scholarly journals Generalized Models for Rock Joint Surface Shapes

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Shigui Du ◽  
Yunjin Hu ◽  
Xiaofei Hu
Keyword(s):  
Rock Joint ◽  
Statistical Analyses ◽  
Relative Amplitude ◽  
Joint Surface ◽  
Mechanical Effects ◽  
Field Investigations ◽  
Extensive Field ◽  
Study Results ◽  
Surface Profiles ◽  
Basic Features

Generalized models of joint surface shapes are the foundation for mechanism studies on the mechanical effects of rock joint surface shapes. Based on extensive field investigations of rock joint surface shapes, generalized models for three level shapes named macroscopic outline, surface undulating shape, and microcosmic roughness were established through statistical analyses of 20,078 rock joint surface profiles. The relative amplitude of profile curves was used as a borderline for the division of different level shapes. The study results show that the macroscopic outline has three basic features such as planar, arc-shaped, and stepped; the surface undulating shape has three basic features such as planar, undulating, and stepped; and the microcosmic roughness has two basic features such as smooth and rough.

Leakage characteristics of flanged pipe joints

1977 ◽  
Vol 12 (1) ◽  
pp. 29-36 ◽  
Author(s):  
H Fessler ◽  
D A Perry
Keyword(s):  
Surface Finish ◽  
Joint Surface ◽  
Clamping Force ◽  
Face Surface ◽  
Joint Efficiency ◽  
Wide Range ◽  
Pipe Joints ◽  
Surface Profiles ◽  
Leakage Characteristics ◽  
Gasket Material

Standard flanges for five widely differing pressure ratings, having a wide range of different joint surface profiles, were sealed by flat rubber or asbestos gaskets. Different initial bolt tensions were applied and the variation of clamping force with internal pressure was measured up to leakage of the joint. The joint efficiency, defined as: (end thrust due to leakage pressure on bore area of pipe)/(total initial bolting force), is not affected by variations in joint-face surface finish if machining grooves across the joint surface are avoided. Minimum values of joint efficiency are given. The effects of gasket material, width and thickness and number of bolts on joint efficiency are considered.

scholarly journals The soil cover structure and elementary soil areas of the Opillia

2017 ◽  
pp. 390-398 ◽  
Author(s):  
Taras Yamelynets ◽  
Mykola Fedotikov
Keyword(s):  
Soil Structure ◽  
Soil Cover ◽  
Contrast Ratio ◽  
Study Results ◽  
Relief Sculpture ◽  
Soil Cover Structure ◽  
Basic Parameters ◽  
Basic Features ◽  
Quantitative Indicators ◽  
Qualitative And Quantitative Characteristics

For studying the soil cover structure of Opillia region, we used methods for the identification (natural-cartometric, relief sculpture, quality-genetic) and interpretation (statistical cartometric, functional and analytical) of the soil cover structure. The natural-cartometric method was used to characterize elementary soil areas of the key area, what makes it possible to determine the parameters of the soil structure and obtain quantitative indicators for the key elementary soil areas parameters, which are: elementary soil areas composition and area ratio, complexity, fractionality, breakdown, contrast ratio and heterogeneity. This article is devoted to the study results of qualitative and quantitative characteristics of elementary soil areas of the Opillia within Khodorivsko-Buchatskyi region, hereinafter Khodorivsko- Buchatske Opillia. With coefficient of the differentiation of the soil outlines and methods of variation statistics were identified and analyzed the degree of variability ESA areas. The degree of tortuosity and elongation of area limits using the coefficient of the dismemberment were studied. Investigated the character of outlines of elementary soil areals within the area of research. Identified the basic features of ESA borders depending on various environmental factors. The certain laws of changing of the basic parameters of elementary soil areas, which form the soil structure of Khodorivsko- Buchatske Opillia were determined and described in the article. Key words: elemental soil areal (ESA), soil structure (SS), coefficient of the differentiation of the soil outlines (CDSO), coefficient of dismemberment (CD), coefficient of variability (CV).

