Judgement In Geotechnical Engineering Practice (Manuel Rocha Lecture)
Professional judgement is the basis for many of the decisions taken by geotechnical engineers to make progress in the design, execution and works supervision. Judgment is a mandatory component of any engineering achievement, essential to assess the various uncertainties that inevitably affect engineering practice. Confidence in such judgements can result in small to big consequences, […]
A Contingency Solution Using Jet Grouting Barrier For A Dam Under Risk Of Piping In Brazil
During routine inspection works in 2006 inspectors found resurgences of water at the toe of a small embankment dam named ″Ribeirão do Gama″, located at Brasília – DF. After technical visits, geotechnical engineers characterized these groundwater leakages as a piping process at an early stage. Intervention only began in 2015 due to obstacles that occasionally […]
Ground Improvement Techniques Applied To Very Soft Clays: State Of Knowledge And Recent Advances
Soft ground improvement techniques have evolved substantially in Brazil in recent years. However, their application in soft and very soft clays requires a good understanding of the fundamentals of ground improvement techniques suited to the problem as well as the actual field behavior when implemented on a real scale. This paper describes some of the […]
A Case History with Combined Physical and Vacuum Preloading in Colombia
The scope of this paper is the back analysis of soft soil treatment case studies in which prefabricated vertical drains together with physical and vacuum surcharge were applied. Initially, the vacuum surcharge systems in vertical drains used worldwide are reviewed. The radial consolidation theory specifically developed for vacuum and physical surcharges is presented, highlighting the […]
Triaxial Compression Test on Consolidated Undrained Shear Strength Characteristics of Fiber Reinforced Soil
This study aims to experimentally analyze the effect of fiber length and fiber content on shear strength and deformation properties of fiber reinforced soil by consolidated-undrained triaxial shear tests. The best mechanical properties are presented by the samples with 1.0 % fiber content and 3.09 cm fiber length. The stress-strain relationship of fiber reinforced soil […]
Lessons Learned From Dam Construction In Patagonia, Argentina (Victor De Mello Lecture)
Three case histories of large dams built in North Patagonia which experienced unforeseen problems during construction, or after several years of operation are described. The necessary remedial and corrective works involved the development of important programs, being economic and programmatic impacts of great magnitude. The lessons learned from these experiences were very useful to the […]
Numerical Simulation of Vertical Pullout of Plate Anchors Embedded in Reinforced Sand
This paper presents a model to predict the ultimate pullout load (Pu) for a shallow single vertical plate anchor embedded in sand and fiber reinforced sand for depth (H)/diameter (D) ratios of 1.0, 1.5 and 2.0. The model was developed based on literature field test results and wide laboratory investigation. The numerical analysis was performed […]
Shear Strength of Tropical Soils and Bentonite Mixtures for Barrier Design
Compacted clayey tropical soils have great potential to be used as barriers in waste disposal facilities, considering that some technical requirements are fulfilled (e.g. hydraulic conductivity; compatibility after disposal; shear strength; swelling/cracking, etc). In turn, the bentonite addition is relevant for the cases where the hydraulic conductivity must be lowered, and therefore investigations on the […]
The Performance of a Sand Reinforced with Coconut Fibers Through Plate Load Tests on a True Scale Physical Model
The use of recycled materials has experienced a growing global interest in the last decades. Products like natural fibers are being studied to replace synthetic fibers in some applications because they are renewable resources that have a lower cost. Fibers can be used as reinforcement for covers of landfill sites, landfilling over soft soils, and […]
Stabilization Of Major Soil Masses Using Drainage Tunnels
The destabilizing effect of groundwater is one of the major causes for landslides, which represent a major hazard to human life and the environment. Groundwater lowering is of ten the most efficient way to stabilize large unstable ground masses. Among groundwater lowering measures, drainage tunnels have several advantages, although construction costs may be proportionally high. […]
Internal Erosion in Dams (Manuel Rocha Lecture)
In embankment dams and dam foundations, internal erosion is the major cause of structural dam failures and incidents. Internal erosion develops locally along concentrated leaks or in the largest flow velocity zones, where the permeability is high, and at the interface between coarse and fine materials, where the flow velocity in coarse material maybe high […]
Dosage Method For Unconfined Strength And Fatigue Life Of Fiber-Reinforced Cement-Treated Sand
Fiber-reinforcement has been reported as an effective and cost-attractive technique to improve the mechanical behavior of cemented soils. However, the dosage methodologies for these mixtures are still limited, especially regarding dynamic loading. The objective of this research was to analyze the dynamic response and strength behavior of fiber-reinforced cement-treated sand. In this sense, fatigue life, […]
