A parameterized fit to 5.3 million years of Benthic foram dO18 data is described, which quantifies the magnitude, phase, and variability of Milankowitz terms. The 41,000y obliquity cycle, and 100,000y ellipticity cycles are dominant, with interglacial periods correlated with large orbital ellipticity. Shorter regular warming peaks correlate with larger obliquity. The fit is then used to extrapolate forward in time implying that the earth will begin cooling in about 2000 years time, eventually entering another 70,000 year long glaciation. Possible causes resulting from effects in the tropics due to increased eccentricity, and to changes in albedo at large obliquity, are discussed.
{"title":"Phenomenology of Ice Ages","authors":"C. Best","doi":"10.5539/ESR.V6N2P131","DOIUrl":"https://doi.org/10.5539/ESR.V6N2P131","url":null,"abstract":"A parameterized fit to 5.3 million years of Benthic foram dO18 data is described, which quantifies the magnitude, phase, and variability of Milankowitz terms. The 41,000y obliquity cycle, and 100,000y ellipticity cycles are dominant, with interglacial periods correlated with large orbital ellipticity. Shorter regular warming peaks correlate with larger obliquity. The fit is then used to extrapolate forward in time implying that the earth will begin cooling in about 2000 years time, eventually entering another 70,000 year long glaciation. Possible causes resulting from effects in the tropics due to increased eccentricity, and to changes in albedo at large obliquity, are discussed.","PeriodicalId":11486,"journal":{"name":"Earth Science Research","volume":"13 1","pages":"131"},"PeriodicalIF":0.0,"publicationDate":"2017-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79097504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In order to analyze the dynamic processes of the Earth interior and the effect of the propagation of the seismic waves to the surface, a comprehensive study of the Earth crust kinematics is necessary. Although the Global Positing System (GPS) is a powerful method to measure ground displacements and velocities both horizontally and vertically as well as to infer the tectonic stress regime generated by the subsurface processes (from local fault systems to huge tectonic plate movements and active volcanoes), the complexity of the deformation pattern generated during such movements is not always easy to be interpreted. Therefore, it is necessary to work on new methodologies and modifying the previous approaches in order to improve the current methods and better understand the crustal movements. In this paper, we focus on western Alaska area, where many complex faults and active volcanoes exist. In particular, we analyze the data acquired each 30 seconds by three GPS stations located in western Alaska (AC31, AB09 and AB11) from January 1, 2012 to December 31, 2012 in order to compute their displacements in horizontal and vertical components by vectorial summation of the average daily and annual velocities components. Furthermore, we design non-parametric DMeyer and Haar wavelets for horizontal and vertical velocities directions in order to identify significant and homogenous displacements during the year 2012. Finally, the non-parametric decomposition of total horizontal and vertical normalized velocities based on level 1 and level 2 coefficients have been applied to compute normal and cumulative probability histograms related to the accuracy and statistical evolution of each applied wavelet. The results present a very good agreement between the designed non-parametric wavelets and their decomposition functions for each of the three above mentioned GPS stations displacements and velocities during the year 2012.
