偏压隧道围岩稳定性及初期支护效果研究

发布时间：2018-04-29 02:06

本文选题：偏压 + 模型试验　；参考：《河北建筑工程学院》2017年硕士论文

【摘要】：随着我国交通事业的迅猛发展,公路隧道的建设规模和数量日益增多。在隧道工程中,由于地形的复杂性和地质构造的不确定性,隧道往往处于偏压状态。为了研究地表倾角和隧道埋深对隧道围岩稳定性的影响,本文以洞跨10m、洞高7m的隧道为研究对象,采用模型试验和数值模拟的方法开展了研究工作。为浅埋偏压条件下隧道稳定性的判断和施工提供了参考。主要研究结论如下:(1)模型试验中测得应力变化量在隧道0倍洞跨处最为明显,隧道拱脚部位应力变化程度比拱腰部位小。当地表倾角大于30°时,两侧拱腰处应力变化显著,地表倾角30°是隧道偏压趋势变得明显的转折点;随着隧道埋深增加,隧道两侧拱脚处应力值增加,两侧变化趋势逐渐趋于一致,当埋深超过25m时,左拱腰部位的应力开始减小,隧道两侧应力变化量趋于对称。(2)随着地表倾角的增加,隧道偏压效用逐渐增强,当地表倾角大于等于30°时,隧道的偏压作用变得明显,必须重视偏压的影响;随着隧道埋深的增加,隧道左右两侧围岩受力及位移分布特征逐渐趋于一致,当隧道埋深超过25m时隧道受到的偏压作用明显减弱,但隧道仍受到偏压作用的影响。(3)对地表倾角为30°的V级围岩隧道,中隔壁法施工对于限制围岩变形、减小塑性区范围效果最好,留核心土法次之,台阶法效果最差,中隔壁法施工会弊端是中隔壁施工较为繁琐,开挖一侧后需要安装临时支护结构,造成工期延长。
[Abstract]:With the rapid development of transportation in China, the construction scale and quantity of highway tunnels are increasing day by day. In tunnel engineering, because of the complexity of topography and the uncertainty of geological structure, the tunnel is often in the state of bias. In order to study the influence of surface inclination and tunnel depth on the stability of tunnel surrounding rock, this paper takes the tunnel with 10 m span and 7 m high as the research object, and adopts the method of model test and numerical simulation to carry out the research. It provides a reference for tunnel stability judgement and construction under the condition of shallow buried bias voltage. The main conclusions are as follows: (1) in the model test, the variation of stress is the most obvious at the span of the tunnel 0 times, and the variation of stress at the arch foot is smaller than that at the waist of the arch. When the local surface inclination angle is greater than 30 掳, the stress at both sides of the arch waist changes significantly, and the surface inclination angle of 30 掳is the turning point of the tunnel bias trend, and with the increase of the buried depth of the tunnel, the stress value at the arch foot of both sides of the tunnel increases. When the depth of burying is more than 25 m, the stress of the left arch waist begins to decrease, and the variation of the stress on both sides of the tunnel tends to be symmetrical. (2) with the increase of the surface inclination, the bias effect of the tunnel increases gradually. When the local slope angle is greater than or equal to 30 掳, the bias effect of the tunnel becomes obvious and the influence of the bias voltage must be paid attention to, and with the increase of the buried depth of the tunnel, the stress and displacement distribution characteristics of the surrounding rock on the left and right sides of the tunnel tend to be consistent. When the depth of the tunnel is more than 25 m, the biasing effect of the tunnel is obviously weakened, but the tunnel is still affected by the biasing effect. (3) for the V-class surrounding rock tunnel with the surface inclination angle of 30 掳, the construction of the next door method can limit the deformation of the surrounding rock. The best effect is to reduce the range of plastic zone, the second is to leave the core soil method, and the worst is the step method. The drawback of the middle and adjoining construction method is that the construction of the middle and next door is more complicated, and the temporary supporting structure needs to be installed after the excavation, which results in the extension of the construction period.
【学位授予单位】：河北建筑工程学院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U455.4

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