Pore Pressure Response During Failure in Soils
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Seismic Pore Water Pressure Generation Models: Numerical Evaluation and Comparison
th The 14 World Conference on Earthquake Engineering October 12-17, 2008, Beijing, China SEISMIC PORE WATER PRESSURE GENERATION MODELS: NUMERICAL EVALUATION AND COMPARISON S. Nabili 1 Y. Jafarian 2 and M.H. Baziar 3 ¹M.Sc, College of Civil Engineering, Iran University of Science and Technology, Tehran, Iran ² Ph.D. Candidates, College of Civil Engineering, Iran University of Science and Technology, Tehran, Iran ³ Professor, College of Civil Engineering, Iran University of Science and Technology, Tehran, Iran ABSTRACT: Researchers have attempted to model excess pore water pressure via numerical modeling, in order to estimate the potential of liquefaction. The attempt of this work is numerical evaluation of excess pore water pressure models using a fully coupled effective stress and uncoupled total stress analysis. For this aim, several cyclic and monotonic element tests and a level ground centrifuge test of VELACS project [1] were utilized. Equivalent linear and non linear numerical models were used to evaluate the excess pore water pressure. Comparing the excess pore pressure buildup time histories of the numerical and experimental models showed that the equivalent linear method can predict better the excess pore water pressure than the non linear approach, but it can not concern the presence of pore pressure in the calculation of the shear strain. KEYWORDS: Excess pore water pressure, effective stress, total stress, equivalent linear, non linear 1. INTRODUCTION Estimation of liquefaction is one of the main objectives in geotechnical engineering. For this purpose, several numerical and experimental methods have been proposed. An important stage to predict the liquefaction is the prediction of excess pore water pressure at a given point. -
Port Silt Loam Oklahoma State Soil
PORT SILT LOAM Oklahoma State Soil SOIL SCIENCE SOCIETY OF AMERICA Introduction Many states have a designated state bird, flower, fish, tree, rock, etc. And, many states also have a state soil – one that has significance or is important to the state. The Port Silt Loam is the official state soil of Oklahoma. Let’s explore how the Port Silt Loam is important to Oklahoma. History Soils are often named after an early pioneer, town, county, community or stream in the vicinity where they are first found. The name “Port” comes from the small com- munity of Port located in Washita County, Oklahoma. The name “silt loam” is the texture of the topsoil. This texture consists mostly of silt size particles (.05 to .002 mm), and when the moist soil is rubbed between the thumb and forefinger, it is loamy to the feel, thus the term silt loam. In 1987, recognizing the importance of soil as a resource, the Governor and Oklahoma Legislature selected Port Silt Loam as the of- ficial State Soil of Oklahoma. What is Port Silt Loam Soil? Every soil can be separated into three separate size fractions called sand, silt, and clay, which makes up the soil texture. They are present in all soils in different propor- tions and say a lot about the character of the soil. Port Silt Loam has a silt loam tex- ture and is usually reddish in color, varying from dark brown to dark reddish brown. The color is derived from upland soil materials weathered from reddish sandstones, siltstones, and shales of the Permian Geologic Era. -
CPT-Geoenviron-Guide-2Nd-Edition
Engineering Units Multiples Micro (P) = 10-6 Milli (m) = 10-3 Kilo (k) = 10+3 Mega (M) = 10+6 Imperial Units SI Units Length feet (ft) meter (m) Area square feet (ft2) square meter (m2) Force pounds (p) Newton (N) Pressure/Stress pounds/foot2 (psf) Pascal (Pa) = (N/m2) Multiple Units Length inches (in) millimeter (mm) Area square feet (ft2) square millimeter (mm2) Force ton (t) kilonewton (kN) Pressure/Stress pounds/inch2 (psi) kilonewton/meter2 kPa) tons/foot2 (tsf) meganewton/meter2 (MPa) Conversion Factors Force: 1 ton = 9.8 kN 1 kg = 9.8 N Pressure/Stress 1kg/cm2 = 100 kPa = 100 kN/m2 = 1 bar 1 tsf = 96 kPa (~100 kPa = 0.1 MPa) 1 t/m2 ~ 10 kPa 14.5 psi = 100 kPa 2.31 foot of water = 1 psi 1 meter of water = 10 kPa