File Name: soil properties testing measurement and evaluation .zip
The manual uses a consistent "Procedure," "Data," and "Calculations" format for each test; contains completely worked examples showing the computations required for the analysis and evaluation of the test data collected; discusses what data, results, and other information should be presented in the test report; and explains what the test results will be used for in practical engineering problems. Blank data reporting forms and graph papers are provided for most tests, and an accompanying diskette contains state-of-the-art, user-friendly software for compiling test data, performing calculations, plotting curves, and obtaining final results. Soil Properties: Testing, Measurement and Evaluation represents a unique soils laboratory manual based on the latest American Society for Testing and Materials ASTM procedures--the most commonly used methods in civil engineering practice.
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In situ tests are generally faster than lab testing as the results can be obtained immediately while on-site.
With many in situ tests, field data are collected more abundantly than laboratory data, thus allowing for a more comprehensive definition of soil strata, zones, layering, and stratigraphy, as well as the identification of lenses, weak zones, and inclusions.
Field tests also allow an investigation of vertical and horizontal variability to determine whether an overall homogeneity or heterogeneity exists across a site. In situ testing also provides an independent evaluation of geotechnical engineering parameters for analysis and design.
A wide variety of in situ geotechnical tests have been developed for assessing and characterizing the ground Broms and Flodin , Robertson , Mayne Figure shows an assortment of selected devices available, along with their associated acronyms. Many of these devices are intended for a particular use and are not widely used in practice. The focus in this chapter is on in situ methods that are commonly used for obtaining undrained shear strength in clays, friction angle in sands, elastic soil modulus, preconsolidation stress, and hydraulic conductivity K.
Hybrid tests have been developed for some of the tests. Hybrid tests include more than one method in a single device, such as the CPTu that combines a penetrometer with a piezo probe. A special category of hybrid tests combines in situ geotechnical and geophysical testing. This optimizes the collection of field data economically, expediently, and efficiently. The in situ tests presented in the following sections have been grouped into three broad categories: 1. Borehole tests in soils 2. Direct-push methods for soils 3.
Rock tests. Selection of in situ tests for geotechnical site characterization Borehole Test Methods Borehole-type field tests can be conducted in open borings, beneath borehole casings, or below the bottoms of HSAs, depending upon the soil conditions and drilling methods used. The SPT test is generally used to estimate the shear strength parameters of sandy soils and overconsolidated clays.
It is unreliable for soils containing course gravel, cobbles, boulders, cohesionless silts, and soft and sensitive clays. Figure depicts the general layout of the SPT using a hammer system, drill rods, and split-spoon or split-barrel sampler. The basic testing procedure consists of driving a hollow steel tube with an outside diameter of 2.
The first increment is considered a seating of the sampler. The blows obtained for the second and third increments are summed to give an N-value, which is reported in blows per foot bpf. The test is typically conducted at 5-ft 1. At shallow depths of less than 10 ft 3 m , the depth intervals are often less e.
Example of SPT N-values 5. Automatic hammers are now predominant in the United States. All systems have a nominal hammer weight of lb. However, actual efficiencies can be significantly less than percent and quite variable, ranging from 30 to 95 percent, depending upon hammer type, commercial system, and age and condition of the equipment.
As a result, it is paramount to calibrate the energy efficiency of the SPT system including rig, hammer, and even the crew approximately once per year so that an energy ratio ER can be obtained for correcting the measured N-value in accordance with ASTM D At the time that the geotechnical profession became aware that energy efficiency was important Seed et al.
Here, the SPTs are conducted in a fine sand layer that extends to a depth of approximately 22 ft 6. After correcting for hammer energy, it is evident that the N60 profiles are in good agreement for both hammer systems.
Comparison of a uncorrected Nm and b energy-corrected N60 SPT blow counts There is a general misconception by geotechnical engineers that SPTs conducted using an automatic hammer do not need to be corrected for hammer energy.
Table shows a compilation of thousands of hammer energy measurements ASTM D by different agencies, all using automatic hammers. The measured values of ER range from 46 to 95 percent.
The results highlight the importance of correcting for hammer efficiency even for automatic hammers. Table The test involves a four-sided blade vane that is pushed into the soil deposit, usually at 3.
Within one minute after blade insertion, a moment is applied to twist the rods at 0. The peak torque reading is used to determine the maximum shear stresses acting on the soil cylinder, which is interpreted as the vane undrained shear strength. VST or field van for clays and silts The standard vane is rectangular with a blade width D of 65 mm 2. Other vane configurations and sizes are available to optimize the range of the load cells and torque gages, depending upon ground conditions Chandler For example, tapered blades facilitate insertion and extraction in stiffer soils.
