Surrounding Rock Mass Quality Evaluation of Huangdao Water Sealed Underground Oil Tank

2011 ◽  
Vol 261-263 ◽  
pp. 1877-1881
Author(s):  
Xiang Chen ◽  
Xiao Bo Qi ◽  
Zhao Yi Xu
Keyword(s):  
Rock Mass ◽  
Rock Sample ◽  
Classification Method ◽  
Rock Quality ◽  
Quality Classification ◽  
Integrity Index ◽  
Oil Tank ◽  
Level I ◽  
Stress Relation

Huangdao water sealed underground oil tank, which lies in Qingdao, Shandong province, is one of strategic reservoir of oil in China. Targeting at a real pragmatic problem that sometimes the rock mass integrity index is more than 1 and taking Huangdao water sealed underground oil tank as an example, the rock sample wave velocity-stress relation tests are carried out. Then unloading index is put forward and formula of raock integrity index is modified so as to improve rock quality classification method. In the end, the improved rock quality classification method is applied to Huangdao water sealed underground oil tank engineering. The result shows that the quality of most rock masses here is level I or II.

Research on Influence of Span on Surrounding Rock Quality of Tunnels

2014 ◽  
Vol 919-921 ◽  
pp. 869-872
Author(s):  
Xiao Jie Geng ◽  
Xiao Wei Du ◽  
Qiong Yan
Keyword(s):  
Rock Mass ◽  
Numerical Experiment ◽  
Quality Index ◽  
Quality Evaluation ◽  
Measured Data ◽  
Surrounding Rock ◽  
National Standard ◽  
Rock Quality ◽  
The Relationship

The influence of tunnel’s span on rock mass quality is getting more and more recognition along with increasing large span tunnels’ construction. As national standard of China, BQ qualification is generally applied. Based on the measured data and numerical experiment, the relationship between surrounding rock displacement and quality evaluation is studied, and span effect correction factor is established. The modified rock quality index can provide the basis of guiding the design and construction of tunnels.

scholarly journals Fine quality evaluation of surrounding rock of an underground hydropower station

2020 ◽  
Vol 194 ◽  
pp. 05041
Author(s):  
Xiaojun Bao ◽  
Zhiyuan Wang ◽  
Shuai Ma ◽  
Gao Liu
Keyword(s):  
Quality Evaluation ◽  
Surrounding Rock ◽  
Classification Method ◽  
Hydropower Station ◽  
Rock Classification ◽  
Rock Quality ◽  
Grade Ii ◽  
Grade Iii

Using RMR surrounding rock classification method, the surrounding rock quality of underground main powerhouse of a hydropower station is evaluated with a small evaluation unit. The results of surrounding rock classification show that the surrounding rock of main powerhouse is mainly Grade III, and Grade II and IV surrounding rock develop intermittently with the depth of main powerhouse, and there is no Grade I or V surrounding rock distribution. Secondly, setting a smaller evaluation section is conducive to improve the accuracy of surrounding rock quality evaluation and better grasp the distribution of different grades of surrounding rock in the evaluation area.

scholarly journals Carbon Dioxide Laser Vulvovaginal Rejuvenation: A Systematic Review

Cosmetics ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 56
Author(s):  
Tassahil Messas ◽  
Achraf Messas ◽  
George Kroumpouzos
Keyword(s):  
Carbon Dioxide ◽  
Systematic Review ◽  
Laser Therapy ◽  
Carbon Dioxide Laser ◽  
Invasive Treatment ◽  
Erbium:Yag Laser ◽  
Non Invasive ◽  
Level I ◽  
Carbon Dioxide Co2

