ABSTRACT

Greywacke rock masses are the most prominent (∼20%) bedrock type across New Zealand. This paper reviews the publicly available laboratory testing data on the geomechanical properties of greywacke from the Wellington region and compares the results with two recent studies. This includes compilations of density, unconfined compressive strengths (UCS), tensile strengths, Poisson’s ratio, Young’s Modulus, and m_i factor. This paper also presents the first published geomechanical data from a cataclasite zone in the greywacke of the Wellington region. The overall results presented in this paper highlight the influence of both weathering and discontinuities on the geomechanical properties derived from the testing of core samples. The results are discussed in the context of sampling bias, scale effects and recent developments in the geomechanical characterisation of discontinuous rock. Two different approaches for characterising the rock mass geomechanical properties of greywacke at the project-scale are presented. The first approach uses the geological strength index (GSI) as the main parameter to capture the change in rock mass character with depth while the UCS remains constant. The second approach uses the UCS as the main parameter to capture the change in rock mass character with depth, while the GSI value remains constant.

摘要

Greywacke 岩体是新西兰最突出的（~20%）基岩类型。本文回顾了惠灵顿地区灰泥岩地质力学特性的公开实验室测试数据，并将结果与​​最近的两项研究进行了比较。这包括密度、无侧限抗压强度 (UCS)、抗拉强度、泊松比、杨氏模量和 m _i的汇编因素。本文还介绍了首次发表的来自惠灵顿地区灰岩碎裂岩带的地质力学数据。本文提出的总体结果突出了风化和不连续性对岩心样品测试得出的地质力学特性的影响。在采样偏差、尺度效应和不连续岩石地质力学表征的最新发展的背景下讨论了结果。提出了两种不同的方法来表征项目规模的灰瓦岩岩体地质力学特性。第一种方法使用地质强度指数 (GSI) 作为主要参数来捕捉岩体特征随深度的变化，而 UCS 保持不变。