Comparison of existing methods and a new tensile strength based model in estimating the Hoek-Brown constant mi for intact rocks
Comparison of existing methods and a new tensile strength based model in estimating the Hoek-Brown constant mi for intact rocks
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DOI：
10.1016/j.enggeo.2017.05.008
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发表时间：
2017-06
影响因子：
7.4
通讯作者：
Wenjing Wang;Jiayi Shen
中科院分区：
文献类型：
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作者：
Wenjing Wang;Jiayi Shen
常数m是Hoek-Brown（HB）破坏准则在估算岩石材料强度时所需的一个基本参数。为了计算偏微分方程，需要进行三轴试验，然而，三轴试验是费时和昂贵的。因此，提出了简化的模型来估计mivalues使用岩石性质，很容易获得在早期阶段的一个项目时，三轴试验数据不可用。这些模型通常是使用统计技术提出的，预测的可靠性取决于所用数据的数量和质量。在本文中，现有的模型（指南，R指数和基于UCS的模型）进行了比较，并使用五种常见岩石类型的三轴试验数据评估其预测性能。此外，通过对岩石数据库的分析，提出了基于抗拉强度的岩石力学模型。为了评估现有的和建议的模型的可靠性，从各种模型估计的mivalues中使用的HB准则来估计完整的岩石的强度。然后将估计的完整岩石强度与使用现有三轴试验数据的实验完整岩石强度进行比较。结果表明，当三轴试验数据不可用时，基于TS模型计算的mivalues具有最佳的强度预测性能，可以可靠地用于HB准则中完整岩石强度的估计。
The constantmiis a fundamental parameter required for the Hoek-Brown (HB) failure criterion in estimating the strength of rock materials. In order to calculatemivalues triaxial tests need to be carried out, however, triaxial tests are time-consuming and expensive. Therefore, simplified models are proposed to estimatemivalues using rock properties that are easily obtained at an early stage of a project when triaxial test data are not available. These models are in general proposed using statistical technique and the reliability of prediction relies on the quantity and quality of the data used. In this paper, existing models (Guidelines, R index and UCS based model) are compared and their prediction performances are assessed using the published triaxial test data of five common rock types. In addition, the tensile strength (TS) based model is also proposed by analyzing the rock database. In order to evaluate the reliability of existing and proposed models,mivalues estimated from the various models are used in the HB criterion to estimate the strength of intact rocks. The estimated intact rock strength is then compared with the experimental intact rock strength using existing triaxial test data. Results show thatmivalues calculated from the proposed TS based model yield the best strength prediction performance and can be reliably used in the HB criterion for estimating the intact rock strength when triaxial test data are not available.