{"title":"Non-Parametric Wavelet Functional Analysis for Horizontal and Vertical displacements Derived from GPS Stations in Western Alaska during the Year 2012","authors":"H. Zahmatkesh, Abbas Abedeni","doi":"10.5539/ESR.V6N2P112","DOIUrl":"https://doi.org/10.5539/ESR.V6N2P112","url":null,"abstract":"In order to analyze the dynamic processes of the Earth interior and the effect of the propagation of the seismic waves to the surface, a comprehensive study of the Earth crust kinematics is necessary. Although the Global Positing System (GPS) is a powerful method to measure ground displacements and velocities both horizontally and vertically as well as to infer the tectonic stress regime generated by the subsurface processes (from local fault systems to huge tectonic plate movements and active volcanoes), the complexity of the deformation pattern generated during such movements is not always easy to be interpreted. Therefore, it is necessary to work on new methodologies and modifying the previous approaches in order to improve the current methods and better understand the crustal movements. In this paper, we focus on western Alaska area, where many complex faults and active volcanoes exist. In particular, we analyze the data acquired each 30 seconds by three GPS stations located in western Alaska (AC31, AB09 and AB11) from January 1, 2012 to December 31, 2012 in order to compute their displacements in horizontal and vertical components by vectorial summation of the average daily and annual velocities components. Furthermore, we design non-parametric DMeyer and Haar wavelets for horizontal and vertical velocities directions in order to identify significant and homogenous displacements during the year 2012. Finally, the non-parametric decomposition of total horizontal and vertical normalized velocities based on level 1 and level 2 coefficients have been applied to compute normal and cumulative probability histograms related to the accuracy and statistical evolution of each applied wavelet. The results present a very good agreement between the designed non-parametric wavelets and their decomposition functions for each of the three above mentioned GPS stations displacements and velocities during the year 2012.","PeriodicalId":11486,"journal":{"name":"Earth Science Research","volume":"5 1","pages":"112"},"PeriodicalIF":0.0,"publicationDate":"2017-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84064285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A statistically and physically based framework is put forward to investigate the relationship between Tropical Moisture Exports (TMEs), extreme precipitation and floods in the Northeastern United States (NE-US). We found that the NE-US floods in the four seasons are closely related to TMEs and four major moisture sources of TMEs in the tropics account for approximately 85% of all the TMEs that enter the NE-US. The seasonality and interannual variation of the birth processes in the four source regions determine their contribution to the NE-US. Moisture born in Gulf of Mexico (GP) and Gulf stream (GS) are the year-around sources, with some winter contribution from Pineapple Express (PE) region, and West Pacific (WP) region contributes the least. The overall order of their contribution to NE-US is GP>GS>PE>WP. Seasonal association between TMEs birth and ENSO are also found. The seasonal and interannual variations in atmospheric circulation patterns also play an important role in determining the TMEs’ entrance to NE-US. Strong influence of active TMEs periods on the occurrence of extreme rainfall is also identified. We show that the extreme daily precipitation events are dominated by extreme TMEs’ entering the NE-US in every season.
{"title":"Tropical Moisture Exports, Extreme Precipitation and Floods in Northeastern US","authors":"Mengqian Lu, Upmanu Lall","doi":"10.5539/ESR.V6N2P91","DOIUrl":"https://doi.org/10.5539/ESR.V6N2P91","url":null,"abstract":"A statistically and physically based framework is put forward to investigate the relationship between Tropical Moisture Exports (TMEs), extreme precipitation and floods in the Northeastern United States (NE-US). We found that the NE-US floods in the four seasons are closely related to TMEs and four major moisture sources of TMEs in the tropics account for approximately 85% of all the TMEs that enter the NE-US. The seasonality and interannual variation of the birth processes in the four source regions determine their contribution to the NE-US. Moisture born in Gulf of Mexico (GP) and Gulf stream (GS) are the year-around sources, with some winter contribution from Pineapple Express (PE) region, and West Pacific (WP) region contributes the least. The overall order of their contribution to NE-US is GP>GS>PE>WP. Seasonal association between TMEs birth and ENSO are also found. The seasonal and interannual variations in atmospheric circulation patterns also play an important role in determining the TMEs’ entrance to NE-US. Strong influence of active TMEs periods on the occurrence of extreme rainfall is also identified. We show that the extreme daily precipitation events are dominated by extreme TMEs’ entering the NE-US in every season.","PeriodicalId":11486,"journal":{"name":"Earth Science Research","volume":"17 1","pages":"91"},"PeriodicalIF":0.0,"publicationDate":"2017-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78268946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Le Chen, Zhipeng Lin, Tai-ju Yin, Jingfu Shan, Qianjun Sun, Fei Wang
The meandering process has always been the topic through years and still remains a lot of unsolved mysteries. One of the most important focus is the migration architectures and models that the meandering channels follow. This article chooses the Nowitna River as the study object of the typical meandering river with high migratory processes. Though the high-resolution historical satellite images by the techniques of Google Earth and ACME Mapper, 50 meanders in the river is studied and 6 of which are chosen for meticulous characterization. During the process, the planform structure of meandering channel is re-examined and 29 kinds of architecture elements are systematically established. More importantly, in order to make a fine quantitative characterization of the channel structure of meandering river, 5 kinds of characterization parameters are proposed, extraordinarily, the parameters of the difference of along-current deflection angle, a difference of counter-current deflection angle, and expansion coefficient, these three are firstly brought forward and applied introduction. In addition, the conception of sinuosity index and curvature are also different from the original definition. Though these architectures elements the meandering process and migration structure of the Nowitna River is demonstrated. 6 kinds of planform migration structures is revealed with the quantitative characterization of characterization parameters and 9 species of meandering channel migration patterns are concluded and discussed.
