To analyse the debris flow type of landslides it is necessary to know the viscosity of the fast-moving soil mass. Such rheological parameters are important in the evaluation of characteristics of propagation of the movement downhill. This paper presents a proposal for the assessment of soil viscosity based on a modified set-up of the well-known concrete slump test. Through the definition of shearing rates in the slump tests, soil viscosity was determined on a plate–plate rheometer. Four natural soils from Rio de Janeiro, Brazil, with differing grain size distribution and plasticity, were used in the investigation. The results obtained are compared with experimental data from the literature, and show that care must be taken in defining viscosities based only on data related to grain size. Correlations between soil moisture and shearing rates, defined in the modified slump tests, and viscosity, defined in the rheometer tests, were obtained. As a result, a fairly good relationship between shearing rate and viscosity was established. Comparing the obtained data with numerical results available in the literature it is concluded that the developed experimental methodology may provide a simple way to evaluate the viscosity of soils for debris flow analysis.

Data on the at-rest coefficient of earth pressure (K₀) in undisturbed, unsaturated residual soils are rarely found in the literature. This article describes a new suction-controlled system developed for measuring K₀ in residual soil samples, as well as corrections required to get a sensible evaluation of K₀. The K₀ device comprises a rigid chamber containing a 4-in diameter triaxial sample. Suction is controlled using the axis translation technique. The results of tests performed in mature and young residual soils originated from phacoidal gneiss are presented and discussed. The testing interpretation using either Bishop’s or Fredund’s approaches provide similar results. It is shown that K₀ varies with both suction and net stress and is affected by the degree of weathering of residual soils.

If the current policy explores the utilization of active ingredients in use quickly and to the maximum, the same does not occur with the ban on the registration of products highly dangerous to both health and the environment. The current policy does not aim at reducing pesticide toxicity and ecotoxicity, required to reduce environmental contamination and human exposure. To this end, it is essential to adjust scientific evaluation parameters concerning lower concentration tolerance limits to modernity standards, in addition to banning products for which there is scientific evidence of carcinogenic, teratogenic, and mutagenic actions. In ecotoxicology, reducing the applicable concentration limits is paramount for preserving bees, birds, and other forms of domestic and wildlife. When evaluating active ingredients, it is imperative to prioritize more biodegradable molecules with low potential for environmental mobilization through volatilization and leaching, preserving both air and water quality. Another goal, among others, is a program for the generalized reduction of successfully implemented in several countries. Brazil, a tropical agriculture leader, should stand out by incorporating sustainability while preserving both health and the environment.

In a homogeneous earth fill dam, an initial process of internal erosion was observed near the base of the downstream slope, which is one of the main dam failure causes in the world. This problem was adequately solved, and research was started aiming to find the causes of the detected anomaly. The history of the structure was investigated, field testing results were analyzed and undisturbed samples were collected in different regions of the dam. Characterization tests, saturated permeability coefficients tests under different effective stresses and flow directions, and Filter Papel tests were run. Results were incorporated into computational models to investigate the behavior of hydraulic gradients and the height of the exit point of the phreatic line defined on the basis of monitored piezometers installed at the site. The software Plaxis LE was used in this study. It was evaluated whether the adoption of unsaturated parameters or 3D analysis would promote any change in the flow pattern in the studied structure, which did not occur. It was also considered whether the soil-atmosphere interaction could generate critical hydraulic gradients through rainfall and evaporation cycles, but there were no critical results either. Finally, it is concluded that effects of natural vegetation previously found in Dam X may have led to the observed internal erosion process. These somewhat unusual findings are relevant for improving the understanding of vegetation impacts on earth dam safety and can help guide future monitoring and, particularly, maintenance practices to prevent similar issues in other similar earth fill dams.