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A hyperspectral detection model for permeability coefficient of debris flow fine-grained sediments, Southwestern China

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International Journal of Digital Earth 2023年第1期16卷 1589-1606页

作者： Qinjun Wang Jingjing Xie Jingyi Yang Peng Liu Dingkun Chang Wentao Xu International Research Center of Big Data for Sustainable Development Goals BeijingPeople’s Republic of China Key Laboratory of Digital Earth Science Aerospace Information Research InstituteChinese Academy of SciencesBeijingPeople’s Republic of China University of Chinese Academy of Sciences Yanqi Lake Campus of Chinese Academy of Sciences UniversityBeijingPeople’s Republic of China Key Laboratory of the Earth Observation of Hainan Province Hainan Aerospace Information Research InstituteSanyaPeople’s Republic of China

Fine-grained sediments are Quaternary sediments with grain sizes of not more than 2 *** startfirst when meeting water,their stability is related to the initial water volume triggering debrisflow,and thus plays an important role in debrisflow hazards early *** permeability coefficient is the inter-controlled factor offine-grained sediment ***,there is no hyperspectral model for detecting thefine-grained sediment permeability coefficient in large areas,which seriously affects the progress of debrisflow hazards early ***,it is of great significance to establish a hyperspectral detection model for the permeability coefficient offine-grained *** Beichuan County,Southwestern China as the case,a permeability coefficient hyperspectral detection model was *** results show that eight bands are sensitive to the permeability coefficient with correlation coefficient(R)of 0.6343.T-test on the model shows that P-a values for sensitive bands are all less than 0.05,indicating the established model has a good prediction ability with a precision of 85.83%.These sensitive bands also indicate the spectral characteristics of the permeability ***,it provides a scientific basis forfine-grained sediment stability detection in large areas and lays a theoretical foundation for debrisflow hazards’early warning.

关键词： Beichuan debris flow fine-grained sediments permeability coefficient hyperspectral detection model

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A Review of Test Methods for the Determination of the permeability coefficient of Gravelly Soils Used for Embankment Dams

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Fluid Dynamics & Materials Processing 2022年第1期18卷 131-144页

作者： Zhenggang Zhan Han Chen Yanyi Zhang Ruilin Cheng Gang Deng PowerChina Guiyang Engineering Co. Ltd.Guiyang550081China State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBeijing100038China Key Laboratory of Construction and Safety of Hydraulic Engineering of Ministry of Water Resources China Institute of Water Resources and Hydropower ResearchBeijing100038China

The factors influencing the permeability coefficient of gravelly soils used for the development of embankment dams(core wall)are *** 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 *** 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.

关键词： Wide-grading gravelly soil core wall materials permeability coefficient test method

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One-dimensional horizontal infiltration experiment for determining permeability coefficient of loamy sand

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Journal of Arid Land 2017年第1期9卷 27-37页

作者： HU Shunjun ZHU Hai CHEN Yongbao State Key Laboratory of Desert and Oasis Ecology Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences Urumqi 830011 China University of Chinese Academy of Sciences Beijing 100049 China Central South Institute of Metallurgical Geology Yichang 443003 China

A knowledge of soil permeability is essential to evaluate hydrologic characteristics of soil, such as water storage and water movement, and soil permeability coefficient is an important parameter that reflects soil permeability. In order to confirm the acceptability of the one-dimensional horizontal infiltration method（one-D method） for simultaneously determining both the saturated and unsaturated permeability coefficients of loamy sand, we first measured the cumulative infiltration and the wetting front distance under various infiltration heads through a series of one-dimensional horizontal infiltration experiments, and then analyzed the relationships of the cumulative horizontal infiltration with the wetting front distance and the square root of infiltration time. We finally compared the permeability results from Gardner model based on the one-D method with the results from other two commonly-used methods（i.e., constant head method and van Genuchten model） to evaluate the acceptability and applicability of the one-D method. The results showed that there was a robust linear relationship between the cumulative horizontal infiltration and the wetting front distance, suggesting that it is more appropriate to take the soil moisture content after infiltration in the entire wetted zone as the average soil moisture content than as the saturated soil moisture content. The results also showed that there was a robust linear relationship between the cumulative horizontal infiltration and the square root of infiltration time, suggesting that the Philip infiltration formula can better reflect the characteristics of cumulative horizontal infiltration under different infiltration heads. The following two facts indicate that it is feasible to use the one-D method for simultaneously determining the saturated and unsaturated permeability coefficients of loamy sand. First, the saturated permeability coefficient（prescribed in the Gardner model） of loamy sand obtained from the one-D me

关键词： permeability coefficient one-dimensional horizontal infiltration cumulative horizontal infiltration wetting front distance Philip infiltration formula Gardner model

