Based on the upper bound of limit analysis, the plane-strain analysis of the slopes reinforced with a row of piles to the 3D case was extended. A 3D rotational failure mechanism was adopted to yield the upper bound of...Based on the upper bound of limit analysis, the plane-strain analysis of the slopes reinforced with a row of piles to the 3D case was extended. A 3D rotational failure mechanism was adopted to yield the upper bound of the factor of safety. Parametric studies were carried out to explore the end effects of the slope failures and the effects of the pile location and diameter on the safety of the reinforced slopes. The results demonstrate that the end effects nearly have no effects on the most suitable location of the installed piles but have significant influence on the safety of the slopes. For a slope constrained to a narrow width, the slope becomes more stable owing to the contribution of the end effects. When the slope is reinforced with a row of piles in small space between piles, the effects of group piles are significant for evaluating the safety of slopes. The presented method is more appropriate for assessing the stability of slopes reinforced with piles and can be also utilized in the design of plies stabilizing the unstable slopes.展开更多
traditional In this paper, two drawbacks pseudo-static method （vertical of the slice method） in the slope stability evaluation have been studied. First, the sliding mass is divided into vertical slices according to...traditional In this paper, two drawbacks pseudo-static method （vertical of the slice method） in the slope stability evaluation have been studied. First, the sliding mass is divided into vertical slices according to this method, which is irrational to some extent in the seismic design of slope. Second, only peak ground acceleration （PGA） is considered, and the effects of shaking frequency and duration on slope stability are neglected. And then, based on the theory of elastic wave and the summarized geological model, this paper put forwards an improved method of pseudo-method by using the theory of elastic wave and Hilbert-Huang transform. The improved pseudostatic method gives reasonable considerations to the time-frequency effects of seismic wave and its rationality has been verified by the shaking table test. This method can evaluate the safety of a slope, the happening time and the scale of landslides. At the same time, this method also can improve the high accuracy of the evaluation of the safety of the slope.展开更多
The core of strength reduction method(SRM) involves finding a critical strength curve that happens to make the slope globally fail and a definition of factor of safety(FOS). A new double reduction method, including a ...The core of strength reduction method(SRM) involves finding a critical strength curve that happens to make the slope globally fail and a definition of factor of safety(FOS). A new double reduction method, including a detailed calculation procedure and a definition of FOS for slope stability was developed based on the understanding of SRM. When constructing the new definition of FOS, efforts were made to make sure that it has concise physical meanings and fully reflects the shear strength of the slope. Two examples, slopes A and B with the slope angles of 63° and 34° respectively, were given to verify the method presented. It is found that, for these two slopes, the FOSs from original strength reduction method are respectively 1.5% and 38% higher than those from double reduction method. It is also found that the double reduction method predicts a deeper potential slide line and a larger slide mass. These results show that on one hand, the double reduction method is comparative to the traditional methods and is reasonable, and on the other hand, the original strength reduction method may overestimate the safety of a slope. The method presented is advised to be considered as an additional option in the practical slope stability evaluations although more useful experience is required.展开更多
In order to establish a rapid method for regional slope stability analysis under rainfall,matric suction and seepage force were taken into account after obtaining explicit solution of infiltration depth.Moreover,simpl...In order to establish a rapid method for regional slope stability analysis under rainfall,matric suction and seepage force were taken into account after obtaining explicit solution of infiltration depth.Moreover,simplified analysis model under 3D condition was put forward based on identification and division of slope units,as well as modification of sliding direction of each column.The result shows that explicit solution of infiltration depth is of good precision;for the given model,safety factors without taking seepage force into account are 1.82-2.94 times higher;the stagnation point of slope angle is located approximately in the range of(45°,50°);the safety factor changes insignificantly when wetting front is deeper than 2 m;when matric suction changes in the specified range,the maximum variations of safety factor are less than 0.5,which proves that matric suction plays an insignificant role in maintaining slope stability compared to the slope angle and infiltration depth.Incorporated with geographic information system,a practical application of regional slope stability assessment verifies the applicability of the proposed method.展开更多
