大跨小净距偏压隧道施工方案优化分析

发布时间：2018-01-11 17:35

本文关键词：大跨小净距偏压隧道施工方案优化分析　出处：《公路》2014年04期 　论文类型：期刊论文

【摘要】：在大跨小净距偏压隧道施工中,合理的施工方法和施工工序对保证围岩稳定性和支护结构受力有很大影响。结合大跨小净距偏压隧道的结构形式,总结了其受力特点,并建立大跨小净距隧道在Ⅴ级围岩浅埋偏压环境下的有限元数值模型,分别采用双侧壁导坑法、CRD法对不同施工工序下围岩位移、应力和塑性区等进行对比分析。结果表明:CRD对控制隧道水平收敛较为有利,但隧道拱脚处应力集中现象明显,围岩塑性区较大,双侧壁导坑法对控制隧道拱顶下沉较为有利;先开挖浅埋侧隧道时中岩柱两侧拱肩、拱腰应力集中较大,而先开挖深埋侧隧道时隧道拱脚应力集中较大;先开挖隧道内侧时,洞周围岩位移较大。
[Abstract]:In the construction of long span and small clear distance bias tunnel, reasonable construction method and construction procedure have great influence on the stability of surrounding rock and the force of supporting structure, combined with the structure form of long span and small clear distance bias tunnel. The stress characteristics of the tunnel are summarized, and the finite element numerical model of the tunnel with large span and small clear distance is established under the condition of shallow burying bias pressure of grade V surrounding rock. The displacement of surrounding rock under different construction procedures is analyzed by using double lateral wall guide pit method and CRD method respectively. The results show that the stress concentration at the arch of the tunnel is obvious and the plastic zone of the surrounding rock is large. The results show that the ratio of the stress to the plastic zone of the tunnel is more favorable to control the horizontal convergence of the tunnel. The method of double-sidewall guide pit is more favorable to control the tunnel dome subsidence. When the shallow buried tunnel is first excavated, the arch shoulder on both sides of the middle rock column is more concentrated, and the stress concentration on the arch foot of the tunnel is greater when the deep buried side tunnel is first excavated. When the inner side of the tunnel is first excavated, the rock displacement around the tunnel is larger.
【作者单位】：西南交通大学交通隧道工程教育部重点实验室;
【基金】：国家自然科学基金项目,项目编号41102220、51178398 教育部创新团队发展计划资助项目,项目编号IRT0955
【分类号】：U455.4
【正文快照】： 随着我国国民经济的持续增长和交通需求量的急剧增加,高速公路的车道数在不断增加,隧道开挖跨度也更大,出现了大量以三车道或四车道为代表的大跨小净距隧道,由于此类隧道开挖断面大、扁平率低、双洞及中间岩柱在施工过程中相互影响较大,其围岩稳定性较差。尤其在偏压荷载的作

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