Flexible pavements, whose surface layers are made from hot mix asphalt, may show rutting in some of these infrastructures during the first months of life. In the city of Ouagadougou, this rutting phenomenon is sometim...Flexible pavements, whose surface layers are made from hot mix asphalt, may show rutting in some of these infrastructures during the first months of life. In the city of Ouagadougou, this rutting phenomenon is sometimes observed. The objective of this article is to quantify the thermal response of the wearing course of national roads 1 and 2, when they are subjected to the braking of heavy trucks of 13 tons and 20 tons per axle. The meteorological conditions retained are those of the Burkinabe climate. The evaluation of the temperature was carried out by numerical simulation using the Comsol Multiphysics 5.2 software. This study showed that the thermal response of the pavement to the combined effects of surface temperature, overloading by a 20 tons heavy truck and braking during a heat wave increase in pavement surface temperature ranging from 1.09% for National Road 1 to 0.91% for National Road 2, particularly in the braking zone. This made it possible to establish the diagnosis according to which the nature of the bitumen used on the wearing course can reduce rigidity modulus. In predictive terms, they allowed us to deduce that an under-dimensioning of the wearing course, even if the bitumen was used is adequate.展开更多
Knowledge of the state of stability of mining pits is both a basic condition, an essential axis and a safety benchmark for mining operations. This stability is largely based on the knowledge of the rock mass shelterin...Knowledge of the state of stability of mining pits is both a basic condition, an essential axis and a safety benchmark for mining operations. This stability is largely based on the knowledge of the rock mass sheltering the mining works and this requires a perfect characterization of all of its structural formations through mapping (manual or digital). The families of discontinuities, namely family 1 (bedding), family 2 (Joint 2) and family 3 (Joint 1) obtained through structural mapping in the Essakane open pit mine, made it possible to analyze the failure modes at the origin of rock instabilities. The respective dips of these different directional families are: 77˚ - 85˚/N 058˚ - 068˚, 66˚ - 74˚/N 133˚ - 143˚, 25˚ - 35˚/N115˚ - 130˚. An average safety factor of 4.3 was estimated for the area with a quality of the rock mass (RMR) estimated at 47. The results obtained reflect on the one hand the risks of instability associated with the quality of the rock mass studied and on the other hand highlights the state of stability of the study area.展开更多
This study aims to make a hydrogeological characterization of the aquifers of the Continental Terminal and the Oligo-Miocene.To do so,an analysis is conducted on the basis of hydrogeological parameters from 172 boreho...This study aims to make a hydrogeological characterization of the aquifers of the Continental Terminal and the Oligo-Miocene.To do so,an analysis is conducted on the basis of hydrogeological parameters from 172 boreholes,10 of which are used for groundwater levels and flows analysis.The results of the statistical analysis of the hydrogeological parameters show that the average flow rate is 42.29 m^(3)/h,the average specific flow rate is 5.96 m^(3)/h/m,and the average transmissivity is 0.024 m^(2)/s.These values highlight the high productivity of aquifers from the Continental Terminal and the Oligo-Miocene.The results of piezometry showed that water flows from the south center to the northwest of Tambacounda where the largest depression is located and could even be the outlet of the system.The groundwater fluctuations between low water level and high water level seasons reveal a rise in the piezometric surface of the aquifers at the scale of the study area.展开更多
Knowledge of the structure and geometry of aquifers is an important prerequisite when one wishes to sit a borehole.Such knowledge is currently obtained by VES(Vertical Electrical Soundings)whose interpretation is not ...Knowledge of the structure and geometry of aquifers is an important prerequisite when one wishes to sit a borehole.Such knowledge is currently obtained by VES(Vertical Electrical Soundings)whose interpretation is not always unequivocal in the sense that several resistivity models derived from VES can explain the same data set.The present study conducted in Obuasi region in Ghana aims at demonstrating the robustness of“cumulative resistivity”method in the characterization of the geometry of aquifers.The methodology developed consisted firstly in carrying out VES.These measurements were then interpreted using“cumulative resistivity method”.Secondly,drillings are conducted at the VES sites and lithologs established from cuttings were compared to the results from VES interpretation.The study reveals that the investigated aquifer consists of a resistant layer consisting of phyllite over 30-40 m topped by a conductive layer of reddish clay 20-30 m thick.These two layers rest on a lower electrical conductivity formation downward.This description can be considered as a typical alteration profile in a volcano sedimentary context.The results also show that the method is quite precise in half of the cases studied but sometimes it is impossible to get rid of the phenomenon of suppression since several layers are merged into a single layer.展开更多
