Study On The Stability Of The No.2 Reinforced Slope In Wushan Airport

In recent years,the construction of airports in the Southwest has developed rapidly.The mountainous airport has complex geological conditions,large terrain fluctuations,high filling slope height,long grading and wide land occupation,while the reinforced slope low cost,simple construction,economical land occupation,strong earthquake resistance and beautiful appearance.The reinforcement technology of high-filled slope has obvious advantages and increasing,such as the Hechi Airport 55 m reinforced high slope and the Shennongjia Airport 61 m reinforced high slope.The reinforcement mechanism of high-filled slopes in mountainous airports is complex,and there are many potential deformation and failure modes.while the stability analysis and calculation are complicated,The stability analysis method of reinforced soil slopes in relevant codes is not fully applicable to high-filled reinforced edges slope.Therefore,it is necessary to carry out the research on the mechanism and stability analysis of the high fill slope reinforcement in mountainous airports.This paper based on the Wushan Shennvfeng Airport Project,studied the stability of the No.2 reinforced slope deeply.Through the methods of field monitoring,laboratory test and numerical simulation,the reinforcement mechanism of reinforced slope,the deformation law of geogrids and reinforced slope,the deformation and mechanical characteristics of slope and reinforced material,the position change and stability of the most dangerous sliding surface under different lengths of reinforced material were systematically studied.The main research contents and results are as follows:The pull-out test of three different types of geogrid was were carried out by self-made modified pull test instrument,and compared with the results of direct shear test,the shear strength value and high fill slope of limestone gravel soil in Wushan area were obtained.The reinforced mechanism of action provides a basis for the numerical values of the parameters.Through the on-site deformation and settlement monitoring of the reinforced slope,the deformation law of the geogrid and the reinforced slope is obtained.Using the finite element method to analyze the deformation and mechanical characteristics of the reinforced slope,compare and analyze the displacement changes before and after the reinforcement of the slope,and analyze the tensile force of the geogrid.The results show that the bite force of the geogrid and the soil restrains the displacement of the soil,thus improving the stability of the slope;the tensile force of the geogrid gradually increases with the increase of the number of geogrid reinforcement layers.The second-stage thirteen-layer geogrid tensile force slowly decreases after reaching the peak value.The method of geogrid parameter value is discussed.The actual tensile force value of the geogrid is calculated by the on-site monitoring data,and then compared with the finite element simulation of the tensile value.Taking the average value of all geogrid tensile forces in this grade as the tensile value of each grade slope geogrid,it provides a reference for numerical simulation of geogrid parameter value method.Based on the limit equilibrium method,the stability of the slope and the change of the slip surface position of the reinforced slope under different reinforced lengths are analyzed.It is concluded that when the length of the geogrid is 24~26m,the geogrid reaches the position of the slip surface and there is no redundant anchoring length,the stability coefficient of the geogrid reaches the peak,which provides the basis for the design of the reinforced slope.