Genitourinary syndrome of menopause (GSM) causes significant symptomatic aggravation that affects the quality of life (QoL). Vulvovaginal atrophy (VVA), the hallmark of GSM, is managed with topical non-hormonal therapy, including moisturizers and lubricants, and topical estrogen application. Patients not responding/being unsatisfied with previous local estrogen therapies are candidates for a noninvasive modality. Carbon dioxide (CO2) laser therapy, especially the fractionated type (FrCO2), has drawn considerable attention over the past two decades as a non-invasive treatment for GSM. This systematic review describes the accumulated evidence from 40 FrCO2 laser studies (3466 participants) in GSM/VVA. MEDLINE, Scopus and Cochrane databases were searched through April 2021. We analyze the effects of FrCO2 laser therapy on symptoms, sexual function, and QoL of patients with GSM/VVA. As shown in this review, FrCO2 laser therapy for GSM shows good efficacy and safety. This modality has the potential to advance female sexual wellness. Patient satisfaction was high in the studies included in this systematic review. However, there is a lack of level I evidence, and more randomized sham-controlled trials are required. Furthermore, several clinical questions, such as the number of sessions required that determine cost-effectiveness, should be addressed. Also, whether FrCO2 laser therapy may exert a synergistic effect with systemic and/or local hormonal/non-hormonal treatments, energy-based devices, and other modalities to treat GMS requires further investigation. Lastly, studies are required to compare FrCO2 laser therapy with other energy-based devices such as erbium:YAG laser and radiofrequency.

scholarly journals Influence of the groundwater level on the bearing capacity of shallow foundations on the rock mass

2021 ◽  
Author(s):  
Ana Alencar ◽  
Rubén Galindo ◽  
Svetlana Melentijevic
Keyword(s):  
Rock Mass ◽  
Bearing Capacity ◽  
Groundwater Level ◽  
Sensitivity Study ◽  
Shallow Foundations ◽  
Unit Weight ◽  
Geological Strength Index ◽  
Strength Index ◽  
Mass Type

AbstractThe presence of the groundwater level (GWL) at the rock mass may significantly affect the mechanical behavior, and consequently the bearing capacity. The water particularly modifies two aspects that influence the bearing capacity: the submerged unit weight and the overall geotechnical quality of the rock mass, because water circulation tends to clean and open the joints. This paper is a study of the influence groundwater level has on the ultimate bearing capacity of shallow foundations on the rock mass. The calculations were developed using the finite difference method. The numerical results included three possible locations of groundwater level: at the foundation level, at a depth equal to a quarter of the footing width from the foundation level, and inexistent location. The analysis was based on a sensitivity study with four parameters: foundation width, rock mass type (mi), uniaxial compressive strength, and geological strength index. Included in the analysis was the influence of the self-weight of the material on the bearing capacity and the critical depth where the GWL no longer affected the bearing capacity. Finally, a simple approximation of the solution estimated in this study is suggested for practical purposes.

PHYSICAL PREREQUISITES FOR GAS PERMEABILITY SIMULATION OF MINED ROCK MASS

2021 ◽  
pp. 78-84
Author(s):  
Oleksandr Shashenko ◽  
◽  
Vladyslava Cherednyk ◽  
Natalia Khoziaikina ◽  
Dmitro Shashenko ◽  
...  
Keyword(s):  
Rock Mass ◽  
Physical Model ◽  
Rock Sample ◽  
Coal Mass ◽  
Dynamic Processes ◽  
Deformation Diagram ◽  
Gas Dynamic ◽  
Laboratory Test Results ◽  
Deformation Properties ◽  
Complete Deformation

Purpose. Justification of the gas collectors formation physical model on the basis of research of conformity of permeability of rock mass to the full diagram of rock sample deformation. Methodology consists in sequential analysis of the stages of the complete deformation diagram of the rock specimen under “hard” loading, comparing them with the stages of formation of the high stress zone in front of the lava bottom and statistical analysis of laboratory test results. Results. Based on the rock’s deformation properties analysis and their comparison with the rock sample full deformation diagram, the physical model of formation of gas reservoirs during the development of gas-saturated coal seam is substantiated. Within the solved problem framework, four stages of the complete deformation process are analyzed, namely: elastic, at the limit of strength, out-of-bounds stage and equivoluminal flow zone. The gas collector boundaries, which are the characteristic points of the rock sample deformation diagram in specified deformations mode (the limit of elastic strength and the limit of final strength) are determined. It is proved that the structural and textural features of the coal mass in connection with the course of gas-dynamic processes are manifested in the change in the pores and cracks volume contained in it, which together make the filtration space. Knowledge regarding the transfer of the permeability changes established regularities and free methane accumulation zones formation to the real rock mass, if the process of its forgery is considered as a consistent change of geomechanical states of rocks, is obtained. Scientific novelty lies in the first substantiated possibility of modeling the stress state before the longwall face by equivalent stages of the rock sample destruction in the given deformations mode. Gradual comparative analysis of the internal mechanism of rock samples deformation along the complete deformation diagram allowed establishing causal relationships between geomechanical and gas-dynamic processes in coal mass, and qualitatively characterizing general trends in permeability and volumetric expansion in changes of these samples. Practical value of the work lies in the justification of the principle of construction of a digital geomechanical model for the detection of man-made gas collectors in a mined coal mass.