Derived Values from CPT Friction ratio: Rf = (fs/qt) x 100% Corrected cone resistance: qt = qc + u2(1-a) Net cone resistance: qn = qt – Vvo Excess pore pressure: 'u = u2 – u0 Pore pressure ratio: Bq = 'u / qn Normalized excess pore pressure: U = (ut – u0) / (ui – u0) where: ut is the pore pressure at time t in a dissipation test, and ui is the initial pore pressure at the start of the dissipation test Guide to Cone Penetration Testing for Geo-Environmental Engineering By P. K. Robertson and K.L. Cabal (Robertson) Gregg Drilling & Testing, Inc. 2nd Edition December 2008 Gregg Drilling & Testing, Inc. Corporate Headquarters 2726 Walnut Avenue Signal Hill, California 90755 Telephone: (562) 427-6899 Fax: (562) 427-3314 E-mail: [email protected] Website: www.greggdrilling.com The publisher and the author make no warranties or representations of any kind concerning the accuracy or suitability of the information contained in this guide for any purpose and cannot accept any legal responsibility for any errors or omissions that may have been made. -
Advanced Crop and Soil Science. a Blacksburg. Agricultural
DOCUMENT RESUME ED 098 289 CB 002 33$ AUTHOR Miller, Larry E. TITLE What Is Soil? Advanced Crop and Soil Science. A Course of Study. INSTITUTION Virginia Polytechnic Inst. and State Univ., Blacksburg. Agricultural Education Program.; Virginia State Dept. of Education, Richmond. Agricultural Education Service. PUB DATE 74 NOTE 42p.; For related courses of study, see CE 002 333-337 and CE 003 222 EDRS PRICE MF-$0.75 HC-$1.85 PLUS POSTAGE DESCRIPTORS *Agricultural Education; *Agronomy; Behavioral Objectives; Conservation (Environment); Course Content; Course Descriptions; *Curriculum Guides; Ecological Factors; Environmental Education; *Instructional Materials; Lesson Plans; Natural Resources; Post Sc-tondary Education; Secondary Education; *Soil Science IDENTIFIERS Virginia ABSTRACT The course of study represents the first of six modules in advanced crop and soil science and introduces the griculture student to the topic of soil management. Upon completing the two day lesson, the student vill be able to define "soil", list the soil forming agencies, define and use soil terminology, and discuss soil formation and what makes up the soil complex. Information and directions necessary to make soil profiles are included for the instructor's use. The course outline suggests teaching procedures, behavioral objectives, teaching aids and references, problems, a summary, and evaluation. Following the lesson plans, pages are coded for use as handouts and overhead transparencies. A materials source list for the complete soil module is included. (MW) Agdex 506 BEST COPY AVAILABLE LJ US DEPARTMENT OFmrAITM E nufAT ION t WE 1. F ARE MAT IONAI. ItiST ifuf I OF EDuCATiCiN :),t; tnArh, t 1.t PI-1, t+ h 4t t wt 44t F.,.."11 4. -
Drummer Illinois State Soil
Drummer Illinois State Soil Soil Science Society of America Introduction Many states have designated state symbols such as bird, flower, fish, tree, rock, and more. Many states also have a state soil – one that has significance or is important to the state. As there are many types of birds, flowers, and trees, there are hundreds of soil types in our state but Drummer is the official state soil of Illinois. How important is the Drummer soil to Illinois? History Drummer was first established as a type of soil in Ford County in 1929. It was named after Drummer Creek in Drummer Township. 1n 1987, Drummer was selected as the state soil by the Illinois Soil Classifiers Association over other soils such as Cisne, Flanagan, Hoyleton, Ipava, Sable, and Saybrook. Since then, Drummer has been repeatedly chosen by other as- sociations who work with soil. In 1992, the Illinois Association of Vocational Agriculture Teachers sponsored a state soil election in their classrooms and Drummer won by a margin of 2 to 1. In 1993, the statewide 4H Youth Conference also selected Drummer out of 6 nomi- nees. Also in 1993 at the FFA state convention, Drummer and Ipava were tied in the contest. Finally, in 2001, after many attempts, it was finally passed by the Illinois Legislature and signed into law by Governor George Ryan. What is Drummer Soil? It is the most common among the dark colored soils or “black dirt” of Illinois. The dark color is due to the high amount of organic matter inherited from the decomposition of the prairie vegetation that is growing on the soil. -
