Consolidation theory states that decreasing the spacing of prefabricated vertical drains will decrease the time required to achieve primary consolidation. Previous field tests have shown that there exists a "critical" drain spacing, which is the point at which further spacing decrease does not decrease the time of primary consolidation. This "critical" spacing is thought to be due to disturbance effects from installation of the drains. Previous studies have found that the "critical" drain spacing may be dependent upon soil layering and drain and mandrel dimensions. Thin, interbedded clay layers have been found to be affected greatly due to the smear zone, while few tests have been conducted to determine the validity for thick bedded clays. Currently two design and analysis methods are in existence, neither of which is standardized. The two methods are the modeling of the smear zone, which requires knowledge of soil parameters within that zone, and the modeling using a back-calculated Ch/Cv ratio.In order to evaluate the validity of these design methods and to obtain more data that can be used in determining the relationship between anchor type, drain spacing, and soil profile, full-scale field tests were conducted at Mountain View Corridor in Lehi, Utah. These field tests were performed along a test section that was divided into sections containing 5.8, 5.0, 4.0 and 3.0 ft triangular spacings and rebar or plate anchors. By using the smear zone model, with a Ch/Cv ratio of 1.25 and ds of 3.07 times dm, the time rate of settlement was able to be predicted reasonably well, while using the back-calculated Ch/Cv ratio, with no smear zone, also predicted the time rate reasonably well. From the testing, it was found that the thick clay profile can facilitate closer spacings than a thin clay profile. Also, it was found that the rebar anchor type causes about twice the disturbance of the plate anchor. The results helped validate the existing models and show that the effectiveness of the drains is dependent upon drain spacing, soil profile, and anchor type

A construção do Rodoanel Trecho Sul movimentou o meio geotécnico, gerando novas informações sobre os solos locais e apresentando novas tecnologias construtivas, já disponíveis em outros mercados, mas pouco ou não utilizadas nas obras brasileiras. Estas novas técnicas de melhoria dos solos prometem solucionar problemas importantes, como a deformabilidade e resistência de uma camada de argila mole depositada na fundação de um aterro, por meios simples, rápidos, econômicos e ambientalmente interessantes. Este trabalho apresenta os problemas de engenharia geotécnica enfrentados durante a implantação deste empreendimento, na região próxima à Represa Billings e da Interseção Imigrantes, e destaca as soluções geotécnicas executadas para estabilizar a fundação dos aterros compactados construídos nesta região, caracterizada pela ocorrência de solos orgânicos muito moles. Destas soluções enfatizam-se neste estudo os tratamentos de solos moles identificados como Consolidação Profunda Radial (CPR) e a Mistura Mecânica de Aglomerante Cimentício com os solos moles saturados locais. O desempenho final destas tecnologias, em relação ao ganho de resistência e o aumento de compressibilidade adquiridos pela camada tratada, foram avaliados através dos ensaios de campo e da instrumentação implantada na área de interesse. / The construction of the South Stretch of Rodoanel Highway created a commotion in the geotechnical segment, generating new information about the local soils and presenting new construction technology, already available in other markets, but still with very limited or even no use in the Brazilian works. This new techniques of soil improvements, promises to solve important issues, like deformability and resistance of a soft clay layer located at the foundation of an embankment, by means that can be qualified as simple, fast, economical and environmentally interesting. This document presents the geotechnical engineering issues encountered during the implantation of this entrepreneur, at the region near Billings Reservoir and at the intersection with Imigrantes Highway, and points out the geotechnical solutions used to stabilize the foundation of compacted earth fill builted at this region, that is characterized by the occurrence of very soft organic soils. This study emphasizes in the solutions of treatment of soft soil identified as Deep Radial Consolidation (CPR) and the Mechanical Mixture of Cimentitius Binder with the local saturated soft soils. The final performance of this technologies, consearning the gain of resistance and the reduction of deformability, acquired by the treated layer, were evaluated through field tests and by the instrumentation placed at the area of interest.

