abstract: The experience base of practitioners with expansive soils is largely devoid of directly measured soil suction. This historical lack of soil suction measurement represents an impediment to adoption of modern unsaturated soil engineering to problems of expansive soils. Most notably, soil suction-based analyses are paramount to proper design of foundations in expansive soils. Naturally, the best method to obtain design suction profiles is to perform an appropriate geotechnical investigation that involves soil moisture change-appropriate drilling depths, sampling intervals, and requisite laboratory testing, including suction measurement. However, as practitioners are slow to embrace changes in methodology, specifically regarding the adoption of even relatively simple suction measurement techniques, it has become imperative to develop a method by which the routine geotechnical procedures currently employed can be used to arrive at acceptable approximations of soil suction profiles. Herein, a substitute, or surrogate, for soil suction is presented, such that the surrogate agrees with observed field soil suction patterns and provides estimates of soil suction that are acceptable for use in practice. Field investigations with extensive laboratory testing, including direct suction measurement, are used in development of the soil suction surrogate. This surrogate, a function of water content and routinely measured soil index properties, is then used in estimation of field expansive soil suction values. The suction surrogate, together with existing geotechnical engineering reports, is used to augment the limited existing database of field soil suction profiles. This augmented soil suction profile database is used in development of recommendations for design suction envelopes and design suction profiles. Using the suction surrogate, it is possible to proceed from the beginning to the end of the Suction-Oedometer soil heave/shrinkage analysis without directly measuring soil suction. The magnitude of suction surrogate-based heave estimates is essentially the same as heave estimates obtained using direct soil suction measurements. The soil suction surrogate-based approach, which uses a complete-stress-state approach, considering both net normal stress and soil suction, is an intermediate step towards the adoption of unsaturated soil engineering in expansive soils analyses, wherein direct soil suction measurements are routinely made. / Dissertation/Thesis / Doctoral Dissertation Civil, Environmental and Sustainable Engineering 2019

Submitted by Mayara Nicolau Ferreira null (mayara_feni@outlook.com) on 2017-12-13T19:33:50Z No. of bitstreams: 1 Dissertação final para o cd.pdf: 8263943 bytes, checksum: a933228a9bd4ca5a348d316c828ae92d (MD5) / Submitted by Mayara Nicolau Ferreira null (mayara_feni@outlook.com) on 2017-12-14T11:25:01Z No. of bitstreams: 1 Dissertação final para o cd.pdf: 8263943 bytes, checksum: a933228a9bd4ca5a348d316c828ae92d (MD5) / Submitted by Mayara Nicolau Ferreira null (mayara_feni@outlook.com) on 2017-12-14T13:50:30Z No. of bitstreams: 1 Dissertação final para o cd.pdf: 8263943 bytes, checksum: a933228a9bd4ca5a348d316c828ae92d (MD5) / Approved for entry into archive by Adriana Aparecida Puerta null (dripuerta@rc.unesp.br) on 2017-12-14T16:02:31Z (GMT) No. of bitstreams: 1 ferreira_mn_me_rcla.pdf: 8244618 bytes, checksum: f6eec6ad55c4fa070d073f0df07c532a (MD5) / Made available in DSpace on 2017-12-14T16:02:31Z (GMT). No. of bitstreams: 1 ferreira_mn_me_rcla.pdf: 8244618 bytes, checksum: f6eec6ad55c4fa070d073f0df07c532a (MD5) Previous issue date: 2017-10-26 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Considerando o crescente número de acidentes com produtos perigosos em rodovias e que este é o modal mais utilizado para o transporte de cargas no Brasil, principalmente hidrocarbonetos e derivados de petróleo. Bem como, os insipientes estudos de índices de sensibilidade ambiental para ambientes terrestres. E que os mapas de sensibilidade são importantes ferramentas técnico-gerenciais utilizadas na tomada de decisões emergenciais em caso de combate a derrames de óleo. Além