Development of Cuttability Criteria for Rocks

9612035岩石的破碎在岩石工程中的许多应用中都很重要。为了适应当今社会的复杂需求，越来越多地寻求挖掘地下设施，开发新的方法来安全和具有成本效益地清除岩石，特别是坚硬的岩石，这一点很重要。很少有机械挖掘机被设计成在坚硬的岩石中工作，主要是因为缺乏对切割过程的了解。这项研究将有助于更好地了解岩石机械破碎的基本机制，从而最终有助于改进岩石挖掘机械的设计和/或操作模式。拟议研究的主要目标是制定(1)可切削性标准和(2)和指数测试，以评估使用机械压痕式工具(如隧道掘进机上使用的盘形刀具)切割岩石的能力。岩石压痕机械破坏的基本机制是形成破碎带，作为拉伸裂纹形成的前奏，最终导致岩石碎裂。这种破碎带的存在限制了用机械手段切割岩石的效率，甚至限制了其能力。事实上，压痕下方岩石的压缩损伤限制了引发和扩展拉伸裂纹所需的压应力的大小。***

9612035 Fragmentation of rock is important for many applications in rock engineering. The excavation of underground facilities is increasingly sought to accommodate the complex demands of today's society, and it is important to develop new ways to safely and cost-effectively remove rock, particularly hard rock. Very few mechanical excavators have been designed to operate in hard rock, basically because of a lack of knowledge of the cutting process. This research will lead to an improved understanding of the basic mechanisms involved in mechanical breakage of rock, and will thus ultimately contribute to improvements in the design and/or mode of operation of rock excavation machines. The main objectives of the proposed research are to develop (1) cuttability criteria and (2) and index test to evaluate the ability to cut rocks using mechanical indentor-type tools (such as disk cutters used on tunnel boring machines, TBMs). The essential mechanism involved in the mechanical breakage of rocks by indentation is the development of a crushed zone as a prelude to the formation of tensile cracks, which eventually cause chipping of the rock. The existence of this crushed zone imposes constraints on the efficiency or even the ability to cut rocks by mechanical means. Indeed, compressive damage of the rock beneath the indentor limits the magnitude of the compressive stress required to initiate and propagate tensile cracks. ***