A construção do Rodoanel Trecho Sul movimentou o meio geotécnico, gerando novas informações sobre os solos locais e apresentando novas tecnologias construtivas, já disponíveis em outros mercados, mas pouco ou não utilizadas nas obras brasileiras. Estas novas técnicas de melhoria dos solos prometem solucionar problemas importantes, como a deformabilidade e resistência de uma camada de argila mole depositada na fundação de um aterro, por meios simples, rápidos, econômicos e ambientalmente interessantes. Este trabalho apresenta os problemas de engenharia geotécnica enfrentados durante a implantação deste empreendimento, na região próxima à Represa Billings e da Interseção Imigrantes, e destaca as soluções geotécnicas executadas para estabilizar a fundação dos aterros compactados construídos nesta região, caracterizada pela ocorrência de solos orgânicos muito moles. Destas soluções enfatizam-se neste estudo os tratamentos de solos moles identificados como Consolidação Profunda Radial (CPR) e a Mistura Mecânica de Aglomerante Cimentício com os solos moles saturados locais. O desempenho final destas tecnologias, em relação ao ganho de resistência e o aumento de compressibilidade adquiridos pela camada tratada, foram avaliados através dos ensaios de campo e da instrumentação implantada na área de interesse. / The construction of the South Stretch of Rodoanel Highway created a commotion in the geotechnical segment, generating new information about the local soils and presenting new construction technology, already available in other markets, but still with very limited or even no use in the Brazilian works. This new techniques of soil improvements, promises to solve important issues, like deformability and resistance of a soft clay layer located at the foundation of an embankment, by means that can be qualified as simple, fast, economical and environmentally interesting. This document presents the geotechnical engineering issues encountered during the implantation of this entrepreneur, at the region near Billings Reservoir and at the intersection with Imigrantes Highway, and points out the geotechnical solutions used to stabilize the foundation of compacted earth fill builted at this region, that is characterized by the occurrence of very soft organic soils. This study emphasizes in the solutions of treatment of soft soil identified as Deep Radial Consolidation (CPR) and the Mechanical Mixture of Cimentitius Binder with the local saturated soft soils. The final performance of this technologies, consearning the gain of resistance and the reduction of deformability, acquired by the treated layer, were evaluated through field tests and by the instrumentation placed at the area of interest.

Las columnas de grava constituyen uno de los métodos habituales de mejora del terreno para la cimentación de terraplenes o estructuras en suelos blandos. Mejoran la capacidad portante y la estabilidad al deslizamiento y reducen el valor del asiento y el tiempo que tarda en producirse.Las columnas acortan el camino de drenaje de una forma similar a los drenes verticales. Por ello, suelen emplearse las mismas soluciones para estudiar su consolidación radial. Sin embargo, las columnas son mucho más rígidas que los drenes y soportan una parte importante de la carga. En esta tesis se ha desarrollado una solución analítica que permite incluir la interacción radial y vertical entre el suelo y la columna en el estudio de su consolidación radial. La solución permite obtener las tensiones y las deformaciones en cualquier instante a través de una sencilla hoja de cálculo.Se presentan también los resultados de la instrumentación realizada en dos obras reales en las que el terreno fue mejorado con columnas de grava. / Stone columns, either by the vibro-replacement or vibro-displacement methods, are one of the most common improvement techniques for foundation of embankments or structures on soft soils. The main effects usually considered with respect to the untreated ground conditions are: improvement of bearing capacity, reduction of total and differential settlements, acceleration of consolidation, improvement of the stability of embankments and natural slopes, and reduction of liquefaction potential.In this thesis, a new closed-form solution that includes the radial and vertical interaction between soil and column has been developed. The solution gives all the stresses and displacements at any time by means of a simple spreadsheet.The instrumentation of two different field sites where the ground was improved with stone columns is shown and analysed.

El estudio del proceso de consolidación radial alrededor de las columna de grava y de la interacción suelo-columna suele realizarse analizando una celda unitaria formada por una columna de grava central y el área de terreno circundante, sobre la cual ejerce su acción de mejora. En esta tesis doctoral se ha modelizado a escala reducida una celda unidad para analizar la transferencia de carga entre la columna y el terreno y el proceso de consolidación que se produce alrededor de la columna, para condiciones de carga vertical rígida.Se han realizado ensayos con columnas de dos diámetros distintos, con el fin de estudiar también la influencia del área de suelo blando reemplazada por la columna. Se presentan los resultados obtenidos en cada ensayo, su interpretación, y la comparación con soluciones teóricas existentes. Todo ello tanto para el análisis de la consolidación radial como para el comportamiento deformacional del conjunto suelo-columna. / The analysis of the radial consolidation process around the column and the column-soil interaction is based on the study of a unit cell approach, which consists of a central column of gravel and the surrounding soil. In this thesis, a unit cell in small scale has been reproduced with the aim of analyzing load transfer between soil and column, settlement reduction and radial consolidation process that happen when a rigid vertical load is applied on surface.Tests with two different geometries are carried out.From the results, some conclusions related to consolidation process, stress concentration factor and settlement reduction have been obtained for each testing geometry.The influence of the replacement area has been studied comparing the results of both geometries.Finally, the results are presented and interpreted using some existing analytical solutions related to consolidation process and stone columns deformation.