Examination of Economical Methods for Repairing Highway Landslides

The Kentucky Transportation Cabinet spends millions of dollars each year in the repairs of highway landslides. In previous research, an inventory of highway landslides showed that about 1440 landslides of various sizes exist on major roadways maintained by the Kentucky Transportation Cabinet. Moreover, emergency repairs can exceed one million dollars for large embankment failures. In many instances, drilled-in, or driven, railroad steel rails were frequently used as a stop-gap measure to halt landslide movements or those efforts were tried as a permanent solution. The use of rails to serve as a restraining structure was usually not successful when the height of fill exceeded about 20 feet. The previous study also showed about 39 percent of the landslides were small and less than 20 feet in height. Cost estimates indicated that railroad steel rails, when drilled and socketed into bedrock, may be effective and economical when the embankment height is less than about 20 feet. This study had two major objectives. Because railroad steel rails are widely used, the development of a theoretical method of analyzing and predicting the success of rails that are drilled-in and socketed into bedrock was a major objective. To enhance this method and possibly extend the height that this technique may be used, theoretical equations were developed that include the use of lightweight backfill materials, such as geofoam, shedded tires, bundled tires, “red dog,” and byproducts from coal-fired power plants. Backfill materials with different unit weights, and existing in a layered system, may be analyzed. To facilitate the use of the approach and make it widely accessible to Cabinet engineers, and as a second major objective, the theoretical algorithms were programmed in a windows computer program and stored in the Kentucky Geotechnical Database. The twelve highway district offices and main central offices of the Cabinet are connected in a client server system. For a selected factor of safety, the program predicts the success of drilled-in rails so that the user may avoid using this technique when the factor of safety is not adequate to prevent failure. However, when failure is predicted using the unit weights of ordinary soil, or rock, backfill, the program shows the thickness of geofoam (or other lightweight material) necessary to increase the factor of safety to value greater than one. The program has been checked by comparing results with results obtained from a program written by KyTC. Several examples are performed to illustrate the use of the new computer program

Resilient Modulus of Kentucky Soils

In recent years, the American Association of State Highway Transportation Officials (AASHTO) has recommended the use of resilient modulus for characterizing highway materials for pavement design. This recommendation evolved as of a result of a trend in pavement design of using mechanistic models, which are based on the theory of elasticity (layered elastic analysis) or linear and non-linear, finite elements (and finite difference methods), or a combination of both of those theoretical approaches. Although much progress has been made in recent years in developing mathematical, mechanistic pavement design models, results obtained from those models are only as good as the material parameters used in the models. Resilient modulus of the subgrade soil is an important parameter in the mechanistic models and in the 1993 AASHTO pavement design equation. The main goal of this study was to establish a simple and efficient means of predicting the resilient modulus of any given type of Kentucky soil. To accomplish this purpose, 128 tests were performed on several different soil types from various locations of Kentucky. Specimens were remolded to simulate compaction conditions encountered in the field. Tests were performed on soaked and unsoaked specimens so that an assessment could be made of the affect of moisture on resilient modulus values. Vast differences were found between soaked and unsoaked values of resilient modulus. Based on an analysis of the data, a new mathematical model is proposed which relates resilient modulus to any given selected, or calculated, principal stresses in the subgrade. This model improves the means of obtaining best data “fits” between resilient modulus and stresses. Furthermore, if the AASHTO classification and group index are known, than the resilient modulus of the soil can be predicted from the new model for any known stress condition in the subgrade. Multiple regression analysis was used to obtain relationships between resilient modulus and confining stress and deviator stress. No difficulties were encountered in testing “as-compacted” (unsoaked) samples. Values of R2 of 91 percent of unsoaked test specimens were greater than, or equal to, 0.87. However, values of R2 of only 35 percent of tested, soaked samples exceeded 0.87. Difficulties were encountered in testing soaked specimens. More research is needed to test saturated, or nearly saturated, soil specimens—conditions that often exist in the field. To make the resilient modulus data and the new model readily available to design personnel of the Kentucky Transportation Cabinet, a “windows” computer software application was developed in a client/server environment. This program is embedded in the Kentucky Geotechnical Database, which resides on a Cabinet server in Frankfort, Kentucky. The resilient predictor model and data are readily available to pavement design personnel statewide

