4) the acceleration amplification law is related to the frequency, and the deep overburden has a wide amplification frequency band. The possible causes of these amplification effects are analyzed preliminarily. On this basis, based on the plane wave hypothesis, a simplified function of the acceleration amplification effect of the deep overlay considering the interlaminar impedance ratio amplification and propagation path attenuation is proposed. The parameters of the 1 / 4 wavelength method are improved and the free surface effect is combined. The amplification effects of the aforementioned array records are estimated and it is found that the predicted results are close to the actual observations in both time and frequency domain. The research results in this paper can provide theoretical basis and simplified analysis method for liquefaction discrimination of deep overburden and selection of acceleration in seismic design.
【作者單位】： 浙江大學(xué)軟弱土與環(huán)境土工教育部重點(diǎn)實(shí)驗(yàn)室;浙江大學(xué)巖土工程研究所;成都理工大學(xué)地質(zhì)災(zāi)害防治與地質(zhì)環(huán)境保護(hù)國(guó)家重點(diǎn)實(shí)驗(yàn)室;中建三局投資發(fā)展有限公司;
【基金】：國(guó)家自然科學(xué)基金項(xiàng)目(51578501) 浙江省自然科學(xué)基金項(xiàng)目(LR15E080001) “國(guó)家特支計(jì)劃”青年拔尖人才項(xiàng)目(2013) 國(guó)家重點(diǎn)基礎(chǔ)研究發(fā)展計(jì)劃(“973”計(jì)劃)項(xiàng)目(2014CB047005) 地質(zhì)災(zāi)害防治與地質(zhì)環(huán)境保護(hù)國(guó)家重點(diǎn)實(shí)驗(yàn)室開放基金項(xiàng)目(SKLGP2015K017)
【分類號(hào)】：P315.9;TU435

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本文編號(hào)：1968965