Abstract

A three-dimensional nonlinear strength criterion for rocks considering both brittle and ductile domains is proposed through the combination of the segmented meridian function and a generalized deviatoric function with one parameter. The segmented meridian function is composed of the Hoek–Brown criterion, the smoothing transition surface, and the modified Drucker–Prager cap model. Besides, two deviatoric functions characterizing the smoothness and convexity based on the Matsuoka–Nakai criterion are suggested to describe the initial yield stage (brittle domain) and compaction yield cap stage (ductile domain). To verify the accuracy of the proposed strength criterion, six representative sets of true triaxial experimental data were selected from the existing literature, including two types of rocks, namely Dunham dolomite, KTB amphibolite, Mizuho trachyte, and Westerly granite that are independent of hydrostatic pressure in the brittle domain, and Bentheim sandstone and Castlegate sandstone which are dependent on hydrostatic pressure in the brittle–ductile domain. The results show that the experimental data are evenly distributed on the surface of the failure envelope in the three-dimensional principal stress space, demonstrating that the proposed strength criterion can accurately describe and predict the strength change of rocks in both brittle and ductile domains.

中文翻译：

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考虑脆性和延性域的岩石三维非线性强度准则

摘要

通过结合分段子午线函数和单参数广义偏函数，提出了一种同时考虑脆性域和延性域的岩石三维非线性强度准则。分段子午线函数由Hoek-Brown准则、平滑过渡面和修正的Drucker-Prager帽模型组成。此外，还提出了基于松冈-中井准则的两个表征光滑度和凸度的偏函数来描述初始屈服阶段（脆性域）和压实屈服上限阶段（延性域）。为了验证所提出的强度准则的准确性，从现有文献中选取了六组具有代表性的真三轴实验数据，包括与静水压力无关的两类岩石，即邓纳姆白云岩、KTB角闪岩、瑞穗粗面岩和西风花岗岩。脆性域中的本特海姆砂岩和卡斯尔盖特砂岩依赖于脆性域中的静水压力。结果表明，实验数据在三维主应力空间中均匀分布在破坏包络线表面，表明所提出的强度准则能够准确描述和预测岩石在脆性域和延性域的强度变化。