A systematic method was proposed to estimate the occurrence probability of defective piles(OPDP) from a site according to quality assurance inspection. The OPDP was firstly suggested as the criterion to weight the per...A systematic method was proposed to estimate the occurrence probability of defective piles(OPDP) from a site according to quality assurance inspection. The OPDP was firstly suggested as the criterion to weight the performance of a pile foundation. Its prior distribution and updating distribution were deduced to follow Beta distributions. To calibrate the OPDP, a dynamic estimation model was established according to the relationships between prior mean and variance and updating mean and variance. Finally, a reliability-control method dealing with uncertainties arising from quality assurance inspection was formalized to judge whether all the bored piles from a site can be accepted. It is exemplified that the OPDP can be substantially improved when more definite prior information and sampling formation become available. For the example studied herein, the Bayesian estimator of updating variance for OPDP is reduced from 0.0037 to 0.0014 for the first inspection, from 0.0014 to 0.0009 for the second inspection, and with less uncertainty by incorporating experience information.展开更多
In the near future, several offshore wind farms are planned to be built in the North Sea. Therefore, jacket and tripod constructions with mainly axially loaded piles are suitable as support structures. The current des...In the near future, several offshore wind farms are planned to be built in the North Sea. Therefore, jacket and tripod constructions with mainly axially loaded piles are suitable as support structures. The current design of axial bearing resistance of these piles leads to deviant results regarding the pile resistance when different design methods are adopted. Hence, a strong deviation regarding the required pile length must be addressed. The reliability of a design method can be evaluated based on a model error which describes the quality of the considered design method by comparing measured and predicted pile bearing resistances. However, only few pile load tests are reported with regard to the boundary conditions in the North Sea. This paper presents 6 large-scale axial pile load tests which were incorporated within a new model error approach for the current design methods used for the axial bearing resistance,namely API Main Text method and cone penetration test(CPT)-based design methods, such as simplified ICP-05, offshore UWA-05, Fugro-05 and NGI-05 methods. Based on these new model errors, a reliabilitybased study towards the safety was conducted by performing a Monte-Carlo simulation. In addition,consequences regarding the deterministic pile design in terms of quality factors were evaluated. It is shown that the current global safety factor(GSF) prescribed and the partial safety factors are only valid for the API Main Text and the offshore UWA-05 design methods; whereas for the simplified ICP-05,Fugro-05 and NGI-05 design methods, an increase in the required embedded pile length and thus in the GSF up to 2.69, 2.95 and 3.27, respectively, should be considered to satisfy the desired safety level according to DIN EN 1990 of b ? 3.8. Further, quality factors for each design method on the basis of all reliability-based design results were derived. Hence, evaluation of each design method regarding the reliability of the pile capacity prediction is possible.展开更多
The safety of water quality in the Three Gorges Reservoir(TGR)is very important.Protections and remediation of environment safety are very crucial for guaranteeing TGR environmental quality.When piled municipal solid ...The safety of water quality in the Three Gorges Reservoir(TGR)is very important.Protections and remediation of environment safety are very crucial for guaranteeing TGR environmental quality.When piled municipal solid waste(MSW) dumps are submerged without treatment,pollutants in the MSW will leach into the water and threaten the water safety of the reservoir.Based on the surveys of the amount,distribution and characteristics of piled MSW in the TGR area,this study focusing on the MSW dumps at the water leve...展开更多
In order to improve the quality of bored piles in bridge construction and ensure the overall quality of the bridge,we analyzed a series of problems in the construction process of bored piles,then propose corresponding...In order to improve the quality of bored piles in bridge construction and ensure the overall quality of the bridge,we analyzed a series of problems in the construction process of bored piles,then propose corresponding quality control measures,in hopes of improving quality control of bored piles in bridge construction in our country.展开更多
CFG pile has been widely applied as one of the common ground treatment techniques. As a concealed work, the construction quality of pile foundation not only relates to the success of the project, but also concerns the...CFG pile has been widely applied as one of the common ground treatment techniques. As a concealed work, the construction quality of pile foundation not only relates to the success of the project, but also concerns the benefits of thousands of hot, seholds. Only strengthening the supervision and management during the construction and strictly designing and specifying CFG pile can ensure the construction quality of CFG pile. But most researches focus on operating mechanism and theoretical analysis, and there are fewer researches about the construction of CFG pile. The real construction of CFG pile has no specified operation and lacks of the construction guidance, which not only causes great problems and has great influence on the intensity of CFG pile, but also makes the real pile body have great difference from the design requirements. Therefore, the study on construction of CFG pile in the paper has great significance.展开更多
基金Project(51278216) supported by the National Natural Science Foundation of ChinaProject(2013BS010) supported by Henan University of Technology Fund for High-level Talent,China
文摘A systematic method was proposed to estimate the occurrence probability of defective piles(OPDP) from a site according to quality assurance inspection. The OPDP was firstly suggested as the criterion to weight the performance of a pile foundation. Its prior distribution and updating distribution were deduced to follow Beta distributions. To calibrate the OPDP, a dynamic estimation model was established according to the relationships between prior mean and variance and updating mean and variance. Finally, a reliability-control method dealing with uncertainties arising from quality assurance inspection was formalized to judge whether all the bored piles from a site can be accepted. It is exemplified that the OPDP can be substantially improved when more definite prior information and sampling formation become available. For the example studied herein, the Bayesian estimator of updating variance for OPDP is reduced from 0.0037 to 0.0014 for the first inspection, from 0.0014 to 0.0009 for the second inspection, and with less uncertainty by incorporating experience information.