de fornecer informações para o planejamento de contenção e limpeza para mitigar os impactos ambientais, auxiliar a identificação de locais sensíveis antes que ocorra o acidente, de modo que as estratégias de proteção e contenção possam ser organizadas antecipadamente, objetiva-se a confecção de um índice de sensibilidade ambiental aos hidrocarbonetos para rodovias, utilizando como área de estudo um trecho da Rodovia Anhanguera (SP-330), segunda maior em números de acidentes com produtos perigosos no estado de São Paulo, e sua respectiva carta de sensibilidade ambiental. Para tanto, procede-se fazendo uso de geotecnologias para confecção de mapas básicos necessários a pesquisa; da compartimentação fisiográfica para dividir a área de estudo em zonas homólogas; do trabalho de campo para corroborar a compartimentação; da escolha dos cinco parâmetros e seus respectivos pesos, que compõem o índice de sensibilidade ambiental aos hidrocarbonetos para rodovias; e consequentemente, a confecção da carta de sensibilidade ambiental. Desse modo, observa-se que no trecho foram encontrados os índices 5, 7 e 8, sendo que o índice 7 é predominante em seis das oito Unidade Básicas de Compartimentação, o que permite concluir que a área estudada tem média-alta sensibilidade ambiental, levando em consideração que o índice vai de 1 a 10 A. Além de colaborar com o desenvolvimento de uma adaptação do método das cartas SAO utilizadas em ambientes costeiros e fluviais para um índice de sensibilidade ambiental aos hidrocarbonetos para rodovias. Por fim, conclui-se que o mapeamento de sensibilidade ambiental aos hidrocarbonetos para o modal rodoviário apresenta-se viável a partir da aplicação de um método adequado ao ambiente em que está inserido e o método da compartimentação fisiográfica foi extremamente apropriado e eficaz para os ambientes terrestres. / Considering the increasing number of accidents with hazardous products on highways and that this is the most used modal for the transport of cargoes in Brazil, mainly hydrocarbons and petroleum products. As well as, the insipient studies of environmental sensitivity indexes for terrestrial environments. And that sensitivity maps are important technical and managerial tools used in making emergency decisions in case of combating oil spills. In addition to providing information for containment and cleanup planning to mitigate environmental impacts, assisting the identification of sensitive locations before the accident occurs, so that protection and containment strategies can be organized in advance, it is aimed to create an Index of environmental sensitivity to hydrocarbons for highways, using as an area of study a section of the Anhanguera Highway (SP-330), second largest in numbers of accidents with dangerous products in the state of São Paulo, and its respective letter of environmental sensitivity. To do so, we make use of geotechnologies to create basic maps necessary for the research; the physiographic compartmentalization to divide the study area into homologous zones; the fieldwork to corroborate the compartmentalization; the choice of the five parameters and their respective weights, which make up the environmental sensitivity index for hydrocarbons for highways; and consequently, the preparation of the environmental sensitivity letter. Therefore, it can be observed that the indexes 5, 7 and 8 were found in this section, with index 7 being predominant in six of the eight Basic Compartmental Units, which allows to conclude that the studied area has medium-high environmental sensitivity, taking into account that the index ranges from 1 to 10 A. In addition to collaborating with the development of an adaptation of the SAO letters used in coastal and fluvial environments to an environmental sensitivity index to hydrocarbons for highways. Finally, it is concluded that the mapping of environmental sensitivity to hydrocarbons for the road modal is feasible from the application of a method appropriate to the environment in which it is inserted and the physiographic compartmentalization method was extremely appropriate and effective for the land environments.