Highway Rock Slope Management Program

Development of a comprehensive geotechnical database for risk management of highway rock slope problems is described. Computer software selected to program the client/server application in windows’ environment, components and structure of the geotechnical database, and some of the primary factors considered in constructing the database are discussed. In the establishment of a large database that will be used widely, it is extremely important to select development software that will allow simultaneous use of the database by numerous users. Major integrated components of the database include rock slope, landslide, and soil and rock engineering data. This report mainly focuses on the rock slope component. The rock slope database program provides procedures for gathering field data and rating the hazardous conditions of rock slopes. Secondary components of the database include statistical analyzers and engineering applications for performing “on-line” analysis of data, developing correlations between different soil parameters, and performing engineering analysis and designs. Procedures for entering historical soil and rock engineering data have been developed and programmed. Methods for “capturing” geotechnical data in a “real-time” mode, which will allow the storage of geotechnical data as it is generated, are currently being programmed. Issues concerning database security, engineering units, and storing and displaying maps, graphics, and photographs are discussed. The database contains procedures for dynamically overlaying the locations of landslides, rock slopes, and borings onto embedded roadway and digitized geological maps. Latitudes and longitudes of rock slopes and landslides were determined using Global Positioning System equipment (sub-meter accuracy). Strategies and illustrations of graphical user interfaces for data entry and retrieval are discussed. About 2086, potentially hazardous, rock slopes were rated numerically using the Rock Fall Hazard Rating system developed by the Oregon Department of Transportation and sponsored by the Federal Highway Administration (FHWA). A priority list of hazardous rock slopes can be generated rapidly

Long-Term Benefits of Stabilizing Soil Subgrades

Chemical admixtures have been used extensively since the mid-eighties in Kentucky to improve bearing strengths of soil subgrades. Most pavements in Kentucky are constructed on clayey soils. Although short-term observations at a small number of sites showed that chemical stabilization worked very well, a need existed to perform a more comprehensive review and to assess the long-term benefits of this subgrade stabilization method. The main intent of this study was an attempt to address questions concerning bearing strengths, longevity, durability, structural credit, economics, and performance of pavements resting on soil subgrades mixed with chemical admixtures. In-depth field and laboratory studies were performed at fourteen roadway sites containing twenty different treated subgrade sections. Ages of the sites range from about 8 to 15 years. About 455 borings were made at the various sites. Air, instead of water, was used as the drilling media. In-situ CBR tests were performed on the treated subgrades and the untreated subgrades lying directly below the treated layers. Index tests and resilient modulus tests were performed on samples collected from the treated and untreated subgrades. Falling weight deflectometer (FWD) tests were performed. At the 85th percentile test value, the in situ CBR values of subgrades mixed with hydrated lime, Portland cement, a combination of hydrated lime and Portland cement, and a byproduct (MKD) obtained in the production of hydrated lime were 12 to 30 times greater than in CBR values of the untreated subgrades. In-situ CBR values of the treated layer ranged from 24 to 59 while the in-situ CBR of the untreated layer at the 85th percentile test value was only 2. Based on rating criteria of the Kentucky Transportation Cabinet, the conditions of the pavements at twelve sites could be rated “good” at the time of the study– pavement ages were 8 to 15 years– and “good” at the end of the twenty-year design period, based on projected data. At two sites, thin asphalt overlays had been constructed after 15 years. However, accumulated values of ESAL at those sites had exceeded or were near the values of ESAL assumed in the pavement designs. At the 20th percentile test value, rutting depths of the pavements resting on the treated subgrades were less than about 0.27 inches. Structural layer coefficients, a3, for use in pavement design of the different chemically stabilized subgrades were developed. The proposed values were verified at sites where reduced pavement thickness was used and “in service” structural coefficients could be observed. Back-calculated values of FWD modulus of the treated layers were about two times the values of modulus of the untreated subgrade. Resilient modulus of the treated subgrades was larger than the resilient modulus of the untreated subgrades. Moisture contents at the top of the untreated subgrade layers showed that a “soft” layer of material exists at the very top of the untreated subgrade. This soft zone did not exist at the top of the treated layer. This discovery has significant engineering implications. Future research will focus attention on an in-depth examination of this weak layer of soil. Chemical admixture stabilization is a good, durable and economical technique for improving subgrade strengths

Genetic polymorphisms in ZFHX3 are associated with atrial fibrillation in a Chinese Han population.

The gene zinc finger homeobox 3 (ZFHX3) encodes a transcription factor with cardiac expression and its genetic variants are associated with atrial fibrillation (AF). We aimed to explore the associations between single nucleotide polymorphisms (SNPs) of ZFHX3 and the risk of AF in a Chinese Han population.We genotyped eight SNPs, including seven potentially functional SNPs and one previously reported SNP by using the middle-throughput iPLEX Sequenom MassARRAY platform. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated in logistic regression models.We enrolled a total of 1,593 Chinese Han origin individuals in the study, including 597 AF patients and 996 non-AF controls. Logistic regression analyses revealed that potentially functional SNPs rs6499600 and rs16971436 were associated with a decreased risk of AF (adjusted OR  = 0.73, 95% CI: 0.63-0.86, P = 1.07×10-4; adjusted OR  = 0.74, 95% CI: 0.56-0.98, P = 0.039, respectively). In addition, rs2106261 showed a robust association with an increased risk of AF (adjusted OR  = 1.71, 95% CI: 1.46-2.00, P = 1.85×10-11). After multiple comparisons, rs16971436 conferred a borderline significant association with the risk of AF. Stratification analysis indicated that the risks of AF were statistically different among subgroups of age for rs2106261, and the effect for rs16971436 was more evident in subgroups of patients with coronary artery disease.In summary, our study investigated the role of genetic variants of ZFHX3 in AF and two SNPs (rs2106261, rs6499600) showed significant associations while rs16971436 conferred a borderline significant association with AF risk in Chinese Han populations. However, further large and functional studies are warranted to confirm our findings

