scholarly journals Methodologies for geological-geotechnical characterization of rock masses: role of geomechanical classifications and indexes

2021 ◽  
Vol 942 (1) ◽  
pp. 012025
Author(s):  
C Santa ◽  
I Fernandes ◽  
HI Chaminé

Abstract The geological and geotechnical description and evaluation are fundamental in engineering projects and the extractive industry, emphasizing underground environments where the rock mass is subjected to high stresses. In excavating rock masses, the classification systems contribute to parameterizing the rock material and rock mass characteristics. In addition, it is essential to the definition of the support to be applied, which limits are often based on the value of the geomechanical classifications. Therefore, determining the characteristics demands structured techniques to reconcile rigour, accuracy, and efficiency in the execution of the site investigation to obtain reliable data in an integrated action of the work cycle. This study analyses the applicability and feasibility of the Geological Strenght Index (GSI), based on field data collected in different underground projects. Various geological environments and distinct excavation purposes were selected to evaluate the possibility of expanding this version of the GSI to other rock types with the inclusion of the influence of groundwater on this classification.

Author(s):  
Gregory Stump

Paradigm Function Morphology (PFM) is an evolving approach to modeling morphological systems in a precise and enlightening way. The fundamental insight of PFM is that words have both content and form and that in the context of an appropriately organized lexicon, a language’s morphology deduces a complex word’s form from its content. PFM is therefore a realizational theory: a language’s grammar and lexicon are assumed to provide a precise characterization of a word’s content, from which the language’s morphology then projects the corresponding form. Morphemes per se have no role in this theory; by contrast, paradigms have the essential role of defining the content that is realized by a language’s morphology. At the core of PFM is the notion of a paradigm function, a formal representation of the relation between a word’s content and its form; the definition of a language’s paradigm function is therefore the definition of its inflectional morphology. Recent elaborations of this idea assume a distinction between content paradigms and form paradigms, which makes it possible to account for a fact that is otherwise irreconcilable with current morphological theory—the fact that the set of morphosyntactic properties that determines a word’s syntax and semantics often differs from the set of properties (some of them morphomic) that determines a word’s inflectional form. Another recent innovation is the assumption that affixes and rules of morphology may be complex in the sense that they may be factored into smaller affixes and rules; the evidence favoring this assumption is manifold.


2020 ◽  
Vol 10 (3) ◽  
pp. 1119
Author(s):  
Jesús Luis Benito Olmeda ◽  
Javier Moreno Robles ◽  
Eugenio Sanz Pérez ◽  
Claudio Olalla Marañón

When inner cavities of significant dimensions exist in natural rocks, problems arise when a shallow foundation for a building, bridge or other structure is builtonthem. Thus, taking one of the most representative cavity geometries in nature, the ellipsoidal horizontal shape, the main objective of this study is to obtain the ultimate bearing capacity of the foundation with cavities of different sizes and positions, on rock masses with different strengths and deformation characteristics. The study focuses on natural rocks of karst origin (in limestones, dolomites or gypsums) and of volcanic origin. The ultimate bearing capacity is determined relative to a situation without the existence of the cavity for different cavern positions and sizes, rock types (mi), strengths (UCS), and states (GSI) of the rock mass. The results showed that the most decisive parameter is the relative eccentricity. The influence of the rock type (Hoek’s parameter mi) is, for practical purposes, negligible (lower than 10%). The strength and condition of the rock mass (parameters UCS and GSI) have relatively little influence on the results obtained. This study aims to provide a simple design criteria for universal use, with different geometric configurations and qualities of rock masses that can be used directly without the need for sophisticated calculations by the designer.


2016 ◽  
Vol 11 (2) ◽  
pp. 367-397
Author(s):  
Harshad PATHAK

AbstractDespite expanding the definition of rape under the Indian Penal Code to include non-penile-vaginal acts of penetration, the said definition continues to conform to a gender-specific notion of rape, based on a predetermined characterization of the victim-perpetrator framework on the basis of their genders. Herein, I will critique this idea of gender specificity in Indian rape law on the grounds that it reinforces a binary notion of gender, and results in gross underinclusion. Instead, it is more appropriate to adopt a human-rights-based approach in defining the offence of rape, and negate the role of gender in identifying the victims and perpetrators of an act of rape. The argument is pillared on a state’s obligation to not discriminate on the basis of sex, the recognition of transgender rights, and an assessment of the common grounds for opposing gender neutrality in Indian rape law.