scholarly journals Development and evaluation of the Lake Multi-biotic Integrity Index for Dongting Lake, China

2015 ◽  
Author(s):  
Xing Wang ◽  
Binghui Zheng ◽  
Lusan Liu ◽  
Lijing Wang
Keyword(s):  
Water Quality ◽  
Water Environment ◽  
Aquatic Organisms ◽  
Dongting Lake ◽  
Assessment System ◽  
Biotic Integrity ◽  
Diatom Index ◽  
Integrity Index ◽  
Biotic Integrity Index

<p>A Lake Multi-biotic Integrity Index (LMII) for the China’s second largest interior lake (Dongting Lake) was developed to assess the water quality status using algal and macroinvertebrate metrics. Algae and benthic macroinvertebrate assemblages were sampled at 10 sections across 3 subregions of Dongting Lake. We used a stepwise process to evaluate properties of candidate metrics and selected ten for the LMII: Pampean diatom index, diatom quotient, trophic diatom index, relative abundance diatoms, Margalef index of algae, percent sensitive diatoms, % facultative individuals, % Chironomidae individuals, % predators individuals, and total number of macroinvertebrate taxa. We then tested the accuracy and feasibility of the LMII by comparing the correlation with physical-chemical parameters. Evaluation of the LMII showed that it discriminated well between reference and impaired sections and was strongly related to the major chemical and physical stressors (r = 0.766, P&lt;0.001). The re-scored results from the 10 sections showed that the water quality of western Dongting Lake was good, while that of southern Dongting Lake was relatively good and whereas that of eastern Dongting Lake was poor. The discriminatory biocriteria of the LMII are suitable for the assessment of the water quality of Dongting Lake. Additionally, more metrics belonging to habitat, hydrology, physics and chemistry should be considered into the LMII, so as to establish comprehensive assessment system which can reflect the community structure of aquatic organisms, physical and chemical characteristics of water environment, human activities, and so on.</p>

scholarly journals Stability Assessment of Mining Excavations: the Impact of Large Depths

2018 ◽  
Vol 40 (3) ◽  
pp. 180-187
Author(s):  
Tadeusz Majcherczyk ◽  
Zbigniew Niedbalski ◽  
Łukasz Bednarek
Keyword(s):  
Rock Mass ◽  
In Situ Monitoring ◽  
Stability Assessment ◽  
Underground Excavations ◽  
Deformation Prediction ◽  
Large Depth ◽  
Coal Deposits ◽  
The Impact

AbstractBack in the early 1980s, coal deposits occurring at depths of ~700 m below surface were already regarded as large-depth deposits. Meanwhile, today the borderline depth of large-depth mining has extended to >1,000 m. Design, excavation and maintenance of mining roadways at the depth of >1,000 m have, therefore, become crucial issues in a practical perspective in recent years. Hence, it is now extremely important to intensify research studies on the influence of large depths on the behaviour of rock mass and deformation of support in underground excavations. The paper presents the results of the study carried out in five mining excavations at depths ranging from 950 to 1,290 m, where monitoring stations with measurement equipment were built. The analysis of data from laboratory and coal mine tests, as well as in situ monitoring, helped to formulate a set of criteria for stability assessment of underground excavations situated at large depths. The proposed methodology of load and deformation prediction in support systems of the excavations unaffected by exploitation is based on the criteria referring to the depth of excavation and the quality of rock mass. The depth parameter is determined by checking whether the analysed excavation lies below the critical depth, whereas the rock mass quality is determined on the basis of the roof lithology index (WL) and the crack intensity factor (n)

scholarly journals Petrographic analysis of carbonate rocks for alkali-aggregate reactivity

