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郑州-西安铁路客运专线穿越西北黄土分布的主要地区,而在黄土地区修建跨度超过15.1m、开挖面积达170m2的超大断面大跨度铁路隧道洞群在国内尚属首次,相关的设计理论与经验均较为欠缺,尤其是系统锚杆在黄土隧道中的作用机制及锚固效果尚不清楚,使得设计遇到关键难题。为研究大断面黄土隧道中系统锚杆的作用,通过理论推导,阐明了锚杆的作用机制,指出了浅埋大跨度黄土隧道中锚杆的受力原因。采用理论锚杆单元模型,计算得到与实测数据一致的结果,说明该理论模型能够解释浅埋黄土的锚杆受力情况。综合研究表明,浅埋黄土隧道中拱部系统锚杆的锚固效果较弱,而边墙部锚杆的锚固效果显著。
Zhengzhou-Xi’an Railway Passenger Dedicated Line traverses the main areas of Northwest Loess Plateau, while the construction of large-span and long-span tunnels with a span of more than 15.1m and an excavation area of 170m2 in the loess area is the first in China with relevant design theory and experience Are relatively lacking. In particular, the mechanism and anchoring effect of the system anchor rod in the loess tunnel are not yet clear, which leads to the design encountering key problems. In order to study the function of system anchor in large section loess tunnel, the mechanism of anchor was clarified through theoretical derivation, and the reason of the stress of anchor in shallow buried long-span tunnel was pointed out. The theoretic model can explain the stress of anchor bolt in shallow loess by theoretical bolt unit model. The result is consistent with the measured data. Comprehensive study shows that the anchoring effect of the anchor system in the arch section of shallow-buried loess tunnel is weak, while the anchor effect of the side wall section anchor is remarkable.