2015 ◽  
Vol 725-726 ◽  
pp. 349-354 ◽  
Author(s):  
Zlatko Zafirovski ◽  
Nikolay Vatin

The investigation in rock masses in interaction with engineering structures is extremely important in a process of design of tunnels. The main problem is how to extrapolate the parameter from the zone of testing to the whole volume that is of interes for interaction analyses of the system rock mass-structure. In this article Empirical-Statical-Dynamical (ESD) methodology of extrapolation is presented. The basis of the methodology lies in combination of the results from geotechnical and geophysical testings and rock mass classification, connected with definition of adequate regressive models.


2017 ◽  
Vol 43 (1) ◽  
pp. 183 ◽  
Author(s):  
G. Tsiambaos

The engineering characterization of heterogeneous and complex geological formations for estimating their rock mass strength and deformability characteristics constitutes a challenge to geo-scientists and engineers dealing with the design and construction of slopes and tunnels. Mélanges and similar heterogeneous mixtures of hard blocks in weaker matrix, known as “bimrocks”, present an overall strength significantly greater than the matrix strength, because the presence of rock blocks, above a threshold volumetric proportion, influences the mechanical characteristics and the behaviour of these rock masses. Moreover, recent studies have shown that the strength and mechanical behaviour of heterogeneous and composite rock masses such as flysch and molasses consisting of alternating layers of competent and incompetent rocks are governed by the presence and volumetric percentage of the interlayers of the weaker rocks.


2015 ◽  
Vol 64 (3) ◽  
pp. 18-25
Author(s):  
Evgeniy Konstantinovich Komarov ◽  
Tamara Aleksandrovna Pluzhnikova

Tasks of investigation were concluded the characterization of insulin resistence (IR) and hormonal features in patients with prediabetes and influence of diet or metformin on the course of pregnancy and perinatal complications. There were examined 61 womans. The OGTT, definition of insulin levels in plasma and index IR were performed in all patiens. OGTT and index IR were normal in 14 womans (control group I). OGTT was normal but index IR was impared in 33 womans (group IR - II). From this group 22 womans were treated with diet (II A group) and 11 womans treated with metformin (IIB group). OGTT and index IR were abnormal in 14 womans (impared OGTT - III group), they were treated with metformin. Dose of metformin was 1500 mg/d, threatment was continueted for 3-4 manths. Conclusion: Used indexes IR basal and two hour after glucose load were significant in definition of normal and decreased insulin sensitivity (IR). Presence of IR is accompanied by high level of free testosterone in blood without impared secretion of ovarian and suprarenal androgens. There was impared sensitivity of endometrium of secretory stage. The frequency of obstetric and perinatal complications in patients receiving diet not differ from patients treated with metformin. There was only a tendercy to low frequency of threatening miscarriages befor 12 weeks of gestations in paitiens receiving metformin. Development of GDM was observed in 13,1 % of patiens only with presence of IR. The use of metformin in pregravidal stage preserved the development of macrosomia in offsprings of patients with prediabetes.


1974 ◽  
Vol 139 (2) ◽  
pp. 355-366 ◽  
Author(s):  
Douglas T. Fearon ◽  
K. Frank Austen ◽  
Shaun Ruddy

The activity of properdin factor D was measured by the generation of the hemolytically active cellular intermediate, EAC43B(D), bearing the C3b-dependent alternate pathway C3 convertase. Treatment of factor D with DFP prevented formation of EAC43B(D); thus, a serine esterase is essential for the generation of the alternate pathway C3 convertase, a situation analogous to the role of C1 in the formation of the classical C3 convertase, C42. The definition of factor D as a serine esterase prompted a search for its proenzyme form, and resulted in the chromatographic isolation from plasma of a single peak of trypsin-inducible factor D activity, distinct from activated factor D. Analytical gel filtration indicated an apparent mol wt of 25,000. This protein from which trypsin elaborated factor D activity, as assessed by the formation of EAC43B(D), the generation of the CoVF-dependent C3 convertase, and the cleavage of factor B in the presence of C3b, was designated "precursor factor D." The DFP resistance of precursor factor D, and the susceptibility of its trypsin-activated form to inactivation by DFP is analogous to the behavior of other plasma serine esterases, including C1.