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Investigating the Relationship between Porosity and permeability coefficient for Pervious Concrete Pavement by Statistical Modelling

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Materials Sciences and Applications 2016年第2期7卷 101-107页

作者： Hassan Tajik Ghashghaei Abolfazl Hassani Parand Islamic Azad University Tarbiat Modares University Tehran Iran

A study evaluating the relationship between porosity and permeability coefficient for pervious concrete (PC) is presented. In addition, the effect of mixture design parameters particularly, water-to-cement ratio (W/C) and size of aggregate on the permeability coefficient of PC was investigated. The PC mixtures were made with 4 range of W/C and 2 range size of aggregate. PC mixes were made from each aggregate and were tested. The results showed that the W/C and aggregate size are key parameters which significantly affect the characteristic performance of PC. permeability coefficient of coarse pervious concrete (CPC) is bigger than fine pervious concrete (FPC) and the porosity of CPC are bigger than porosity of FPC. A regression model (RM) along with analysis of variance (ANOVA) was conducted to study the significance of porosity distribution on permeability coefficient of PC. The statistical model developed in this study can facilitate prediction permeability coefficient of CPC and FPC as the sustainable pavements.

关键词： Pervious Concrete W/C Porosity permeability coefficient

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Stochastic back analysis of permeability coefficient using generalized Bayesian method

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Water Science and Engineering 2008年第3期1卷 83-92页

作者： Zheng Guilan Wang Yuan Wang Fei Yang Jian College of Traffic College of Ocean Hohai University Nanjing 210098 P. R. China Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Hohai University Nanjing 210098 R R. China Geotechnical Research Institute of Hohai University Nanjing 210098 P. R. China

Owing to the fact that the conventional deterministic back analysis of the permeability coefficient cannot reflect the uncertainties of parameters, including the hydraulic head at the boundary, the permeability coefficient and measured hydraulic head, a stochastic back analysis taking consideration of uncertainties of parameters was performed using the generalized Bayesian method. Based on the stochastic finite element method （SFEM） for a seepage field, the variable metric algorithm and the generalized Bayesian method, formulas for stochastic back analysis of the permeability coefficient were derived. A case study of seepage analysis of a sluice foundation was performed to illustrate the proposed method. The results indicate that, with the generalized Bayesian method that considers the uncertainties of measured hydraulic head, the permeability coefficient and the hydraulic head at the boundary, both the mean and standard deviation of the permeability coefficient can be obtained and the standard deviation is less than that obtained by the conventional Bayesian method. Therefore, the present method is valid and applicable.

关键词： permeability coefficient stochastic back analysis generalized Bayesian method variable metric algorithm

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Test and analysis of influencing factors on the permeability coefficient of steel slag permeable concrete

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Baosteel Technical Research 2011年第2期5卷 24-26页

作者： YANG Gang WANG Youqin WANG Hailong JIN Qiang Research Center of Metallurgical Slag SBMCC Shanghai 200941 China

The steel slag （SS） permeable concrete was prepared by SS. The influences of the aggregate-cement rate, the aggregate particle size, the water-cement rate, the admixture dosage and other factors on the permeability coefficient of SS permeable concrete were analyzed. The law of influence was also investigated. The study serves as a technological reference for the construction and design of SS permeable concrete.

关键词： steel slag permeable concrete permeability coefficient influencing factors

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THE ALGORITHMS AND APPLICATIONS FOR DETERMINING permeability coefficientS BY PULSE SPECTRUM TECHNIQUE

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Journal of Hydrodynamics 2002年第2期14卷 112-115页

作者： Wang Ling-ling College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing 210098, China Coll. of Water Conservancy Hohai Univ. Nanjing 210098 China

The determination of inhomogeneous permeability coefficient was studied as a parameter-control inverse problem for parabolic-type equation in this paper. By virtue of PST, the solution of the inverse problem is converted into an iteration procedure of solving a direct problem and solving a Fredholm integral equation of the first kind. Besides, Tikhonov normalization method is introduced to treat the uncertainty caused by the integral equation. Thus an algorithm for determining inhomogeneous permeability coefficient has been formulated and implemented. Numerical results show: (1) The algorithm presented in the paper is suitable to strongly inhomogeneous seepagel; (2) The additional information needed for solution is merely the seepage velocity on partical boundary, so that drill works can be reduced remarkably; (3) The algorithm is applicable to determining inhomogeneous transmission coefficients in groundwater engineering or other engineering.