{"title":"Meandering Process and Migration Architecture: Based on the Nowitna River","authors":"Le Chen, Zhipeng Lin, Tai-ju Yin, Jingfu Shan, Qianjun Sun, Fei Wang","doi":"10.5539/ESR.V6N2P76","DOIUrl":"https://doi.org/10.5539/ESR.V6N2P76","url":null,"abstract":"The meandering process has always been the topic through years and still remains a lot of unsolved mysteries. One of the most important focus is the migration architectures and models that the meandering channels follow. This article chooses the Nowitna River as the study object of the typical meandering river with high migratory processes. Though the high-resolution historical satellite images by the techniques of Google Earth and ACME Mapper, 50 meanders in the river is studied and 6 of which are chosen for meticulous characterization. During the process, the planform structure of meandering channel is re-examined and 29 kinds of architecture elements are systematically established. More importantly, in order to make a fine quantitative characterization of the channel structure of meandering river, 5 kinds of characterization parameters are proposed, extraordinarily, the parameters of the difference of along-current deflection angle, a difference of counter-current deflection angle, and expansion coefficient, these three are firstly brought forward and applied introduction. In addition, the conception of sinuosity index and curvature are also different from the original definition. Though these architectures elements the meandering process and migration structure of the Nowitna River is demonstrated. 6 kinds of planform migration structures is revealed with the quantitative characterization of characterization parameters and 9 species of meandering channel migration patterns are concluded and discussed.","PeriodicalId":11486,"journal":{"name":"Earth Science Research","volume":"49 1","pages":"76"},"PeriodicalIF":0.0,"publicationDate":"2017-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79130548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Heavy minerals are extremely sensitive indicators of provenance. Applying the methods of heavy mineral combination analysis, content distribution analysis, SPSS statistical component analysis, and correlation analysis, 18 heavy minerals are identified in the northwestern margin of the Junggar Basin (NW Junggar). According to the analysis of the heavy mineral characteristics and coefficients, 4 heavy mineral combinations are developed in the study area: Zircon-tourmaline-monazite-apatite-anatase, rutile-ilmenite-leucoxene-apatite-galenite, hematite-limonite-pyrite, and magnetite-epidote-hornblende. Previous results predicted that source rocks consist of intermediate-acidic magmatite, sedimentary rocks and metamorphic rocks, and intermediate-acidic magmatite is considered to be the main source rock. Furthermore, combined with the geological background of NW Junggar, Qier-Halaalat Mountain, which belongs to the Zaire Mountain front, is shown to be the provenance of the study area. The main sources of sediments are flesh-red granite, grey and greyish-green andesite, andesitic-porphyrite, grey and grayish-black tuff, siltstone, and sandstone of the Lower Carboniferous Tailegula Formation. Additionally, because of the high content of the angular-subangular and subangular-subrounded heavy mineral grains, these heavy minerals are both from near and distal provenance, with most being near-provenance deposits. During the process of provenance propulsion on the margin of the basin, clastics are mixed together and affected by regional dynamic metamorphism, which is probably the main reason for the existence of the metamorphic component.