2017 ◽  
Vol 54 (6) ◽  
pp. 825-834 ◽  
Author(s):  
P.J. Pells ◽  
Z.T. Bieniawski ◽  
S.R. Hencher ◽  
S.E. Pells

Rock quality designation (RQD) was introduced by Don Deere in the mid-1960s as a means of using diamond core to classify rock for engineering purposes. Subsequently, it was incorporated into the rock mass rating (RMR) and Q-system classification methods that, worldwide, now play substantial roles in rock mechanics design, whether for tunnels, foundations, rock slopes or rock excavation. It is shown that a key facet of the definition of RQD is ignored in many parts of the world, and it is noted that there are several inherent limitations to the use of RQD. Based on mapping of rock formations by 17 independent professionals at different locations in Australia and South Africa, it is shown that differences in assessed RQD values result in significant errors in computed RMR and Q ratings, and also in geological strength index (GSI) and mining rock mass rating (MRMR). The introduction of a look-up chart for assessing GSI has effectively removed the need to measure, or estimate, RQD. It has been found that GSI values derived from the look-up chart are as valid as those derived by calculation from the original component parameters, and are satisfactorily consistent between professionals from diverse backgrounds. The look-up charts provide a quick and appropriate means of assessing GSI from exposures. GSI is, in turn, a useful rock mass strength index; one new application is presented for assessing potential erosion of unlined spillways in rock. Incorporation of RQD within the RMR and Q classification systems was a matter of historical development, and its incorporation into rock mass classifications is no longer necessary.


2017 ◽  
Vol 131 (14) ◽  
pp. 1617-1629 ◽  
Author(s):  
Maria Dolores Sanchez-Niño ◽  
Ana B. Sanz ◽  
Adrian M. Ramos ◽  
Marta Ruiz-Ortega ◽  
Alberto Ortiz

The KDIGO definition of chronic kidney disease (CKD) allowed a more detailed characterization of CKD causes, epidemiology and consequences. The picture that has emerged is worrisome from the point of view of translation. CKD was among the fastest growing causes of death in the past 20 years in age-adjusted terms. The gap between recent advances and the growing worldwide mortality appears to result from sequential roadblocks that limit the flow from basic research to clinical development (translational research type 1, T1), from clinical development to clinical practice (translational research T2) and result in deficient widespread worldwide implementation of already available medical advances (translational research T3). We now review recent advances and novel concepts that have the potential to change the practice of nephrology in order to improve the outcomes of the maximal number of individuals in the shortest possible interval. These include: (i) updating the CKD concept, shifting the emphasis to the identification, risk stratification and care of early CKD and redefining the concept of aging-associated ‘physiological’ decline of renal function; (ii) advances in the characterization of aetiological factors, including challenging the concept of hypertensive nephropathy, the better definition of the genetic contribution to CKD progression, assessing the role of the liquid biopsy in aetiological diagnosis and characterizing the role of drugs that may be applied to the earliest stages of injury, such as SGLT2 inhibitors in diabetic kidney disease (DKD); (iii) embracing the complexity of CKD as a network disease and (iv) exploring ways to optimize implementation of existing knowledge.


2011 ◽  
Vol 312-315 ◽  
pp. 770-775 ◽  
Author(s):  
Guido Sassi ◽  
Marco Bernocco ◽  
Mariapaola Sassi

The regenerative medicine uses gel and porous solid matrices as scaffolds for the growth of the stem cells in 3D structures. The structural and fluid dynamic properties of the matrices have been recognized to highly affect the behaviour and functions of the cells. The procedures of production and the clinical use of the matrices need a reliable and reproducible characterization of their properties, this means that the concepts of metrology must be applied to the measurement and definition of all the relevant properties. This paper deals with the calculation of uncertainty for diffusivity measurement in solids and the role of uncertainty in designing the measurement. Diffusion of a solute in spherical solid particles dispersed in a limited liquid volume where considered as measurement method for a Ca-alginate polymer. The model sensitivity to the concentration measurements, the model parameters and the fitting procedures have been discussed.


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