Orientador: Sergio dos Anjos Ferreira Pinto / Banca: Antonio Marcos Machado de Oliveira / Banca: Archimedes Perez Filho / Resumo: Dentre as diversas formas de erosão, a erosão laminar é um dos principais processos de degradação do solo, acarretando sérios danos ao setor produtivo. Este processo pode ser intensificado devido ao uso inadequado que o homem faz da terra, em especial, nas áreas agrícolas. Para minimizar a degradação ambiental, bem como promover o desenvolvimento sócio-econômico, é necessário a elaboração de um planejamento territorial que vise a manutenção da qualidade do ambiente físico, biológico e social. Tendo a bacia hidrográfica como unidade natural para o planejamento, deve-se considerar que nela estão contidas propriedades rurais, que representam grande barreira ao desenvolvimento das práticas exigidas para a sua gestão, além de colaborar com o processo de erosão dos solos. Neste contexto, a presente pesquisa teve como objetivo estimar o aporte de sedimentos, resultante da erosão hídrica laminar do solo, considerando a fragmentação da área da bacia hidrográfica do ribeirão Monjolo Grande (SP), em termos das propriedades rurais nela contidas, com apoio do modelo preditivo Modificação da Equação Universal de Perda de Solo (MEUPS) e das técnicas de Sensoriamento Remoto e Sistemas de Informações Geográficas. Os resultados obtidos indicaram que a perda relativa de solo por propriedade é dinâmica no tempo e no espaço, de modo que aquela que apresenta, em relação a outras propriedades, porcentagens elevadas de perda no período chuvoso, não necessariamente manterá a taxa relativa na época de estiagem. Observou-se também que a bacia apresenta elevado grau de sensibilidade ao manejo agrícola das terras, sendo que 13 propriedades rurais (que correspondem a 72% da área da bacia) apresentaram alto potencial a processos erosivos, com perdas de solo acima de limites toleráveis, condicionado pela influência antrópica na área / Abstract: Among various forms of erosion, the laminate erosion is a major soil degradation processes, causing serious damage to the productive sector. This process can be intensified due to inappropriate use man makes of the land, especially in agricultural areas. For to minimize environmental degradation and promote socio-economic development, it is necessary to elaborate a regional planning aimed at maintaining the quality of the physical, biological and social. Considering the watershed as a natural unit for planning, one should consider that it is contained rural properities, which represent cumber to the development of the practices required to manage, and collaborate with the process of soil erosion. In this context, the goal this research has estimate yields of sediment resulting from soil erosion laminar, considering the fragmentation of the area's Monjolo Grande (SP) watershed in terms of rural properties contained therein, with support from predictive model of Modified Universal Soil Loss Equation (MUSLE) and the remote sensing and geographic information systems. The results indicated that the relative loss of soil from properties is dynamic in time and space, so that it presents, in relation to other properties, high percentages of loss in the rainy season, not necessarily maintain the relative rate at the time of drought. It was also noted that the watershed has a high sensibility to agricultural management of land, with 13 farms (which represent 72% of the basin area) showed high potential erosion, soil losses above tolerable limits, conditioned by human influence in the area / Mestre

Submitted by Socorro Pontes (socorrop@ufersa.edu.br) on 2016-11-07T13:56:26Z No. of bitstreams: 1 HermínioSOJ_DISSERT.pdf: 5693282 bytes, checksum: 45e6daa99caecacf106da7ec8f534e50 (MD5) / Rejected by Vanessa Christiane (referencia@ufersa.edu.br), reason: TCC de mestrado e trocar arquivo on 2016-11-07T14:16:00Z (GMT) / Submitted by Socorro Pontes (socorrop@ufersa.edu.br) on 2016-11-09T12:00:24Z No. of bitstreams: 1 HermínioSOJ_DISSERT.pdf: 5693282 bytes, checksum: 45e6daa99caecacf106da7ec8f534e50 (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2016-11-14T13:29:09Z (GMT) No. of bitstreams: 1 HermínioSOJ_DISSERT.pdf: 5693282 bytes, checksum: 45e6daa99caecacf106da7ec8f534e50 (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2016-11-14T13:29:24Z (GMT) No. of bitstreams: 1 HermínioSOJ_DISSERT.pdf: 5693282 bytes, checksum: 45e6daa99caecacf106da7ec8f534e50 (MD5) / Made available in DSpace on 2017-03-21T14:56:14Z (GMT). No. of bitstreams: 1 HermínioSOJ_DISSERT.pdf: 5693282 bytes, checksum: 45e6daa99caecacf106da7ec8f534e50 (MD5) Previous issue date: 2016-06-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Water resources are essential elements for life and environmental modifiers processes, therefore be aware of the current situation can ensure efficient management that makes possible a more sustained use. Groundwaters have a great importance for the development of human activities. They play a crucial role in supplying the cities and as well as in the private sector, with the most different uses, both in urban centers and rural communities, as well as in private