The in situ density and shearing resistance of the Hampshire Basin Plateau Gravels

1991 ◽  
Vol 7 (1) ◽  
pp. 415-422 ◽  
Author(s):  
M. E. Barton ◽  
G. J. Evans ◽  
S. B. Haji Yusof ◽  
Ho Wai Kin
Keyword(s):  
Dry Density ◽  
Sandy Gravel ◽  
Direct Shear Tests ◽  
Fluvial Terraces ◽  
Shearing Resistance ◽  
Replacement Technique ◽  
Grain Size Distributions ◽  
Different Grain Size ◽  
Best Fit

AbstractOne of the principal Quaternary deposits in Central Southern England are extensive spreads of sandy fine to coarse, mainly flint gravels: those at the higher elevations being referred to as “Plateau” Gravels to distinguish them from the “Valley” Gravels. The most widely accepted view of the origin of the Plateau Gravels is that they represent fluvial terraces deposited under periglacial conditions. Although they have provided excellent conditions for foundations, their actual in-situ density and shear strength characteristics were virtually unknown. To remedy this deficiency, a series of in-situ density tests using the sand replacement technique and direct shear tests using 300 mm square samples have been carried out.Samples of sandy gravel from Highcliffe were compacted by hand tamping to minimise particle breakdown and tested in a saturated condition with a dry density approximately 97% of the in-situ value. The results show a curved failure envelope which in the usual form of power law notation gives a best fit result of:- τ = 1.475 σn ′ 0-955 Over the range of normal Stresses from 80 to 370 kPa used in the tests, this corresponds to secant φ′ values from 51°. to 48°. Tests carried out on dry samples gave φ′ values up to 4° higher. Tests on other samples with different grain size distributions show that the shearing resistance increases with the percentage gravel (as opposed to sand) content. These results have been combined with published work on other well graded, mainly flint gravels to give a preliminary quantitative evaluation of the influence of percentage gravel content on shearing resistance.

Quantifying In Situ Tack Coat Performance Using the TackBond Tester for Quality Control

2021 ◽  
pp. 036119812110581
Author(s):  
Blaine M. Wruck ◽  
Erdem Coleri ◽  
Richard Villarreal ◽  
Vikas Kumar ◽  
James Batti
Keyword(s):  
Control Process ◽  
Test System ◽  
Strong Correlations ◽  
Bond Quality ◽  
Test Device ◽  
Bond Performance ◽  
Direct Shear Tests ◽  
Construction Specifications ◽  
Tack Coat

In light of the various quality assurance (QA) issues pertaining to tack coats that occur during construction, there is a need for a means of verifying interlayer bond quality in situ. Despite the immense use of tack coat as a constituent in paving, there are no construction specifications with provisions for the quantification of tack coat bond quality in laboratory or field settings. In this study, a construction QA process for tack coat bond performance was proposed. A novel field tack coat bond strength test device, TackBond, was developed and used for this purpose. The performance of engineered (new tack coat technologies that are tracking less) and conventional tack coats was also evaluated in the laboratory and the field using the developed TackBond test system. The TackBond device was improved in this study by adding features that render it more practical, portable, accurate, and better suited for a variety of pavement surface conditions. Engineered tack coat performance was compared with that of tack coats used conventionally on both milled and overlay surface types. The suitability of the TackBond Test device for capturing the true response of each tack coat was first evaluated by comparing results from TackBond laboratory tests with monotonic direct shear tests (DST) on laboratory-produced samples. Strong correlations between the two test types were achieved. Results of field and laboratory TackBond tests showed that the in situ QA control process developed in this study could be effectively used to improve the in situ tack coat bond performance.

scholarly journals Multi-source SO<sub>2</sub> emissions retrievals and consistency of satellite and surface measurements with reported emissions

