Different techniques have been proposed to increase the bearing capacity of open-ended piles.Welding helices to the shaft and tapering the pile shaft could be used simultaneously to enhance the static and dynamic beha...Different techniques have been proposed to increase the bearing capacity of open-ended piles.Welding helices to the shaft and tapering the pile shaft could be used simultaneously to enhance the static and dynamic behaviors of these piles.This paper subjects the bearing capacity,stiffness,frictional behavior,and material efficiency of the tapered helical piles to scrutiny.Tapered helical piles are introduced herein as an alternative option to improve the material efficiency of hollow piles.Based on the Taguchi method,a series of experiments was designed and conducted.The axial responses of tapered helical piles are also investigated using finite element analyses.The results derived from loadedisplacement curves and strain gages are used to characterize the axial compression responses of tapered helical piles.The effects of tapered angle,helices diameter and helices distance are examined using dimensionless parameters,and the degree of contribution of these factors is calculated on each of the enumerated variables individually.Experimental results show that the shaft friction resistance of tapered helical piles increases continuously with the pile head settlement.Furthermore,the effect of tapered wall on the shaft friction resistance is more tangible at low stress levels.The results showed that the relative material efficiency factor of the optimum pile could be 2.5 times that of unoptimized pile with a similar quantity of material.展开更多
Sichuan Province,East Western of China,within the area of east longitude 97°21′-108°31′,north latitude 26°03′-34°19′,which is on the Mediterranean seismic zone;with its complicated geological b...Sichuan Province,East Western of China,within the area of east longitude 97°21′-108°31′,north latitude 26°03′-34°19′,which is on the Mediterranean seismic zone;with its complicated geological background,several strong shocks occurred in this district since ancient times.Earthquake catalogue of this area could date back to B.C.26,however,limited by the conditions—technology or funds,lots of minor earthquake have been lost,which could be展开更多
The seismic pattern of the southem extension of the East African Rift in Mozambique is presented in this study with a special reference to the M=7.0 earthquake that occurred on 23 February 2006.Tectonic seismicity in ...The seismic pattern of the southem extension of the East African Rift in Mozambique is presented in this study with a special reference to the M=7.0 earthquake that occurred on 23 February 2006.Tectonic seismicity in Mozambique is associated with activity along the East African Rift,which forms the boundary between African(Nubian) plate in the west and the Somalian plate in the east.Simplified,the Rift展开更多
In this paper, the 231 earthquake data of magnitude 5 and higher, between north (39.00o-42.00o) and east (26.00o-45.00o) coordinates in Turkey from July 12, 1900 to October 23, 2011 are statistically analyzed. The pro...In this paper, the 231 earthquake data of magnitude 5 and higher, between north (39.00o-42.00o) and east (26.00o-45.00o) coordinates in Turkey from July 12, 1900 to October 23, 2011 are statistically analyzed. The probability density function and cumulative function of the magnitude are derived. It is shown that magnitude random variable is distrib-uted as the exponential distribution. The recurrence periods is also calculated. Recurrence period is estimatedapproxi-matelytwo times a year for an earthquake having magnitude 5.2. Using the Gutenberg-Richter function, the relation between magnitude and frequency is represented.展开更多
In this paper, the frequency of an earthquake occurrence and magnitude relationship has been modeled with generalized linear models for the set of earthquake data of Nepal. A goodness of fit of a statistical model is ...In this paper, the frequency of an earthquake occurrence and magnitude relationship has been modeled with generalized linear models for the set of earthquake data of Nepal. A goodness of fit of a statistical model is applied for generalized linear models and considering the model selection information criterion, Akaike information criterion and Bayesian information criterion, generalized Poisson regression model has been selected as a suitable model for the study. The objective of this study is to determine the parameters (a and b values), estimate the probability of an earthquake occurrence and its return period using a Poisson regression model and compared with the Gutenberg-Richter model. The study suggests that the probabilities of earthquake occurrences and return periods estimated by both the models are relatively close to each other. The return periods from the generalized Poisson regression model are comparatively smaller than the Gutenberg-Richter model.展开更多
文摘Different techniques have been proposed to increase the bearing capacity of open-ended piles.Welding helices to the shaft and tapering the pile shaft could be used simultaneously to enhance the static and dynamic behaviors of these piles.This paper subjects the bearing capacity,stiffness,frictional behavior,and material efficiency of the tapered helical piles to scrutiny.Tapered helical piles are introduced herein as an alternative option to improve the material efficiency of hollow piles.Based on the Taguchi method,a series of experiments was designed and conducted.The axial responses of tapered helical piles are also investigated using finite element analyses.The results derived from loadedisplacement curves and strain gages are used to characterize the axial compression responses of tapered helical piles.The effects of tapered angle,helices diameter and helices distance are examined using dimensionless parameters,and the degree of contribution of these factors is calculated on each of the enumerated variables individually.Experimental results show that the shaft friction resistance of tapered helical piles increases continuously with the pile head settlement.Furthermore,the effect of tapered wall on the shaft friction resistance is more tangible at low stress levels.The results showed that the relative material efficiency factor of the optimum pile could be 2.5 times that of unoptimized pile with a similar quantity of material.
文摘Sichuan Province,East Western of China,within the area of east longitude 97°21′-108°31′,north latitude 26°03′-34°19′,which is on the Mediterranean seismic zone;with its complicated geological background,several strong shocks occurred in this district since ancient times.Earthquake catalogue of this area could date back to B.C.26,however,limited by the conditions—technology or funds,lots of minor earthquake have been lost,which could be
文摘The seismic pattern of the southem extension of the East African Rift in Mozambique is presented in this study with a special reference to the M=7.0 earthquake that occurred on 23 February 2006.Tectonic seismicity in Mozambique is associated with activity along the East African Rift,which forms the boundary between African(Nubian) plate in the west and the Somalian plate in the east.Simplified,the Rift
文摘In this paper, the 231 earthquake data of magnitude 5 and higher, between north (39.00o-42.00o) and east (26.00o-45.00o) coordinates in Turkey from July 12, 1900 to October 23, 2011 are statistically analyzed. The probability density function and cumulative function of the magnitude are derived. It is shown that magnitude random variable is distrib-uted as the exponential distribution. The recurrence periods is also calculated. Recurrence period is estimatedapproxi-matelytwo times a year for an earthquake having magnitude 5.2. Using the Gutenberg-Richter function, the relation between magnitude and frequency is represented.
文摘In this paper, the frequency of an earthquake occurrence and magnitude relationship has been modeled with generalized linear models for the set of earthquake data of Nepal. A goodness of fit of a statistical model is applied for generalized linear models and considering the model selection information criterion, Akaike information criterion and Bayesian information criterion, generalized Poisson regression model has been selected as a suitable model for the study. The objective of this study is to determine the parameters (a and b values), estimate the probability of an earthquake occurrence and its return period using a Poisson regression model and compared with the Gutenberg-Richter model. The study suggests that the probabilities of earthquake occurrences and return periods estimated by both the models are relatively close to each other. The return periods from the generalized Poisson regression model are comparatively smaller than the Gutenberg-Richter model.