scholarly journals Experimental Study on 3D Roughness and Shear Failure Mechanism of Rock Mass Discontinuity

2018 ◽  
Vol 2018 ◽  
pp. 1-20 ◽  
Author(s):  
Jihong Wei ◽  
Yan Men ◽  
Shaorui Sun ◽  
Huilin Le ◽  
Feng Zhu
Keyword(s):  
Surface Topography ◽  
Physical Model ◽  
Residual Strength ◽  
Failure Modes ◽  
Rock Joint ◽  
Model Construction ◽  
Joint Surface ◽  
Shear Direction ◽  
Direct Shear ◽  
Normal Stresses

A set of systematic experimental methods, including 3D accuracy scanning and identification of discontinuous surface topography, physical model construction, and laboratory direct shear experiment under different directions and normal stresses, was proposed to research the influence of discontinuity roughness on strength and deformation of discontinuity. During physical model construction of discontinuity, three types of discontinuity and rough natural rock joint surface models were constructed and moulded. Meanwhile, many influence factors of discontinuity surface topography, such as asperity inclination angle (AIA), asperity height (AH), normal stress (NS), and shear direction (SD), were considered during the direct shear experiment. On the basis of the experimental results, it can be found that there were two types of failure modes under different loading conditions, which were named “failure by shearing through the asperities” and “failure by sliding over the asperities”. The obvious stress concentration phenomenon, climbing, and cutting effects appeared in the process of the direct shear experiment. In addition, the accurate identification of surface topography of natural rough rock joint surface was carried out using three-dimensional sensing system (3DSS) and self-programming software before and after the experiment. The subsamples with the same surface topography as the original samples were moulded using a self-developed instrument. Then, the mechanical behavior of the original samples and subsamples for the natural rough rock joint surface under different shear directions and normal stresses was studied. The results show that the shear displacement under different shear directions and normal stresses is very large before it reaches the failure state. And the residual strength of the original samples is higher than that of the subsamples. In addition, failure modes of the subsamples are main failure by shearing through the asperities due to the significant difference between peak shear strength and residual strength. The failure modes for parts of the original samples are failure by sliding over the asperities. The change ratio of area for the discontinuity after the experiment depends on surface topography, strength of heave on the surface of discontinuity, and particle size of minerals on the surface of discontinuity.

scholarly journals Geological Composition and Structure of the Filling Zone and Its Water-Resisting Property Evaluation on the Top of Ordovician Limestone

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
Qiqing Wang ◽  
Wenping Li ◽  
Qiangqiang Liu
Keyword(s):  
North China ◽  
Clay Material ◽  
Water Control ◽  
Ordovician Limestone ◽  
Mining Depth ◽  
Property Evaluation ◽  
Field Investigations ◽  
Composition And Structure ◽  
Study Results ◽  
Lithological Composition

With the gradual increase in mining depth of coal fields in North China, the threat posed by karstic Ordovician limestone water to the safe stoping of mines is becoming increasingly prominent. Investigating the water-resisting property of the filling zone on the top of the Ordovician limestone provides the key to safe mining under pressure. This paper analyzed the formation process of the filling zone on the top of Ordovician limestone in North China, and by combining analysis results of several geological field investigations on Ordovician outcrops, the filling zone on the top of Ordovician limestone was divided into three water-resisting structures: (1) completely filled, (2) incompletely filled, and (3) nonfilled. Based on the lithological composition, logging curves, and the water inflow status of several field boreholes, various characteristics of these clay-filled zones were used to determine the mudstone content from top to bottom. Using the interbedded mudstone thickness ratio, relative argillaceous content, impermeable filling zone thickness, rock quality designation (RQD), and faulting as evaluation factors, this paper evaluated the water-resisting property of the filling zone in the study area based on feature-weighted fuzzy C-means clustering (WFCM) algorithm and determined the extent of each zone. The completely filled zone accounts for 46.9% of the total area, incompletely filled zone accounts for 23.9%, and the zone not filled with clay material accounts for 29.2%. As indicated by field investigations on the boreholes, the actual percent of each zone is similar to the theoretical results. The study results present a vital guide for Ordovician limestone water control in deep mining.

