In this work the possibility of identifying two important aspects in the process of adopting soil parameters for calculating stability analysis models in tailing dams is discussed. The use of commercial computer progr...In this work the possibility of identifying two important aspects in the process of adopting soil parameters for calculating stability analysis models in tailing dams is discussed. The use of commercial computer programs for stability calculations allows obtaining numerically exact results. Its representativeness, however, will be linked to the correct definition of the phreatic regime and to the prediction of volumetric soil behavior during shearing (contractile vs. dilating materials). The theoretical principles for the selection of soils parameters for different failure models are briefly presented. Also, how the incorrect assumptions regarding material behavior can significantly affect the estimation of tailing dams’ stability. The results of CPTu tests for the diagnosis of the phreatic and mechanical condition of the materials are discussed and two examples are presented to remark on the care that should be taken to avoid incorrect soils parameters adoption.展开更多
One of the main uses of the cone penetration test (CPT) is to determinate the underground stratigraphy identifying the soils types present. Diverse researchers intended to identify the soils in function of results of ...One of the main uses of the cone penetration test (CPT) is to determinate the underground stratigraphy identifying the soils types present. Diverse researchers intended to identify the soils in function of results of CPT by means of the use of classification graphics based on empiric correlations. Also, they stand out the necessity to continue getting into these studies and they emphasize that local experiences could differ from the studies carried out. The experience in the NEA region of our country regarding the use of the CPT is recent;it was incorporated by the middle of the 90s. However, its continuous and systematic use in geotechnical studies makes that today it has a big database enough to verify the application of international correlations to the soils of the region. The objective of the work consists of verifying the application of the method of identification of soils to the sedimentary soils of the NEA, by means of the analysis of tests of CPT made in different points of the states of Chaco and Corrientes. The results of the study reveal that a good agreement exists among the stratigraphy obtained from CPT tests and those obtained by traditional methods. Although the analyzed universe of data is not of great magnitude and it should be enlarged, it is concluded in a preliminary way that for the soils of the region a good correlation exists between the classification chart with base in CPT and the traditional Unified Soil Classification System (USCS).展开更多
The current practice of geotechnical engineering commonly uses a combination of theoretical and empirical correlations to estimate the soil undrained shear strength in clays from the piezocone test. In order to comple...The current practice of geotechnical engineering commonly uses a combination of theoretical and empirical correlations to estimate the soil undrained shear strength in clays from the piezocone test. In order to complement the use of such correlations, the application of a method to estimate the soil undrained shear strength, using measures of the excess pore pressure in dissipation tests of piezocone is presented. In cohesive soils, excess pore pressure and undrained shear strength are dependent on the same variables (stress state, stress history, soil stiffness), which allows them to be related by the theoretical cavity expansion-critical state framework. This paper mentions the mathematical formulation that supports the theoretical framework used, its relationship with the Nkt and NΔu factors and their estimation in a case studied. The results obtained are consistent within the dispersion found in the international literature and encourage the use of the method in engineering practice.展开更多
文摘In this work the possibility of identifying two important aspects in the process of adopting soil parameters for calculating stability analysis models in tailing dams is discussed. The use of commercial computer programs for stability calculations allows obtaining numerically exact results. Its representativeness, however, will be linked to the correct definition of the phreatic regime and to the prediction of volumetric soil behavior during shearing (contractile vs. dilating materials). The theoretical principles for the selection of soils parameters for different failure models are briefly presented. Also, how the incorrect assumptions regarding material behavior can significantly affect the estimation of tailing dams’ stability. The results of CPTu tests for the diagnosis of the phreatic and mechanical condition of the materials are discussed and two examples are presented to remark on the care that should be taken to avoid incorrect soils parameters adoption.
文摘One of the main uses of the cone penetration test (CPT) is to determinate the underground stratigraphy identifying the soils types present. Diverse researchers intended to identify the soils in function of results of CPT by means of the use of classification graphics based on empiric correlations. Also, they stand out the necessity to continue getting into these studies and they emphasize that local experiences could differ from the studies carried out. The experience in the NEA region of our country regarding the use of the CPT is recent;it was incorporated by the middle of the 90s. However, its continuous and systematic use in geotechnical studies makes that today it has a big database enough to verify the application of international correlations to the soils of the region. The objective of the work consists of verifying the application of the method of identification of soils to the sedimentary soils of the NEA, by means of the analysis of tests of CPT made in different points of the states of Chaco and Corrientes. The results of the study reveal that a good agreement exists among the stratigraphy obtained from CPT tests and those obtained by traditional methods. Although the analyzed universe of data is not of great magnitude and it should be enlarged, it is concluded in a preliminary way that for the soils of the region a good correlation exists between the classification chart with base in CPT and the traditional Unified Soil Classification System (USCS).
文摘The current practice of geotechnical engineering commonly uses a combination of theoretical and empirical correlations to estimate the soil undrained shear strength in clays from the piezocone test. In order to complement the use of such correlations, the application of a method to estimate the soil undrained shear strength, using measures of the excess pore pressure in dissipation tests of piezocone is presented. In cohesive soils, excess pore pressure and undrained shear strength are dependent on the same variables (stress state, stress history, soil stiffness), which allows them to be related by the theoretical cavity expansion-critical state framework. This paper mentions the mathematical formulation that supports the theoretical framework used, its relationship with the Nkt and NΔu factors and their estimation in a case studied. The results obtained are consistent within the dispersion found in the international literature and encourage the use of the method in engineering practice.