1970 ◽  
Vol 14 ◽  
pp. 15-20
Author(s):  
Naresh Kazi Tamrakar ◽  
Lalu Prasad Paudel
Keyword(s):  
Rock Sample ◽  
Rock Type ◽  
Significant Proportion ◽  
Carbonaceous Material ◽  
Petrographic Analysis ◽  
Rock Types ◽  
Alkali Silica Reactivity ◽  
Alkali Carbonate ◽  
Alkali Aggregate Reactivity

Quality of aggregate is of extreme concern when it is to be used for infrastructures. Besides, many physical and mechanicalproperties of the aggregate, presence or absence of deleterious constituents and alkali-silica reactivity are especially importantwhen aggregates are to be used in concrete structures. High potential of alkali-silica reactivity or alkali-carbonate reactivity andpresence of deleterious constituents may impair the infrastructures.A ledge rock sample from the heap to be taken for crushing was petrographically analysed for alkali-silica reactivity. Inoverall, two rock clans (dolosparstone and dolomicrosparstone) with three sub clans (rock type X, Y and Z) from the sample 2 areidentified. Rock type X (dolosparstone) constitutes 82.94% of the whole sample, and shows notable amount of quartz and calciteveins, and carbonaceous material and hematite on the mosaic of dolospars. Rock types Y (dolosparstone) and Z (dolomicrosparstone)contain trace amount of microquartz, mega quartz (>15 mm) and carbonaceous opaques. The rock type Z is dominantly composedof dolomicrospars. Major portions of all the rock types are characterised by mosaics of dolomite in association with variableamounts of muscovite, quartz, and calcite. Calcite often replaces the mosaics of dolomite and bands of quartz, forming a veinnetworks in rock types X and Y. Silica is represented by a low-temperature mega quartz either in ground or in veins, a trace amountof microquartz in rock types Y and Z. There is no other reactive silica components, thus showing a low potential to alkali-silicareactivity. However, the sample shows potential of alkali-carbonate reactivity as significant proportion of rock type havingdolomicrospars are found.DOI: http://dx.doi.org/10.3126/bdg.v14i0.5433Bulletin of the Department of Geology Vol.14 2011, pp.15-20

Community quality of life. A case study of the new Popești Leordeni, Ilfov

2020 ◽  
Vol 31 (4) ◽  
pp. 335-361
Author(s):  
Andreea Acasandre
Keyword(s):  
Quality Of Life ◽  
Urban Sprawl ◽  
Public Transportation ◽  
Local Level ◽  
Residential Areas ◽  
Community Quality Of Life ◽  
Leisure Services ◽  
The People ◽  
Level I

This paper is concerned with the analysis of some worrying present tendencies of urban sprawl in the large, important economic centers of Romania. It focuses on the tendency of building new residential apartments on the outskirts of the big cities. Most of these developments target young people that belong to a still-developing middle class. Big problems emerge, however, when real estate investors take advantage of the buyers’ lack of experience and of the authorities’ poor management, offering small, badly-built apartments in new residential areas which are designed around only one function: housing. The absence of complementary functions that could support the development of communities gravely impairs the inhabitants’ quality of life. At the local level, I was able to identify two main problems: the absence of the necessary infrastructure to support such a massive increase in population, and the absence of local amenities. On a larger scale, the consequences are significant as well: chronic traffic jams due to the large number of people who commute to Bucharest daily, for work. Even though at first Popeşti-Leordeni (a satellite-town of Romania’s capital) was considered a good housing option, the people living there are rapidly becoming highly unsatisfied with their quality of life. In their opinion, the biggest problems of this urban area are the absence of green spaces, of leisure services, of parking options, and of means of public transportation. To these complaints, the inhabitants add dissatisfaction with the general problems caused by the endless building sites, which also represent one of the main causes for the lack of cleanliness, bad roads, noise and pollution plaguing the area. This paper, based both on the analysis of statistical data and on empirical research, aims to show that Popeşti-Leordeni, especially the New Popeşti neighborhood, is an example of bad housing caused by corruption, investors’ greed, bad management on the part of the authorities, and the young buyers’ inexperience. Keywords: quality of life; urban sprawl; satellite-town; mono-functionality; community.

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