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91.
92.
Assuming a perfect fluid distribution of matter Bianchi type Vspace-time is considered and using a new generation techniqueit is shown that the field equations are solvable for anyarbitrary cosmic scale function. Solutions for particularforms of cosmic scale functions are obtained, and thegeometrical and physical properties of these solutions discussed. 相似文献
93.
Juraj Holec Martin Bednarik Marián Šabo Jozef Minár Isik Yilmaz Marián Marschalko 《Natural Hazards》2013,69(1):1081-1107
This study presented herein compares the bivariate and multivariate landslide susceptibility mapping methods and presents the landslide susceptibility map of the territory of Western Carpathians in small scale. This study also describes pioneer work for the territory of Western Carpathians, overreaching state borders, using verified sophisticated statistical methods. In the susceptibility mapping, digital elevation model was first constructed using a GIS software, and parameter maps affecting the slope stability such as geology, seismicity, precipitation, topographical elevation, slope angle, slope aspect and land cover were considered. In the last stage of the analyses, landslide susceptibility maps were produced using bivariate and multivariate analyses, and they were then compared by means of their validations. The validation of the bivariate analysis data was performed using the results of bivariate analysis for landslide areas of Slovakia containing five classes of susceptibility in scale 1:500,000. The validation area is the area of Western Carpathians within Slovakia. Eighty-two per cent of area does not differ in more than one class. The validation of the multivariate analysis data was performed using the results from the Kysuce region in the northern part of Slovakia in scale 1:10,000. The raster calculator was used to express the difference between each pair of pixels within these two layers. Seventy-seven per cent of the pixels do not differ in more than 25 %, 94 % of the pixels do not differ in more than 50 %. The maximal possible difference is 100 % (one pixel with value 0 and other with value 1, or vice versa). Receiver operating characteristic analysis was also performed, the area under curve value for bivariate model was calculated to be 0.735, while it was 0.823 for multivariate. The results of the validation can be considered as satisfactory. 相似文献
94.
H. M. Yilmaz M. Yakar O. Mutluoglu M. M. Kavurmaci K. Yurt 《Environmental Earth Sciences》2012,66(1):75-81
A fairy chimney is a conical rock formation, typically found in the Cappadocia region of Turkey. The geology of areas where
fairy chimneys exist typically comprise a thick layer of tuff, covered by a thin layer of basalt or other volcanic rocks that
are more resistant to erosion than the underlying tuff. Fairy chimneys are formed where a small cap or boulder of the original
basalt remains, protecting a cone of tuff beneath it from erosion. Eventually, the tuff will be undercut to the extent that
the cap falls off, and the remaining cone is then quickly eroded. In this study, the formation of fairy chimneys in the Cappadocia
region was examined by investigating the surface soil erosion. A study area was selected and then scanned at five different
times by a geodetic robotic total station at 40 cm horizontal and vertical intervals. The volumes of the study area were calculated
from the same height and erosion was calculated from the volume differences indicated by the data. The relationship between
erosion and meteorological data was analyzed, and showed that erosion had increased due to climatic conditions, particularly
from the effect of rainfall. 相似文献
95.
Texture and grain size is of great importance in understanding the mechanical properties of rocks. The aim of this study was to investigate textural and slaking durability characteristics, and correlate them with the gypsum types where the dolines occurred, with particular reference to the texture and crystal size. The investigation comprised two stages: field work and laboratory testing. Initially, rock samples were obtained from various representative karstified and non-karstified locations. Thereafter, mineralogical, physical and slaking durability characteristics of the gypsum samples were determined by means of laboratory testing. After the field and laboratory works, the geological, mineralogical and slaking durability characteristics of the study area gypsum were reviewed and discussed from the point of view of doline formation. Results showed that fine grain sized alabastrine gypsum tends to be karstified and leads to doline formation. This is closely related to the crystal size, texture and attributable to the slaking durability of the gypsum. Consequently, the results demonstrate that the texture, especially crystal size, and effective porosity are important parameters controlling the slake durability of the gypsum and doline formation. 相似文献
96.
Investigation of rainfall–run-off modelling is an important subject to develop any available means to water supply, which maintains human life such as run-off harvesting method. This study aims to analyse and understand the rainfall–run-off relationship in a part of Babil city, Iraq. Curve number which is a function of land use, soil texture, soil moisture and land slope is used in this study. Remote sensing and GIS are used to analyse the data and to produce the run-off depth map for the study area. Then, the run-off depth is used with rainfall to investigate the relationship between them using linear correlation. This study showed a strong linear relationship between rainfall and run-off (R2 = 0.992). It indicates that in the absence of rainfall data, run-off data can be used to estimate rainfall amount. Also, the study revealed through water balance analysis that there is an average monthly change in storage. 相似文献
97.
