基于修正的压力场理论MCFT(The Modified Compression Field Theory)和纤维单元模型建立了钢筋混凝土桥墩的弯剪数值分析模型,以MCFT理论确定桥墩的剪切力-剪切位移关系,并与考虑桥墩弯曲变形的纤维单元模型组合,共同考虑桥墩的弯-剪-...基于修正的压力场理论MCFT(The Modified Compression Field Theory)和纤维单元模型建立了钢筋混凝土桥墩的弯剪数值分析模型,以MCFT理论确定桥墩的剪切力-剪切位移关系,并与考虑桥墩弯曲变形的纤维单元模型组合,共同考虑桥墩的弯-剪-轴力耦合作用。通过与六个弯剪破坏控制的圆形截面钢筋混凝土桥墩拟静力试验结果的对比,对分析模型进行了验证。主要认识结论为基于MCFT理论可准确地计算弯剪破坏桥墩的屈服荷载、极限荷载和弹性阶段剪切刚度,剪切开裂是引起钢筋混凝土构件剪切力-剪切位移关系刚度突变的主要因素,而弯曲开裂与纵筋屈服对刚度的影响较小;分析模型对弯剪破坏桥墩的滞回曲线、弯曲与剪切变形成分均进行了较为准确的模拟分析。展开更多
We conducted a detailed analysis of along-trench variations in the flexural bending of the subducting Pacific Plate at the Tonga-Kermadec Trench.Inversions were conducted to obtain best-fitting solutions of trench-axi...We conducted a detailed analysis of along-trench variations in the flexural bending of the subducting Pacific Plate at the Tonga-Kermadec Trench.Inversions were conducted to obtain best-fitting solutions of trench-axis loadings and variations in the effective elastic plate thickness for the analyzed flexural bending profiles.Results of the analyses revealed significant along-trench variations in plate flexural bending:the trench relief(W0)of 1.9 to 5.1 km;trench-axis vertical loading(V0)of-0.5×10^12 to 2.2×10^12 N/m;axial bending moment(M0)of 0.1×10^17 to 2.2×10^17 N;effective elastic plate thickness seaward of the outer-rise region(Te^M)of 20 to 65 km,trench-ward of the outer-rise(Te^M)of 11 to 33 km,and the transition distance(Xr)of 20 to 95 km.The Horizon Deep,the second greatest trench depth in the world,has the greatest trench relief(W0 of 5.1km)and trench-axis loading(V0 of 2.2×10^12N/m);these values are only slightly smaller than that of the Challenger Deep(W0 of 5.7km and V0 of 2.9×10^12N/m)and similar to that of the Sirena Deep(W0 of 5.2 km and V0 of 2.0×10^12 N/m)of the Mariana Trench,suggesting that these deeps are linked to great flexural bending of the subducting plates.Analyses using three independent methods,i.e.,the/inversion,the flexural curvature/yield strength envelope analysis,and the elasto-plastic bending model with normal faults,all yielded similar average Te reduction of 28%-36% and average Te reduction area S△Te of 1195-1402 km^2 near the trench axis.The calculated brittle yield zone depth from the flexural curvature/yield strength envelope analysis is also consistent with the distribution of the observed normal faulting earthquakes.Comparisons of the Manila,Philippine,Tonga-Kermadec,Japan,and Mariana Trenches revealed that the average values Te^M of Te^M and both in general increase with the subducting plate age.展开更多
文摘基于修正的压力场理论MCFT(The Modified Compression Field Theory)和纤维单元模型建立了钢筋混凝土桥墩的弯剪数值分析模型,以MCFT理论确定桥墩的剪切力-剪切位移关系,并与考虑桥墩弯曲变形的纤维单元模型组合,共同考虑桥墩的弯-剪-轴力耦合作用。通过与六个弯剪破坏控制的圆形截面钢筋混凝土桥墩拟静力试验结果的对比,对分析模型进行了验证。主要认识结论为基于MCFT理论可准确地计算弯剪破坏桥墩的屈服荷载、极限荷载和弹性阶段剪切刚度,剪切开裂是引起钢筋混凝土构件剪切力-剪切位移关系刚度突变的主要因素,而弯曲开裂与纵筋屈服对刚度的影响较小;分析模型对弯剪破坏桥墩的滞回曲线、弯曲与剪切变形成分均进行了较为准确的模拟分析。
基金The National Natural Science Foundation of China under contract Nos 41976064,91958211,41890813,91858207,91628301,U1606401,41976066 and 41706056the Programs of the Chinese Academy of Sciences under contract Nos Y4SL021001,QYZDY-SSW-DQC005 and 133244KYSB20180029+1 种基金the National Key Research and Development Program of China under contract Nos2018YFC0309800 and 2018YFC0310100the China Ocean Mineral Resources R&D Association under contract No.DY135-S2-1-04
文摘We conducted a detailed analysis of along-trench variations in the flexural bending of the subducting Pacific Plate at the Tonga-Kermadec Trench.Inversions were conducted to obtain best-fitting solutions of trench-axis loadings and variations in the effective elastic plate thickness for the analyzed flexural bending profiles.Results of the analyses revealed significant along-trench variations in plate flexural bending:the trench relief(W0)of 1.9 to 5.1 km;trench-axis vertical loading(V0)of-0.5×10^12 to 2.2×10^12 N/m;axial bending moment(M0)of 0.1×10^17 to 2.2×10^17 N;effective elastic plate thickness seaward of the outer-rise region(Te^M)of 20 to 65 km,trench-ward of the outer-rise(Te^M)of 11 to 33 km,and the transition distance(Xr)of 20 to 95 km.The Horizon Deep,the second greatest trench depth in the world,has the greatest trench relief(W0 of 5.1km)and trench-axis loading(V0 of 2.2×10^12N/m);these values are only slightly smaller than that of the Challenger Deep(W0 of 5.7km and V0 of 2.9×10^12N/m)and similar to that of the Sirena Deep(W0 of 5.2 km and V0 of 2.0×10^12 N/m)of the Mariana Trench,suggesting that these deeps are linked to great flexural bending of the subducting plates.Analyses using three independent methods,i.e.,the/inversion,the flexural curvature/yield strength envelope analysis,and the elasto-plastic bending model with normal faults,all yielded similar average Te reduction of 28%-36% and average Te reduction area S△Te of 1195-1402 km^2 near the trench axis.The calculated brittle yield zone depth from the flexural curvature/yield strength envelope analysis is also consistent with the distribution of the observed normal faulting earthquakes.Comparisons of the Manila,Philippine,Tonga-Kermadec,Japan,and Mariana Trenches revealed that the average values Te^M of Te^M and both in general increase with the subducting plate age.
