The factors influencing the permeability coefficient of gravelly soils used for the development of embankment dams(core wall)are analyzed.Such factors include(but are not limited to)soil size,anisotropy,density and bo...The factors influencing the permeability coefficient of gravelly soils used for the development of embankment dams(core wall)are analyzed.Such factors include(but are not limited to)soil size,anisotropy,density and boundary effects.A review of the literature is conducted and new directions of research are proposed.In such a framework,it is shown that gravelly soil with controlled density and vertical stress should be used to optimize the measurement of the vertical and horizontal permeability coefficients,respectively.展开更多
The current paper introduces an empirical method for estimating the vertical distribution of background stratospheric aerosol extinction profiles covering the latitude bands of 50±5°N,40±5°N,30...The current paper introduces an empirical method for estimating the vertical distribution of background stratospheric aerosol extinction profiles covering the latitude bands of 50±5°N,40±5°N,30±5°N,and 20±5°N and the longitude range of 75 135°E based on Stratospheric Aerosol and Gas Experiment (SAGE) II aerosol extinction measurements at wavelengths of 1020 nm,525 nm,452 nm,and 386 nm for the volcanically calm years between 1998 2004.With this method,the vertical distribution of stratospheric aerosol extinction coefficients can be estimated according to latitude and wavelength.Comparisons of the empirically calculated aerosol extinction profiles and the SAGE II aerosol measurements show that the empirically calculated aerosol extinction coefficients are consistent with SAGE II values,with relative differences within 10% from 2 km above the tropopause to 33 km,and within 22% from 33 km to 35 km.The empirically calculated aerosol stratospheric optical depths (vertically integrated aerosol extinction coefficient) at the four wavelengths are also consistent with the corresponding SAGE II optical depth measurements,with differences within 2.2% in the altitude range from 2 km above the tropopause to 35 km.展开更多
With the high-quality development of urban buildings,higher requirements are come up with for lateral bearing capacity of laterally loaded piles.Consequently,a more accurate analysis to predict the lateral response of...With the high-quality development of urban buildings,higher requirements are come up with for lateral bearing capacity of laterally loaded piles.Consequently,a more accurate analysis to predict the lateral response of the pile within an allowable displacement is an important issue.However,the current p-y curve methods cannot fully take into account the pile-soil interaction,which will lead to a large calculation difference.In this paper,a new analytical p-y curve is established and a finite difference method for determining the lateral response of pile is proposed,which can consider the separation effect of pile-soil interface and the coefficient of circumferential friction resistance.In particular,an analytical expression is developed to determine the compressive soil pressure by dividing the compressive soil pressure into two parts:initial compressive soil pressure and increment of compressive soil pressure.In addition,the relationship between compressive soil pressure and horizontal displacement of the pile is established based on the reasonable assumption.The correctness of the proposed method is verified through four examples.Based on the verified method,a parametric analysis is also conducted to investigate the influences of factors on lateral response of the pile,including internal friction angle,pile length and elastic modulus of pile.展开更多
The Edlén empirical equations and the two-color method are the commonly used approaches to converting a length measured in air to the corresponding length in vacuum to eliminate the influence of the refractive in...The Edlén empirical equations and the two-color method are the commonly used approaches to converting a length measured in air to the corresponding length in vacuum to eliminate the influence of the refractive index of air. However, it is not well known whether the two-color method is superior to empirical equations in refractive index compensation. We investigated the uncertainties of these approaches via numerical calculations of their sensitivity coefficients of environmental parameters. On the basis of a comparison of their uncertainties, we found that in a 0% humidity environment, the two-color method had potential to provide greater measurement accuracy than the empirical equations.展开更多
基金The work is supported by National Key Research and Development Program of China(No.2017YFC0404803)Guizhou High-Level Innovative Talents Project[2018](No.5630)+2 种基金Guizhou Science and Support[2019](No.2869)State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin(No.SKL2020ZY09)Science and Technology Project of Huaneng Group Headquarters(HNKJ17-H18).
文摘The factors influencing the permeability coefficient of gravelly soils used for the development of embankment dams(core wall)are analyzed.Such factors include(but are not limited to)soil size,anisotropy,density and boundary effects.A review of the literature is conducted and new directions of research are proposed.In such a framework,it is shown that gravelly soil with controlled density and vertical stress should be used to optimize the measurement of the vertical and horizontal permeability coefficients,respectively.
基金supported by the National Basic Research Program of China(Grant No.2011CB403401)the National Natural Science Foundation of China(Grant No.40875084)
文摘The current paper introduces an empirical method for estimating the vertical distribution of background stratospheric aerosol extinction profiles covering the latitude bands of 50±5°N,40±5°N,30±5°N,and 20±5°N and the longitude range of 75 135°E based on Stratospheric Aerosol and Gas Experiment (SAGE) II aerosol extinction measurements at wavelengths of 1020 nm,525 nm,452 nm,and 386 nm for the volcanically calm years between 1998 2004.With this method,the vertical distribution of stratospheric aerosol extinction coefficients can be estimated according to latitude and wavelength.Comparisons of the empirically calculated aerosol extinction profiles and the SAGE II aerosol measurements show that the empirically calculated aerosol extinction coefficients are consistent with SAGE II values,with relative differences within 10% from 2 km above the tropopause to 33 km,and within 22% from 33 km to 35 km.The empirically calculated aerosol stratospheric optical depths (vertically integrated aerosol extinction coefficient) at the four wavelengths are also consistent with the corresponding SAGE II optical depth measurements,with differences within 2.2% in the altitude range from 2 km above the tropopause to 35 km.
基金Project(52068004)supported by the National Natural Science Foundation of ChinaProject(2018JJA160134)supported by the Natural Science Foundation of Guangxi Province,ChinaProject(AB19245018)supported by Key Research Projects of Guangxi Province,China。
文摘With the high-quality development of urban buildings,higher requirements are come up with for lateral bearing capacity of laterally loaded piles.Consequently,a more accurate analysis to predict the lateral response of the pile within an allowable displacement is an important issue.However,the current p-y curve methods cannot fully take into account the pile-soil interaction,which will lead to a large calculation difference.In this paper,a new analytical p-y curve is established and a finite difference method for determining the lateral response of pile is proposed,which can consider the separation effect of pile-soil interface and the coefficient of circumferential friction resistance.In particular,an analytical expression is developed to determine the compressive soil pressure by dividing the compressive soil pressure into two parts:initial compressive soil pressure and increment of compressive soil pressure.In addition,the relationship between compressive soil pressure and horizontal displacement of the pile is established based on the reasonable assumption.The correctness of the proposed method is verified through four examples.Based on the verified method,a parametric analysis is also conducted to investigate the influences of factors on lateral response of the pile,including internal friction angle,pile length and elastic modulus of pile.
文摘The Edlén empirical equations and the two-color method are the commonly used approaches to converting a length measured in air to the corresponding length in vacuum to eliminate the influence of the refractive index of air. However, it is not well known whether the two-color method is superior to empirical equations in refractive index compensation. We investigated the uncertainties of these approaches via numerical calculations of their sensitivity coefficients of environmental parameters. On the basis of a comparison of their uncertainties, we found that in a 0% humidity environment, the two-color method had potential to provide greater measurement accuracy than the empirical equations.