Experimental investigation of the effect of grading characteristics on the liquefaction resistance of various graded sands 总被引:1,自引:1,他引:0
The liquefaction susceptibility of various graded fine to medium saturated sands are evaluated by stress controlled cyclic triaxial laboratory tests. Cyclic triaxial tests are performed on reconstituted specimens having global relative density of 60%. In all cyclic triaxial tests; loading pattern is selected as a sinusoidal wave form with 1.0 Hz frequency, and effective consolidation pressure is chosen to be 100 kPa. Liquefaction resistance is defined as the required cyclic stress ratio which caused initial liquefaction in 10 cycles during the cyclic triaxial test. The results are used to draw relationship between grading characteristics (e.g. coefficient of uniformity and coefficient of curvature) and the liquefaction resistance of various graded sands. It is found that a relationship between cyclic resistance and any of the size (i.e. D10, D30 or D60) would be more realistic than to build a relation between grading characteristics and the cyclic resistance. 相似文献
98.
Structural and geomorphological aspects of the Kat landslides (Tokat—Turkey) and susceptibility mapping by means of GIS 总被引:3,自引:0,他引:3
Kat County, which is located in a slope of hilly region and constructed in the side of a mountain along the North Anatolian Fault Zone, is frequently subject to landslides. The slides occur during periods of heavy rainfall, and these events cause destruction to property, roads, agricultural lands and buildings. In the last few decades, a lot of houses and buildings have been damaged and destroyed. Settlement areas have remained evacuated for a long time. The slope instabilities in the study area are a complex landslide extending from north to south containing a lot of landslides. Field investigations, interpretation of aerial photography, analyses of geological data and laboratory tests suggest that some factors have acted together on the slopes to cause the sliding. In the wet season, the slopes became saturated. As the saturation of the earth material on the slope causesa rise in water pressure, the shear strength (resisting forces) decreases and the weight (driving forces) increases; thus, the net effect was to lower the safety factor. Previous failures have affected the rock mass, leading to the presence of already sheared surfaces at residual strengths. The relation between the joint planes and the instability of the slope in the study area was discussed and it was found that the potential slope instabilities are mainly in the directions of NW–SE, NE–SW and N–S. The landslide susceptibility map obtained by using the geographical information system showed that a large area is susceptible and prone to landslides in the northern part of the study area.An erratum to this article can be found at 相似文献
99.
Soil liquefaction susceptibility and hazard mapping in the residential area of Kütahya (Turkey) 总被引:2,自引:0,他引:2
This study presents the results of both field and laboratory tests that have been undertaken to assess liquefaction susceptibilities
of the soils in Kütahya city, located in the well-known seismically active fault zone. Liquefaction potentials of the sub-surface
materials at Kütahya city were estimated by using the geological aspect and geotechnical methods such as SPT method of field
testing. And, the data obtained have been mapped according to susceptibility and hazard. The susceptibility map indicated
“liquefable” and “marginally liquefable” areas in alluvium, and “non-liquefable” areas in Neogene unit for the magnitude of
earthquake of M=6.5; whereas, liquefaction hazard map produced by using of liquefaction potential index showed the severity categories from
“very low” to “high.” However, a large area in the study area is prone to liquefy according to liquefaction susceptibility
map; the large parts of the liquefable horizon are mapped as “low” class of severity by the use of the liquefaction potential
index. It can be said that hazard mapping of liquefaction for a given site is crucial than producing liquefaction susceptibility
map for estimating the severity. Both the susceptibility and hazard maps should be produced and correlated with each other
for planning in an engineering point of view. 相似文献
100.
Muhammet Yilmaz 《水文科学杂志》2019,64(7):820-834
A comprehensive evaluation of trends in annual instantaneous maximum flows (AIMF) from 153 gauge stations located in 26 river basins in Turkey is presented. Two traditional non-parametric trend tests, the Mann-Kendall (MK) and Spearman’s rho (SR), are used to quantify the significance of trends, while Sen’s slope method is applied to determine the magnitude of trends. The traditional tests indicate that the AIMF records of 57 stations showed statistically decreasing trends, while those of six stations showed an increasing trend. Sen’s trend method, which provides more detailed assessment of the trends in different clusters (low, medium and high), was applied to the AIMF series and the results were compared with traditional tests. Sen’s trend method indicated that all flow clusters at nine stations have increasing or decreasing trends, although no significant trend was detected by the MK and SR tests. 相似文献