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Methodologies for investigating rock mass stability around underground excavations
Published in Yan Xing, Pinnaduwa H.S.W. Kulatilake, Louis Sandbak, Rock Mass Stability Around Underground Excavations in a Mine, 2019
Yan Xing, Pinnaduwa H.S.W. Kulatilake, Louis Sandbak
The discontinuum modeling, represented by the distinct element method (Cundall, 1971, 1988) and the discontinuous deformation analysis (DDA) (Shi, 1988), considers the medium as an assemblage of discrete blocks which are connected by contacts or interfaces. The discontinuities are explicitly represented and their behaviors can be described with specific joint constitutive models. This method allows for the large displacements and rotations of the discrete blocks, including the complete detachment. Several representative numerical codes and their applications are summarized as follows.
Distinct element formulations
Published in William G. Pariseau, Notes on Numerical Modeling in Geomechanics, 2022
Discontinuous deformation analysis (DDA) is another numerical method for describing the motion of blocky or particulate rock systems and was first formulated by Shi and Goodman (1984, 1985). Details are given in Shi (1988). While forces are the focus of DEM, displacements are emphasized in DDA. However, the core of both formulations is the mechanics of contacts.
Dynamic stability assessment of consequent rock slopes considering multiple transmissions and reflections of stress waves
Published in Waves in Random and Complex Media, 2023
Yun Zheng, Congxin Chen, Tingting Liu, Chaoyi Sun
With the development of computer hardware and software technology, numerical methods offer a good alternative for assessing the dynamic properties of the rock mass [29,30]. Many numerical methods have been successfully used to model the dynamic behavior of slopes, such as traditional finite element method [31,32] and discrete element method [33–35], as well as discontinuous deformation analysis (DDA) method [36,37] and numerical manifold method [38–41], which have been developed in recent years. Numerical methods allow the dynamic analysis of various types of slopes, even these with complex geological conditions. Moreover, the corresponding acceleration, velocity and displacement time history curves at any position can be easily obtained. Liu et al. [33] successfully simulated the dynamic response of jointed rock slope under explosion using UDEC. The deviation of the computational peak particle velocity from that of field measurements was less than 20%. Using the DDA method, Feng et al. [36] studied the influence of vertical earthquake on the dynamic response of dip bedded rock slope. They found that the amplification coefficients increase with increasing acceleration amplitude under sinusoidal waves shaking condition. Compared to experimental methods [42–44], numerical methods are much more economical and convenient.
Micromechanical Modeling of Unreinforced Masonry Arches Accounting for Flexural Hinges and Shear Slidings
Published in International Journal of Architectural Heritage, 2022
Mariacarla Nocera, Cristina Gatta, Daniela Addessi, Domenico Liberatore
The complexity of the arch mechanics, proved by many experimental campaigns (Cancelliere, Imbimbo, and Sacco 2010; Misseri, DeJong, and Rovero 2018; Oliveira, Basilio, and Lourenço 2010; Zampieri et al. 2018), led the scientific community to develop others efficient and accurate numerical models. These are based on various formulations (D’Altri et al. 2020), typically referring to the discrete element method, the discontinuous deformation analysis and the finite element (FE) approach. Among these, the FE models appear to be a suitable and efficient tool to accurately describe evolution of degrading mechanisms and capture the typical collapse modes of arches (Bertolesi, Milani, and Fedele 2016; Di Re, Addessi, and Sacco 2018; Milani and Lourenço 2012). The importance of accounting for both shear and flexural behavior emerges, even more, when the response of strengthened arches is analyzed. Their failure is, in fact, often caused by voussoirs sliding, as well as reinforcement rupture, debonding of the strengthening material or delamination (Zampieri et al. 2018).
Discontinuous rock slope stability analysis by limit equilibrium approaches – a review
Published in International Journal of Digital Earth, 2021
Mohammad Azarafza, Haluk Akgün, Akbar Ghazifard, Ebrahim Asghari-Kaljahi, Jafar Rahnamarad, Reza Derakhshani
Turanboy, Ülker, and Küçüksütçü (2018) described a new method to model a discontinuity that intersects rock bodies. They used the k-means vector quantization cluster as an unsupervised machine learning technique to extract the three-dimensional discontinuity emplacements in surface rock cuts. He et al. (2018) presented the couple method as a nodal variable-based discontinuous deformation analysis, named NDDA based on DDA and finite-element method (FEM) which was developed according to kinematic and block principles. Wang et al. (2018) used a framework based on block theory multi-level rock slope characterization by the analytic hierarchy process (AHP) and GeoSMA-3D. Mohebbi et al. (2019) developed an analytical approach based on the key-group method (named TFS_KGM) for the investigation of toppling free fall-sliding events. They stated that the computer evaluation results of this method significantly helped to describe the free fall toppling conditions in slope cuts. Mohammad et al. (2020a) have presented a fuzzy logical decision-making method based on block theory to effectively determine discontinuous rock slope reliability under various wedge and planar slip scenarios. The method is capable to investigate the reliability (or stability-instability) degree to prepare the response operations without the extensive requirements. Mohammad et al. (2020b) established the new methodology based on simplified semi-distinct element and block theory to estimate the stability conditions for main toppling failures (block, flexural and block-flexural types).