The anchor stress extent of a prestress anchor cable project has a direct relation with the project safety and performance. Prestressed tensioning method is a kind of nondestructive testing method, by which a reverse ...The anchor stress extent of a prestress anchor cable project has a direct relation with the project safety and performance. Prestressed tensioning method is a kind of nondestructive testing method, by which a reverse stretching load is applied on the external exposure section of anchor cable under construction or in service, and then the elongation variation of stress bars is measured to determine the anchor stress. We elaborated the theory and testing mechanism of prestressed tensioning method, and systematically studied key issues during the prestressed tensioning process of anchor cable by using physical model test, including the composition of tension stress-elongation curve, the variation of anchor stress, the compensation of locked anchor stress, and the judgment of anchor stress, and verified the theory feasibility of prestressed tensioning method. A case study on slope anchor cable of one highway project was conducted to further discuss on the test method, operation procedures and judgment of prestressed tensioning method on obtaining anchor stress, and then the test data of three situations were analyzed. The result provides a theoretical basis and technical base for the application of prestressed tensioning method to the evaluation of construction quality and operation conditions of anchor cable project.展开更多
With the theoretical and technological developments related to cratonic strike-slip faults,the Shuntuoguole Low Uplift in the Tarim Basin has attracted considerable attention recently.Affected by multi-stage tectonic ...With the theoretical and technological developments related to cratonic strike-slip faults,the Shuntuoguole Low Uplift in the Tarim Basin has attracted considerable attention recently.Affected by multi-stage tectonic movements,the strike-slip faults have controlled the distribution of hydrocarbon resources owing to the special fault characteristics and fault-related structures.In contrast,the kinematics and formation mechanism of strike-slip faults in buried sedimentary basins are difficult to investigate,limiting the discussion of these faults and hydrocarbon accumulation.In this study,we identified the characteristics of massive sigmoidal tension gashes(STGs)that formed in the Shunnan area of the Tarim Basin.High-resolution three-dimensional seismic data and attribute analyses were used to investigate their geometric and kinematic characteristics.Then,the stress state of each point of the STGs was calculated using seismic curvature attributes.Finally,the formation mechanism of the STGs and their roles in controlling hydrocarbon migration and accumulation were discussed.The results suggest that:(1)the STGs developed in the Shunnan area have a wide distribution,with a tensile fault arranged in an enéchelon pattern,showing an S-shaped bending.These STGs formed in multiple stages,and differential rotation occurred along the direction of strike-slip stress during formation.(2)Near the principal displacement zone of the strike-slip faults,the stress value of the STGs was higher,gradually decreasing at both ends.The shallow layer deformation was greater than the deep layer deformation.(3)STGs are critical for connecting source rocks,migrating oil and gas,sealing horizontally,and developing efficient reservoirs.This study not only provides seismic evidence for the formation and evolution of super large STGs,but also provides certain guidance for oil and gas exploration in this area.展开更多
Background Inside out transobturator vaginal tape （TVT-O） and tension-free vaginal tape （TVT） are predominant surgical treatments for female stress urinary incontinence. This meta-analysis evaluated the complicati...Background Inside out transobturator vaginal tape （TVT-O） and tension-free vaginal tape （TVT） are predominant surgical treatments for female stress urinary incontinence. This meta-analysis evaluated the complications and cure rates of TVT-O versus TVT. Methods A comprehensive literature search was conducted according to the Cochrane Collaboration methodology to identify randomized controlled clinical trials with no language restriction. Two authors independently assessed papers for eligibility and methodological quality. Estimates were measured by relative risk with 95% confidence intervals. Outcome measures were objective cure, subjective cure and complications. Quality rating for each outcome of the meta-analysis and recommendations were performed by the Grading of Recommendations Assessment, Development, and Evaluation （GRADE） system. Results Twenty randomized controlled trials met the inclusion criteria, and a pooled estimate of effectiveness and complications was made. Relative risks with 95% confidence intervals for pooled effects under the fixed effects model were： 0.20 （0.09-0.45）, for bladder injury, 0.37 （0.16-0.86） for hematoma, and 2.35 （1.57-3.51） for postoperative pain, suggesting an 80% risk reduction of bladder injury, 63% risk reduction of hematoma, and a 1.35% risk elevation for postoperative pain with TVT-O. There was no significant difference between complications of urinary tract infection 1.14 （0.78-1.65）, lower urinary tract symptoms 1.60 （0.67-3.79）, recatheterization 0.93 （0.59-1.44）, and tape erosion 0.90 （0.48-1.67）, total objective cure rate 1.06 （0.39-2.84） and for the subjective cure rate 0.98 （0.93-1.04）. The quality rating for each outcome and recommendations was high for objective cure, bladder injury, hematoma, lower urinary tract symptoms, and tape erosion and moderate for subjective cure, pain, and urinary tract infection. Conclusions TVT-O is associated with a reduced risk of bladder injury and hematoma and an elevated risk of postoperative pain. Other complications, including tape erosion,urinary tract infection, lower urinary tract symptoms, and recatheterization, are similar to those of TVT.展开更多
基金Funded by the Science and Technolog Program of Ministry of Transport of P.R.China(No.2012318352100)
文摘The anchor stress extent of a prestress anchor cable project has a direct relation with the project safety and performance. Prestressed tensioning method is a kind of nondestructive testing method, by which a reverse stretching load is applied on the external exposure section of anchor cable under construction or in service, and then the elongation variation of stress bars is measured to determine the anchor stress. We elaborated the theory and testing mechanism of prestressed tensioning method, and systematically studied key issues during the prestressed tensioning process of anchor cable by using physical model test, including the composition of tension stress-elongation curve, the variation of anchor stress, the compensation of locked anchor stress, and the judgment of anchor stress, and verified the theory feasibility of prestressed tensioning method. A case study on slope anchor cable of one highway project was conducted to further discuss on the test method, operation procedures and judgment of prestressed tensioning method on obtaining anchor stress, and then the test data of three situations were analyzed. The result provides a theoretical basis and technical base for the application of prestressed tensioning method to the evaluation of construction quality and operation conditions of anchor cable project.