文摘Flexible pavements, whose surface layers are made from hot mix asphalt, may show rutting in some of these infrastructures during the first months of life. In the city of Ouagadougou, this rutting phenomenon is sometimes observed. The objective of this article is to quantify the thermal response of the wearing course of national roads 1 and 2, when they are subjected to the braking of heavy trucks of 13 tons and 20 tons per axle. The meteorological conditions retained are those of the Burkinabe climate. The evaluation of the temperature was carried out by numerical simulation using the Comsol Multiphysics 5.2 software. This study showed that the thermal response of the pavement to the combined effects of surface temperature, overloading by a 20 tons heavy truck and braking during a heat wave increase in pavement surface temperature ranging from 1.09% for National Road 1 to 0.91% for National Road 2, particularly in the braking zone. This made it possible to establish the diagnosis according to which the nature of the bitumen used on the wearing course can reduce rigidity modulus. In predictive terms, they allowed us to deduce that an under-dimensioning of the wearing course, even if the bitumen was used is adequate.
文摘Knowledge of the state of stability of mining pits is both a basic condition, an essential axis and a safety benchmark for mining operations. This stability is largely based on the knowledge of the rock mass sheltering the mining works and this requires a perfect characterization of all of its structural formations through mapping (manual or digital). The families of discontinuities, namely family 1 (bedding), family 2 (Joint 2) and family 3 (Joint 1) obtained through structural mapping in the Essakane open pit mine, made it possible to analyze the failure modes at the origin of rock instabilities. The respective dips of these different directional families are: 77˚ - 85˚/N 058˚ - 068˚, 66˚ - 74˚/N 133˚ - 143˚, 25˚ - 35˚/N115˚ - 130˚. An average safety factor of 4.3 was estimated for the area with a quality of the rock mass (RMR) estimated at 47. The results obtained reflect on the one hand the risks of instability associated with the quality of the rock mass studied and on the other hand highlights the state of stability of the study area.
文摘This study aims to make a hydrogeological characterization of the aquifers of the Continental Terminal and the Oligo-Miocene.To do so,an analysis is conducted on the basis of hydrogeological parameters from 172 boreholes,10 of which are used for groundwater levels and flows analysis.The results of the statistical analysis of the hydrogeological parameters show that the average flow rate is 42.29 m^(3)/h,the average specific flow rate is 5.96 m^(3)/h/m,and the average transmissivity is 0.024 m^(2)/s.These values highlight the high productivity of aquifers from the Continental Terminal and the Oligo-Miocene.The results of piezometry showed that water flows from the south center to the northwest of Tambacounda where the largest depression is located and could even be the outlet of the system.The groundwater fluctuations between low water level and high water level seasons reveal a rise in the piezometric surface of the aquifers at the scale of the study area.
文摘Knowledge of the structure and geometry of aquifers is an important prerequisite when one wishes to sit a borehole.Such knowledge is currently obtained by VES(Vertical Electrical Soundings)whose interpretation is not always unequivocal in the sense that several resistivity models derived from VES can explain the same data set.The present study conducted in Obuasi region in Ghana aims at demonstrating the robustness of“cumulative resistivity”method in the characterization of the geometry of aquifers.The methodology developed consisted firstly in carrying out VES.These measurements were then interpreted using“cumulative resistivity method”.Secondly,drillings are conducted at the VES sites and lithologs established from cuttings were compared to the results from VES interpretation.The study reveals that the investigated aquifer consists of a resistant layer consisting of phyllite over 30-40 m topped by a conductive layer of reddish clay 20-30 m thick.These two layers rest on a lower electrical conductivity formation downward.This description can be considered as a typical alteration profile in a volcano sedimentary context.The results also show that the method is quite precise in half of the cases studied but sometimes it is impossible to get rid of the phenomenon of suppression since several layers are merged into a single layer.