关键词： inverse problem Pulse Spectrum Technique (PST) permeability coefficient parameter identification

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Pore Characteristic Design Method of High-strength Pervious Concrete Based on the Mechanical Properties and Rainstorm Waterlogging Resistance

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Journal of Wuhan University of Technology(Materials Science) 2023年第3期38卷 567-574页

作者：朱平华 SHI Zhihao LIU Hui YAN Xiancui YANG Lei ZONG Meirong Department of Civil Engineering Changzhou UniversityChangzhou 213164China

High-strength pervious concrete(HSPC) with porosity ranging from 0.08% to 2.011% was prepared. The mechanical properties and rainstorm waterlogging resistance of HSPC were evaluated,and a design method of HSPC pore characteristics(porosity and pore diameter) based on the mechanical properties and rainstorm waterlogging resistance was proposed. The results showed that the reduction of effective cross-sectional area caused by artificial channels was the main factor affecting flexural strength but had limited influence on compressive strength. Compared with the concrete matrix without artificial channels,the compressive strength of HSPC with porosity of 2.011% decreased by 7.4%, while the flexural strength decreased by 48.3%. The permeability coefficient of HSPC can reach 16.35 mm/s even at low porosity(2.011%).HSPC can meet the requirements of no rainstorm waterlogging, even if exposed to 100-year rainstorms. When the mechanical properties and rainstorm waterlogging resistance are compromised, the recommended porosity ranges from 1.1% to 3.5%, and the recommended pore diameter ranges from 0.8 to 2.7 mm.

关键词： pervious concrete artificial channel pore characteristic permeability coefficient rainstorm waterlogging

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Air tightness of compressed air storage energy caverns with polymer sealing layer subjected to various air pressures

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第8期15卷 2105-2116页

作者： Shikang Qin Caichu Xia Shuwei Zhou College of Civil Engineering Tongji UniversityShanghai200092China Institute of Rock Mechanics Ningbo UniversityNingbo315211China

During the operation of compressed air storage energy system,the rapid change of air pressure in a cavern will cause drastic changes in air density and permeability coefficient of sealing *** calculate and properly evaluate air tightness of polymer sealing caverns,the air-pressure-related air density and permeability must be *** this context,the high-pressure air penetration in the polymer sealing layer is studied in consideration of thermodynamic change of the cavern structure during the system *** air tightness model of compressed air storage energy caverns is then *** the model,the permeability coefficient and air density of sealing layer vary with air pressure,and the effectiveness of the model is verified by field data in two test ***,a compressed air storage energy cavern is taken as an example to understand the air *** air leakage rate in the caverns is larger than that using air-pressure-independent permeability coefficient and air density,which is constant and small in the previous leakage rate *** the operating pressure of 4.5-10 MPa,the daily air leakage in the compressed air storage energy cavern of Yungang Mine with high polymer butyl rubber as the sealing material is 0.62%,which can meet the sealing requirements of compressed air storage energy *** air tightness of the polymer sealing cavern is mainly affected by the cavern operating pressure,injected air temperature,cavern radius,and sealing layer *** cavern air leakage rate will be decreased to reduce the cavern operating pressure the injection air temperature,or the cavern radius and sealing layer thickness will be increased.

关键词： Compressed air storage energy Polymer sealing layer Air tightness permeability coefficient Air density

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Numerical investigation on the spewing mechanism of earth pressure balance shield in a high-pressure water-rich sand stratum

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Deep Underground Science and Engineering 2023年第1期2卷 74-87页

作者： Zhiyong Yang Weiqiang Qi Yanjie Ding Yusheng Jiang Xinkang Yang Xing Yang Xiaokang Shao School of Mechanics and Civil Engineering China University of Mining and Technology‐BeijingBeijingChina China Railway First Survey and Design Institute Group Co. LtdXi'anChina

The spewing of a screw conveyor easily occurs from the earth pressure balance(called EPB)shield in a water-rich sand *** may lead to the collapse of the tunnel face and even serious subsidence of the ground *** understand the spewing mechanism of the shield screw conveyor and explore the critical hydraulic condition of soil spewing in a shield–soil chamber,a simplified theoretical model for the spewing of the screw conveyor was developed based on the equation of groundwater flow in the screw conveyor under turbulent ***,coupling Darcy's law with Brinkman's equation,this model was implemented within the COMSOL Multiphysics *** underground water flow in the shield screw conveyor was simulated so as to obtain its velocity and flow *** simulations show that the water pressure distribution is concentrated in the lower part of the soil chamber after the groundwater enters the soil *** the groundwater enters the screw conveyor,its pressure gradually decreases along the direction of the screw *** the water flow reaches the stratum–shield interface,the flow velocity changes markedly:first increases and concentrates at the entrance of the lower soil chamber,plummets and stabilizes gradually,and increases again at the *** soil chamber and screw conveyor are significantly *** is also found that the soil permeability coefficient can be reduced to k<2.6×10^(−4)cm/s through appropriate soil improvement,which can effectively prevent the occurrence of spewing disasters.

关键词： EPB shield multiphysical coupling permeability coefficient screw conveyor spewing

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