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进行了云桂高铁膨胀土新型路堑基床综合试验段现场激振试验,借助有限差分软件FLAC3D,建立了三维轨道-路基-地基动力学模型,分析了新型路堑基床动力响应与防排水结构层参数敏感性。分析结果表明:铺设新型防排水结构层可加速基床内动应力的衰减,降低路基表面动位移;增加防排水结构层厚度和弹性模量可降低基床动位移,减弱防排水结构层下方基床动应力,但会提高防排水结构层顶面的动应力水平;防排水结构层铺设位置下移时会增大路基表面动应力,但对路基表面动位移影响不大;为满足《高速铁路设计规范》(TB 10621—2009)要求,建议防排水结构层铺设厚度不小于15cm;路基表面动应力、动位移与地基表面动应力敏感性因素依次是防排水结构层的铺设位置、弹性模量与铺设厚度;考虑新型防排水结构层参数对基床动响应的影响,确定的最优方案为:铺设厚度为20cm,弹性模量为1.0GPa,铺设位置为基床表层底部。
The on-the-spot excitation test was carried out on the comprehensive test section of the new cutting bed with expansive soil of Yunnan-Guangxi High Speed Railway. With the help of finite difference software FLAC3D, the dynamic model of three-dimensional track-subgrade-foundation was established. Parameter sensitivity. The results show that the laying of a new type of anti-drainage structure layer can accelerate the dynamic stress attenuation in the foundation bed and reduce the dynamic displacement of the subgrade surface. Increasing the thickness and elastic modulus of the drainage and drainage structure can reduce the dynamic displacement of the foundation bed, Bed dynamic stress, but will increase the level of dynamic stress on the top of the drainage and drainage structure layer; when the drainage and drainage structure layer laying down position will increase the dynamic stress on the surface of the roadbed, but has little effect on the dynamic displacement of the roadbed surface; (TB 10621-2009), it is recommended that the thickness of the drainage and drainage structure should be no less than 15cm. The dynamic stress and dynamic displacement of the roadbed surface and the dynamic stress sensitivity of the foundation surface are the laying position of the drainage and drainage structure layer, the elastic modulus Considering the influence of the new waterproof and drainage structural parameters on the dynamic response of the bed, the optimal solution is as follows: the laying thickness is 20cm, the elastic modulus is 1.0GPa, and the laying position is the bottom of the bed surface.