Lateral displacement due to liquefaction(D_(H))is the most destructive effect of earthquakes in saturated loose or semi-loose sandy soil.Among all earthquake parameters,the standardized cumulative absolute velocity(CA...Lateral displacement due to liquefaction(D_(H))is the most destructive effect of earthquakes in saturated loose or semi-loose sandy soil.Among all earthquake parameters,the standardized cumulative absolute velocity(CAV_(5))exhibits the largest correlation with increasing pore water pressure and liquefaction.Furthermore,the complex effect of fine content(FC)at different values has been studied and demonstrated.Nevertheless,these two contexts have not been entered into empirical and semi-empirical models to predict D_(H)This study bridges this gap by adding CAV_(5)to the data set and developing two artificial neural network(ANN)models.The first model is based on the entire range of the parameters,whereas the second model is based on the samples with FC values that are less than the 28%critical value.The results demonstrate the higher accuracy of the second model that is developed even with less data.Additionally,according to the uncertainties in the geotechnical and earthquake parameters,sensitivity analysis was performed via Monte Carlo simulation(MCS)using the second developed ANN model that exhibited higher accuracy.The results demonstrated the significant influence of the uncertainties of earthquake parameters on predicting D_(H).展开更多
The distribution of many active faults in western China is an important reasonfor the frequent earthquakes. With the rapid development of the western region, manymajor projects have been built there and the existence ...The distribution of many active faults in western China is an important reasonfor the frequent earthquakes. With the rapid development of the western region, manymajor projects have been built there and the existence of active faults is bound to have aninfluence on the safety of the engineering structure. Therefore, it is of great significanceto study the mechanism of fault slip instability for evaluating the geological stability ofthe region and for the site selection of major projects. In this paper, cusp catastrophetheory is used to establish a cusp catastrophe model with general softened form ofstrike-slip faults on the basis of strike-slip faults. In this model, the influence of thesoftening property of fault zone on fault instability is considered. Based on this model,the conditions of slip instability of strike-slip faults are derived and further the half-slipdistance, far-field displacement and energy release equation of sliding-slip fault arerevealed. The influences of the system stiffness ratio and the softening property of thefault zone on the half-wave displacement, the far-field displacement and the energyrelease are shown. Which lays a good foundation for further research on activefault-induced earthquake mechanism.展开更多
The degradation of the shear stress between pile-clay interface caused by undrained cyclic jacking affects the jacking force.A series of large displacement monotonic shear,cyclic shear and post-cyclic monotonic steel ...The degradation of the shear stress between pile-clay interface caused by undrained cyclic jacking affects the jacking force.A series of large displacement monotonic shear,cyclic shear and post-cyclic monotonic steel plate-clay interface shear te sts were performed under the constant normal load(CNL)condition to inve stigate the effects of normal stre ss,cyclic amplitude,and number of cycles on a steel plate-clay interface using the GDS multi-function interface shear tester.Based on the experimental results,in monotonic shear tests,change of shear stress took place in the specimen,the shear stress rapidly reached the peak value at shear displacement of 1 mm,and then abruptly decreased to the residual value.In cyclic shear te sts,accumulated displacement was a better parameter to describe the soil degradation characteristics,and the degradation degree of shear stress became greater with the increasing of normal stress and accumulated displacement.Shear stress in post-cyclic monotonic shear tests did not generate a peak value and was lower than that in monotonic shear tests under the same normal stress.The soil was completely disturbed and reached the residual strength when the cumulative displacement approached 6 m.An empirical equation to evaluate shear stress degradation mechanism was formulated and the procedure of parameter identification was presented.展开更多
基金The authors are grateful for the technical and financial support provided by the Scientific Innovation Group for Youths of Sichuan Province(No.2019JDTD0017).
文摘Lateral displacement due to liquefaction(D_(H))is the most destructive effect of earthquakes in saturated loose or semi-loose sandy soil.Among all earthquake parameters,the standardized cumulative absolute velocity(CAV_(5))exhibits the largest correlation with increasing pore water pressure and liquefaction.Furthermore,the complex effect of fine content(FC)at different values has been studied and demonstrated.Nevertheless,these two contexts have not been entered into empirical and semi-empirical models to predict D_(H)This study bridges this gap by adding CAV_(5)to the data set and developing two artificial neural network(ANN)models.The first model is based on the entire range of the parameters,whereas the second model is based on the samples with FC values that are less than the 28%critical value.The results demonstrate the higher accuracy of the second model that is developed even with less data.Additionally,according to the uncertainties in the geotechnical and earthquake parameters,sensitivity analysis was performed via Monte Carlo simulation(MCS)using the second developed ANN model that exhibited higher accuracy.The results demonstrated the significant influence of the uncertainties of earthquake parameters on predicting D_(H).
文摘The distribution of many active faults in western China is an important reasonfor the frequent earthquakes. With the rapid development of the western region, manymajor projects have been built there and the existence of active faults is bound to have aninfluence on the safety of the engineering structure. Therefore, it is of great significanceto study the mechanism of fault slip instability for evaluating the geological stability ofthe region and for the site selection of major projects. In this paper, cusp catastrophetheory is used to establish a cusp catastrophe model with general softened form ofstrike-slip faults on the basis of strike-slip faults. In this model, the influence of thesoftening property of fault zone on fault instability is considered. Based on this model,the conditions of slip instability of strike-slip faults are derived and further the half-slipdistance, far-field displacement and energy release equation of sliding-slip fault arerevealed. The influences of the system stiffness ratio and the softening property of thefault zone on the half-wave displacement, the far-field displacement and the energyrelease are shown. Which lays a good foundation for further research on activefault-induced earthquake mechanism.
基金financially supported by the Fundamental Research Funds for the Study on Formation and Evolution Mechanism of Soil Plug of Jacked Pipe Pile Cyclic Penetration in Clay (Grant No.52078483)。
文摘The degradation of the shear stress between pile-clay interface caused by undrained cyclic jacking affects the jacking force.A series of large displacement monotonic shear,cyclic shear and post-cyclic monotonic steel plate-clay interface shear te sts were performed under the constant normal load(CNL)condition to inve stigate the effects of normal stre ss,cyclic amplitude,and number of cycles on a steel plate-clay interface using the GDS multi-function interface shear tester.Based on the experimental results,in monotonic shear tests,change of shear stress took place in the specimen,the shear stress rapidly reached the peak value at shear displacement of 1 mm,and then abruptly decreased to the residual value.In cyclic shear te sts,accumulated displacement was a better parameter to describe the soil degradation characteristics,and the degradation degree of shear stress became greater with the increasing of normal stress and accumulated displacement.Shear stress in post-cyclic monotonic shear tests did not generate a peak value and was lower than that in monotonic shear tests under the same normal stress.The soil was completely disturbed and reached the residual strength when the cumulative displacement approached 6 m.An empirical equation to evaluate shear stress degradation mechanism was formulated and the procedure of parameter identification was presented.
