A method for estimating the stress state during the construction of underground facilities such as deep geological disposal repositories is necessary to enhance the reliability of their design, construction, and long-term performance. For this purpose, numerous in situ measurements of variables such as hydraulic fracturing or the stress relief method have been typically performed to estimate the stress state. However, it is difficult in some cases to validate the stress state, particularly in sedimentary rock, because of the variation related to heterogeneous rock masses and topography. This study developed a new method for reliably estimating the in situ stress state of rocks using the measured initial elastic displacement of the loop gallery at 350 m depth in the Horonobe Underground Research Laboratory (URL), Japan. The estimated magnitudes of the maximum and minimum horizontal stresses are 11.25 and 6.25 MPa, respectively, which are similar to the stresses measured using the hydraulic fracturing method performed before excavating the facility. Although the proposed method could only be applied after excavation of the gallery in the studied case, it yielded an estimate of the stress state over a region of hundreds of square meters with high accuracy, as assessed by comparison with measured results. We conclude that the method can be applied to optimizing the design, construction, and performance of large underground facilities, such as deep geological repositories.

中文翻译：

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利用在泥岩中开挖的环形巷道中测量的隧道收敛性来估计应力状态


需要一种估算深层地质处置库等地下设施建设过程中应力状态的方法，以提高其设计、施工和长期性能的可靠性。为此，通常对诸如水力压裂或应力消除方法等变量进行大量现场测量来估计应力状态。然而，在某些情况下，由于与异质岩体和地形相关的变化，很难验证应力状态，特别是在沉积岩中。这项研究开发了一种新方法，利用日本 Horonobe 地下研究实验室 (URL) 350 米深的回环廊道的测量初始弹性位移来可靠地估计岩石的地应力状态。最大和最小水平应力的估计值分别为 11.25 和 6.25 MPa，与挖掘设施之前使用水力压裂方法测量的应力相似。尽管所提出的方法只能在研究案例中的廊道开挖后应用，但通过与测量结果的比较进行评估，它可以高精度地估计数百平方米区域的应力状态。我们的结论是，该方法可用于优化大型地下设施（例如深层地质处置库）的设计、施工和性能。