本文選題：爆破 + 拱橋結(jié)構(gòu)��； 參考：《重慶交通大學(xué)》2014年碩士論文

【摘要】：近年來，隨著爆破技術(shù)的應(yīng)用越來越多的深入到工程建設(shè)領(lǐng)域，對(duì)于采用爆破開挖方式所引起的地面震動(dòng)對(duì)周圍結(jié)構(gòu)的影響和危害引起了廣泛的關(guān)注。而橋梁結(jié)構(gòu)作為主要的基礎(chǔ)交通設(shè)施之一，無論在平時(shí)使用、抗震救災(zāi)還是災(zāi)后重建中都發(fā)揮了極其重要的作用。因此采用爆破技術(shù)所引起的震動(dòng)荷載對(duì)橋梁結(jié)構(gòu)受力影響的研究也愈加迫切。 本文研究近距離爆破開挖對(duì)周圍已建拱橋結(jié)構(gòu)受力行為的影響，首先對(duì)爆破地震波的產(chǎn)生機(jī)理和傳播、衰減規(guī)律進(jìn)行理論分析，并運(yùn)用ANSYS/LS-DYNA軟件對(duì)不同起爆藥量和起爆方式條件下的巖石爆破進(jìn)行數(shù)值模擬，得到爆區(qū)內(nèi)已建拱橋拱腳中心位置處的加速度時(shí)程曲線；然后通過橋梁抗震動(dòng)力分析方法并運(yùn)用MIDAS/Civil軟件建立已有拱橋的有限元模型，分析其受力特性，分別輸入霍永基爆破地震反應(yīng)譜和爆破模擬得到的加速度時(shí)程曲線，進(jìn)而對(duì)結(jié)構(gòu)進(jìn)行反應(yīng)譜和時(shí)程動(dòng)力分析，對(duì)比拱橋結(jié)構(gòu)在不同震動(dòng)荷載作用下的響應(yīng)情況，得到了以下結(jié)論： ①不同起爆藥量所引起的爆破震動(dòng)對(duì)拱橋結(jié)構(gòu)的動(dòng)力影響不同。對(duì)比起爆藥量分別為40.0kg、102.4kg和160.0kg時(shí)拱橋的動(dòng)力響應(yīng)得到：隨著起爆藥量的增加，結(jié)構(gòu)的內(nèi)力響應(yīng)顯著增加，但兩者并不成線性關(guān)系。藥量較小時(shí)，，可忽略爆破震動(dòng)對(duì)結(jié)構(gòu)的影響，但當(dāng)爆破藥量達(dá)到一定量值，其影響不容忽視，而且還可能對(duì)結(jié)構(gòu)的安全性產(chǎn)生嚴(yán)重的危害，因此在實(shí)際爆破開挖時(shí)應(yīng)合理選擇起爆藥量。 ②當(dāng)起爆藥量相同時(shí)，不同的起爆方式也會(huì)對(duì)結(jié)構(gòu)產(chǎn)生不同的影響。相對(duì)于單點(diǎn)起爆，多點(diǎn)起爆會(huì)使結(jié)構(gòu)產(chǎn)生了更大的位移、彎矩以及等效應(yīng)力，但是藥量較小時(shí)，其影響程度小，增加起爆藥量會(huì)使其影響增大，但增長(zhǎng)幅度不明顯。 ③其他條件相同時(shí)，爆心距的增加使得爆破地震效應(yīng)對(duì)結(jié)構(gòu)的影響逐漸減小，在起爆藥量為102.4kg的情況下，通過分析不同爆心距條件下拱橋結(jié)構(gòu)的內(nèi)力響應(yīng)得到在100m范圍內(nèi)進(jìn)行爆破開挖，結(jié)構(gòu)均處于不安全狀態(tài)，因此在爆破工程中應(yīng)根據(jù)工程實(shí)際情況尋求合理的安全距離，為爆破設(shè)計(jì)提供參考依據(jù)。
[Abstract]:In recent years, with the application of blasting technology more and more deep into the field of engineering construction, the impact and harm of ground vibration caused by blasting excavation on the surrounding structure has attracted extensive attention. As one of the main basic transportation facilities, bridge structure plays an extremely important role in earthquake relief and reconstruction. Therefore, it is more and more urgent to study the effect of vibration load on bridge structure caused by blasting technology. In this paper, the influence of blasting excavation on the mechanical behavior of the surrounding arch bridge is studied. Firstly, the mechanism, propagation and attenuation of blasting seismic waves are analyzed theoretically. The numerical simulation of rock blasting under different detonation charge and mode is carried out by using ANSYS/LS-DYNA software, and the acceleration time history curve at the center of arch foot of built arch bridge in blasting zone is obtained. Then the finite element model of the existing arch bridge is established by using the seismic dynamic analysis method of the bridge and the MIDAS/Civil software. The stress characteristics of the arch bridge are analyzed, and the seismic response spectrum of blasting and the acceleration time history curve obtained by blasting simulation are inputted into the seismic response spectrum of Huo Yongji blasting respectively. Then, the response spectrum and time-history dynamic analysis of the structure are carried out, and the response of arch bridge structure under different vibration loads is compared, and the following conclusions are obtained: 1 the dynamic effect of blasting vibration caused by different initial charge on the structure of arch bridge is different. Compared with the dynamic response of the arch bridge with the initial charge of 40.0kg / 102.4kg and 160.0kg, the internal force response of the structure increases significantly with the increase of the explosive content, but there is no linear relationship between the two. The influence of blasting vibration on the structure can be neglected when the charge is small, but when the explosive quantity reaches a certain value, the influence can not be ignored, and it may also cause serious harm to the safety of the structure. Therefore, the quantity of priming charge should be reasonably selected in actual blasting excavation. When the amount of detonation charge is the same, different initiation modes will have different effects on the structure. Compared with single point detonation, multi-point initiation will make the structure produce greater displacement, bending moment and equivalent stress, but the influence degree is small when the amount of charge is small, and the increase of detonating charge quantity will increase its influence, but the increase range is not obvious. (3) when other conditions are the same, the effect of blasting seismic effect on the structure decreases gradually with the increase of blasting center distance, and when the amount of detonation charge is 102.4kg, By analyzing the internal force response of arch bridge structure under different blasting center distance, it is obtained that blasting excavation is carried out within 100 m range, and the structure is in an unsafe state. Therefore, reasonable safe distance should be found in blasting engineering according to the actual situation of the project. It provides reference for blasting design.
【學(xué)位授予單位】：重慶交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：U448.22

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