Qualitative Rating System for Drainability of Roadway Base Materials

2022 ◽  
pp. 036119812110642
Author(s):  
Hyunjun Oh ◽  
William J. Likos ◽  
Tuncer B. Edil
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Cost Savings ◽  
Unit Weight ◽  
Rating Systems ◽  
Base Materials ◽  
Base Course ◽  
Materials Used

Poor drainage of roadway base/subbase materials can lead to increased pore water pressure, reduction of strength and stiffness, and freeze-thaw damage. Base course drainability is dependent on physical properties of the material that affect its water flow and retention behavior including particle size distribution, fines content, density or porosity, the geometric and boundary conditions of the pavement system, and site-specific environmental conditions. Objectives of this project are to quantitatively assess permeability and water retention characteristics of representative roadway base materials, to derive predictive equations for indirect estimation of material properties that control drainability, and to develop and recommend rating systems for assessing more general base materials. Laboratory tests were conducted on 16 samples of materials used in or considered for use in roadway applications to determine grain size distribution, hydraulic conductivity, and soil-water characteristic curves. Results are correlated to grain size characteristics including percent gravel, percent fines, grain size indices (e.g., D10, D30), and unit weight. Procedures are provided to qualitatively assess drainability as “excellent,”“marginal,” or “poor,” from grain size, thereby offering a rationale to reduce pavement life cycle costs, improve safety, realize material cost savings, and reduce environmental impacts.

scholarly journals PENURUNAN OPRIT JEMBATAN SEMARANG LINGKAR UTARA DAN JEMBATAN KALI JAJAR DEMAK JAWA TENGAH DENGAN PRE-FABRICATED VERTICAL DRAIN

2021 ◽  
Vol 4 (1) ◽  
pp. 27
Author(s):  
M Zaki ◽  
Wardani SPR ◽  
Muhrozi Muhrozi
Keyword(s):  
Bearing Capacity ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Soil ◽  
Soil Improvement ◽  
Unit Weight ◽  
Fast Time ◽  
Foundation Soil ◽  
Vertical Drain ◽  
Long Time

<p><em>Construction on soft soil, often creates problems. The Semarang North Ring Bridge and Kali Jajar Bridge are the Recent soft Marine Alluvium zones located in the Pantura area which have very soft soil characteristics with a depth of more than -30.0 meters this has resulted in a very large settlement due to very small grains, flood, rob, pore water pressure increases so that the shear strength of the soil will be small, the compression is large and the permeability coefficient is small so that if the construction load exceeds the critical bearing capacity, the damage to the foundation soil will occur. To get the increase in soil bearing capacity, it can be achieved by changing the properties of the soil from the shear angle (</em>f<em>), cohesion (c) and unit weight (</em>g<em>). The settlement can be reduced by increasing the cavity density from the compression of the soil particles (Wesley, 1977). Soil improvement takes a long time, aiming to increase shear resistance so that it requires a fast time in this case is to use Pre-Fabricated Vertical Drain (Bowles 1981). The results of the analysis of the pattern of decline and the effectiveness of the use of PVD (pre-fabricated vertical drain) at the Oprit Bridge in the two research locations have the same decrease in the range of the same heap height at (H = 4 meters) there is a decrease of 117.53 cm at 64 months on the bridge. Kali Jajar (STA. 3 + 200) and there was a decrease of 268.94 cm at 37 months at the Semarang North Ring Bridge</em></p>

scholarly journals A Bayesian Approach in the Evaluation of Unit Weight of Mineral and Organic Soils Based on Dilatometer Tests (DMT)

2019 ◽  
Vol 9 (18) ◽  
pp. 3779
Author(s):  
Rabarijoely
Keyword(s):  
Bayesian Approach ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Field Research ◽  
Unit Weight ◽  
Organic Soils ◽  
Geotechnical Parameters ◽  
Statistical Measures ◽  
Characteristic Values ◽  
High Degree

