本文選題：移動荷載　切入點：Biot理論　出處：《浙江大學》2017年碩士論文

【摘要】：鐵路高速化已成為當今世界交通運輸?shù)陌l(fā)展趨勢,在高鐵規(guī)�？焖贁U大的同時,高鐵運行速度也得到了極大的提高。已有文獻指出,當列車低速運行時,其在地基中引起的動力響應較小,與按靜力方法得到的結果差距較小。然而,隨著列車運行速度的增加,下部結構的振動水平以及車輛-軌道結構的動力相互作用都將隨之加劇,威脅列車的運行安全。且在我國經濟發(fā)達的東南沿海地區(qū),廣泛分布著飽和軟土地基。由于軟土中Rayleigh波的傳播速度較小,這些地區(qū)高速列車較易超過地基的Rayleigh波速而產生劇烈的地基振動,不僅影響鐵路的安全運營和旅客的舒適性,還將對周邊環(huán)境帶來不可忽視的影響。因此,非常有必要開展對高速列車荷載作用下飽和軟土地基的動力響應的研究。本文首先研究了均質飽和地基的動力響應,基于Biot理論與歐拉-伯努利梁理論,建立了飽和多孔介質半空間上覆單位寬度無限長度梁模型。為確保在施加垂向荷載時,梁與半空間之間可以緊密貼合不會脫離,在梁與半空間的界面處使用了一種改進的光滑接觸條件。在將等效剛度的表達式由圍道積分解析得出后,計算了不同工況下的等效剛度,從而得出三種體波(P1波,P2波與S波)的Rayleigh極點與散布枝點。而后畫出了不同土體滲透系數(shù)條件下Rayleigh極點與分枝點的軌跡,研究了梁-半空間界面上連續(xù)性條件與土體滲透系數(shù)對等效剛度的影響。其次,本文將均質飽和地基推廣為成層飽和地基,建立了一個三維成層飽和地基模型,通過在水平方向使用傅里葉變換和正交變換從而將飽和地基Biot動力公式化為Love和Rayleigh模態(tài)方程。在豎直方向使用薄層法將地基劃分為數(shù)個單元,得到單個薄層單元的控制方程后通過組裝獲得模型總體控制方程,最終推導出了三維成層飽和土地基的頻域動力Green函數(shù)。數(shù)值計算時通過將每兩層視作一個周期結構單元,研究了 Love模態(tài)與Rayleigh模態(tài)在不同激振頻率與土體參數(shù)下的彌散特性,從而得到了波在周期飽和軟土地基中的通帶和禁帶,并研究了周期結構單元數(shù)對通帶與禁帶分布規(guī)律的影響。最后,在第二部分中已建立的三維層狀飽和地基模型的基礎上建立了鐵路高架橋的三維數(shù)值模型。該模型為無碴軌道模型,其部件包括無限長的鐵軌、鐵軌扣件、不連續(xù)的軌道板及其墊層和架設于無限多跨彈性支撐梁上的混凝土底座。地基模型使用了已建立的三維層狀飽和地基模型,樁則離散為歐拉-伯努利梁。使用一系列移動簡諧點荷載模擬了列車荷載。通過數(shù)值計算,首先研究了飽和土地基中群樁基礎的阻抗,其次研究了不同速度下地表振動速度與孔壓的空間分布規(guī)律以及列車速度的變化對地表最大振動速度與地下最大孔壓的影響,最后研究了荷載激振頻率對地基動力響應的影響。以上研究為鐵路高架橋引起的地基振動提供了理論分析模型和方法,可豐富飽和土體波動理論,對鐵路高架橋周邊建筑的設計與施工具有重要的指導意義。
[Abstract]:High speed railway has become the development trend of world transportation, high-speed rail in the rapid expansion of the scale at the same time, high-speed rail running speed has been greatly improved. It has been pointed out that, when the train is running at low speed, the dynamic response of the smaller caused in the foundation, according to the gap with the static method results in smaller. However, with the increase of train speed, the dynamic substructure vibration level and vehicle track structure interaction will be intensified, a threat to the safe operation of the train. And in China's economically developed southeast coastal areas, widely distributed in saturated soft soil. Because of the transmission speed of the smaller Rayleigh wave in soft soil these areas, high-speed trains more easily than Rayleigh wave velocity of the foundation caused severe ground vibration not only affects the safe operation, and the railway passenger comfort, will not bring to the surrounding environment Ignored. Therefore, it is necessary to carry out research on the power of the high-speed train load response of saturated soft soil. This paper studies the dynamic response of homogeneous saturated soil, Biot theory and Euler Bernoulli beam based on the theory of saturated porous media was established with unit width of half space infinite length beam model. Ensure the applied vertical load, between the beam and the half space can be tightly not out, at the interface in the beam and a half space using an improved smooth contact conditions. The formula of equivalent stiffness by contour integral analysis, equivalent stiffness calculation under different working conditions, so that three kinds of body waves (P1 wave, P2 wave and S wave) Rayleigh pole and branch point spread. And then draw the different permeability coefficients of soil under the condition of Rayleigh pole and branch point trajectory of beam - half space interface. The continuity conditions and soil permeability coefficient affecting equivalent stiffness. Secondly, the foundation for the promotion of homogeneous saturated layered saturated soil, a three-dimensional layered saturated soil model, by using Fourier transform and orthogonal transformation in the horizontal direction and the saturated soil Biot dynamic formula for Love and Rayleigh modal equations. Using the thin layer method in the vertical direction the foundation is divided into a plurality of units, the governing equations are obtained by assembling the single layer unit model overall control equation, we deduced the three-dimensional domain layer saturated soil dynamic Green function. Numerical calculation by each of the two layer as a periodic structure unit, dispersion characteristics study on the Love mode and the Rayleigh mode in different vibration frequency and soil parameters, thus obtained the periodic wave in saturated soft soil in the passband and stopband, and study The number of units through periodic structure influence and the band gap distribution. Finally, the foundation has been established in the second part of the three-dimensional layered soil model was established on the three-dimensional numerical model of railway viaduct. The model for ballastless track model, its components including infinite rail fastening, discontinuous rail plate and cushion and erected in the infinite multi span concrete base beam on elastic support. The foundation model uses the established three-dimensional layered saturated soil pile model, discrete Euler Bernoulli beam. The train load was simulated using a series of harmonic moving point load. By numerical calculation, firstly studies the impedance of pile group foundation of saturated soil in the medium, then the speed speed and the hole surface vibration pressure distribution and train speed variation of the maximum vibration velocity of surface and underground maximum pore pressure. Effect of sound, finally studied the response of vibration frequency on the foundation. The above research foundation for vibration induced by railway viaduct provides a theoretical model and analysis method that can enrich the soil wave theory, which has important guiding significance to the design and construction of the railway viaduct surrounding buildings.

