平面SH波作用下部分充填圓弧形沉積谷的二維土層和地形放大效應
發(fā)布時間:2018-03-21 07:10
本文選題:二維土層效應 切入點:地形效應 出處:《地震學報》2017年05期 論文類型:期刊論文
【摘要】:場地效應通常包含土層放大效應和地形放大效應,為了揭示二者的相對貢獻,本文構造了平面SH波作用下部分充填沉積谷的解析模型,借助于區(qū)域分解策略,在波函數(shù)展開法的框架下,提出了超定方程組解法,得到了部分充填圓弧形沉積谷對平面SH波散射的波函數(shù)級數(shù)解,而且級數(shù)解的收斂測試表明了超定方程組解法的必要性.通過與文獻結果進行對比,驗證了本文方法的正確性.通過調(diào)整解析模型中兩個子區(qū)域內(nèi)的材料參數(shù),計算了沉積谷引起的場地放大效應和相應的空河谷引起的地形放大效應.對二維土層與地形效應進行對比分析,結果顯示,在沉積谷內(nèi)二維土層放大效應通常強于地形放大效應,而地形放大效應決定了沉積谷外的地面運動放大形態(tài).針對最大地面運動,進行了沉積谷和相應空河谷的參數(shù)分析,進一步描述了二維土層放大效應,研究結果表明二維土層放大效應引起的最大地面運動通常遠遠大于地形放大效應引起的最大地面運動,并且二維土層效應通常隨著土層與基巖的阻抗比的增大而增大,但不是一維土層放大效應與二維地形放大效應的簡單線性疊加.
[Abstract]:In order to reveal their relative contribution, an analytical model of partially filling sedimentary valleys under the action of plane SH waves is constructed, which is based on the regional decomposition strategy. In the framework of wave function expansion method, a solution to overdetermined equations is proposed, and a series of wave function solutions for scattering of plane SH waves by partially filled circular arc depositional valleys are obtained. Moreover, the convergence test of the series solution shows the necessity of solving the overdetermined equations. The correctness of the method is verified by comparing with the results of the literature. The material parameters in the two sub-regions of the analytical model are adjusted. The site magnification effect caused by sedimentary valley and the terrain magnification effect caused by corresponding hollow valley are calculated. The magnification effect of two-dimensional soil layer in the sedimentary valley is usually stronger than that of the topographic amplification effect, and the topographic amplification effect determines the magnification form of the ground motion outside the sedimentary valley. The parameters of the sedimentary valley and the corresponding empty valley are analyzed for the maximum ground motion. The results show that the maximum ground motion caused by the two-dimensional soil layer amplification is much larger than the maximum ground motion caused by the topographic amplification effect. And the two-dimensional soil layer effect usually increases with the increase of the impedance ratio of the soil layer to the bedrock, but it is not a simple linear superposition of the one-dimensional soil layer amplification effect and the two-dimensional topographic amplification effect.
【作者單位】: 河海大學巖土力學與堤壩工程教育部重點實驗室;河海大學土木與交通學院巖土工程科學研究所;
【基金】:國家自然科學基金(51608172,41630638,51479050) 國家重點基礎研究發(fā)展計劃(973)(2015CB057901) 水利部公益性行業(yè)科研專項(201501035-03) 國家重點研發(fā)計劃項目(2016YFC0800205) 中央高校基本科研業(yè)務費(2015B01214)聯(lián)合資助
【分類號】:P315.9;TU435
【相似文獻】
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1 王超;王輝;靳超宇;肖遙;;遼寧省地震重點監(jiān)視防御區(qū)Ⅱ類場地放大效應研究[J];防災減災學報;2014年02期
2 劉洪兵,朱f^;地震中地形放大效應的觀測和研究進展[J];世界地震工程;1999年03期
3 羅奇峰,,X且荒
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