2017 ◽  
Author(s):  
Vitali Fioletov ◽  
Chris A. McLinden ◽  
Shailesh K. Kharol ◽  
Nickolay A. Krotkov ◽  
Can Li ◽  
...  
Keyword(s):  
Point Source ◽  
Single Point ◽  
Control Measures ◽  
Ozone Monitoring Instrument ◽  
So2 Emissions ◽  
Vertical Column ◽  
Wind Speeds ◽  
Surface Measurements ◽  
Best Fit

Abstract. Reported sulfur dioxide (SO2) emissions from U.S. and Canadian sources have declined dramatically since the 1990s as a result of emissions control measures. Observations from the Ozone Monitoring Instrument (OMI) on NASA's Aura satellite and ground-based in-situ measurements are examined to verify whether the observed changes from SO2 abundance measurements are quantitatively consistent with the reported changes in emissions. To make this connection, a new method to link SO2 emissions and satellite SO2 measurements was developed. The method is based on fitting satellite SO2 vertical column densities (VCDs) to a set of functions of OMI pixel coordinates and wind speeds, where each function represents a statistical model of a plume from a single point source. The concept is first demonstrated using sources in North America, and then applied to Europe. The correlation coefficient between OMI-measured VCDs (with a local bias removed) and SO2 VCDs derived here using reported emissions for 1° by 1° gridded data is 0.91 and the best-fit line has a slope near unity, confirming a very good agreement between observed SO2 VCDs and reported emissions. Having demonstrated their consistency, seasonal and annual mean SO2 VCD distributions are calculated, based on reported point-source emissions for the period 1980–2015, as would have been seen by OMI. This consistency is further substantiated as the emissions-derived VCDs also show a high correlation with annual mean SO2 surface concentrations at 50 regional monitoring stations.

scholarly journals Geotechnical properties of reinforced clayey soil using nylons carry’s bags by products

2018 ◽  
Vol 162 ◽  
pp. 01020 ◽  
Author(s):  
Nahla Salim ◽  
Kawther Al-Soudany ◽  
Nora Jajjawi
Keyword(s):  
Soil Stabilization ◽  
Clayey Soil ◽  
Ground Improvement ◽  
Soft Soil ◽  
Liquid Limit ◽  
Waste Material ◽  
Industrial Wastes ◽  
Dry Density ◽  
Maximum Dry Density ◽  
Replacement Technique

All structures built on soft soil may experience uncontrollable settlement and critical bearing capacity. This may not meet the design requirements for the geotechnical engineer. Soil stabilization is the change of these undesirable properties in order to meet the requirements. Traditional methods of stabilizing or through in-situ ground improvement such as compaction or replacement technique is usually costly. Now a safe and economic disposal of industrial wastes and development of economically feasible ground improvement techniques are the important challenges being faced by the engineering community. This work focuses on improving the soft soil brought from Baghdad by utilizing the local waste material for stabilization of soil, such as by using “Nylon carry bag’s by product” with the different percentage and corresponding to 1 %, 3% and 5% (the portion of stabilizer matters to soil net weight) of dried soil. The results indicated that as Nylon’s fiber content increases, the liquid limit decreases while the plastic limit increases, so the plasticity index decreases. Furthermore, the maximum dry density decreases while, the optimum moisture content increases as the Nylon’s fiber percentage increases. The compression index (decreases as the Nylon’s fiber increases and provides a maximum of 43% reduction by adding 5% nylon waste material. In addition, the results indicated that, the undrained shear strength increases as the nylon fiber increases.

scholarly journals Study on a test procedure and evaluation in-situ tracer in sandy gravel aquifer

2021 ◽  
Vol 16 (2) ◽  
pp. 117-129
Author(s):  
Hiroki NOMI ◽  
Makoto SUZUKI ◽  
Shinji TAKEUCHI ◽  
Tomoyuki HISHIYA ◽  
Hirotaka TAGISHI
Keyword(s):  
Test Procedure ◽  
Sandy Gravel ◽  
Gravel Aquifer

scholarly journals An Experimental Study on the Shear Behaviors of Polymer-Sand Composite Materials after Immersion