{"title":"Heavy Mineral Characteristics and Their Implication for Provenance of the Middle to Upper Triassic on the Northwest Margin of Junggar Basin, North China","authors":"M. He, Liwei Zhang, Jian-xin Yao, Shuai Li, Qi Li","doi":"10.5539/ESR.V6N2P65","DOIUrl":"https://doi.org/10.5539/ESR.V6N2P65","url":null,"abstract":"Heavy minerals are extremely sensitive indicators of provenance. Applying the methods of heavy mineral combination analysis, content distribution analysis, SPSS statistical component analysis, and correlation analysis, 18 heavy minerals are identified in the northwestern margin of the Junggar Basin (NW Junggar). According to the analysis of the heavy mineral characteristics and coefficients, 4 heavy mineral combinations are developed in the study area: Zircon-tourmaline-monazite-apatite-anatase, rutile-ilmenite-leucoxene-apatite-galenite, hematite-limonite-pyrite, and magnetite-epidote-hornblende. Previous results predicted that source rocks consist of intermediate-acidic magmatite, sedimentary rocks and metamorphic rocks, and intermediate-acidic magmatite is considered to be the main source rock. Furthermore, combined with the geological background of NW Junggar, Qier-Halaalat Mountain, which belongs to the Zaire Mountain front, is shown to be the provenance of the study area. The main sources of sediments are flesh-red granite, grey and greyish-green andesite, andesitic-porphyrite, grey and grayish-black tuff, siltstone, and sandstone of the Lower Carboniferous Tailegula Formation. Additionally, because of the high content of the angular-subangular and subangular-subrounded heavy mineral grains, these heavy minerals are both from near and distal provenance, with most being near-provenance deposits. During the process of provenance propulsion on the margin of the basin, clastics are mixed together and affected by regional dynamic metamorphism, which is probably the main reason for the existence of the metamorphic component.","PeriodicalId":11486,"journal":{"name":"Earth Science Research","volume":"50 1","pages":"65"},"PeriodicalIF":0.0,"publicationDate":"2017-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85463603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The prediction and evaluation of reservoir productivity is a comprehensive index of the dynamic characteristics of gas reservoirs, which can provide a reasonable basis for the design and rational distribution of gasfield development plan. Proration of gas well is an important procedure in the development process, Absolute open flow as a key indicator of rational production of gas well. It is very important to determine the absolute open flow of the gas well. The Permian in Ordos Basin is a typical tight sandstone gas reservoir. The paper analyses correlation relations between different logging parameters and absolute open flow, and get the four parameters, porosity, permeability, storage coefficient（the product of porosity and effective thickness）with better correlation relations and effective thickness with best correlation relation by combining a large amount of gas logging data and static logging data and means of linear regression analysis, Then on the basis of this, a new empirical formula for calculating the absolute open flow of gas wells is obtained by using the method of multiple linear regression. The example shows that the result of this method is reasonable and reliable and the method can provide scientific basis for the prediction of natural gas absolute open flow of tight sandstone gas reservoirs.
{"title":"Determination of Gas Well Productivity by Logging Parameters","authors":"Weijun Hao, Zhihong Kang, Dehua Wu","doi":"10.5539/ESR.V6N2P56","DOIUrl":"https://doi.org/10.5539/ESR.V6N2P56","url":null,"abstract":"The prediction and evaluation of reservoir productivity is a comprehensive index of the dynamic characteristics of gas reservoirs, which can provide a reasonable basis for the design and rational distribution of gasfield development plan. Proration of gas well is an important procedure in the development process, Absolute open flow as a key indicator of rational production of gas well. It is very important to determine the absolute open flow of the gas well. The Permian in Ordos Basin is a typical tight sandstone gas reservoir. The paper analyses correlation relations between different logging parameters and absolute open flow, and get the four parameters, porosity, permeability, storage coefficient（the product of porosity and effective thickness）with better correlation relations and effective thickness with best correlation relation by combining a large amount of gas logging data and static logging data and means of linear regression analysis, Then on the basis of this, a new empirical formula for calculating the absolute open flow of gas wells is obtained by using the method of multiple linear regression. The example shows that the result of this method is reasonable and reliable and the method can provide scientific basis for the prediction of natural gas absolute open flow of tight sandstone gas reservoirs.","PeriodicalId":11486,"journal":{"name":"Earth Science Research","volume":"52 3 1","pages":"56"},"PeriodicalIF":0.0,"publicationDate":"2017-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82686634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mineralogical and chemical analysis of two well cutting in quaternary sediments at Basrah city. This study have been focused on the quaternary clay minerals variations which give a clear indication to marine transgression and or / regression in Hammar formation. Kaolinite, Illite, Palygoreskite, Illite-Palygorestike mixed layer, Chlorite, Montmorillonite, Vermiculte, and