Agricultural Soil Carbon Credits: Making Sense of Protocols for Carbon Sequestration and Net Greenhouse Gas Removals
Agricultural Soil Carbon Credits: Making sense of protocols for carbon sequestration and net greenhouse gas removals NATURAL CLIMATE SOLUTIONS About this report This synthesis is for federal and state We contacted each carbon registry and policymakers looking to shape public marketplace to ensure that details investments in climate mitigation presented in this report and through agricultural soil carbon credits, accompanying appendix are accurate. protocol developers, project developers This report does not address carbon and aggregators, buyers of credits and accounting outside of published others interested in learning about the protocols meant to generate verified landscape of soil carbon and net carbon credits. greenhouse gas measurement, reporting While not a focus of the report, we and verification protocols. We use the remain concerned that any end-use of term MRV broadly to encompass the carbon credits as an offset, without range of quantification activities, robust local pollution regulations, will structural considerations and perpetuate the historic and ongoing requirements intended to ensure the negative impacts of carbon trading on integrity of quantified credits. disadvantaged communities and Black, This report is based on careful review Indigenous and other communities of and synthesis of publicly available soil color. Carbon markets have enormous organic carbon MRV protocols published potential to incentivize and reward by nonprofit carbon registries and by climate progress, but markets must be private carbon crediting marketplaces. paired with a strong regulatory backing. Acknowledgements This report was supported through a gift Conservation Cropping Protocol; Miguel to Environmental Defense Fund from the Taboada who provided feedback on the High Meadows Foundation for post- FAO GSOC protocol; Radhika Moolgavkar doctoral fellowships and through the at Nori; Robin Rather, Jim Blackburn, Bezos Earth Fund. -
The Soil Food Web
THE SOIL FOOD WEB HEALTHY SOIL HEALTHY ENVIRONMENT The Soil Food Web Alan Sundermeier Extension Educator and Program Leader, Wood County Extension, The Ohio State University. Vinayak Shedekar Postdoctural Researcher, The Ohio State University. A healthy soil depends on the interaction of many organisms that make up the soil food web. These organisms live all or part of their life cycle in the soil and are respon- sible for converting energy as one organism consumes another. Source: Soil Biology Primer The phospholipid fatty acid (PLFA) test can be used to measure the activity of the soil food web. The following chart shows that mi-crobial activity peaks in early summer when soil is warm and moisture is adequate. Soil sampling for detecting soil microbes should follow this timetable to better capture soil microbe activity. The soil food web begins with the ener- gy from the sun, which triggers photo- synthesis in plants. Photosynthesis re- sults in plants using the sun’s energy to fix carbon dioxide from the atmosphere. This process creates the carbon and organic compounds contained in plant material. This is the first trophic level. Then begins building of soil organic matter, which contains both long-last- ing humus, and active organic matter. Active organic matter contains readily available energy, which can be used by simple soil organisms in the second trophic level of the soil food web. Source: Soil Biology Primer SOILHEALTH.OSU.EDU THE SOIL FOOD WEB - PAGE 2 The second trophic level contains simple soil organisms, which Agriculture can enhance the soil food web to create more decompose plant material. -
Eskişehir Teknik Üniversitesi Bilim Ve Teknoloji Dergisi B- Teorik Bilimler
