The purpose of this study was to characterize the rock mass at Mount Rushmore National Memorial (MORU) and to evaluate the stability of the presidential sculptures. The sculptures are carved in granite, but quartz-mica schist and minor outcrops of pegmatite are also present within the site area. We divided the MORU area into four “regions” to collect discontinuity data. Since the sculptures were not accessible during this study, we used light detection and ranging (LiDAR) data and Split-FX software to determine the orientations of both the discontinuities and the slopes on the sculptures. The rock mass characterization results, using both the Rock Mass Rating system and the Q-system, indicate the granite, schist, and pegmatite classify as fair to good rock. Kinematic analysis results indicate that the potential for planar, wedge, and toppling failures exists for various slopes on each of the sculptures. The factor of safety (FS) values against planar and wedge sliding, ignoring cohesion, range from 0.1 to 0.8 and from 0.2 to 1.3, respectively. Since failures have not been observed at the memorial, we back-calculated the amount of cohesion required to raise the FS values to >1. The back-calculation results show that both cohesion and friction contribute to stability of the sculptures. Using the Slide program, we performed an overall slope probabilistic analysis for the slopes on which the MORU sculptures are located. The analysis determines the mean factor of safety (FSM), reliability index (RI), and probability of failure (PF) for the slopes. For the static condition, the analysis resulted in FSM, RI, and PF values ranging from 3.3 to 4.5 percent, 3.3 to 7.8 percent, and 0 percent, respectively. With a seismic load coefficient of 0.14 applied to the slopes, the corresponding values were: 2.6 to 4.1 percent, 2.9 to 4.7 percent, and 0 percent. For both the static and seismic conditions, the results indicate that, overall, the slopes of the sculptures are stable.
{"title":"Rock Mass Characterization and Stability Evaluation of Mount Rushmore National Memorial, Keystone, South Dakota","authors":"S. L. Poluga, A. Shakoor, E. Bilderback","doi":"10.2113/EEG-2042","DOIUrl":"https://doi.org/10.2113/EEG-2042","url":null,"abstract":"The purpose of this study was to characterize the rock mass at Mount Rushmore National Memorial (MORU) and to evaluate the stability of the presidential sculptures. The sculptures are carved in granite, but quartz-mica schist and minor outcrops of pegmatite are also present within the site area. We divided the MORU area into four “regions” to collect discontinuity data. Since the sculptures were not accessible during this study, we used light detection and ranging (LiDAR) data and Split-FX software to determine the orientations of both the discontinuities and the slopes on the sculptures. The rock mass characterization results, using both the Rock Mass Rating system and the Q-system, indicate the granite, schist, and pegmatite classify as fair to good rock. Kinematic analysis results indicate that the potential for planar, wedge, and toppling failures exists for various slopes on each of the sculptures. The factor of safety (FS) values against planar and wedge sliding, ignoring cohesion, range from 0.1 to 0.8 and from 0.2 to 1.3, respectively. Since failures have not been observed at the memorial, we back-calculated the amount of cohesion required to raise the FS values to >1. The back-calculation results show that both cohesion and friction contribute to stability of the sculptures. Using the Slide program, we performed an overall slope probabilistic analysis for the slopes on which the MORU sculptures are located. The analysis determines the mean factor of safety (FSM), reliability index (RI), and probability of failure (PF) for the slopes. For the static condition, the analysis resulted in FSM, RI, and PF values ranging from 3.3 to 4.5 percent, 3.3 to 7.8 percent, and 0 percent, respectively. With a seismic load coefficient of 0.14 applied to the slopes, the corresponding values were: 2.6 to 4.1 percent, 2.9 to 4.7 percent, and 0 percent. For both the static and seismic conditions, the results indicate that, overall, the slopes of the sculptures are stable.","PeriodicalId":138906,"journal":{"name":"Environmental and Engineering Geoscience","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117100736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this work, we analyzed the results of a geochemical analysis aimed to define the origin of pH anomalies (pH > 11) in water samples collected inside a tunnel located in southern Calabria (southern Italy). We also analyzed the precipitates found close to the main drainage pipes. The hydrogeochemical study allowed us to identify a main NaOH water facies for the many samples collected close to the tunnel. In addition, the correlation diagrams highlighted high concentrations of Na, K, and Al, unrelated to simple water-rock interaction. Further evaluation excluded the possibility that interaction between the water and the outcropping lithologies was the only cause of the ongoing processes. This consideration is supported by the high Na and K concentrations, which cannot be accounted for by interaction between water and calcareous marl. Excluding a natural origin and some anthropogenic factors, one possible explanation is an interaction between the groundwater and the mortars used for consolidation during the excavation phase of the tunnel. Mortar and concrete degradation in aqueous environments produces a great increase in pH, initially deriving from interstitial fluids containing strong alkali (NaOH and KOH) and non-negligible K and Na concentrations, such as we observed in the collected samples.
