本文關(guān)鍵詞：工程用地震動模擬隨機性方法研究　出處：《大連理工大學(xué)》2016年博士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 土木工程 地震動模擬 隨機性方法 小波包分解 設(shè)計譜擬合

【摘要】：地震動模擬可以為工程界提供大量的結(jié)構(gòu)抗震設(shè)計所需的地震動數(shù)據(jù)。其中,隨機性方法因其概念清晰、簡單易用且模擬效果較好,受到了地震學(xué)界和工程界的普遍關(guān)注。目前使用比較廣泛的地震動模擬隨機性方法是基于點源法的有限斷層法。然而,點源法和有限斷層法在參數(shù)取值完全一致時,可能導(dǎo)致結(jié)果相差較大。有限斷層法在大量數(shù)據(jù)的模擬效率上仍然較低。另外,基于傅里葉變換的點源法和有限斷層法在模擬地震動時對于具有頻率非平穩(wěn)性的地震動模擬效果較差,在時頻非平穩(wěn)性方面具有一定的局限性。本文從工程用地震動的角度,對隨機點源法和有限斷層法之間的異同性進行了研究,同時研究了小波包方法在地震動非平穩(wěn)性模擬方面的應(yīng)用,主要研究內(nèi)容如下：(1) 針對點源法與有限斷層法之間的差異,提出了一種基于等效距離的隨機點源法模型用來考慮地震斷層面上的非一致滑動分布,并分析了該模型與有限斷層法的一致性。利用該模型,對發(fā)生在中國的汶川地震(2008年)和魯?shù)榈卣?2014年)分別進行了地震動加速度時程和反應(yīng)譜模擬,以及地震等震線模擬。用以驗證基于等效距離的隨機點源法的正確性和高效性,以及與有限斷層法的一致性。(2) 基于小波包分解和重構(gòu)方法,提出了一種時頻非平穩(wěn)地震動模擬方法。根據(jù)實際地震動小波包系數(shù)矩陣的特點,采用6個模型參數(shù)將地震動時程的時間和頻率軸展開,研究了時域和頻域的聯(lián)合非平穩(wěn)性。對實際地震動加速度時程和已有非平穩(wěn)隨機模型進行了對比,對比結(jié)果證明了模型的有效性。(3) 進一步基于小波包模型,提出了一種“先模擬后擬合”的擬合工程抗震設(shè)計譜的隨機性方法。利用小波包在頻域上分辨率較高的特點,根據(jù)設(shè)計譜幅值對小波包系數(shù)矩陣進行調(diào)整。擬合算例證明本方法具有較好的靈活性和模擬精度。(4) 依據(jù)小波包模型,對包含有1222條實際地震加速度時程的數(shù)據(jù)庫進行了兩階段回歸分析,將地震參數(shù)與小波包參數(shù)聯(lián)系起來,提出了本文帶有地震間和地震內(nèi)殘差的模擬回歸模型。通過對屬于地震數(shù)據(jù)庫中的地震進行模擬和不屬于數(shù)據(jù)庫中的地震進行的“預(yù)測”,說明回歸模型同時具有確定性和隨機性的特點。與已有地震動衰減關(guān)系進行的對比,進一步證明了回歸模型的有效性。(5) 對本文提出的基于等效距離的點源法和小波包方法進行了模擬地震動的有效性檢驗。利用編制的EQSIM和WPSIM程序?qū)?次歷史地震進行了模擬,計算并對比了4個工程常用的結(jié)構(gòu)反應(yīng)指標。證明了本文提出的兩種隨機性方法是有效的。
[Abstract]:Ground motion simulation can provide a large amount of seismic data for seismic design of structures. Among them, the randomness method is simple and easy to use because of its clear concept and good simulation results. At present, the widely used stochastic method of ground motion simulation is the finite fault method based on point source method. Point source method and finite fault method may lead to a large difference in the results when the parameter values are completely consistent. The simulation efficiency of finite fault method in a large number of data is still relatively low. The point source method and finite fault method based on Fourier transform are not effective in simulating ground motion with frequency nonstationary. There are some limitations in time-frequency nonstationarity. In this paper, the similarities and differences between random point source method and finite fault method are studied from the point of view of engineering land motion. At the same time, the application of wavelet packet method in the simulation of non-stationary ground motion is studied. The main contents are as follows: 1) aiming at the difference between point source method and finite fault method. A stochastic point source model based on equivalent distance is proposed to consider the non-uniform sliding distribution on seismic fault plane, and the consistency between the model and the finite fault method is analyzed. Ground motion acceleration time history and response spectrum of Wenchuan earthquake (2008) and Ludian earthquake (2014) occurred in China were simulated respectively. To verify the validity and efficiency of the random point source method based on equivalent distance, and the consistency with the finite fault method. 2) the wavelet packet decomposition and reconstruction method is used to verify the validity of the random point source method based on the equivalent distance and the consistency with the finite fault method. A time-frequency non-stationary ground motion simulation method is proposed. According to the characteristics of the wavelet packet coefficient matrix of the actual ground motion, the time-frequency axis of the time-history of the ground motion is expanded by using six model parameters. The joint nonstationarity of time domain and frequency domain is studied, and the time history of actual ground motion acceleration is compared with the existing non-stationary stochastic model. The results show that the model is effective and based on the wavelet packet model. In this paper, a random method of fitting the seismic design spectrum of engineering is presented, which is "first simulated and then fitted". The wavelet packet has high resolution in frequency domain. The wavelet packet coefficient matrix is adjusted according to the design spectrum amplitude. The fitting example shows that this method has good flexibility and simulation accuracy. A two-stage regression analysis is carried out on a database containing 1222 actual seismic acceleration time histories, which links the seismic parameters with wavelet packet parameters. In this paper, a simulated regression model with inter-earthquake and intra-seismic residuals is put forward. Through the simulation of earthquakes in seismic database and the prediction of earthquakes not in database. The results show that the regression model has the characteristics of certainty and randomness, and compared with the existing attenuation relation of ground motion. The validity of the regression model is further proved. The point source method based on equivalent distance and wavelet packet method proposed in this paper are used to verify the validity of the simulated ground motion. Four historical earthquakes are simulated by using the EQSIM and WPSIM programs developed in this paper. Four commonly used structural response indexes are calculated and compared. It is proved that the two randomness methods proposed in this paper are effective.
【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2016
【分類號】：P315.9
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本文編號：1435457