2D profile lines play a critical role in cost-effectively evaluating rock joint properties and shear strength. However, the interval (Δ) between these lines significantly impacts roughness and shear strength assessments. A detailed study of 45 joint samples using four statistical measures across 500 different Δ values identified a clear line interval effect with two stages: stable and fluctuation-discrete. Further statistical analysis showed a linear relationship between the error bounds of four parameters, shear strength evaluation, and their corresponding maximum Δ values, where the gradient of this linear relationship was influenced by the basic friction angle and normal stress. Accounting for these factors, lower-limit linear models were employed to determine the optimal Δ values that met error tolerances (1%–10%) for all metrics and shear strength. The study also explored the consistent size effect on joints regardless of Δ changes, revealing three types of size effects based on morphological heterogeneity. Notably, larger joints required generally higher Δ to maintain the predefined error limits, suggesting an increased interval for large joint analyses. Consequently, this research provides a basis for determining the optimal Δ, improving accuracy in 2D profile line assessments of joint characteristics.

中文翻译：

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优化剖面线间隔以提高岩石节理形态和抗剪强度评估的准确性


二维剖面线在经济有效地评估岩石节理特性和剪切强度方面发挥着关键作用。然而，这些线之间的间隔 (Δ) 会显着影响粗糙度和剪切强度评估。使用 500 个不同 Δ 值的四种统计测量对 45 个联合样本进行详细研究，确定了具有两个阶段的清晰线间隔效应：稳定阶段和波动离散阶段。进一步的统计分析表明，剪切强度评价四个参数的误差范围与其对应的最大Δ值之间存在线性关系，其中该线性关系的梯度受基本摩擦角和法向应力的影响。考虑到这些因素，采用下限线性模型来确定所有指标和剪切强度满足误差容限 (1%–10%) 的最佳 Δ 值。该研究还探讨了无论 Δ 变化如何，关节的一致尺寸效应，揭示了基于形态异质性的三种类型的尺寸效应。值得注意的是，较大的关节通常需要较高的 Δ 来维持预定义的误差限制，这表明大型关节分析的间隔会增加。因此，这项研究为确定最佳 Δ 提供了基础，提高了接头特性二维轮廓线评估的准确性。