Reliability Study Of One-Dimensional Soil Seismic Response Analysis Programs For Deep Soil Sites

The phenomenon of actual seismic damage has confirmed that site conditions have a significant impact on ground motion and earthquake hazards,which is known as site effects.Site effects have always been a fundamental topic in earthquake engineering research.Its physical essence lies in the filtering and amplifying effect of the site soil layers on seismic waves,thereby modifying the interaction between seismic waves and engineering structures.The seismic response of deep soft soil sites is complex and significantly affects structural damage,making it a key and challenging aspect of geotechnical earthquake engineering research both domestically and internationally.The analysis and calculation of soil layer seismic response can visually assess the influence of site soil conditions on seismic parameters,evaluate site effects,and provide seismic motion parameters for seismic design,which is an important component of engineering seismic design and seismic safety evaluation work.The commonly used soil response analysis programs at present are mainly based on one-dimensional wave theory.Programs based on equivalent linearization theory and algorithms are still the mainstream for one-dimensional soil response analysis.These programs have the advantages of simple modeling,readily available parameters,high computational efficiency,and good convergence,making them highly favored in engineering practice.Traditional equivalent linearization algorithms assume that the maximum shear strain of the soil is 0.65 times the equivalent shear strain,which amplifies high-frequency components and reduces low-frequency components in the calculation of acceleration response.To address this issue,scholars have proposed frequency-consistent equivalent linearization methods and global equivalent linearization methods,and developed new calculation programs.The reliability of one-dimensional soil response analysis programs in calculating seismic response of deep soil layers has not been systematically addressed.To address this issue,the Japanese KiK-net strong motion database was used to collect data from 30 strong motion stations with soil layer thickness greater than 50 meters as the research objects.A total of 1218 strong motion records and 5 major earthquake events were collected.Five commonly used one-dimensional soil response analysis programs,namely DEEPSOIL7.0,LSSRLI-1,SHAKE2000,SOILQUAKE,and SOILRESPONSE,were used to calculate the ground surface acceleration and response spectra at 5%damping.The calculated values of three characteristic parameters of the normalized response spectra,including peak acceleration(a_max),predominant period（Tg）,and plateau value(β_max),were compared with the actual recorded values.The reliability of existing soil response analysis programs in calculating soil seismic response for deep soil layer sites was studied.The main work and research achievements can be summarized as follows:（1）Collected data from 30 deep soil site stations within the KiK-net network,and selected 1218 horizontal ground motion records with peak acceleration greater than 0.02g.Used five different soil response analysis programs to calculate the ground surface acceleration time history and 5%damped response spectra.Conducted a comparative analysis of the characteristic parameters,including peak acceleration(a_max),predominant period（T_g）,and plateau value(β_max).Identified an issue with DEEPSOIL7.0,LSSRLI-1,and SHAKE2000 that resulted in underestimated amax values under strong earthquake effects.（2）The reliability of five one-dimensional seismic response analysis programs in calculating deep soil response was analyzed.Through statistical analysis of the calculated values of three characteristic parameters,namely peak acceleration(a_max),predominant period（T_g）,and plateau value(β_max),it was found that the program "SOILRESPONSE"had the highest accuracy in calculating amax,while "SOILQUAKE" had the lowest accuracy.The differences in Tg calculation results among the programs were not significant,with "SOILQUAKE" showing slightly higher accuracy compared to the others.There was no significant difference in the accuracy of β_maxcalculations among the five programs.（3）The applicability of existing one-dimensional seismic response analysis programs under typical earthquakes was studied.By selecting horizontal ground motion data from five earthquakes within the KiK-net network with peak accelerations greater than 0.05g,the three characteristic parameters of response spectra were calculated using five different programs.The calculated values of the characteristic parameters were compared with the actual recorded values to evaluate the reliability of the predictions made by the different programs.The suitability of the programs was assessed based on the reliability of the parameter calculations and the occurrence of program malfunctions,and recommendations for selecting seismic response analysis programs for deep soil sites were provided.