Stability Analysis And Prevention Plan Of Highway Soft Soil Foundation In Pingtan Area

With the large-scale construction of foundation engineering and road engineering in China.,and because of the distribution of a large number of soft soil geology in China,especially in coastal areas,including inland plains and mountainous areas.This geological structure will inevitably be touched during the construction process.If it is not properly handled,it will easily lead to various geological disasters.Among them,the instability caused by the stability of soft soil foundation is particularly prominent,which has a certain impact on the construction of the project and the surrounding environment.In serious cases,it also causes heavy losses such as casualties.The Pingtan Comprehensive Experimental Zone,located in the eastern part of Fujian Province in the southeastern coast of Fujian Province,is in a period of rapid development.The demand for land and engineering quality are also increasing.Therefore,how to deal with soft soil foundation is even more important.It is necessary to carry out in-depth research on the treatment of soft soil foundation.Aiming at this problem,this paper combines the background of the road project of Pingtan Luzhong Road to carry out related research on the stability and prevention measures of the soft soil foundation in the area.The specific research contents and results are as follows:On the basis of collecting and analyzing the geological constituents of roads in Fujian Province,the characteristics and causes of various soft soil types are elaborated.Through the investigation of the geological conditions of the Pingtan Luzhong Road project,it is found that the soil in this area belongs to the coastal soft phase.The soil is analyzed for the geological structure of the area and the distribution and properties of the subgrade soil.After the geological evaluation,the uniformity of the subgrade is poor.It is necessary to treat some soil layers along the line to meet the subgrade settlement requirements.The subgrade settlement of the ground was analyzed and calculated by the soft foundation settlement deformation mechanism.Five sets of borehole exploration results were selected by surveying the drilling arrangement and the e～p curves obtained by the late’ral distribution and lateral compression experiments were obtained.the settlement characteristics are checked,the calculation of the compression of the foundation soil is completed,and finally the total settlement is obtained by summing the compression of each layer of the foundation by the stratified sum method.It was found that the estimated settlements of LKO2-Y and QK16-Y exceeded the requirements of the specification.At the same time,the main influencing factors affecting the settlement of highway subgrade in Pingtan area are pond soft soil,filling rate,groundwater level and lateral displacement of subgrade.Using ABAQUS finite element software to select the typical section of the three sections(road slope,excavation cutting slope,embankment slope at the filling pond)to establish three kinds of slope instability analysis models for simulation analysis and calculation,and conduct research on pavement settlement and slope stability analysis.It is found that the settlement value of the road surface still exceeds the specification requirements,and there are also problems such as slope instability.The various treatment methods for soft soil foundation are summarized from principle to feature.Combining the above stability analysis results with the Luzhong Road road engineering design plan and the engineering geological conditions of the site,the alternatives are listed,and the fuzzy optimal decision theory is adopted to comprehensively consider the cost,construction period,liquefaction resistance,reinforcement effect,etc.One factor,the one with the highest relative popularity is selected,that is,the high pressure rotary jet method is used to reinforce the foundation.The best comprehensive protection measures for the soft foundation settlement of Pingtan area were developed.Finally,through the finite element analysis of the effect of reinforcement measures,it was found that the settlement value was significantly reduced and the settlement was even,which proved that it was safe and reasonable.This result is consistent with the scheme adopted in the actual project,and demonstrates the superiority and rationality of the fuzzy optimal decision theory in the soft base scheme.Based on the existing soft foundation treatment technology and the calculation and analysis of the actual situation of the project,the soft foundation treatment measures suitable for the soft soil area of Pingtan area are obtained.The conclusions drawn in this paper have certain reference significance for guiding similar projects in the future.