residential autonomous systems, industries, services, agricultural irrigation and recreation. This study aimed to the analysis of groundwater quality distributed to the population of the urban area of Mossoro-RN. The samples were collected in 16 active wells that are part of the water supply system in the urban area of the city of Mossoro and the analyzes were performed in the quality lab of water of Rio Grande do Norte's Water and Sewerage Company – CAERN in Natal city. The wells with lower dynamic levels are the PT - 02 PT - 23 PT - 20. These are located on the left riverbank and have previous drilling dates to 1980, since the wells with higher turbidity values were PT - 8 PT - 11 and PT - 14. We found a very strong and positive correlation between the EC with chloride, sulphates and STD. All the values found in the physical-chemical analyzes of water from 16 wells were below the maximum allowed by Ordinance No. 2,194 / 2011 of the Health Ministry classified as suitable for human consumption. The aid of geotechnology facilitated in data interpretation to show quickly the spatial variables through interpolation and maps, and may help in decision making. A Geographic Information System – GIS can improve the interpretation of the analyzes behavior of water quality in wells, in addition to decreasing the time spent and storage space, since the paper sheets would be replaced by a database / Os recursos hídricos são elementos essenciais para a vida e para os processos modificadores do ambiente, por isso ter conhecimento da atual situação pode garantir uma gestão eficiente que torne possível o uso mais sustentável. As águas subterrâneas possuem uma grande importância para desenvolvimento das atividades humanas. Elas exercem papel fundamental no abastecimento nas cidades e assim como no setor privado, com os mais diferenciados usos, tanto nos centros urbanos como nas comunidades rurais e, também, como em sistemas autônomos residenciais privados, indústrias, serviços, irrigação agrícola, turismo e lazer. O presente trabalho teve como objetivo geral a análise da qualidade da água subterrânea distribuída à população da área urbana de Mossoró-RN. As amostraras foram coletadas nos 16 poços ativos que fazem parte do sistema de abastecimento de água na zona urbana da cidade de Mossoró e as análises das foram realizadas no laboratório de qualidade de água da Companhia de Águas e Esgotos do Rio Grande do Norte – CAERN. Os poços com menores níveis dinâmicos são os PT – 02, PT – 23, PT – 20. Esses estão localizados à margem esquerda do rio, e possuindo datas de perfuração anterior a 1980. Já os poços com maiores valores de turbidez foram PT - 8, PT – 11 e PT – 14. Constatou-se uma fortíssima e positiva correlação entre a CE com Cloreto, sulfatos e STD Todos os valores encontrados nas análises físico-química das águas dos 16 poços ficaram abaixo dos máximos permitidos na Portaria nº 2.194/2011 do Ministério da Saúde enquadradas como adequadas para o consumo humano. O auxílio das geotecnologias facilitou na interpretação dos dados de modo a mostrar de forma rápida e eficiente a espacialização das variáveis, através da interpolação e dos mapas, podendo auxiliar nas tomadas de decisões. Um Sistema de Informações Geográficas - SIG pode melhorar a interpretação das análises do comportamento da qualidade da água dos poços, além de diminuir o tempo gasto e espaço de armazenamento, já que as planilhas de papel seriam substituídas por um banco de dados / 2016-10-18

Orientador: Roberto Wagner Lourenço / Resumo: Os estágios de sucessão dos fragmentos florestais podem ser avaliados por diferentes procedimentos e variáveis, entretanto requerem bastante tempo e esforços de trabalhos em campo, além de elevados custos e pessoal qualificado para sua avaliação. Diversas pesquisas propõem métodos alternativos, utilizando técnicas de geoprocessamento e o sensoriamento remoto, porém observa-se a necessidade de incorporar novos métodos para essa avaliação, visando aprimorar e reduzir os custos de levantamento de dados. A presente pesquisa teve por objetivo estudar fragmentos florestais de Mata Atlântica, priorizando o conhecimento dos estágios de sucessão com o intuito de propor um método de avaliação desses estágios visando contribuir com o planejamento e a gestão ambiental para preservação e conservação dos recursos florestais. A área de estudo foi a Bacia Hidrográfica do Rio Murundú-Paiol, inserida no bioma Mata Atlântica, localizada no município de Ibiúna, São Paulo. Inicialmente a metodologia consistiu na construção de uma base cartográfica de apoio a partir de cartas topográficas do município de Ibiúna/SP (escala 1:10.000), compartimentação morfométrica em três níveis de altitude (baixo, médio e alto), e no mapeamento do uso e cobertura da terra a partir de ortoimagens do sensor Vexcel Ultracam. Do mapeamento do uso e cobertura da terra, foram extraídos os fragmentos florestais para avaliação de suas métricas, bem como para a avaliação do efeito antrópico em seu entorno. Os fragmentos flo... