Understanding Failure Mechanism of Non-Persistent Discontinuities Using 3D-Printed Synthetic Rock Mass

使用 3D 打印合成岩体了解非持久性不连续性的破坏机制

• 批准号: 463538034
• 负责人: Professor Dr. Florian Amann, Ph.D.
• 金额: --
• 依托单位: Lehrstuhl für Ingenieurgeologie und Hydrogeologie (LIH)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/463538034?language=en
• 关键词: Understanding; Failure; Mechanism; Non; Persistent

The mechanical and hydraulic characteristics and failure mechanism of intact rocks and rock joints are commonly determined by carrying out laboratory testing on small scale samples. The results from laboratory tests are fundamental for estimating the strength parameters and evaluating the failure behavior of a rock mass, that consists of a complex interplay of two components: intact rock and spatially distributed joints of various orientation and persistence. Although the individual geomechanical properties of these fundamental components can be properly determined in the laboratory, estimates of geomechanical properties at the rock mass scale and its failure behavior remain highly uncertain.These major uncertainties are mainly related to the often limited persistence of joints and the spatial distribution of intact rock bridges in the plane or between individual joints. Thus, the behaviour of non-persistent joints and rock mass containing non-persistent joints are dominated by complex interactions. The interpretation of laboratory tests on rock samples that contain non-persistent joints suffer from two major difficulties: 1) it is very difficult to adequately characterize the persistence of natural joints or spatial distribution of rock bridges, and 2) the natural variability in geomechanical properties of intact rock is very high. As a consequence, it is extremely difficult to adequately quantify the effect of spatially distributed non-persistent discontinuities on the rock mass strength and failure behaviour.In this project we focus on understanding the strength, deformational characteristics and failure mechanism of non-persistent joints and rock mass containing non-persistent joints. In order to overcome the two above mentioned limitations, we use 3D-printed “synthetic” sandstone samples which behave similar to brittle rocks. Both, the rock strength and the spatial distribution of joints can be precisely designed and printed in 3D using 3D printer. The approach requires to demonstrate that 1) the printed synthetic intact rock behaves similar a natural brittle rock, 2) fully persistent joints can show similar strength compared to natural joints and 3) various configuration of pre-defined rock bridge distributions need to be systematically tested. The key advantage of the proposed method is to allow for carrying out “repeatable” laboratory testing on samples with the same physical conditions, reducing the level of uncertainties. The primary outcome of proposed approach is to improve the current understanding of the strength and failure mechanism of the rock mass with non-persistent joints.

完整岩石和岩石节理的力学、水力特性和破坏机理通常通过小尺度试样的室内试验来确定。实验室试验的结果是基本的强度参数估计和评估岩体的破坏行为，这是由两个组成部分的复杂的相互作用：完整的岩石和空间分布的节理的各种方向和持久性。虽然这些基本组成部分的个别地质力学性质可以在实验室中适当地确定，但岩体规模的地质力学性质及其破坏行为的估计仍然高度不确定。这些主要的不确定性主要与节理的持久性通常有限以及平面内或单个节理之间完整岩桥的空间分布有关。因此，非持久性节理和含有非持久性节理的岩体的行为由复杂的相互作用支配。对含有非持久性节理的岩石样品进行实验室试验的解释存在两个主要困难：1）很难充分表征天然节理的持久性或岩桥的空间分布，以及2）完整岩石的地质力学性质的自然变异性非常高。因此，很难充分量化空间分布的非持久性结构面对岩体强度和破坏行为的影响，在本项目中，我们专注于了解非持久性节理和含非持久性节理的岩体的强度，变形特征和破坏机制。为了克服上述两个限制，我们使用3D打印的“合成”砂岩样品，其表现类似于脆性岩石。岩石强度和节理的空间分布都可以使用3D打印机进行精确设计和3D打印。该方法需要证明：1）打印的合成完整岩石的行为类似于天然脆性岩石，2）与天然节理相比，完全持久的节理可以显示出类似的强度，以及3）需要系统地测试预定义岩桥分布的各种配置。所提出的方法的主要优点是允许对具有相同物理条件的样品进行“可重复的”实验室测试，从而降低不确定性水平。所提出的方法的主要成果是提高目前的强度和非持久性节理岩体的破坏机制的理解。