【摘要】：近年來隨著高速鐵路、高速公路的快速發(fā)展,地基的動力響應問題受到相關學者的廣泛關注。眾所周知,高速鐵路、高速公路對路基的沉降要求非常嚴格,而路基的沉降問題與列車荷載、地基類型以及路軌系統(tǒng)等因素有著密不可分的關系�；诖�,本文對飽和地基、非飽和地基以及軌道-地基的耦合系統(tǒng)在移動荷載作用下的動力響應進行了詳細的研究和探索。 首先結合飽和土的Biot動力控制方程,利用Fourier變換技術和Cauchy-Reimann條件,求解得到了飽和地基的位移、應力的積分形式解。同時,采用Fourier逆變換并結合數(shù)值算例,詳細討論了移動荷載速度、荷載頻率以及飽和土體的滲透系數(shù)等因素對飽和地基動力響應的影響。 用解析的方法研究了軌道—非飽和地基的耦合系統(tǒng)在移動荷載作用下的動力響應。將鋼軌簡化為無限長彈性Euler梁,同時考慮了枕木、道渣層的影響。在Fourier變換域內(nèi)聯(lián)立軌道和下臥非飽和土體的動力方程,求解得到了移動荷載作用下耦合系統(tǒng)位移、應力的積分形式解。最后通過數(shù)值計算考察了非飽和地基飽和度、鋼軌剛度等因素對動力響應的影響。 天然地基是由復雜的三相體構成的。一般來說,地下水位以下土體可近似地視為飽和土；而地下水位以上土體中由于存在較多氣體,將其視為非飽和土才更符合實際。針對這一情況,本文開展了相關研究工作。利用飽和土的Biot動力控制方程以及非飽和土的動力控制方程,得到了移動荷載作用下上覆非飽和層的飽和地基位移、應力積分形式解。并且采用Fourier逆變換給出了數(shù)值計算結果,討論了上覆非飽和土層的飽和度、厚度以及地表排氣排水條件等因素對動力響應的影響。
[Abstract]:In recent years, with the rapid development of high-speed railway and expressway, the dynamic response of foundation has been concerned widely. As we all know, the settlement requirement of the high speed railway and highway is very strict, and the settlement problem of the subgrade is closely related to the train load, the type of foundation and the rail system and so on. Based on this, the dynamic response of the coupled system of saturated foundation, unsaturated foundation and rail-foundation under moving load is studied and explored in detail in this paper. Based on the Biot dynamic control equation of saturated soil, the integral solution of displacement and stress of saturated soil is obtained by using Fourier transform technique and Cauchy-Reimann condition. At the same time, the effects of moving load velocity, load frequency and permeability coefficient of saturated soil on the dynamic response of saturated soil are discussed in detail by using Fourier inverse transformation and numerical examples. In this paper, the dynamic response of the coupled system of track to unsaturated foundation under moving load is studied by analytical method. The rail is simplified as an infinite elastic Euler beam and the influence of sleeper and slag layer is considered. The integral solutions of displacement and stress of the coupled system under moving load are obtained by solving the dynamic equations of the simultaneous track and the underlying unsaturated soil in the domain of Fourier transform. Finally, the effects of saturation of unsaturated foundation and rail stiffness on dynamic response are investigated numerically. The natural foundation is made up of complex three-phase bodies. Generally speaking, soil below groundwater level can be considered as saturated soil approximately, but it is more practical to treat soil below groundwater level as unsaturated soil because of the existence of more gases in the soil above groundwater level. In view of this situation, this article has carried out the related research work. By using the Biot dynamic control equation of saturated soil and the dynamic control equation of unsaturated soil, the solutions of displacement and stress integral of saturated foundation overlying unsaturated layer under moving load are obtained. The numerical results are obtained by using the inverse Fourier transform. The effects of saturation, thickness of the overlying unsaturated soil layer and the exhaust and drainage conditions of the surface on the dynamic response are discussed.
【學位授予單位】：浙江大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TU435

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