Recently, geotechnical problems that are characterized by a high degree of complexity and uncertainty with respect to input data have been solved using Bayesian analysis. One example is the problem of cautious estimation of geotechnical parameters according to Eurocode 7 requirements. The research included various types of soil such as peat, gyttja, organic mud, and clays. These were studied in order to develop an empirical correlation for determining the unit weight of mineral and organic soils. The compiled database of documented field research sites for different types of soil was used to investigate and develop direct relationships between measured results and dilatometer (DMT) readings, i.e., po and p1 together with pore water pressure (uo) and pressure (Pa). The soil unit weights were determined for both mineral and organic soils. The paper addresses the applicability of the Bayesian approach in geotechnics via a simple example related to the determination of characteristic values of geotechnical parameters for design structures. The results show that it is possible to conduct a more reliable forecast with improved statistical measures compared to other available methods for multilayer subsoils.

Numerical modeling of sand drain performance — a case study of the Salter Street Bridge construction

2008 ◽  
Vol 45 (6) ◽  
pp. 751-767 ◽  
Author(s):  
Michael J. Van Helden ◽  
James A. Blatz ◽  
Nelson J. Ferreira ◽  
Ken Skaftfeld
Keyword(s):  
Sensitivity Analysis ◽  
Hydraulic Conductivity ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Axisymmetric Flow ◽  
Cost Savings ◽  
Local Data ◽  
Undisturbed Soil ◽  
Excess Pore

Several bridge crossings proposed for the Red River Floodway expansion project were recently constructed using vertical sand drains to accelerate excess pore-water pressure dissipation and settlement caused by embankment fill loading. With limited local data regarding the performance of sand drains, the calibrated model presented here addresses the need to optimize the design of sand drain configurations, maximize cost savings, and minimize construction delays for future structures. This study presents a coupled finite element embankment consolidation model calibrated against measured pore-water pressure and settlement data from the Salter Street Bridge embankment fill construction, which used vertical sand drains to dissipate excess pore-water pressures. A hydraulic conductivity modification procedure was used to simulate the axisymmetric flow conditions with a plane-strain model neglecting well resistance but incorporating the effects of a smear zone. A sensitivity analysis was performed using the calibrated model by varying the smear zone radius and hydraulic conductivity and the undisturbed soil hydraulic conductivity. The sensitivity analysis predicted that the observed behaviour was predominantly sensitive to the hydraulic conductivity of the smear zone and the surrounding soil.

scholarly journals Origin of the power-law exponent in the landslide frequency-size distribution

2018 ◽  
Author(s):  
Ahoura Jafarimanesh ◽  
Arnaud Mignan ◽  
Laurentiu Danciu
Keyword(s):  
Size Distribution ◽  
Power Law ◽  
Hazard Assessment ◽  
Water Pressure ◽  
Slope Angle ◽  
Unit Weight ◽  
Power Exponent ◽  
Soil Thickness ◽  
Initiation Phase ◽  
Triggering Process

Abstract. Landslide statistics is characterized by a power-law frequency-size distribution (FSD) with power exponent α centered on 2.2–2.4, independently of the landslide trigger. So far, the origin of the α-value, critical to probabilistic hazard assessment, remains hypothetical. We present a generic landslide cellular automaton (LSgCA) based on the rules of Self Organized Criticality and on the Factor of Safety (FS) concept. We show that it reproduces the power-law FSD for realistic parameter ranges (i.e. cohesion, soil unit weight, soil thickness, angle of friction, slope angle, pore water pressure) with LSgCA simulations yielding α = 2.17±0.49, which is in agreement with α = 2.21±0.53 obtained from an updated meta-analysis of the landslide literature. The parameter α remains stable despite changes in the landslide triggering process, with the trigger only influencing the spatial extent of the landslide initiation phase defined from an FS contour. Furthermore, different FS formulations do not significantly alter the results. We find that α is constrained during the initiation phase of the landslide by the fractal properties of the topography, as we observed a positive correlation between fractal dimension and α while α did not change during the propagation phase of the LSgCA. Our results thus suggest that α can be estimated directly from the FS map for probabilistic landslide hazard assessment. However full modeling (including the propagation phase) would be required to combine the spatial distributions of landslide and exposure in probabilistic risk analysis.