{"title":"Water-mortar Interaction in a Tunnel Located in Southern Calabria (southern Italy)","authors":"G. Vespasiano, P. Notaro, G. Cianflone","doi":"10.2113/EEG-1978","DOIUrl":"https://doi.org/10.2113/EEG-1978","url":null,"abstract":"\u0000 In this work, we analyzed the results of a geochemical analysis aimed to define the origin of pH anomalies (pH > 11) in water samples collected inside a tunnel located in southern Calabria (southern Italy). We also analyzed the precipitates found close to the main drainage pipes. The hydrogeochemical study allowed us to identify a main NaOH water facies for the many samples collected close to the tunnel. In addition, the correlation diagrams highlighted high concentrations of Na, K, and Al, unrelated to simple water-rock interaction. Further evaluation excluded the possibility that interaction between the water and the outcropping lithologies was the only cause of the ongoing processes. This consideration is supported by the high Na and K concentrations, which cannot be accounted for by interaction between water and calcareous marl. Excluding a natural origin and some anthropogenic factors, one possible explanation is an interaction between the groundwater and the mortars used for consolidation during the excavation phase of the tunnel. Mortar and concrete degradation in aqueous environments produces a great increase in pH, initially deriving from interstitial fluids containing strong alkali (NaOH and KOH) and non-negligible K and Na concentrations, such as we observed in the collected samples.","PeriodicalId":138906,"journal":{"name":"Environmental and Engineering Geoscience","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117340009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I. Chenini, Adel Zghibi, M. Msaddek, Mahmoud Dlala
The groundwater vulnerability assessment is normally applied to rural watersheds. However, urbanization modifies the hydrogeological processes. A modified DRASTIC model was adopted to establish a groundwater vulnerability map in an urbanized watershed. The modified DRASTIC model incorporated a land-use map, and net recharge was calculated taking into account the specificity of the urban hydrogeological system. The application of the proposed approach to the Mannouba watershed demonstrates that the groundwater vulnerability indexes range from 80 to 165. The study's results shows that 30 percent of the Mannouba watershed area has a high vulnerability index, 45 percent of the area has a medium index, and 25 percent of the study area has a low vulnerability index. To specify the effect of each DRASTIC factor on the calculated vulnerability index, sensitivity analyses were performed. Land use, topography, and soil media have an important theoretical weight greater than the effective weight. The impact of the vadose zone factor has the most important effective weight and affects the vulnerability index. The sensitivity assessment explored the variation in vulnerability after thematic layer removal. In this analysis, the removal of hydraulic conductivity and impact of vadose zone modified the vulnerability index. Groundwater vulnerability assessment in urbanized watersheds is difficult and has to consider the impact of urbanization in the hydrogeological parameters.
{"title":"Groundwater Vulnerability Mapping in Urbanized Hydrological System Using Modified Drastic Model and Sensitivity Analysis","authors":"I. Chenini, Adel Zghibi, M. Msaddek, Mahmoud Dlala","doi":"10.2113/EEG-1967","DOIUrl":"https://doi.org/10.2113/EEG-1967","url":null,"abstract":"\u0000 The groundwater vulnerability assessment is normally applied to rural watersheds. However, urbanization modifies the hydrogeological processes. A modified DRASTIC model was adopted to establish a groundwater vulnerability map in an urbanized watershed. The modified DRASTIC model incorporated a land-use map, and net recharge was calculated taking into account the specificity of the urban hydrogeological system. The application of the proposed approach to the Mannouba watershed demonstrates that the groundwater vulnerability indexes range from 80 to 165. The study's results shows that 30 percent of the Mannouba watershed area has a high vulnerability index, 45 percent of the area has a medium index, and 25 percent of the study area has a low vulnerability index. To specify the effect of each DRASTIC factor on the calculated vulnerability index, sensitivity analyses were performed. Land use, topography, and soil media have an important theoretical weight greater than the effective weight. The impact of the vadose zone factor has the most important effective weight and affects the vulnerability index. The sensitivity assessment explored the variation in vulnerability after thematic layer removal. In this analysis, the removal of hydraulic conductivity and impact of vadose zone modified the vulnerability index. Groundwater vulnerability assessment in urbanized watersheds is difficult and has to consider the impact of urbanization in the hydrogeological parameters.","PeriodicalId":138906,"journal":{"name":"Environmental and Engineering Geoscience","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127809412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Technical Note: The El Indio Mine Closure Plan Effects Over the Water Quality of the Upper Elqui Basin","authors":"J. Oyarzún, J. Núñez, H. Maturana, R. Oyarzún","doi":"10.2113/EEG-2022","DOIUrl":"https://doi.org/10.2113/EEG-2022","url":null,"abstract":"","PeriodicalId":138906,"journal":{"name":"Environmental and Engineering Geoscience","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129849202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
N. Maerz, Kenneth J. Boyko, G. Pendergrass, Justin W. Brown
A development in a karstic area of southwest Missouri initiated a geophysical survey as part of an initial site investigation. After conducting an extensive geophysical survey over the proposed site, a significant anomaly was discovered. Subsequently drilling of a 0.15 m (6 in.) borehole into the anomaly intersected a void between 16.2 m (53 ft) and 28.7 m (94 ft) of depth. The property is at the top of the watershed, so both the borehole and the void were dry. In order to model the stability of the cavern in response to the proposed development, it was necessary to determine both the size and the shape of the void.