As a novel heart rate lowing agent, ivabradine can reduce the heart rate by inhibiting the If （pacemaker） current in the sinoatrial node without affecting blood pressure or left ventricular systolic function. Howeve...As a novel heart rate lowing agent, ivabradine can reduce the heart rate by inhibiting the If （pacemaker） current in the sinoatrial node without affecting blood pressure or left ventricular systolic function. However, the safety of ivabradine remains controversial. In the present work, we aimed to assess any risk of cardiovascular mortality, bradycardia, phosphenes and atrial fibrillation associated with the ivabradine administration by recta-analysis. Studies were retrieved from PubMed, EMBASE, MEDLINE, Web of Science, Cochrane, www.clinicaltrials.gov web site and related conferences. Randomized controlled trials comparing ivabradine with comparators were identified and analyzed. Two reviewers independently extracted relevant information from the eligible trials and processed the data. This recta-analysis was performed by using Review Manager （5.3） and Stata （14.1） software. Moreover, sensitivity analysis and publication bias of the included studies were evaluated. A total of 12 randomized controlled trials meeting the inclusion criteria were included. Results of the meta-analysis revealed that there was no significant difference between ivabradine group and control groups in cardiovascular mortality （RR = 0.97, 95% CI： 0.89-1.06, P = 0.49）. While the administration of ivabradine was associated with a significant increase in the incidence of bradycardia （RR = 3.90, 95% CI： 2.47-6.17, P〈0.00001） and phosphenes （RR = 4.95, 95% CI： 3.24-7.55, P〈0.00001） as well as atrial fibrillation （RR = 1.24, 95% CI： 1.07-1.43, P = 0.003）. High quality of the included studies was confirmed by quality assessment. No publication bias was observed, and sensitivity analysis confirmed that the obtained results were stable. In conclusion, the meta-analysis proved that the use of ivabradine was associated with a significant increase in the risk of bradycardia, phosphenes and atrial fibrillation. Therefore, clinicians need to take these risks into account when using ivabradine in treatment.展开更多
基金Projects(51278382,51479050)supported by the National Natural Science Foundation of ChinaProject(2015CB057901)supported by the National Key Basic Research Program of China+3 种基金Project(201501035-03)supported by the Public Service Sector R&D Project of Ministry of Water Resource of ChinaProject(2014B06814)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(B13024)supported by the"111"ProjectProject(YK913004)supported by the Open Foundation of Key Laboratory of Failure Mechanism and Safety Control Techniques of Earthrock Dam of the Ministry of Water Resources,China
文摘Based on the upper bound of limit analysis, the plane-strain analysis of the slopes reinforced with a row of piles to the 3D case was extended. A 3D rotational failure mechanism was adopted to yield the upper bound of the factor of safety. Parametric studies were carried out to explore the end effects of the slope failures and the effects of the pile location and diameter on the safety of the reinforced slopes. The results demonstrate that the end effects nearly have no effects on the most suitable location of the installed piles but have significant influence on the safety of the slopes. For a slope constrained to a narrow width, the slope becomes more stable owing to the contribution of the end effects. When the slope is reinforced with a row of piles in small space between piles, the effects of group piles are significant for evaluating the safety of slopes. The presented method is more appropriate for assessing the stability of slopes reinforced with piles and can be also utilized in the design of plies stabilizing the unstable slopes.
基金supported in part by National Science Foundation of China (Contract NO. 41030742)Guangxi Science Foundation and the Program for Science & Technology of Henan Province in China (Grant No. 142300410200)
文摘traditional In this paper, two drawbacks pseudo-static method （vertical of the slice method） in the slope stability evaluation have been studied. First, the sliding mass is divided into vertical slices according to this method, which is irrational to some extent in the seismic design of slope. Second, only peak ground acceleration （PGA） is considered, and the effects of shaking frequency and duration on slope stability are neglected. And then, based on the theory of elastic wave and the summarized geological model, this paper put forwards an improved method of pseudo-method by using the theory of elastic wave and Hilbert-Huang transform. The improved pseudostatic method gives reasonable considerations to the time-frequency effects of seismic wave and its rationality has been verified by the shaking table test. This method can evaluate the safety of a slope, the happening time and the scale of landslides. At the same time, this method also can improve the high accuracy of the evaluation of the safety of the slope.
