The focus of this work is toward an investigation of the mechanical response of a variety of rocks to indentation loading as a close condition to drilling application. A rock classification method is introduced based on the mechanical response of the rock when loaded by a spherical indenter. Spherical shape is selected for the indenter as a common geometry, which to some extent represents most of the new or worn inserts in drill bits. Both of the force–penetration and fragmentation responses are studied and the results are categorized accordingly. Indentation loading of a quasi-brittle medium like rock contains a complex three-dimensional stress state, in which the compressive strength, tensile strength, compaction behavior and the brittleness of the rock all together are reflected in its mechanical response. Therefore, depending on the type of the rock and its properties, this response is also very diverse for different rocks. Eight types of rocks are investigated and the results from the force–penetration and fragmentation responses are summarized into three different classes.

中文翻译：

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对从非常硬到软的范围内选定岩石的机械响应的球形压痕研究，特别关注钻井应用

这项工作的重点是研究各种岩石对压痕载荷的机械响应，作为钻井应用的一个接近条件。介绍了一种基于岩石在球形压头加载时的力学响应的岩石分类方法。为压头选择球面形状作为常见几何形状，这在一定程度上代表了钻头中大多数新的或磨损的刀片。研究了力 - 穿透和破碎响应，并相应地对结果进行了分类。岩石等准脆性介质的压痕载荷包含复杂的三维应力状态，其中岩石的抗压强度、抗拉强度、压实行为和脆性共同反映在其力学响应中。所以，根据岩石的类型及其性质，不同岩石的这种响应也非常不同。研究了八种类型的岩石，并将力-渗透和破碎响应的结果总结为三个不同的类别。