EFFECT OF ABRASIVE PARTICLE SHAPE ON TWO-BODY ABRASIVE WEAR OF STEEL

Tribologia ◽  
2021 ◽  
Vol 294 (6) ◽  
pp. 21-27
Author(s):  
Krzysztof Ligier ◽  
Magdalena Lemecha
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Wear Rate ◽  
Size Distribution ◽  
Grain Shape ◽  
Abrasive Particle ◽  
Test Results ◽  
Natural Sand ◽  
Rate Testing ◽  
Materials Used

This paper presents the results of Hardox Extreme steel wear rate testing using an abrasive mass of varying grain shapes. The tests were conducted by the ASTM G65 method using crushed and natural sand with a grain-size distribution of 0.05–2 mm, obtained from a gravel pit. The abrasive materials used in the tests differed in grain shape, while the particle-size distribution was similar. The test results show that the wear rate in crushed sand is four times higher than that in natural sand, which is attributable to the shape of grains and the geometry of their edges.

scholarly journals The variation of grain size distribution in rock granular material in seepage process considering the mechanical–hydrological–chemical coupling effect: an experimental research

2020 ◽  
Vol 7 (1) ◽  
pp. 190590 ◽  
Author(s):  
Hailing Kong ◽  
Luzhen Wang ◽  
Hualei Zhang
Keyword(s):  
Grain Size ◽  
Granular Material ◽  
Size Distribution ◽  
Granular Materials ◽  
Grain Size Distribution ◽  
Coupling Effect ◽  
Water Pressure ◽  
Geotechnical Engineering ◽  
Material Structure ◽  
Filling Material

As a common solid waste in geotechnical engineering, rock granular material should be properly treated and recycled. Rock granular material often coexists with water when it is used as the filling material in geotechnical engineering. Water flowing in rock granular materials is a complex progress with the mechanical–hydrological–chemical (MHC) coupling effect, i.e. the water scours in the gaps and spaces in the rock granular material structure, produces chemical reactions with rock grains, rock grains squeeze each other under the water pressure and compression leading to re-breakage and producing secondary rock grains, and the fine rock grains are migrated with water and rushed out. In this process, rock grain size distribution (GSD) changes, it affects the physical and mechanical characteristics of the rock granular materials, and even influences the seepage stability of the rock granular materials. To study the variation of GSD in the rock granular material considering the MHC coupling effect after the seepage process, seepage experiments of rock grain samples are carried out and analysed in this paper. The result is expected to have a positive impact on further studies of the properties of the rock granular material.

scholarly journals Slope Stability Evaluation of Geosynthetic Reinforced Soil

2019 ◽  
Vol 8 (4) ◽  
pp. 7143-7147
Keyword(s):  
Slope Stability ◽  
Slope Failure ◽  
Pore Water Pressure ◽  
Limit Equilibrium ◽  
Water Pressure ◽  
Friction Angle ◽  
Calculation Model ◽  
Reinforced Soil ◽  
Unit Weight ◽  
Soil Parameters

The slippery of natural slope is sometimes ruled by combination of soil parameters and earthquake characteristics. Geotextiles could be a reinforcing materials and an application in numerous areas still as in geotechnical application to supply additional lateral restraint and forestall the high rise hill from failure. The analysis was aimed to analyze slope stability analysis, strengthened the Finite slope with non-woven geotextiles. The modal of hill was created within the SLOPE/W software system of GeoStudio that is predicated on limit equilibrium of slope analysis. The results of issue of safety square measure compared while not and with use of geotextiles in several layers. The issue of safety of slope failure will increase from three.437M to 9.978M victimization 3 layers of geotextiles at optimum height. Thus, this study confirms that the non-woven geotextiles may be applied in slope so as to enhance the soundness of natural or mam-made slope. During this regard, special stress is given to the sensitivity of the Calculation model input parameters like friction angle, cohesion, Pore water pressure and unit weight of soil that ought to contribute to raising awareness regarding these problems, as a requirement to create the proper selections and optimum technical resolution during this space.

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