mixed layers of Illite- Smectite are the most quantitatively important phyllosilicates in soil studies in both boreholes. The mineralogical composition of cutting sediments shows significant variability in the different size fractions and depth distribution. Chlorite and kaolinite minerals were increase in the fine grain size especially in the clayey silt, whereas montmoriolllinite and vermiculite minerals were increase in coarse grains especially in silty sand texture. Kaolinite decrease in abundance with depth, which give indicative of a transition from non-marine in quaternary recent sediment ( fresh or brackish water silt) to marine facies in quaternary Hammar formation ( marine shelly silt) during last transgression of quaternary. Palygoreskite mineral percentages increasing at depths 27 and 28 meter , after decreased at 30, 32, 35 , and 40 m respectively , which give data indication that early quaternary marine transgression happened in 32m , and center of quaternary marine transgression detected in 27 and 28 meters , while late marine transgression detected in 17 m , and all of these represent by Hammar formation. Soil ageing also caused to downward increase of montmorillonite suggest to climate became more arid during the early quaternary. Variations ratio of montmorillonite versus kaolinite can be indicated to climatic fluctuation. Illite-Semectite featured indicates changes in both sediment source and paleoclimate. Illite transformation for Illite-Palygoreskite mixed layers with ageing. Vermiculite has strong susceptibility to increase with age. SiO₂, Al₂O₃, CaO, MgO, K₂O, and Fe₂O₃ were the major oxides that identified in present study and used as indicated of clay minerals in studied sediments.
{"title":"Clay Minerals Variations in Quaternary Sediments of Basrah City-Iraq","authors":"M. Al-Jaberi","doi":"10.5539/esr.v6n2p41","DOIUrl":"https://doi.org/10.5539/esr.v6n2p41","url":null,"abstract":"Mineralogical and chemical analysis of two well cutting in quaternary sediments at Basrah city. This study have been focused on the quaternary clay minerals variations which give a clear indication to marine transgression and or / regression in Hammar formation. Kaolinite, Illite, Palygoreskite, Illite-Palygorestike mixed layer, Chlorite, Montmorillonite, Vermiculte, and mixed layers of Illite- Smectite are the most quantitatively important phyllosilicates in soil studies in both boreholes. The mineralogical composition of cutting sediments shows significant variability in the different size fractions and depth distribution. Chlorite and kaolinite minerals were increase in the fine grain size especially in the clayey silt, whereas montmoriolllinite and vermiculite minerals were increase in coarse grains especially in silty sand texture. Kaolinite decrease in abundance with depth, which give indicative of a transition from non-marine in quaternary recent sediment ( fresh or brackish water silt) to marine facies in quaternary Hammar formation ( marine shelly silt) during last transgression of quaternary. Palygoreskite mineral percentages increasing at depths 27 and 28 meter , after decreased at 30, 32, 35 , and 40 m respectively , which give data indication that early quaternary marine transgression happened in 32m , and center of quaternary marine transgression detected in 27 and 28 meters , while late marine transgression detected in 17 m , and all of these represent by Hammar formation. Soil ageing also caused to downward increase of montmorillonite suggest to climate became more arid during the early quaternary. Variations ratio of montmorillonite versus kaolinite can be indicated to climatic fluctuation. Illite-Semectite featured indicates changes in both sediment source and paleoclimate. Illite transformation for Illite-Palygoreskite mixed layers with ageing. Vermiculite has strong susceptibility to increase with age. SiO₂, Al₂O₃, CaO, MgO, K₂O, and Fe₂O₃ were the major oxides that identified in present study and used as indicated of clay minerals in studied sediments.","PeriodicalId":11486,"journal":{"name":"Earth Science Research","volume":"4 1","pages":"41"},"PeriodicalIF":0.0,"publicationDate":"2017-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82331997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Wen, H. Shimada, Wei Zeng, T. Sasaoka, A. Hamanaka
In this paper, a series of parametric three-dimension numerical simulations were carried out to estimate the face stability and to calculate the minimum allowable slurry pressure of pipe jacking tunnel in frozen ground for the first time. In total, 5120 of simulation schemes were done with different ground temperature, diameter and cover thickness of tunnel, cohesion and friction angle of frozen soil. In order to figure out the optimal grouting pressure, 4 groups of additional simulations are computed with the uniform face support pressure of 0.5, 1.0, 1.5 and 2.0 times of horizontal stress, σ H , at tunnel axis. The qualitative analysis of heading face deformation mechanism and quantitative analysis between deformation profiles and influential factors were implemented to comprehend the heading face deformation characteristics when conducting pipe jacking tunnel in frozen ground. The results show that ground temperature plays a dominant role to control the face deformation of jacking tunnel in frozen ground. And, factors of tunnel diameter and cover thickness have relatively greater influence on the deformation regulation than that of shearing parameters of frozen soil, cohesion and friction angle. Finally, the minimum allowable slurry pressure for each simulation schemes are obtained, which may be used in construction the pipe jacking tunnel in frozen ground.