基金Project(11102218) supported by the National Natural Science Foundation of China
文摘The core of strength reduction method(SRM) involves finding a critical strength curve that happens to make the slope globally fail and a definition of factor of safety(FOS). A new double reduction method, including a detailed calculation procedure and a definition of FOS for slope stability was developed based on the understanding of SRM. When constructing the new definition of FOS, efforts were made to make sure that it has concise physical meanings and fully reflects the shear strength of the slope. Two examples, slopes A and B with the slope angles of 63° and 34° respectively, were given to verify the method presented. It is found that, for these two slopes, the FOSs from original strength reduction method are respectively 1.5% and 38% higher than those from double reduction method. It is also found that the double reduction method predicts a deeper potential slide line and a larger slide mass. These results show that on one hand, the double reduction method is comparative to the traditional methods and is reasonable, and on the other hand, the original strength reduction method may overestimate the safety of a slope. The method presented is advised to be considered as an additional option in the practical slope stability evaluations although more useful experience is required.
基金Project(kfj110207) supported by Open Fund of Key Laboratory of Road Structure and Material of Ministry of Transport,China
文摘In order to establish a rapid method for regional slope stability analysis under rainfall,matric suction and seepage force were taken into account after obtaining explicit solution of infiltration depth.Moreover,simplified analysis model under 3D condition was put forward based on identification and division of slope units,as well as modification of sliding direction of each column.The result shows that explicit solution of infiltration depth is of good precision;for the given model,safety factors without taking seepage force into account are 1.82-2.94 times higher;the stagnation point of slope angle is located approximately in the range of(45°,50°);the safety factor changes insignificantly when wetting front is deeper than 2 m;when matric suction changes in the specified range,the maximum variations of safety factor are less than 0.5,which proves that matric suction plays an insignificant role in maintaining slope stability compared to the slope angle and infiltration depth.Incorporated with geographic information system,a practical application of regional slope stability assessment verifies the applicability of the proposed method.
文摘As a novel heart rate lowing agent, ivabradine can reduce the heart rate by inhibiting the If （pacemaker） current in the sinoatrial node without affecting blood pressure or left ventricular systolic function. However, the safety of ivabradine remains controversial. In the present work, we aimed to assess any risk of cardiovascular mortality, bradycardia, phosphenes and atrial fibrillation associated with the ivabradine administration by recta-analysis. Studies were retrieved from PubMed, EMBASE, MEDLINE, Web of Science, Cochrane, www.clinicaltrials.gov web site and related conferences. Randomized controlled trials comparing ivabradine with comparators were identified and analyzed. Two reviewers independently extracted relevant information from the eligible trials and processed the data. This recta-analysis was performed by using Review Manager （5.3） and Stata （14.1） software. Moreover, sensitivity analysis and publication bias of the included studies were evaluated. A total of 12 randomized controlled trials meeting the inclusion criteria were included. Results of the meta-analysis revealed that there was no significant difference between ivabradine group and control groups in cardiovascular mortality （RR = 0.97, 95% CI： 0.89-1.06, P = 0.49）. While the administration of ivabradine was associated with a significant increase in the incidence of bradycardia （RR = 3.90, 95% CI： 2.47-6.17, P〈0.00001） and phosphenes （RR = 4.95, 95% CI： 3.24-7.55, P〈0.00001） as well as atrial fibrillation （RR = 1.24, 95% CI： 1.07-1.43, P = 0.003）. High quality of the included studies was confirmed by quality assessment. No publication bias was observed, and sensitivity analysis confirmed that the obtained results were stable. In conclusion, the meta-analysis proved that the use of ivabradine was associated with a significant increase in the risk of bradycardia, phosphenes and atrial fibrillation. Therefore, clinicians need to take these risks into account when using ivabradine in treatment.