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The stages of succession of the forest fragments can be evaluated by different procedures and variables, however they require a lot of time and fieldwork efforts, as well as high costs and qualified personnel for evaluation. Several researches propose alternative methods, using geoprocessing techniques and remote sensing, but it is necessary to incorporate new methods for this evaluation, in order to improve and reduce the costs of data collection. The present research had the objective to study forest fragments of Atlantic Forest, prioritizing the knowledge of succession stages with the purpose of proposing a method of evaluation of these stages in order to contribute to environmental planning and management for the preservation and conservation of forest resources. The study area was the Murundú-Paiol river watershed, inserted in the Mata Atlântica biome, located in Ibiúna, São Paulo. Initially, the methodology consisted in the composition of a cartographic base of support from topographic maps of the city of Ibiúna/SP (scale 1: 10,000), morphometric subdivision at three levels of altitude (low, medium and high), and in the mapping of land use from orthoimages of the Vexcel Ultracam sensor. From the land use mapping, the forest fragments were extracted to evaluate their metrics, as well as to evaluate the anthropic effect in their environment. The forest fragments were also evaluated for the physical conditions of the terrain (altitude, slope and aspect) and later on their ... (Complete abstract click electronic access below) / Mestre

Made available in DSpace on 2015-12-10T14:22:24Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-07-21. Added 1 bitstream(s) on 2015-12-10T14:28:29Z : No. of bitstreams: 1 000853136.pdf: 3048817 bytes, checksum: b5e652f618cbf824d494a1fad2d1b38e (MD5) / A crescente demanda por água torna imprescindível a adoção de mecanismos que garantam uma gestão mais eficiente desse recurso. As bacias hidrográficas rurais caracterizam-se por apresentar intensa atividade antrópica, onde, dependendo do uso e manejo do solo, pode ocorrer um comprometimento dos recursos hídricos. A parte inicial da bacia do rio Pardo, no município de Pardinho - SP, foi adotada como área territorial para o estudo. A escolha da bacia levou em consideração o fato do rio Pardo ser um importante manancial para vários munícipios da região. Com o objetivo de caracterizar as áreas hidrológicamente homogêneas para o potencial de infiltração da água, bem como para formação do escoamento superficial, adotou-se uma metodologia baseada no uso de geotecnologias, onde foram gerados planos de informação para atributos da paisagem, como: uso e cobertura da terra, solos, declividade, curvatura vertical, curvatura horizontal e geologia. Os atributos foram combinados utilizando álgebra de mapas, mais precisamente, a técnica de combinação linear ponderada, onde cada atributo passou a ser considerado como um fator condicionante à infiltração e escoamento superficial. Aos fatores foram aplicadas funções de pertinência fuzzy, para a sua normalização e a determinação dos pesos pelo método do Processo Hierárquico Analítico. Para a discriminação das áreas mais suscetíveis ao escoamento superficial, denominadas áreas hidrologicamente sensíveis, adotou-se o índice topográfico de umidade, utilizado como uma forma simplificada de espacialização dos padrões de área variável de afluência na bacia. Os resultados indicaram que grande parte da área de estudo possui médio potencial de infiltração (58,1% da área total), seguida por áreas com alto potencial de infiltração (17,8%), sendo esse fortemente influenciado pelos fatores uso e cobertura da terra ... / Growing demand for water makes it necessary to adopt mechanisms to ensure a more efficient management of this resource. The presence of intense anthropic activity characterizes rural watersheds, where, depending on the soil use and management, can promote impairments of water resources. The initial part of Pardo river watershed was adopted as study area, and is located in the county of Pardinho, São Paulo state, Brazil. The choice of this watershed is due the fact that the Pardo river is an important wellspring for many counties of São Paulo state. With the goal to characterize the hydrologically homogenous areas for water infiltration potential, as well as runoff formation, it was adopted a methodology based on the geotechnologies use. For this, there were adopted information layers to landscape attributes, such as land use and land cover, soil, slope, vertical curvature, horizontal curvature and geology. The attributes were combined using map algebra, more precisely, the weighted linear combination technique, where each attribute has been considered as a conditioning factor to infiltration and surface runoff. To the factors were applied fuzzy membership functions for their standardization and the determination of weights through the Analytical Hierarchical Process method. To identify more susceptible areas to runoff, denominated hydrologically sensitive areas, was adopted the topographic wetness index, used as a simplified form of variable source area patterns spatialization in the watershed. The results showed that most of study area has medium ...