A smartphone-based crowd-sourced real-time surveillance platform (apple snail inspector) for the invasive snails: a design and development study

Abstract Background The large amphibious freshwater apple snail is an important invasive species in China, but there is currently no method available for their surveillance. The development and popularization of smartphones provide a new platform for research on surveillance technologies for the early detection and effective control of invasive species. Methods The ASI surveillance system was developed based on the infrastructure of the WeChat platform and Amap. The user can directly enter the game interface through the WeChat port on their mobile phone, and the system automatically obtains their location. The user can then report the location of apple snails. The administrator can audit the reported information, and all information can be exported to Microsoft Excel version 2016 for analysis. The map was generated by ArcGIS 10.2 and was used to characterize the spatial and temporal distribution of apple snails in Jiangsu Province. Results The architecture of ASI consists of three parts: a mobile terminal, a server terminal and a desktop terminal. We published more than 10 tweets on the official WeChat account of the system to announce it to the public, and a total of 207 users in 2020 and 2021 correctly reported sightings of apple snails. We identified 550 apple snails breeding sites in 2020 and 2021, featuring ponds (81%), parks (17%) and farmland (2%). In addition, most of the locations contained snail eggs, and the reporting times mainly occurred between May and September. Conclusions The ASI is an effective surveillance system that can be used to identify the breeding locations of apple snails and provides the basis of prevention and control for its dispersal. Its successful development and operation provide new potential avenues for surveillance of other public health issues. Graphical Abstrac

One-year characterization of organic aerosol markers in urban Beijing: Seasonal variation and spatiotemporal comparison

Organic aerosol (OA) is a major component of fine particulate matter (PM); however, only 10%-30% of OA have been identified as individual compounds, and some are used as markers to trace the sources and formation mechanisms of OA. The temporal and spatial coverage of these OA markers nonetheless remain inadequately characterized. This study presents a year-long measurement of 92 organic markers in PM2.5 samples collected at an urban site in Beijing from 2014 to 2015. Saccharides were the most abundant (340.1 ng m(-3)) species detected, followed by phthalic adds (283.4 ng m(-3)). In summer, high proportions (8%-24%) of phthalic acids, n-alkanes, fatty acids, and n-alcohols indicate dominant contributions of biogenic emission and atmospheric oxidation to OA in Beijing. In winter, when anthropogenic sources prevail, saccharides, polycyclic aromatic hydrocarbons, and hopanes are more prominent (4%-25%). The spatial distributions of these OA markers in China show higher concentrations in northern cities (mainly from coal combustion and biomass burning) than in southern cities (mainly from vehicular emission). The inter-annual variations of OA markers, except for hopanes, from 2001 to 2015 suggest significant alleviation of the primary OA pollution in Beijing, with an average reduction of 35%-89% compared with those before 2008. The diagnostic ratio analyses between OA markers indicate that contributions from coal combustion and biomass burning decreased, whereas those from vehicular emission increased. Increasingly large vehicle fleets have increased hopane concentrations since 2008, but the levels were 35% lower in 2015 than those in 2010-2011 because of the tightening of emission controls for vehicles. This study provides a long-term and geographical comparison (from Beijing to other locations in China and beyond) of OA markers, demonstrating the temporal and spatial variations in primary OA, and calls for more studies on secondary OA. (C) 2020 Elsevier B.V. All rights reserved

Summary of associations between 8 SNPs in <i>ZFHX3</i> and the risk of AF.

<p>SNP, single nucleotide polymorphism; AF, atrial fibrillation; MAF, minor allele frequency; <i>P</i>_HWE, <i>P</i> values for Hardy–Weinberg equilibrium tests in control groups; OR odds ratio; CI confidence interval.</p>a<p>Individuals homozygous for the minor allele/heterozygous/homozygous for the major allele.</p>b<p>OR (95%CI) and <i>P</i> values were derived from logistic regression analysis in the additive model adjusting for age, gender, hypertension, diabetes and coronary artery disease.</p>c<p>Multiple comparisons <i>P</i> values for false discovery rate.</p