本文選題：落石 + 沖擊力　； 參考：《西南交通大學(xué)》2017年碩士論文

【摘要】：由于線路平順性以及展線的要求,西部山區(qū)線路的橋隧比較高。受地質(zhì)條件影響,西部山區(qū)的山體滑坡以及落石現(xiàn)象較為嚴(yán)重,尤其是在汶川地震之后,落石撞擊橋梁的現(xiàn)象時有發(fā)生,因此研究落石沖擊以及對車橋的影響十分必要。本文依次就落石運動特性、落石沖擊力計算以及落石-車-橋相互作用進行了研究。首先,根據(jù)相鄰坡面的角度關(guān)系將坡面進行分類,并分析了落石在各類坡面類型中可能存在的運動形式,然后結(jié)合運動學(xué)理論對落石的運動過程進行計算分析,并與專業(yè)落石計算程序Rockfall的計算結(jié)果相對比以驗證計算結(jié)果。其次,基于動力分析軟件LS-DYNA對落石撞擊橋梁結(jié)構(gòu)進行數(shù)值仿真,計算不同沖擊速度和不同沖擊位置下落石的撞擊力時程,將不同速度下落石的沖擊力與規(guī)范公式的計算結(jié)果進行對比,驗證落石撞擊力模擬的準(zhǔn)確性,在此基礎(chǔ)上考查落石撞擊作用下橋梁結(jié)構(gòu)的響應(yīng)。最后,采用軟件BANSYS研究了落石沖擊對車-橋系統(tǒng)動力性能的影響,分析了落石沖擊作用下,橋梁結(jié)構(gòu)動態(tài)響應(yīng)以及列車的動態(tài)響應(yīng),并就沖擊速度、沖擊位置和列車位置等參數(shù)展開研究。結(jié)果表明:落石沖擊力的平均值和最大值均隨沖擊速度的增加而增加,但由于沖擊的持續(xù)時間也會隨之增加,故沖擊力的平均值并非如規(guī)范所規(guī)定的和落石速度成正比。沖擊位置的不同對沖擊力的最大值幾乎沒有影響,但隨沖擊位置的增高,沖擊持時增加,導(dǎo)致沖擊力的平均值降低。落石沖擊作用下,列車橫向加速度、輪軸橫向力、輪重減載率、脫軌系數(shù)顯著增大,但對豎向加速度影響很小;且沖擊速度越大、沖擊位置越高,對車輛響應(yīng)的影響越顯著。碰撞發(fā)生時,列車距離沖擊點越近,列車的響應(yīng)也會越大。
[Abstract]:The bridge and tunnel of the western mountainous area are relatively high due to the smoothness of the line and the requirements of the expansion of the route. Under the influence of geological conditions, the landslide and rock fall in the western mountainous area are serious, especially after the Wenchuan earthquake, the phenomenon of falling stone hitting the bridge occurs frequently, so it is very necessary to study the impact of falling stone and the impact on the vehicle and bridge. In this paper, the characteristics of rock falling motion, the calculation of rock falling impact force and the interaction between stone drop and vehicle-bridge are studied in turn. Firstly, according to the angle relation of adjacent slope, the slope surface is classified, and the movement forms of rock falling in various slope types are analyzed, and then the movement process of falling stone is calculated and analyzed by combining kinematics theory. The calculation results are compared with the results of the professional stone drop program Rockfall to verify the calculation results. Secondly, based on the dynamic analysis software LS-DYNA, the impact force time history of falling stone with different impact velocity and different impact position is calculated by numerical simulation. The impact force of falling stone at different velocities is compared with the calculated results of the standard formula to verify the accuracy of the impact force simulation of the falling stone, and the response of the bridge structure under the impact of the falling stone is examined on this basis. Finally, the influence of rock impact on the dynamic performance of vehicle-bridge system is studied by using software BANSYS. The dynamic response of bridge structure and the dynamic response of train under the impact of falling stone are analyzed, and the impact velocity is analyzed. The impact position and train position are studied. The results show that the average value and maximum value of impact force increase with the increase of impact velocity, but because the duration of impact will also increase, the average value of impact force is not in direct proportion to the velocity of falling stone as stipulated in the code. The difference of impact position has little effect on the maximum impact force, but with the increase of impact position, the impact duration increases, which results in the decrease of the average impact force. The lateral acceleration of the train, the lateral force of the axle, the load reduction rate of the wheel and the derailment coefficient increase significantly, but have little effect on the vertical acceleration, and the greater the impact speed, the higher the impact position, the more significant the impact on the vehicle response. When the collision occurs, the closer the train is to the impact point, the larger the train response will be.
【學(xué)位授予單位】：西南交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：U441

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本文編號：1803485