Made available in DSpace on 2014-06-11T19:26:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-05-11Bitstream added on 2014-06-13T20:34:06Z : No. of bitstreams: 1 yamasaki_mt_me_bauru.pdf: 2126849 bytes, checksum: 4896e264bafeff1d70577b538318f03e (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A resistividade elétrica vem sendo somada junto aos estudos de investigação geotécnica devido ao seu apelo ambiental, visto que esta técnica se dá por meio da imposição de um fluxo de corrente elétrica em uma amostra de solo, permitindo-se avaliar as condições geológicas locais por um método não destrutivo. A obtenção dessa medida vem sendo somada aos estudos de investigação geotécnica devido ao seu apelo ambiental, otimizando as amostragens e permitindo a avaliação das condições geológicas locais por meio de um método não destrutivo. Dessa maneira, o objetivo dessa dissertação de mestrado é avaliar, em laboratório, o comportamento da resistividade elétrica variando-se o teor de salinidade no fluido de percolação em dois solos tropicais: um arenoso, sedimentar, característico da região de Bauru, e outro argiloso, resultado do intemperismo do Diabásio, proveniente do município de Piracicaba. As análises foram realizadas utilizando-se resultados, dos ensaios de caracterização, compactação, permeabilidade e curva de retenção. o teor de salinidade do fluido foi considerado, tanto na compactação, como na percolação em três concentrações: água destilada, 250 ppm e 500 ppm de NaCI, além de abastecimento, controlando-se o teor de umidade, a compactação, o índice de vazios e o grau de saturação. Os resultados mostraram-se que a resistividade elétrica tende a ser constante no ramo úmido da curva de compactação e também quando o grau de saturação está acima de 80%. Notou-se também que a curva de resistividade versus sucção pode ser divida em dois trechos: o primeiro corresponde às baixas sucções, com a continuidade da água nos poros e resistividade menores; o segundo trecho, que se inicia na primeira entrada de dar, conduz a um nítido aumento nos valores de... / The electrical resitivity of a homogeneous material could be defined as the measurements of the difficult of crossing of the electrical current and it depends of the dimension and type of material. However, when that material is soil, composed by three phases (solid, liquid and gas), this measure is influenced by several factors that could be controlled in laboratory tests. The electrical resistivity has been used geotechnical research studies since this technique improve the sampling of environmental works and allowing the evaluation of local geological conditions through a non-destructive method. Thus, the goal of the study was evaluate the behavior of electrical resistivity of two tropical soils varying the salinity concentration in the percolation fluid: a sandy sediment, characteristic of the Bauru city; a clayey soil, Weathered of Diabase from Piracicaba City. Results of soil mechanics laboratory tests as characterization tests, compaction, permeability and soil-water retention curve were used in the analyses. In both, compaction and permeability tests, the procedure were carried out varying the fluid salinity: distilled water, water supply; 250ppm and 500ppm of NaCi. The moisture content, compaction energy, void ratio and degree of saturation. The tests results showed the rsistivity values tend to be constant in the wet density curve and when the degree of saturation is above 80%. It was also noted that the curve of resistivity suction could be divided into two segments: the first corresponds to low suctions where there is continuity of water in the porous leading to low resistivity values; the second segment begins in the first air entrance, with discountinuous state of pore-water and sa sharphy increase in the resistivity values. The formation factors (FF) were obtained during the permeability tests: 7,5 to the sandy soil and... (Complete abstract click electronic access below)

abstract: In enzyme induced carbonate precipitation (EICP), calcium carbonate (CaCO3) precipitation is catalyzed by plant-derived urease enzyme. In EICP, urea hydrolyzes into ammonia and inorganic carbon, altering geochemical conditions in a manner that promotes carbonate mineral precipitation. The calcium source in this process comes from calcium chloride (CaCl2) in aqueous solution. Research work conducted for this dissertation has demonstrated that EICP can be employed for a variety of geotechnical purposes, including mass soil stabilization, columnar soil stabilization, and stabilization of erodible surficial soils. The research presented herein also shows that the optimal ratio of urea to CaCl2 at ionic strengths of less than 1 molar is approximately 1.75:1. EICP solutions of very high initial ionic strength (i.e. 6 M) as well as high urea concentrations (> 2 M) resulted in enzyme precipitation (salting-out) which hindered carbonate precipitation. In addition, the production of NH4+ may also result in enzyme precipitation. However, enzyme precipitation appeared to be reversible to some extent. Mass soil stabilization was demonstrated via percolation and mix-and-compact methods using