基金the European Union funded project Integrated Research Project Wind (IRPWind, European Union Seventh Framework Program under Grant No. 609795)
文摘In the near future, several offshore wind farms are planned to be built in the North Sea. Therefore, jacket and tripod constructions with mainly axially loaded piles are suitable as support structures. The current design of axial bearing resistance of these piles leads to deviant results regarding the pile resistance when different design methods are adopted. Hence, a strong deviation regarding the required pile length must be addressed. The reliability of a design method can be evaluated based on a model error which describes the quality of the considered design method by comparing measured and predicted pile bearing resistances. However, only few pile load tests are reported with regard to the boundary conditions in the North Sea. This paper presents 6 large-scale axial pile load tests which were incorporated within a new model error approach for the current design methods used for the axial bearing resistance,namely API Main Text method and cone penetration test(CPT)-based design methods, such as simplified ICP-05, offshore UWA-05, Fugro-05 and NGI-05 methods. Based on these new model errors, a reliabilitybased study towards the safety was conducted by performing a Monte-Carlo simulation. In addition,consequences regarding the deterministic pile design in terms of quality factors were evaluated. It is shown that the current global safety factor(GSF) prescribed and the partial safety factors are only valid for the API Main Text and the offshore UWA-05 design methods; whereas for the simplified ICP-05,Fugro-05 and NGI-05 design methods, an increase in the required embedded pile length and thus in the GSF up to 2.69, 2.95 and 3.27, respectively, should be considered to satisfy the desired safety level according to DIN EN 1990 of b ? 3.8. Further, quality factors for each design method on the basis of all reliability-based design results were derived. Hence, evaluation of each design method regarding the reliability of the pile capacity prediction is possible.
文摘The safety of water quality in the Three Gorges Reservoir(TGR)is very important.Protections and remediation of environment safety are very crucial for guaranteeing TGR environmental quality.When piled municipal solid waste(MSW) dumps are submerged without treatment,pollutants in the MSW will leach into the water and threaten the water safety of the reservoir.Based on the surveys of the amount,distribution and characteristics of piled MSW in the TGR area,this study focusing on the MSW dumps at the water leve...
文摘In order to improve the quality of bored piles in bridge construction and ensure the overall quality of the bridge,we analyzed a series of problems in the construction process of bored piles,then propose corresponding quality control measures,in hopes of improving quality control of bored piles in bridge construction in our country.
文摘CFG pile has been widely applied as one of the common ground treatment techniques. As a concealed work, the construction quality of pile foundation not only relates to the success of the project, but also concerns the benefits of thousands of hot, seholds. Only strengthening the supervision and management during the construction and strictly designing and specifying CFG pile can ensure the construction quality of CFG pile. But most researches focus on operating mechanism and theoretical analysis, and there are fewer researches about the construction of CFG pile. The real construction of CFG pile has no specified operation and lacks of the construction guidance, which not only causes great problems and has great influence on the intensity of CFG pile, but also makes the real pile body have great difference from the design requirements. Therefore, the study on construction of CFG pile in the paper has great significance.
