铁路隧道施工阶段监测等级划分方法及应用

Classification Method of Monitoring Level in Railway Tunnel Construction Phase and Its Application

铁路隧道施工阶段监控量测是保障信息化施工的重要手段,目前关于隧道监控量测项目及内容主要通过围岩级别定性判定,未建立统一的定量化评价体系。基于风险分析理论,依据隧道发生风险概率指数与风险后果指数,建立铁路隧道施工阶段监测等级及划分方法。将未确知测度理论作为风险概率指数评价方法,选取岩石风化程度、岩石质量指标和单轴饱和抗压强度等8个影响指标,构建指标测度函数,结合改进层次分析法对各评价指标进行赋权,依照置信度识别准则判定风险概率指数,定量计算监测等级指数确定监控量测等级及相应的监测内容。以渝昆铁路小草坝隧道为例,对该隧道3个里程区段进行施工阶段监测等级划分,评价结果显示DK344+200~DK344+220区段监测等级为C。

The instrumentation and monitoring in the construction phase of railway tunnels is an important means to ensure the informatization construction. At present, the instrumentation and monitoring items and contents of the tunnel are mainly determined by the qualitative determination of the surrounding rock level. No unified quantitative evaluation system has been established. Based on the risk analysis theory and the risk probability index & risk consequence index faced by tunnel, the monitoring level and classification method of railway tunnel construction phase are established. We take the unascertained measurement theory as the risk probability index evaluation method, select eight impact indexes, such as rock weathering degree, rock quality index and uniaxial saturated compressive strength, and construct the index measurement function. Also, we combine the improved analytic hierarchy process to weight each evaluation index, determine the risk probability index according to the confidence identification criteria, and calculate the monitoring level index quantitatively to determine the monitoring level and corresponding monitoring content. Taking Xiaocaoba Tunnel of Chongqing-Kunming Railway as an example, the monitoring level of the three mileage sections of the tunnel during construction phase is divided. The evaluation results show that the monitoring level of DK344+200~DK344+220 section is C.