{"title":"Lidar Scanning of an Air-filled Cavern Accessed Through a Borehole","authors":"N. Maerz, Kenneth J. Boyko, G. Pendergrass, Justin W. Brown","doi":"10.2113/EEG-2020","DOIUrl":"https://doi.org/10.2113/EEG-2020","url":null,"abstract":"\u0000 A development in a karstic area of southwest Missouri initiated a geophysical survey as part of an initial site investigation. After conducting an extensive geophysical survey over the proposed site, a significant anomaly was discovered. Subsequently drilling of a 0.15 m (6 in.) borehole into the anomaly intersected a void between 16.2 m (53 ft) and 28.7 m (94 ft) of depth. The property is at the top of the watershed, so both the borehole and the void were dry.\u0000 In order to model the stability of the cavern in response to the proposed development, it was necessary to determine both the size and the shape of the void.","PeriodicalId":138906,"journal":{"name":"Environmental and Engineering Geoscience","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124013926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sinkholes are inherent features of the karst terrain of Greene County, Missouri, that present hazards and engineering challenges to construction/infrastructure development. Analysis of relationships between the spatial distribution of sinkholes and possible influencing factors can help in understanding the controls involved in the formation of sinkholes. The spatial analysis outlined herein can aid in the assessment of potential sinkhole hazards. In this research, Geographic Information System–based ordinary least squares regression (OLS) and geographically weighted regression (GWR) methods were used to determine and evaluate principal factors appearing to influence the formation and distribution of karst sinkholes. From the OLS result, seven out of 12 possible influencing factors were found to exert significant control on sinkhole formation processes in the study area. These factors are overburden thickness, depth to groundwater, slope of the ground surface, distance to the nearest surface drainage line, distance to the nearest geological structure (such as faults or folds), distance to the nearest road, and distance to the nearest spring. These factors were then used as independent variables in the GWR model. The GWR model examined the spatial non-stationarity among the various factors and demonstrated better performance over OLS. GWR model coefficient estimates for each variable were mapped. These maps provide spatial insights into the influence of the variables on sinkhole densities throughout the study area. GWR spatial analysis appears to be an effective approach to understand sinkhole-influencing factors. The results could be useful to provide an objective means of parameter weighting in models of sinkhole susceptibility or hazard mapping.
{"title":"Using Gis-based Spatial Analysis To Determine Factors Influencing the Formation of Sinkholes in Greene County, Missouri","authors":"Shishay T. Kidanu, N. Anderson, J. Rogers","doi":"10.2113/EEG-2014","DOIUrl":"https://doi.org/10.2113/EEG-2014","url":null,"abstract":"\u0000 Sinkholes are inherent features of the karst terrain of Greene County, Missouri, that present hazards and engineering challenges to construction/infrastructure development. Analysis of relationships between the spatial distribution of sinkholes and possible influencing factors can help in understanding the controls involved in the formation of sinkholes. The spatial analysis outlined herein can aid in the assessment of potential sinkhole hazards. In this research, Geographic Information System–based ordinary least squares regression (OLS) and geographically weighted regression (GWR) methods were used to determine and evaluate principal factors appearing to influence the formation and distribution of karst sinkholes. From the OLS result, seven out of 12 possible influencing factors were found to exert significant control on sinkhole formation processes in the study area. These factors are overburden thickness, depth to groundwater, slope of the ground surface, distance to the nearest surface drainage line, distance to the nearest geological structure (such as faults or folds), distance to the nearest road, and distance to the nearest spring. These factors were then used as independent variables in the GWR model. The GWR model examined the spatial non-stationarity among the various factors and demonstrated better performance over OLS. GWR model coefficient estimates for each variable were mapped. These maps provide spatial insights into the influence of the variables on sinkhole densities throughout the study area. GWR spatial analysis appears to be an effective approach to understand sinkhole-influencing factors. The results could be useful to provide an objective means of parameter weighting in models of sinkhole susceptibility or hazard mapping.","PeriodicalId":138906,"journal":{"name":"Environmental and Engineering Geoscience","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133447230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Geology Applied To Engineering","authors":"T. West","doi":"10.2113/EEG-24-04-07","DOIUrl":"https://doi.org/10.2113/EEG-24-04-07","url":null,"abstract":"","PeriodicalId":138906,"journal":{"name":"Environmental and Engineering Geoscience","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128729855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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