ESKİŞEHİR TEKNİK ÜNİVERSİTESİ BİLİM VE TEKNOLOJİ DERGİSİ B- TEORİK BİLİMLER Eskişehir Technical University Journal of Science and Technology B- Theoritical Sciences 2018, Volume:6 - pp. 183 - 191, DOI: 10.20290/aubtdb.489424 4th INTERNATIONAL CONFERENCE ON EARTHQUAKE ENGINEERING AND SEISMOLOGY BEHAVIOR OF A DENSE NONPLASTIC SILT UNDER CYCLIC LOADING Eyyüb KARAKAN 1, *, Alper SEZER 2, Nazar TANRINIAN 2, Selim ALTUN 2 1 Civil Engineering Department, Faculty of Engineering, Kilis 7 Aralik University, Kilis, Turkey 2 Civil Engineering Department, Faculty of Engineering, Ege University, İzmir, Turkey ABSTRACT Density of granular soils is increased after being subjected to seismic loading, leading to settlements in deeper layers. Foundation systems and shallow buried structures are affected from possible damage due to settlements induced by seismic action. Since studies on liquefaction behavior of silts is limited, it was considered to carry out an experimental study for evaluation of strength behavior of dense silts under cyclic loading conditions. All the tests were performed on specimens at a relative density of 80%, by application of constant level sinusoidal stresses under a frequency of 0.1 Hz. As a consequence, cyclic behavior of a dense silt is experimentally determined and evaluated by application of ten different cyclic stress ratio values. Keywords: Nonplastic silt, Cyclic triaxial tests, Liquefaction 1. INTRODUCTION During seismic excitations, propagation of shear waves cause undrained shear stresses under certain conditions. Formation of undrained shear stresses during shear wave propagation leads to deformations along with increase in pore water pressure. Increasing pore water pressure is accompanied with a decrease in soil rigidity by initiating a vicious circle comprising increasing levels of shear deformation and pore water pressure. -
Summarization and Comparison of Engineering Properties of Loess in the United States
Summarization and Comparison of Engineering Properties of Loess in the United States J. B. SHEELER, Associate Professor of Civil Engineering, Iowa State University •LARGE deposits of loess are found in many parts of the United States, but published values of the engineering properties of loess are relatively scarce. The data in this paper were gathered to indicate similarities and compare the properties of loess from one area with another. Loess is composed primarily of rather loosely arranged angular grains of sand, silt, and clay. Silt is usually the dominant size. Calcite is also generally present in amounts ranging from zero to more than 10 percent of the total soil.. The aeolian hypothesis of loess deposition is compatible with the physical charac teristics of undisturbed loess masses. This hypothesis states that fine-grained ma terial was transported, sorted, and redeposited by wind action and thus became loess. During deposition, moisture and clay minerals are believed responsible for cementing the coarser grains together to form a loose structure. The loess is therefore subject to loss of shear strength due to water softening the clay bonds and to severe consolida tion caused by a combination of loading and moisture. Loess is usually thought of as an aeolian material that was deposited thousands of years ago and has remained in place since the time of deposition. Loess that has been eroded and redeposited is often referred to as redeposited loess, reworked loess or more simply as a silt deposit. This implies that the word loess indicates an aeolian soil, undisturbed since deposition. Certain engineering properties of loess, such as shear strength, are quite drastically changed by erosion and redeposition. -
In Situ and Laboratory Evaluation of Liquefaction Resistance of a Fine Sand
Louisiana State University LSU Digital Commons LSU Historical Dissertations and Theses Graduate School 1990 In Situ and Laboratory Evaluation of Liquefaction Resistance of a Fine Sand. Behnam Mahmoodzadegan Louisiana State University and Agricultural & Mechanical College Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_disstheses Recommended Citation Mahmoodzadegan, Behnam, "In Situ and Laboratory Evaluation of Liquefaction Resistance of a Fine Sand." (1990). LSU Historical Dissertations and Theses. 5075. https://digitalcommons.lsu.edu/gradschool_disstheses/5075 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Historical Dissertations and Theses by an authorized administrator of LSU Digital Commons. For more information, please contact [email protected]. INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. The quality of this reproduction isdependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand corner and continuing from left to right in equal sections with small overlaps. -
