Summary of Illinois Regulations and Review of Treatment Alternatives for Contaminated Soils in Right-of-Ways

Industrial activities and vehicular transportation often pollute roadside soils with toxic mixtures of petroleum derivatives, combustion byproducts, and metal contaminants. Of these contaminants, semi-volatile organic compounds and metallic inorganics are commonly present at levels exceeding regulatory limits and require special handling if found in land to be acquired by the Illinois Department of Transportation (IDOT) for right-of-way (ROW). The objective of this review was to investigate various on-site and in situ treatment alternatives capable of remediating soil contaminated with high-molecular-weight polycyclic aromatic hydrocarbons and/or metals. Current environmental laws, regulations, and remediation best management practices were also reviewed as they pertain to contaminated soils in construction ROWs. The goal of the review was to provide IDOT with the information needed to reexamine the current practice of hauling contaminated soil off site for disposal at sites where contemporary technologies can achieve reductions in cost, time, and nuisance. The ultimate goal was to evaluate both conventional and emerging technologies adaptable for use at construction sites in Illinois, capable of treating soil to the extent it may be reused as fill material in line with state and federal regulations. Findings from this review were used to develop an experimental program and recommend effective on-site treatment options to minimize the generation of non-special, special, and hazardous wastes. The suggested treatments herein are conditionally cost-effective processes that minimize construction delays while demonstrating respect for the environment.IDOT-R27-183-HSOpe

Bio-inspired geotechnical engineering: Principles, current work, opportunities and challenges

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Bio-inspired geotechnical engineering: principles, current work, opportunities and challenges

A broad diversity of biological organisms and systems interact with soil in ways that facilitate their growth and survival. These interactions are made possible by strategies that enable organisms to accomplish functions that can be analogous to those required in geotechnical engineering systems. Examples include anchorage in soft and weak ground, penetration into hard and stiff subsurface materials and movement in loose sand. Since the biological strategies have been ‘vetted’ by the process of natural selection, and the functions they accomplish are governed by the same physical laws in both the natural and engineered environments, they represent a unique source of principles and design ideas for addressing geotechnical challenges. Prior to implementation as engineering solutions, however, the differences in spatial and temporal scales and material properties between the biological environment and engineered system must be addressed. Current bio-inspired geotechnics research is addressing topics such as soil excavation and penetration, soil–structure interface shearing, load transfer between foundation and anchorage elements and soils, and mass and thermal transport, having gained inspiration from organisms such as worms, clams, ants, termites, fish, snakes and plant roots. This work highlights the potential benefits to both geotechnical engineering through new or improved solutions and biology through understanding of mechanisms as a result of cross-disciplinary interactions and collaborations

Post-Wildfire Stability and Improvement of Hillslopes near Pacific Northwest Transportation Infrastructure to Increase Mobility

An increased incidence of wildfires followed by a wet season in the Pacific Northwest of the United States has resulted in surficial stability issues (erosion, shallow landslides). If a wetting-induced shallow landslide occurs on a highway embankment or on a natural hillslope near Pacific Northwest infrastructure, in addition to human life and property loss, there are significant economic consequences when hillslope material blocks the highway, damages the transportation infrastructure, and thus reduces mobility. This study updated an existing slope stability model (level one stability analysis, LISA) by incorporating suction stress and then tested the model performance by estimating the landslide susceptibility of a past landslide. In addition, the study tested the effect of surficial application of a soil stabilizer (xanthan gum) on the shear strength of subsurface soil. The results showed that 2.8 g of xanthan gum applied on the soil surface (68.5 cm x 68.5 cm) reduced erosion by 2.9 times and increased runoff only by ~12 percent, while also increasing the normal stress-shear stress behavior of the subsurface soil at the end of three wetting events.Pacific Northwest Transportation Consortium US Department of Transportation Washington State Universit

