场地条件对高速铁路地基土振动影响的研究

Variation Characteristics of Foundation Soil Vibration Caused by High Speed Train with Depth Under Different Site Conditions

发展高速铁路是解决城市间交通问题的有效途径,但其所产生的振动和噪声引起的环境问题,对铁路沿线居民及周围建筑等造成不利影响。在对高速铁路引起的振动问题进行的研究中,关于高速列车引起的地基土振动随深度变化的相对较少。因此,本文针对Ⅱ、Ⅲ和Ⅳ类场地条件下的路堤式和高架桥式高速铁路,对0—5m不同深度处地基土的振动加速度响应进行了现场测试,并以测试数据为基础,分析了不同场地条件下高速列车引起的地基土振动加速度响应随深度的变化规律。结果表明,不同场地条件下,高速列车引起的振动加速度响应随深度的变化规律具有显著差异;Ⅱ类和Ⅲ类场地条件下,高速列车引起的地基土振动加速度响应总体随深度的增加而逐渐减小,并呈先快后慢的衰减趋势;而Ⅳ类场地条件下,高速列车引起的地基土振动加速度响应随深度的增加呈现先减小后放大的趋势,在深3m处加速度达到最大值。高速列车运行引起的振动频带随深度的变化特征与场地相关。

The development of high speed railway system is an effective way to solve the problem of intercity traffic, but the environmental problems of vibration and noise produced by it have important effects on surrounding residents and buildings along the railway. Therefore, great attention must be paid to it. In the vibration problem caused by rail traffic, the research of vibration at different depths is relatively scarce. On embankment and elevated high-speed railway subgrade under site conditions of II, III and IV, field tests were carried out respectively for vibration acceleration responses at different depths between 0-5 m,and based on test date,the dynamic response of subsoil vibration induced by high speed train under different site conditions is analyzed with the variation of depth. The results show that the changes of vibration acceleration response caused by high speed train at different depths is significantly different under different site conditions. Under the conditions of site class II and site class III, the response of subsoil vibration acceleration caused by high speed train gradually decreases with the increase of depth, and the decrease rate of vibration acceleration is fast firstly and then slow. However, under the condition of site class IV, the acceleration response of subsoil induced by high speed train decreases firstly and then increases, increasing to the maximum at the depth of 3 m. The frequency band of vibration caused by the high-speed train at different depths is related to the site conditions.