Undrained Pore Pressure Development on Cohesive Soil in Triaxial Cyclic Loading
applied sciences Article Undrained Pore Pressure Development on Cohesive Soil in Triaxial Cyclic Loading Andrzej Głuchowski 1,* , Emil Soból 2 , Alojzy Szyma ´nski 2 and Wojciech Sas 1 1 Water Centre-Laboratory, Faculty of Civil and Environmental Engineering, Warsaw University of Life Sciences-SGGW, 02787 Warsaw, Poland 2 Department of Geotechnical Engineering, Faculty of Civil and Environmental Engineering, Warsaw University of Life Sciences-SGGW, 02787 Warsaw, Poland * Correspondence: [email protected]; Tel.: +48-225-935-405 Received: 5 July 2019; Accepted: 5 September 2019; Published: 12 September 2019 Abstract: Cohesive soils subjected to cyclic loading in undrained conditions respond with pore pressure generation and plastic strain accumulation. The article focus on the pore pressure development of soils tested in isotropic and anisotropic consolidation conditions. Due to the consolidation differences, soil response to cyclic loading is also different. Analysis of the cyclic triaxial test results in terms of pore pressure development produces some indication of the relevant mechanisms at the particulate level. Test results show that the greater susceptibility to accumulate the plastic strain of cohesive soil during cyclic loading is connected with the pore pressure generation pattern. The value of excess pore pressure required to soil sample failure differs as a consequence of different consolidation pressure and anisotropic stress state. Effective stresses and pore pressures are the main factors that govern the soil behavior in undrained conditions. Therefore, the pore pressure generated in the first few cycles plays a key role in the accumulation of plastic strains and constitutes the major amount of excess pore water pressure. Soil samples consolidated in the anisotropic and isotropic stress state behave differently responding differently to cyclic loading. -
Achieving the Post-Construction Soil Standard
Achieving the Post-construction Soil Standard Meeting King County’s regulations to preserve and restore healthy soils { on developments in King County } Why do we need post-construction standards? Land development and landscaping practices can damage natural soil functions by removing or compacting topsoil. The result is increased runoff, erosion, unhealthy landscapes that are difficult and expensive to maintain, polluted water, destroyed fish habitat, and increased need for costly storm water management structures. How does building healthy soil help? Healthy soil is vital to a clean environment and healthy landscapes. Deep soil that is rich in organic material absorbs rainwater, helps prevent flooding and soil erosion, and filters out water pollutants. Healthy soil also stores water and nutrients for plants to use in dry times, promoting healthy plants that require less irrigation, toxic pesticides, and other resources. For more information, visit www.soilsforsalmon.org. Regulatory requirements for post-construction soils King County’s Clearing and Grading regulations (King County Code 16.82) were developed to preserve and restore healthy soils on developments. They apply to all construction site development activities, whether permits are required or not, except for surface mine operations conducted pursuant to permits issued by King County and the Washington Department of Natural Resources. To the maximum extent possible, construction areas that have been cleared and graded must have the soil moisture holding capacity restored to that of the original undisturbed native soil. Areas exempt from this rule are those that will be covered by impervious surfaces, or have been incorporated into a stormwater facility. Areas that have been compacted or had the topsoil or duff layer removed must be amended by adding compost, importing topsoil, stockpiling site topsoil, or through other techniques that are capable of mitigating lost moisture holding capacity.