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正在修建的郑州—西安铁路客运专线大断面黄土隧道,开挖面积达160m2,因此,开展型钢拱架与格栅拱架研究,明确型钢拱架和格栅拱架的适用条件对设计和施工都具有重要的指导意义。研究方法采用现场对比试验,为了使试验结果有可比性,选取试验条件基本相同的贺家庄隧道洞身段作为试验段,分别设置型钢拱架段40m和格栅拱架段40m。测试内容有:拱顶下沉、拱脚下沉、水平收敛、围岩压力、初支钢架应力等。试验结果表明:格栅拱架比型钢拱架的沉降略大,水平收敛基本相等;格栅拱架比型钢拱架应力小,且应力分布相对均匀;土压力普遍很小,但格栅拱架土压力更小些;隧道掘进四榀钢架(3.2m)后,钢架沉降达总沉降的26%左右,最大应力达总应力的33%左右。经综合分析认为型钢拱架及格栅拱架均能适用于IV级黏质老黄土隧道,但格栅拱架更具优越性。
The Zhengzhou-Xi’an Railway Passenger Dedicated Line Large Section Loess Tunnel under construction has an excavation area of 160m2. Therefore, the research on steel arch frame and grille arch is underway. The conditions for the application of steel arch frame and grille arch frame to the design and construction It has important guiding significance. In order to make the test results comparable, the tunnel section of Hejiazhuang tunnel with the same test conditions was chosen as the test section, and the sections of section steel arch 40m and section grate 40m were set respectively. Test content: vault sinking, arch feet sinking, horizontal convergence, pressure of the surrounding rock, the first branch of steel stress and so on. The test results show that: the geogrids are slightly larger than the geogrids and the horizontal convergence is basically the same; the stresses of geogrids are smaller than that of steel archs and the stress distribution is relatively uniform; the earth pressure is generally small, but the geogrids The soil pressure is smaller; after the tunnel excavation of four-story steel frame (3.2m), the settlement of the steel frame reaches about 26% of the total settlement and the maximum stress reaches about 33% of the total stress. The comprehensive analysis shows that the steel arch frame and grille arch can be applied to Class IV viscous clay old loess tunnel, but the grille arch has more advantages.