山区单线铁路隧道下穿高速公路隧道影响分区研究

Study on Influence Zoning of Single-track Railway Tunnel Under-passing Expressway Tunnel at Mountainous Areas

随着基础建设的不断推进,不可避免产生大量立交工程,其中铁路隧道下穿高速公路隧道工程问题十分突出。以福建省中部某山区铁路设计为例,对山区铁路下穿高速公路隧道影响分区进行研究。主要研究内容和结论如下:1)利用Midas GTS软件对不同净距和地质条件下铁路隧道下穿高速公路隧道施工进行数值试验,以高速公路隧道的沉降为判断准则,15 mm为判断阈值,得到基于几何近接度和地质情况的影响分区(强、弱、无)。通过影响分区图,可以将全线下穿高速公路隧道工点对号入座,以采用在相应分区内的经济合理的施工措施;2)地层条件不同,其决定强弱影响的净距分界点也不同,随地层条件的恶化而逐渐增大,强、弱影响区分界理论最小净距为0.5D,最大净距为1.8D;弱、无影响区最小净距为1.3D,最大净距为2.8D。

With the development of infrastructure,large amounts of interchange projects appear inevitably. The railway tunnel under-passing expressway tunnel is prominent. Taking the design of a railway in mountain area of central Fujian province as an example,the influence zoning of single-track railway tunnel under-passing expressway tunnel is studied.The study contents and conclusions are as follows： 1） The numerical experiment of railway tunnel under-passing expressway tunnel is carried out by means of Midas GTS under different clear distances and geological conditions. The influenced zones,i. e. strongly influenced zone,weakly influenced zone and non-influenced zone,are abtained based on geometric adjacent degree and geological conditions and by using the settlement of expressway tunnel of 15 mm as a reference. The economical and rational construction countermeasure for every working point can be chose according to the influence zoning diagram. 2） The clear distance increases gradually with the deterioration of ground conditions. The demarcation point of strongly influenced zone and that of weakly influenced zone are 0. 5D- 1. 8D theoretically; and the separating point of weakly influenced zone and that of non-influenced zone are 1. 3D- 2. 8D theoretically.