{"title":"Numerical Analysis of Face Stability of Slurry Pipe Jacking Tunnel in Frozen Ground","authors":"K. Wen, H. Shimada, Wei Zeng, T. Sasaoka, A. Hamanaka","doi":"10.5539/ESR.V6N2P1","DOIUrl":"https://doi.org/10.5539/ESR.V6N2P1","url":null,"abstract":"In this paper, a series of parametric three-dimension numerical simulations were carried out to estimate the face stability and to calculate the minimum allowable slurry pressure of pipe jacking tunnel in frozen ground for the first time. In total, 5120 of simulation schemes were done with different ground temperature, diameter and cover thickness of tunnel, cohesion and friction angle of frozen soil. In order to figure out the optimal grouting pressure, 4 groups of additional simulations are computed with the uniform face support pressure of 0.5, 1.0, 1.5 and 2.0 times of horizontal stress, σ H , at tunnel axis. The qualitative analysis of heading face deformation mechanism and quantitative analysis between deformation profiles and influential factors were implemented to comprehend the heading face deformation characteristics when conducting pipe jacking tunnel in frozen ground. The results show that ground temperature plays a dominant role to control the face deformation of jacking tunnel in frozen ground. And, factors of tunnel diameter and cover thickness have relatively greater influence on the deformation regulation than that of shearing parameters of frozen soil, cohesion and friction angle. Finally, the minimum allowable slurry pressure for each simulation schemes are obtained, which may be used in construction the pipe jacking tunnel in frozen ground.","PeriodicalId":11486,"journal":{"name":"Earth Science Research","volume":"27 1","pages":"1"},"PeriodicalIF":0.0,"publicationDate":"2017-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82937411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Current research on unconformity belt mainly concentrates on the analysis and description of unconformity surface and contact relationship with overlying and underlying strata. Too much emphasis on the division of the “three-layer structure” of unconformity yields obvious disadvantages, i.e., that studies are not only insufficient in the authenticity of architecture but also in the characterization of the combination of the two- and three-dimensional perspectives. Thus, the analysis of genetic mechanism and meticulous depiction is ignored. Accordingly, by making full use of the outcrops and combining previous research findings, this study aims to provide a detailed description and analysis for the unconformity belt structure, and points out the non-uniqueness of the three-layer structure of the unconformity belt. Based on the theory of depositional process and according to the method and principle of the “point-line-surface”, a comprehensive characterization method combined with a kind of “two-dimensional structure” and “three-dimensional structure” is proposed. A two-dimensional structure is a kind of surface structure, while the three-dimensional structure is a kind of body structure, Moreover, this study discusses the recognition significance of the visual unconformity line and visual unconformity surface with respect to the unconformity belt structure. According to the spatial allocation and geological significance of the unconformity belt, two types of models are established in order to depict the structure of unconformity belt better. Combined with the structural elements of the unconformity belt and complied from the viewpoint of the sedimentary environment, the formation mechanism of two-and three-dimensional structures is summarized.