Figure presents the general solution for calculating suv for vanes with any D, H, and taper angles at top and bottom , as well as the most common geometries. Limit equilibrium solutions for calculating undrained shear strength of rectangular and tapered vanes Modern field vanes employ downhole electronic torque meters and rheometers to measure moment and rotation of the blades Peuchen and Mayne The data are obtained in either analog or digital format and then transmitted uphole using an electronic cable for data logging onto a field computer.
With modern data acquisition systems, the electrovane shear test EVST provides continuous records of the entire torque vs.
This data can be interpreted to provide a shear stress vs. The shear stress vs. Source: Paul Mayne Figure EVST results from selected depths in clay deposit If desired, an additional 10 revolutions are performed faster rate permitted during this phase , and, subsequently, the residual torque reading is recorded at the aforementioned standard rate to evaluate the remolded undrained shear strength.
Example of EVST in soft clay 5. The testing process involves lowering the pressuremeter to the desired test depth, inflating the cylindrical rubber balloon by injecting fluid, and measuring the associated changes in pressure and volume of the injected fluid. Tests are usually conducted at 3. For soils, the injected fluid is typically water, while in hard soils and rocks, hydraulic oil is typically used.
It is also feasible to use gas or air pressure while testing soils, especially with computerized PMT systems. The components of the PMT are illustrated in Figure Basic components and procedures of the PMT Figure shows an example of a pressure vs. The recorded pressure-volume change response allows the derivation of an entire stress-strain-strength curve and the evaluation four specific soil parameters at each test depth.
The four soil parameters include i lift-off pressure , ii stiffness or modulus, iii shear strength, and iv limit pressure. Example PMT pressure-volume curve.
Depending on the data reduction method adopted, the stiffness is expressed as either a Young's modulus or or shear modulus or , where the subscript "u" indicates an assumed undrained condition at constant volume, and the prime indicates a fully drained condition.
In Figure , an unload-reload cycle was performed at an applied pressure of psi to better define the elastic modulus. The shear strength is evaluated as either the undrained shear strength for undrained loading i. The Menard version includes three air-inflated guard cells: two situated above and one below the water-filled center testing probe cell.
The testing time is slow because pressures for all three cells must be recorded, and readings are taken at predefined times before advancing to the next pressure increment. This design omits the upper and lower guard cells and has only the middle probe cell that is water-inflated Briaud Several commercial types of monocell probes are available e.
In these designs, the self-boring pressuremeter probe is lowered to the bottom of a borehole and then a small rotary cutter is used to insert the probe to the desired test depth.
The probe is hollow, thus allowing the soil cuttings to be flushed out during advancement. Newer designs provide a water-jetting feature to cut soil at the front end and to facilitate soil removal. These direct-push methods often employ large The hydraulic frames are mounted on trucks, tracks, and portable setups. The basic components of the CPT are illustrated in Figure In this test, ton hydraulic pushing systems mounted on wheeled trucks or track vehicles providing deadweight reaction are typically used to push the penetrometer into the ground.
Also, anchored rigs can develop the necessary reaction forces for penetration. The standard CPT penetrometer has a cross-section area of cm2 1. In addition to the standard sizes, there are versions that include sizes between 1-cm2 0. Smaller sizes are used for profiling in varved clays and highly stratified layers, as well as for soils requiring frequent pore pressure dissipation testing. Larger size penetrometers have found use in testing of gravelly soils. Table lists the several types of cone penetrometers available and their applications.
Basic setup and equipment for electric CPT Table Uses inner and outer rods to convey loads uphole Stratigraphic profiling, fill control, natural sands, hard ground Electric Friction Cone ECPT qc and fs taken at 0.
Index to contaminant plumes 5. This allows the simultaneous measurement of dynamic pore pressures with cone tip resistance and sleeve friction. Porous filter elements can be positioned at various elevations on the penetrometer, including the apex and midface of the cone Type 1 , shoulder Type 2 , behind the sleeve Type 3 , as well as higher elevations Lunne et al.
The common configurations are shown in Figure The standard position is the Type 2; however, there can be advantages to using Type 1 piezocone in desiccated clays for better profiling results and at sites requiring many dissipation tests for soil hydraulic conductivity evaluations.
In soils with high fines content, a piezocone-type penetrometer is essential because the measured cone tip resistance is affected by pore pressures and must be corrected to the total cone tip resistance.
However, in many investigations, the subsurface conditions are not known, and thus a piezocone should be used so that the proper data and results are obtained. Common piezocone configurations for pore pressure readings. Example results from CPTu showing a total cone resistance, qt, b sleeve friction, fs, and c pore pressures, u2 The piezocone is an efficient test for site characterization because it collects three independent and continuous readings related to soil behavior with depth.
As a rule, the total cone tip resistance can be visually examined to get a basic understanding of the various layers and soil types encountered. For the CPTu sounding shown in Figure a , the profile indicates that most of the soil profile is sandy, yet distinct clay layers are found at depths of 3.
