Seismic Risk And Safety Assessment Of Levee Project In Soft Soil Foundation

Levee project is an important part of city flood control system, and the safetybarrier of safeguarding the people’s lives and property. But there were some Leveesdamaged in every large earthquake. So it is necessary to study the seismic stability ofthe levee project. In our country, many Levee were build on the soft soil foundation,and made of sand or soil. The foundation and seismic capability is weak. Besides thesoil parameters have large variability, which does not make the levee to be absolutelystability with the single safety coefficient. Risk analysis can make up the deficiency.Based on these reasons, the article had built earthquake risk assessment methods oflevee project according to the general risk theory. The main contents of the study aredescribed as follow:(1) The method was deduced to calculate the probability of specific earthquakeintensity according to the common seismic risk analysis method. The basic seismicintensity and shape parameters of research areas were the main variables.(2) Sandy soil liquefaction is the main seismic failure mode of sandy levees,andone of the main causes of other damage of levees, which is also the focuses of the study.Firstly, based on the study of the classic methods for evaluating soil liquefactionresistance, the program for calculating soil liquefaction probability was developed. Thereliability theory of JC and the method of soil liquefaction resistance evaluation usingSPT were the basis of the program.(3) The principle of landslide stability analysis were discussed and the programcombined with Morgenstern—Price and Monte Carlo methods was used to calculatethe failure probability of levee seismic landslides.(4) The calculation method of levee seismic vulnerability probability and theseismic damage standard of levee were discussed on the basis of soil liquefaction andlandslide failure probability.(5) The calculation method for levee earthquake economic losses and the seismicrisk assessment of levee project were discussed based on the analysis of vulnerabilityprobability(6) The analysis method was used to evaluate the seismic risk of a sand dikewhich located in downstream of minjiang river in fuzhou. First, some tests for evaluating of soil liquefaction such as SPT, CPT, wave velocity test and dynamictriaxial test were done on the levee. Both the test and program were discussed toanalysis the soil liquefaction hazard. Overall seismic vulnerability of the levee wasstudied considering soil liquefaction and landslide failure mode. The seismic risk of thelevee was estimated by calculating the losses of the dike caused by different intensityearthquake.