基金Thanks to the Northwest Oilfield Branch,SINOPEC,for providing the seismic data.We thank Dr.Yi-Duo Liu of University of Houston,Ying-Chang Cao and Fang Hao of China University of Petroleum(East China)for their constructive suggestions of this manuscript.We also thank two anonymous reviewers for their comments that helped us to improve the manuscript.This research is jointly supported by the National Natural Science Foundation of China(No.42272155)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA14010301)+1 种基金the Science Fund for Creative Research Groups of the National Natural Science Foundation of China(Grant No.41821002)National Natural Science Foundation of China(No.41702138).
文摘With the theoretical and technological developments related to cratonic strike-slip faults,the Shuntuoguole Low Uplift in the Tarim Basin has attracted considerable attention recently.Affected by multi-stage tectonic movements,the strike-slip faults have controlled the distribution of hydrocarbon resources owing to the special fault characteristics and fault-related structures.In contrast,the kinematics and formation mechanism of strike-slip faults in buried sedimentary basins are difficult to investigate,limiting the discussion of these faults and hydrocarbon accumulation.In this study,we identified the characteristics of massive sigmoidal tension gashes(STGs)that formed in the Shunnan area of the Tarim Basin.High-resolution three-dimensional seismic data and attribute analyses were used to investigate their geometric and kinematic characteristics.Then,the stress state of each point of the STGs was calculated using seismic curvature attributes.Finally,the formation mechanism of the STGs and their roles in controlling hydrocarbon migration and accumulation were discussed.The results suggest that:(1)the STGs developed in the Shunnan area have a wide distribution,with a tensile fault arranged in an enéchelon pattern,showing an S-shaped bending.These STGs formed in multiple stages,and differential rotation occurred along the direction of strike-slip stress during formation.(2)Near the principal displacement zone of the strike-slip faults,the stress value of the STGs was higher,gradually decreasing at both ends.The shallow layer deformation was greater than the deep layer deformation.(3)STGs are critical for connecting source rocks,migrating oil and gas,sealing horizontally,and developing efficient reservoirs.This study not only provides seismic evidence for the formation and evolution of super large STGs,but also provides certain guidance for oil and gas exploration in this area.
文摘Background Inside out transobturator vaginal tape （TVT-O） and tension-free vaginal tape （TVT） are predominant surgical treatments for female stress urinary incontinence. This meta-analysis evaluated the complications and cure rates of TVT-O versus TVT. Methods A comprehensive literature search was conducted according to the Cochrane Collaboration methodology to identify randomized controlled clinical trials with no language restriction. Two authors independently assessed papers for eligibility and methodological quality. Estimates were measured by relative risk with 95% confidence intervals. Outcome measures were objective cure, subjective cure and complications. Quality rating for each outcome of the meta-analysis and recommendations were performed by the Grading of Recommendations Assessment, Development, and Evaluation （GRADE） system. Results Twenty randomized controlled trials met the inclusion criteria, and a pooled estimate of effectiveness and complications was made. Relative risks with 95% confidence intervals for pooled effects under the fixed effects model were： 0.20 （0.09-0.45）, for bladder injury, 0.37 （0.16-0.86） for hematoma, and 2.35 （1.57-3.51） for postoperative pain, suggesting an 80% risk reduction of bladder injury, 63% risk reduction of hematoma, and a 1.35% risk elevation for postoperative pain with TVT-O. There was no significant difference between complications of urinary tract infection 1.14 （0.78-1.65）, lower urinary tract symptoms 1.60 （0.67-3.79）, recatheterization 0.93 （0.59-1.44）, and tape erosion 0.90 （0.48-1.67）, total objective cure rate 1.06 （0.39-2.84） and for the subjective cure rate 0.98 （0.93-1.04）. The quality rating for each outcome and recommendations was high for objective cure, bladder injury, hematoma, lower urinary tract symptoms, and tape erosion and moderate for subjective cure, pain, and urinary tract infection. Conclusions TVT-O is associated with a reduced risk of bladder injury and hematoma and an elevated risk of postoperative pain. Other complications, including tape erosion,urinary tract infection, lower urinary tract symptoms, and recatheterization, are similar to those of TVT.