Below the groundwater table, the pore pressure can also be used to assess soil type.
The soil bulk density BD , also known as dry bulk density, is the weight of dry soil M solids divided by the total soil volume V soil. The total soil volume is the combined volume of solids and pores which may contain air V air or water V water , or both figure 1. The average values of air, water and solid in soil are easily measured and are a useful indication of a soils physical condition. Soil BD and porosity the number of pore spaces reflects the size, shape and arrangement of particles and voids soil structure. Both BD and porosity V pores give a good indication of the suitability for root growth and soil permeability and are vitally important for the soil-plant-atmosphere system Cresswell and Hamilton, ; McKenzie et al. Figure 1: Structural composition of soil, containing soil fraction V solids and pore space for air V air and water V water. Bulk density measurements can be done if you suspect your soil is compacted or as part of fertiliser or irrigation management plans see Bulk Density — On Farm Use factsheet.
View larger. Additional order info. K educators : This link is for individuals purchasing with credit cards or PayPal only. This laboratory textbook reflects the most commonly used methods of both field and laboratory testing to evaluate soil properties for engineering purposes. Designed to conform to the latest information from the American Society for Testing and Materials, it familiarizes students with the standards that practicing engineers and architects cite in contracts and specifications.
Embed Size px x x x x ISBN Soil mechanics. Evett, Jack B. L
Soil Health Assessment. Soil Health. The Science Behind Healthy Soil. Soil Health Kit Guides and Videos help teachers and educators implement their soils curriculum. Each guide includes an introduction to the soil property, discussion of the inherent and management factors influencing it, and explanation of the property's relationship to soil function.
Двое суток встроенные часы устройств обменивались бесконечными потоками зашифрованной синхронизирующейся информации. АНБ, перехватывая эти информационные импульсы, игнорировало их, считая аномалией сети, безобидной тарабарщиной. Но когда ТРАНСТЕКСТ расшифровал эти потоки информации, аналитики тут же увидели в них синхронизированный через Интернет отсчет времени.
Глаза его неотрывно смотрели на Чатрукьяна. - В него попал зараженный файл, сэр. Я абсолютно в этом уверен.
Один из прямоугольников вдруг закрыла чья-то тень. Даже не взглянув на верхушку башни, Халохот бросился к лестнице. ГЛАВА 99 Фонтейн время от времени стучал кулаком по ладони другой руки, мерил шагами комнату для заседаний, то и дело посматривая на вращающиеся огни шифровалки. - Отключить. Черт побери, немедленно отключить. Мидж появилась в дверях со свежей распечаткой в руке.
Хотя Стратмор и сожалел о смерти своего молодого сотрудника, он был уверен, что ее можно отнести к числу оправданных потерь. Фил Чатрукьян не оставил ему выбора. Когда запыхавшийся сотрудник лаборатории безопасности завопил о вирусе, Стратмор, столкнувшийся с ним на лестнице служебного помещения, попытался наставить его на путь истинный. Но Чатрукьян отказывался прислушаться к голосу разума. У нас вирус. Я звоню Джаббе. Когда он попытался обойти Стратмора, тот преградил ему дорогу.
Algo? - настаивал бармен. - Fino. Jerez. Откуда-то сверху накатывали приглушенные волны классической музыки. Бранденбургский концерт, - подумал Беккер. - Номер четыре.
- И частью программы они явно не являются. - Да бросьте вы это, - проворчал Джабба. - Хватаетесь за соломинку.
Вскоре спуск закончился, переключились какие-то шестеренки, и лифт снова начал движение, на этот раз горизонтальное. Сьюзан чувствовала, как кабина набирает скорость, двигаясь в сторону главного здания АНБ. Наконец она остановилась, и дверь открылась. Покашливая, Сьюзан неуверенно шагнула в темный коридор с цементными стенами.
- Yel autobus. Охранник пожал плечами. - Через сорок пять минут. Беккер замахал руками. Ну и порядки.
Aeropuerto? - повторил человек, внимательно следя за движением губ Двухцветного в зеркале. - Панк кивнул.
Soil properties testing measurement and evaluation. Author(S). Cheng Liu (Author) Jack B. Evett. (Author). Publication. Data. Upper Saddle River, N.J.: Pearson/.Aliwood 19.05.2021 at 09:30
The standard penetration test SPT is an in-situ dynamic penetration test designed to provide information on the geotechnical engineering properties of soil.Perpetuo T. 20.05.2021 at 03:35
Soil Properties: Testing, Measurement, and Evaluation (6th Edition) [Liu, Cheng, Evett Ph.D., Jack] on drugtruthaustralia.org *FREE* shipping on qualifying offers.Gaetane P. 20.05.2021 at 16:07
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