In tunneling, rock mass grouting is a method applied to reduce water ingress. Grouting is influenced by rock mass conditions, especially apertures, frequency, and continuation of fracturing. These rock mass conditions can partly be determined by rock mass classification systems. At the Stockholm bypass, the Measurement While Drilling (MWD) Fracturing Index was applied to characterize the rock mass for grouting purposes, with a focus on adjusting the grout hole drill plan to minimize environmental impact. This study divided the rock mass in a 1.9 km tunnel into six categories based on rock mass conditions, identifying rock mass quality, apparent fracturing, and grout consumption. These categories were then compared with the mean fracturing index based on the coefficients of penetration rate and rotation pressure variations, as well as grout consumption at each grout umbrella. The fracturing index was 93% successful in assessing favorable and unfavorable rock mass conditions in the studied tunnel and 85% successful in determining grout consumption. Finally, a conceptual method was developed to reduce the grouting activities using the MWD fracturing index and water loss tests. The introduction of this conceptual method for grouting decisions could potentially reduce 59% of the umbrellas found in the case study.

中文翻译：

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岩体灌浆的钻孔监测：斯德哥尔摩旁路的案例研究

在隧道掘进中，岩体灌浆是一种用于减少进水的方法。注浆受岩体条件的影响，尤其是孔隙、频率和压裂的持续性。这些岩体条件可以部分地由岩体分类系统确定。在斯德哥尔摩旁路，随钻测量 (MWD) 压裂指数被用于表征岩体以进行灌浆，重点是调整灌浆钻孔计划以尽量减少对环境的影响。本研究根据岩体条件、识别岩体质量、明显裂缝和注浆消耗将 1.9 公里隧道中的岩体分为六类。然后将这些类别与基于渗透率和旋转压力变化系数的平均压裂指数进行比较，以及每个灌浆伞的灌浆消耗量。压裂指数在评估研究隧道中有利和不利的岩体条件方面的成功率为 93%，在确定灌浆消耗方面的成功率为 85%。最后，开发了一种使用 MWD 压裂指数和失水测试减少灌浆活动的概念方法。引入这种用于灌浆决策的概念方法可能会减少案例研究中发现的 59% 的雨伞。