软弱围岩隧道洞口段预加固技术研究

发布时间：2018-07-07 20:44

  本文选题：隧道加固 + 数值模型　； 参考：《长安大学》2014年硕士论文

【摘要】：近年来我国公路行业迅猛发展，山区高速公路也越来越多，由于地形以及线路的限制，必然会出现大量的公路隧道。隧道洞口段作为整条隧道中最重要的一部分，由于其围岩条件较差，需要施做预加固措施以保证隧道施工的安全进行。 本文依托宁波市花山隧道现场地质条件，集成已有研究成果，建立数值模型，研究管棚和小导管的作用机理以及适用条件，并通过现场监测资料对成果进行了验证。主要研究内容如下： 1.对管棚预加固方案钢管的受力情况进行计算分析，分析钢管内力随隧道开挖产生的变化规律，对小导管的自身加固原理和注浆加固原理进行研究，，并指出只有小导管和浆液达到最佳匹配时才能发挥出最好的支护效果。 2.通过MIDAS/GTS软件建立三维有限元模型，对隧道洞口段分别处于不同埋深条件下，围岩级别为Ⅴ级和Ⅳ级，采用管棚和小导管预加固时在隧道开挖过程中产生的围岩应力、塑性区和初期支护应力进行分析，得出管棚和小导管都可以在一定程度上加固围岩，但管棚的效果更好。 3.对管棚预加固和小导管预加固时隧道的拱顶沉降位移和地表沉降量进行分析，得出在围岩条件较差的隧道洞口段最好采用管棚进行预加固。 4.通过依托工程隧道洞口段采用管棚预加固现场量测结果与数值模拟结果对比，分析表明本文研究成果具有一定的参考价值，可为软弱围岩隧道洞口段预加固措施的选择提供一定参考。
[Abstract]:In recent years, with the rapid development of highway industry in China, there are more and more highways in mountainous areas. Due to the limitation of terrain and route, a large number of highway tunnels will inevitably appear. As the most important part of the whole tunnel, because of the poor surrounding rock conditions, pre-reinforcement measures are needed to ensure the safety of the tunnel construction. Based on the field geological conditions of Huashan Tunnel in Ningbo City, this paper integrates the existing research results, establishes a numerical model, studies the action mechanism and applicable conditions of the pipe shed and small conduit, and verifies the results through the field monitoring data. The main contents are as follows: 1. This paper calculates and analyzes the stress of the steel pipe in the prestrengthening scheme of pipe shed, analyzes the variation law of the internal force of the pipe with the tunnel excavation, and studies the reinforcement principle of the small pipe and the grouting reinforcement principle. It is pointed out that only when the small pipe and the slurry reach the best match can the best support effect be brought into play. The 3D finite element model was established by MIDAS-GTS software. The surrounding rock stress in tunnel excavation process was induced by pipe shed and small pipe pre-reinforcement under the condition of different buried depth, the surrounding rock grade was grade 鈪

本文编号：2106221