{"title":"Meticulous Depiction and Genetic Mechanism of Unconformity Belt Structure","authors":"Zhipeng Lin, Jingfu Shan, Le Chen","doi":"10.5539/ESR.V6N2P19","DOIUrl":"https://doi.org/10.5539/ESR.V6N2P19","url":null,"abstract":"Current research on unconformity belt mainly concentrates on the analysis and description of unconformity surface and contact relationship with overlying and underlying strata. Too much emphasis on the division of the “three-layer structure” of unconformity yields obvious disadvantages, i.e., that studies are not only insufficient in the authenticity of architecture but also in the characterization of the combination of the two- and three-dimensional perspectives. Thus, the analysis of genetic mechanism and meticulous depiction is ignored. Accordingly, by making full use of the outcrops and combining previous research findings, this study aims to provide a detailed description and analysis for the unconformity belt structure, and points out the non-uniqueness of the three-layer structure of the unconformity belt. Based on the theory of depositional process and according to the method and principle of the “point-line-surface”, a comprehensive characterization method combined with a kind of “two-dimensional structure” and “three-dimensional structure” is proposed. A two-dimensional structure is a kind of surface structure, while the three-dimensional structure is a kind of body structure, Moreover, this study discusses the recognition significance of the visual unconformity line and visual unconformity surface with respect to the unconformity belt structure. According to the spatial allocation and geological significance of the unconformity belt, two types of models are established in order to depict the structure of unconformity belt better. Combined with the structural elements of the unconformity belt and complied from the viewpoint of the sedimentary environment, the formation mechanism of two-and three-dimensional structures is summarized.","PeriodicalId":11486,"journal":{"name":"Earth Science Research","volume":"31 1","pages":"19"},"PeriodicalIF":0.0,"publicationDate":"2017-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86768851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kenfack Jean Victor, Kamguia Joseph, Kagou Dongmo Armand, K. Lucas, Mbog Michel Bertrand, Tassongwa Bernard, Tabod Tabod Charles
The Mount Cameroon region is investigated using 2-D spectral analysis of the gravity data, in order to determine the depth of subsurface interfaces beneath the region. New gravity data are combined to existing ones to determine the depth of the major subsurface discontinuities throughout the region. Depths are established from the slope of the log-power radial spectrum et the lower end of the wave number band. Three major subsurface density discontinuities are determined beneath the Mount Cameroon: (1) 0.41 ± 0.02 km, (2) 1.26 ± 0.06 km, (3) 4.73 ± 0.24 km. This result has the best precision comparing with the those from the former Bouguer anomaly where the major subsurface discontinuities obtained are: (1) 0.48 ± 0.02 km for the first layer, 1.81 ± 0.09 km for the second and 6.87 ± 0.34 km for the third. This difference is probabely due to the densification of gravity data. The knowledge on the depth of different interfaces in the crust is very important in the reconstitution of the earth history. These results will the support of prospective investigations throughout this region.
{"title":"Estimation of the Depth of Major Subsurface Discontinuities Beneath the Mount Cameroon Region, Central Africa, Based on New and Existing Gravity Data Analysis","authors":"Kenfack Jean Victor, Kamguia Joseph, Kagou Dongmo Armand, K. Lucas, Mbog Michel Bertrand, Tassongwa Bernard, Tabod Tabod Charles","doi":"10.5539/ESR.V6N1P142","DOIUrl":"https://doi.org/10.5539/ESR.V6N1P142","url":null,"abstract":"The Mount Cameroon region is investigated using 2-D spectral analysis of the gravity data, in order to determine the depth of subsurface interfaces beneath the region. New gravity data are combined to existing ones to determine the depth of the major subsurface discontinuities throughout the region. Depths are established from the slope of the log-power radial spectrum et the lower end of the wave number band. Three major subsurface density discontinuities are determined beneath the Mount Cameroon: (1) 0.41 ± 0.02 km, (2) 1.26 ± 0.06 km, (3) 4.73 ± 0.24 km. This result has the best precision comparing with the those from the former Bouguer anomaly where the major subsurface discontinuities obtained are: (1) 0.48 ± 0.02 km for the first layer, 1.81 ± 0.09 km for the second and 6.87 ± 0.34 km for the third. This difference is probabely due to the densification of gravity data. The knowledge on the depth of different interfaces in the crust is very important in the reconstitution of the earth history. These results will the support of prospective investigations throughout this region.","PeriodicalId":11486,"journal":{"name":"Earth Science Research","volume":"16 1","pages":"142"},"PeriodicalIF":0.0,"publicationDate":"2017-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80845245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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