【學位授予單位】：浙江大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：U211;TU435

【參考文獻】

相關期刊論文 前10條

1 王鵬;史吏;王軍;劉凱;;三維層狀飽和地基動力Green函數(shù)的薄層法求解[J];巖土力學;2014年12期

2 時剛;高廣運;馮世進;;飽和層狀地基的薄層法基本解及其旁軸邊界[J];巖土工程學報;2010年05期

3 蔣通;宋曉星;;用薄層法分析層狀地基中條形基礎的阻抗函數(shù)[J];力學季刊;2009年01期

4 蔣通;程昌熟;;用薄層法分析高架軌道交通引發(fā)的環(huán)境振動[J];振動工程學報;2007年06期

5 蔣通;程昌熟;;用薄層法分析層狀地基中各種基礎的阻抗函數(shù)[J];力學季刊;2007年02期

6 蔣通;程昌熟;;用二次形函數(shù)薄層法分析彈性層狀地基中的動力問題[J];力學季刊;2006年03期

7 黃義;王小崗;;橫觀各向同性飽和層狀地基的三維穩(wěn)態(tài)動力響應[J];固體力學學報;2006年03期

8 蔡袁強;徐長節(jié);鄭灶鋒;吳大志;;軸對稱飽和地基豎向振動分析[J];應用數(shù)學和力學;2006年01期

9 熊輝,鄒銀生;層狀土中考慮頻域內軸向力分擔的群樁水平動力阻抗[J];計算力學學報;2004年06期

10 蒯行成,田建華;低承臺群樁動力阻抗的有限元分析[J];湖南大學學報(自然科學版);2004年04期

，

本文編號：1693594