scholarly journals Scale Dependence of Waviness and Unevenness of Natural Rock Joints through Fractal Analysis

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Yingchun Li ◽  
Shengyue Sun ◽  
Hongwei Yang
Keyword(s):  
Surface Roughness ◽  
Rock Joint ◽  
Fractal Dimensions ◽  
Window Size ◽  
Scale Dependence ◽  
Rock Joints ◽  
Joint Surface ◽  
Triangular Prism ◽  
Natural Rock ◽  
Waviness And Unevenness

The scale dependence of surface roughness is critical in characterising the hydromechanical properties of field-scale rock joints but is still not well understood, particularly when different orders of roughness are considered. We experimentally reveal the scale dependence of two-order roughness, i.e., waviness and unevenness through fractal parameters using the triangular prism surface area method (TPM). The surfaces of three natural joints of granite with the same dimension of 1000 mm×1000 mm are digitised using a 3D laser scanner at three different measurement resolutions. Waviness and unevenness are quantitatively separated by considering the area variation of joint surface as grid size changes. The corresponding fractal dimensions of waviness and unevenness in sampling window sizes ranging from 100 mm×100 mm to 1000 mm×1000 mm at an interval of 100 mm×100 mm are determined. We find that both the fractal dimensions of waviness and unevenness vary as the window size increases. No obvious stationarity threshold has been found for the three rock joint samples, indicating the surface roughness of natural rock joints should be quantified at the scale of the rock mass in the field.

scholarly journals Field work in central west Disko, 1979

1980 ◽  
Vol 100 ◽  
pp. 51-55
Author(s):  
A.K Pedersen ◽  
F Ulff-Møller
Keyword(s):  
West Coast ◽  
Field Work ◽  
The West ◽  
Field Investigations ◽  
Extensive Field ◽  
Geological Map

Field work in the summer 1979 was concentrated in the area between 69°45'N and 70°00'N from the west coast into central Disko (fig. 15). Transport facilities were provided by the GGU cutter J. F. Johnstrup and by a helicopter. Two field teams led by A.K.P. and F.U.-M. completed extensive field investigations which together with work reported by Pedersen (1977) and Ulff-Møller (1979) will enable a final photogrammetric compilation af the geological map sheet 69 V. 1 N to be made. A.K.P. studied the Vaigat Formation and the Nordfjord and Niaqussat members of the Maligât Formation. F.U.-M. studied the Rinks Dal member of the Maligât Formation and dyke intrusions with native iran bearing rocks contaminated by sediment.

scholarly journals Runoff and drainage pattern derived from digital elevation models, Finsterwalderbreen, Svalbard

2000 ◽  
Vol 31 ◽  
pp. 147-152 ◽  
Author(s):  
Jon Ove Hagen ◽  
Bernd Etzelmüller ◽  
Anne-Marie Nuttall
Keyword(s):  
Water Channel ◽  
Relative Importance ◽  
Drainage Pattern ◽  
Bed Topography ◽  
Total Runoff ◽  
Direct Observations ◽  
Field Investigations ◽  
Extensive Field ◽  
Digital Elevation ◽  
Map Analysis

AbstractFinsterwalderbreen (77°26’ N, 15° 15’ E) is a 35 km2 polythermal, surge-type glacier in southern Spitsbergen, Svalbard. Extensive field investigations have been carried out on the glacier, including mapping of bed topography by radio-echo soundings, mass-balance measurements and hydrological and meteorological registrations. In this paper we have used surface and bed topography and observations of summer ablation to estimate total runoff and subglacial drainage pattern by means of spatial map analysis in standard geographic information system software. The location and relative importance of the water-channel outlets from the glacier were estimated, as well as the change in drainage pattern over the period 1970–90. The results could be compared to direct observations of drainage pattern and discharge recordings. The analyses indicate that the location of the subglacial channels is dominated by the surface topography and thus that the channels are partly pressurized.

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