Polymers ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 924 ◽  
Author(s):  
Jin Liu ◽  
Yuxia Bai ◽  
Ding Li ◽  
Qiongya Wang ◽  
Wei Qian ◽  
...  
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Void Ratio ◽  
Dry Density ◽  
Chemical Additives ◽  
Shear Tests ◽  
Direct Shear Tests ◽  
Sand Particles ◽  
Shear Behaviors ◽  
Sand Material

Sand mixed with geotextile/fiber/cement/lime or non-traditional chemical additives to form composite materials is recognized as an effective method for improving the sand properties. In this work, the variation in properties of composite materials after immersion is reported which has rarely appeared in the literature. The focus of this study is to evaluate the shear behaviors of polymer-sand composite material after immersion with direct shear tests. Several factors which may influence the shear behaviors after immersion are analyzed. The results demonstrate that this composite material still has good shear behaviors after immersion when compared to the purely sand material. The shear behaviors are improved with an increment in the curing time, polymer content and sand dry density while there is a decrease in the shear behaviors with increasing immersion time. The interaction between sand particles and the polymer are analyzed with Scanning Electron Microscope (SEM). The polymer membranes are formed by polymer enwrapping and connected sand particles to build an elastic and viscous structure in the sand that increases the interlocking forces between sand particles and decreases the void ratio of this material. The membranes are softened in water resulting in a decrease in the shear strength. Moreover, other factors affect the shear behaviors by improving the completeness and stability of this structure.

scholarly journals X-ray extinction from interstellar dust

2019 ◽  
Vol 629 ◽  
pp. A78 ◽  
Author(s):  
E. Costantini ◽  
S. T. Zeegers ◽  
D. Rogantini ◽  
C. P. de Vries ◽  
A. G. G. M. Tielens ◽  
...  
Keyword(s):  
Interstellar Medium ◽  
Interstellar Dust ◽  
Simulated Data ◽  
X Ray ◽  
Cosmic Abundance ◽  
Grain Size Distributions ◽  
Edge Features ◽  
Different Grain Size ◽  
Near Future

Aims. We present a study on the prospects of observing carbon, sulfur, and other lower abundance elements (namely Al, Ca, Ti, and Ni) present in the interstellar medium using future X-ray instruments. We focus in particular on the detection and characterization of interstellar dust along the lines of sight. Methods. We compared the simulated data with different sets of dust aggregates, either obtained from past literature or measured by us using the SOLEIL-LUCIA synchrotron beamline. Extinction by interstellar grains induces modulations of a given photolelectric edge, which can be in principle traced back to the chemistry of the absorbing grains. We simulated data of instruments with characteristics of resolution and sensitivity of the current Athena, XRISM, and Arcus concepts. Results. In the relatively near future, the depletion and abundances of the elements under study will be determined with confidence. In the case of carbon and sulfur, the characterization of the chemistry of the absorbing dust will be also determined, depending on the dominant compound. For aluminum and calcium, despite the large depletion in the interstellar medium and the prominent dust absorption, in many cases the edge feature may not be changing significantly with the change of chemistry in the Al- or Ca-bearing compounds. The exinction signature of large grains may be detected and modeled, allowing a test on different grain size distributions for these elements. The low cosmic abundance of Ti and Ni will not allow us a detailed study of the edge features.

scholarly journals Two Different Grain Size Distributions within the Protoplanetary Disk around HD 142527 Revealed by ALMA Polarization Observation

2018 ◽  
Vol 864 (1) ◽  
pp. 81 ◽  
Author(s):  
Satoshi Ohashi ◽  
Akimasa Kataoka ◽  
Hiroshi Nagai ◽  
Munetake Momose ◽  
Takayuki Muto ◽  
...  
Keyword(s):  
Grain Size ◽  
Protoplanetary Disk ◽  
Size Distributions ◽  
Polarization Observation ◽  
Grain Size Distributions ◽  
Different Grain Size
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