CLAY SURFACE PROPERTIES BY WATER VAPOR SORPTION METHODS

ABSTRACT Classification of expansive soils is a required component of geotechnical design to improve the long-term performance of structures. The current methods to classify swelling soils are based primarily on indices like the Atterberg limits, which are indirectly related to clay mineralogy and clay structure. The long-term goal of this research is to explore alternative ways to classify clays and to modernize geotechnical soil classification methods using measurement and analysis techniques based on clay surface properties. Clay surface properties such as specific surface area (SSA) and cation exchange capacity (CEC) are indicative of the clay mineralogy. For expansive clays, interactions of the clay surface with water molecules influence behavior. Consequently, water vapor sorption methods may potentially be used to determine clay surface properties. SSA is the measure of surface area per unit mass (m2/g). SSA measurement methods can be classified into three main categories: physical methods, positive adsorption methods, and negative adsorption methods. The most common techniques are positive sorption methods, where the sorption of molecules on the surface is measured. The sorbates can be either polar (e.g., N2) or non-polar (e.g., Ethylene Glycol Monoethyl Ether (EGME), water vapor). CEC is a measure of exchangeable mineral charge. Common measurement techniques include those based on replacing the cations in the natural exchange complex with a known cation species (e.g., ammonium displacement method) A water vapor sorption isotherm characterizes the relationship between relative humidity (RH) and the equilibrium moisture content of some material in that environment obtained along an adsorption (wetting) or desorption (drying) path at some temperature. A water vapor sorption isotherm is equivalent to a soil water characteristic curve (SWCC) since RH and soil suction can be directly related by Kelvin?s equation. A sorption isotherm, therefore, is a direct measurement of how the physical and chemical interactions between water and the soil surface result in water retention, and thus is an indirect measurement of the fundamental compositional and surface properties of the material (mineralogy, SSA, CEC). In the first chapter of this thesis SSA values obtained by Brunauer-Emmett-Teller (BET) Theory are determined from water vapor sorption isotherms obtained at low relative humidity values, and compared with values obtained using the more conventional EGME retention method. Thirteen samples of natural clayey soils and a suite of mixtures of end member Wyoming bentonite and Georgia kaolinite are tested. Additional comparisons are made for a suite of Mg+2, Ca+2, Na+, K+, and Li+-saturated forms of the bentonite to examine influences of exchangeable cation type and to extend the possible range of water vapor sorption isotherms over a wide range. The second chapter examines the performance and applicability of six existing isotherm models (Freundlich, Brunauer-Emmett-Teller, Frenkel-Halsey-Hill, Guggenheim-Anderson-de Boer, Double Log Polynomial, and Dubinin-Astakhov) for representing the water vapor sorption behavior of clayey soils. Dry mixtures of Wyoming bentonite and Georgia kaolinite are tested to cover a wide range of possible isotherms. Trends observed in the equation parameters with increasing bentonite content are discussed and analyzed separately for adsorption and desorption processes. In the third chapter, an original empirical method is proposed to indirectly estimate the CEC of clayey soils based on relatively simple water vapor sorption measurements. A master curve is obtained from measured water vapor sorption isotherms of 24 clayey soil samples. The validation of the proposed method is independently tested using twelve samples of natural clayey soils and nine water vapor sorption isotherms available in the literature

SHEAR STRENGTH AND STIFFNESS BEHAVIOR OF FINE-GRAINED SOILS AT DIFFERENT SURFACE HYDRATION CONDITIONS

We developed an experimental program to monitor how interparticle forces control fine-grained soils' mechanical behavior when saturation changes from the tightly adsorbed regime to saturation. The testing program uses stiffness (i.e., S-wave velocity) and strength (i.e., Brazilian tensile strength) tests on kaolinite, silica flour, and diatomaceous earth soil samples at very low confining stresses (The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Success-Breeds-Success in Collective Political Behavior: Evidence from a Field Experiment

Scholars have proposed that the emergence of political movements is highly pathdependent, such that early mobilization successes may lead to disproportionately greater eventual success. This article replicates a unique field experiment testing for positive feedback in internet petition signing (van de Rijt et al. 2014). The prior study found no significant effect of signatures bestowed by the experimenters on the signing rate of 200 online petitions posted to a political petitions website (http://www.change.org), but this may have lacked power because of its sample size and variation across petitions. We report on results of a new field experiment in which we posted 400 petitions differing only in tightly controlled ways to the same website, varying the number of experimentally bestowed signatures across a wider range than in the original experiment. Subsequent petition signing increased monotonically with the treatment, confirming the presence of positive feedback. These results support the existence of success-breeds-success dynamics in the mobilization of collective political behavior, confirming that early success can increase the attractiveness of collective action to potential supporters. However, while significant, the effect of prior signatures was small, suggesting that cumulative advantage effects resulting from popularity metrics may play a minor role in collective action outcomes

Success-Breeds-Success in Collective Political Behavior: Evidence from a Field Experiment

Scholars have proposed that the emergence of political movements is highly pathdependent, such that early mobilization successes may lead to disproportionately greater eventual success. This article replicates a unique field experiment testing for positive feedback in internet petition signing (van de Rijt et al. 2014). The prior study found no significant effect of signatures bestowed by the experimenters on the signing rate of 200 online petitions posted to a political petitions website (http://www.change.org), but this may have lacked power because of its sample size and variation across petitions. We report on results of a new field experiment in which we posted 400 petitions differing only in tightly controlled ways to the same website, varying the number of experimentally bestowed signatures across a wider range than in the original experiment. Subsequent petition signing increased monotonically with the treatment, confirming the presence of positive feedback. These results support the existence of success-breeds-success dynamics in the mobilization of collective political behavior, confirming that early success can increase the attractiveness of collective action to potential supporters. However, while significant, the effect of prior signatures was small, suggesting that cumulative advantage effects resulting from popularity metrics may play a minor role in collective action outcomes