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岩溶地区修建公路隧道时,把溶洞的处理和施工监测工作放在首要位置,准确掌握围岩沉降、收敛规律以及支护压力的变化,便于及时调整支护和施工参数。针对隧道穿过特大溶洞边墙的情况,采取上下台阶法施工并施做了支顶结构和临时支撑墙确保在隧道开挖过程中围岩的稳定性及施工安全。通过对白须公特大溶洞隧道的溶洞支顶结构的应力应变以及老虎嘴处临时支撑结构承受上部围岩压力在施工过程时间变化特性分析,探讨不同的隧道开挖方式对围岩的扰动影响,并分析了地下附属结构物的回应。通过对结构物的监测分析可以看出:溶洞对支顶结构的影响主要表现为水平推力,竖直压力较小;老虎嘴上部岩层中软弱夹层对围岩整体稳定影响较小,没有产生过大松动压力。
When constructing highway tunnels in karst areas, the treatment of karst caves and the monitoring of construction work are the top priority. Accurate grasping of the settlement and convergence of surrounding rock and the variation of supporting pressure make it convenient to timely adjust the supporting and construction parameters. Aiming at the situation that the tunnel passes through the side wall of the extra large cave, the construction of the top-and-bottom step method and the temporary support wall are applied to ensure the stability and construction safety of the surrounding rock during tunnel excavation. Through the analysis of the stress and strain of the cave-top structure of the Baikuogongte cave tunnel and the characteristics of the temporary support structure at the tiger mouth subjected to the pressure of the surrounding rock during construction, the influence of different tunneling methods on the disturbance of the surrounding rock is discussed Analysis of the response of underground structures. Through the monitoring and analysis of the structure, it can be seen that the influence of the cave on the structure of the top is mainly horizontal thrust and the vertical pressure is small. The weak intercalation in the upper part of the tiger mouth has little influence on the overall stability of the surrounding rock, Loose pressure.