coarse silica sand (Ottawa 20-30) and medium-fine silica sand (F-60) to produce cemented soil specimens whose strength improvement correlated with CaCO3 content, independent of the method employed to prepare the specimen. Columnar stabilization, i.e. creating columns of soil cemented by carbonate precipitation, using Ottawa 20-30, F-60, and native AZ soil was demonstrated at several scales beginning with small columns (102-mm diameter) and culminating in a 1-m3 soil-filled box. Wind tunnel tests demonstrated that surficial soil stabilization equivalent to that provided by thoroughly wetting the soil can be achieved through a topically-applied solution of CaCl2, urea, and the urease enzyme. The topically applied solution was shown to form an erosion-resistant CaCO3 crust on fine sand and silty soils. Cementation of erodible surficial soils was also achieved via EICP by including a biodegradable hydrogel in the stabilization solution. A dilute hydrogel solution extended the time frame over which the precipitation reaction could occur and provided improved spatial control of the EICP solution. / Dissertation/Thesis / Doctoral Dissertation Civil and Environmental Engineering 2015

abstract: The dissimilatory reduction of nitrate, or denitrification, offers the potential of a sustainable, cost effective method for the non-disruptive mitigation of earthquake-induced soil liquefaction. Worldwide, trillions of dollars of infrastructure are at risk for liquefaction damage in earthquake prone regions. However, most techniques for remediating liquefiable soils are either not applicable to sites near existing infrastructure, or are prohibitively expensive. Recently, laboratory studies have shown the potential for biogeotechnical soil improvement techniques such as microbially induced carbonate precipitation (MICP) to mitigate liquefaction potential in a non-disruptive manner. Multiple microbial processes have been identified for MICP, but only two have been extensively studied. Ureolysis, the most commonly studied process for MICP, has been shown to quickly and efficiently induce carbonate precipitation on particle surfaces and at particle contacts to improve the stiffness, strength, and dilatant behavior of liquefiable soils. However, ureolysis also produces copious amounts of ammonium, a potentially toxic byproduct. The second process studied for MICP, denitrification, has been shown to precipitate carbonate, and hence improve soil properties, much more slowly than ureolysis. However, the byproducts of denitrification, nitrogen and carbon dioxide gas, are non-toxic, and present the added benefit of rapidly desaturating the treated soil. Small amounts of desaturation have been shown to increase the cyclic resistance, and hence the liquefaction resistance, of liquefiable soils. So, denitrification offers the potential to mitigate liquefaction as a two-stage process, with desaturation providing short term mitigation, and MICP providing long term liquefaction resistance. This study presents the results of soil testing, stoichiometric modeling, and microbial ecology characterization to better characterize the potential use of denitrification as a two-stage process for liquefaction mitigation. / Dissertation/Thesis / Doctoral Dissertation Civil and Environmental Engineering 2016

abstract: A numerical model for design of the geomembrane elements of waste containment systems has been validated by laboratory testing. Due to the absence of any instrumented case histories of seismic performance of geomembrane liner systems, a large scale centrifuge test of a model geomembrane-lined landfill subject to seismic loading was conducted at the University of California at Davis Centrifuge Test facility as part of National Science Foundation Network for Earthquake the Engineering Simulation Research (NEESR) program. Data collected in the large scale centrifuge test included waste settlement, liner strains and earthquake accelerations at various locations throughout the model. This data on landfill and liner seismic performance has been supplemented with additional laboratory and small scale centrifuge tests to determine the parameters required for the numerical model, including strength and stiffness of the model materials, interface shear strengths, and interface stiffness. The numerical model explicitly assesses the forces and strains in the geomembrane elements of a containment system to subject to both static and seismic loads the computer code FLACTM, a finite difference program for non-linear analysis of continua. The model employs a beam element with zero moment of inertia and with interface elements on both sides to model to represent the geomembrane elements in the liner system. The model also includes non-linear constitutive models for the stress-strain behavior of geomembrane beam elements and an elastic-perfectly plastic model for the load-displacement behavior of the beam interfaces. Parametric studies are conducted with the validated numerical model to develop recommendations for landfill design, construction, and construction quality assurance. / Dissertation/Thesis / Doctoral Dissertation Civil and Environmental Engineering 2017