Study On Reinforcement Mechanism And Stability Analysis Method Of Bilaterally Wrapped Geosynthetic-reinforcement Earth Embankment

Bilaterally wrapped geosynthetic-reinforcement embankment is a new type of reinforced earth structure,which has the advantages of strong reinforcement capacity,low cost and high efficiency of the reinforcement effect.This article relies on the foundation engineering of the Padma Bridge of Bengal Railway in Bangladesh,and uses theoretical analysis and numerical simulation methods for the bilaterally wrapped geosynthetic-reinforcement embankment to reveal its action mechanism and instability and failure mode.The local and overall stability analysis methods for such reinforced soil embankment slopes are established,and then the suitability of the principle of quasi-cohesive force of reinforced soil is analyzed.And the influence of main factors on the stability and quasi cohesion of reinforced earth embankment is also discussed.The main research work and results are as follows:(1)The action mechanism and embankment instability model of the bilaterally wrapped geosynthetic-reinforcement embankment are revealed.On the one hand,the same tie bar forms a counter-pull effect on both sides of the anti-wrapped section,and the invalid section of one side of the tie bar becomes the effective section of the other side of the tie bar;on the other hand,the parcel section is equivalent to a wall panel and fully bears the resistance to earth pressure.At the same time,this type of embankment has the most dangerous rupture surface,and only the local instability mode in the embankment filling and the overall instability mode appearing both in the embankment filling and foundation.(2)Based on the limit theorem of plastic limit analysis and the stability analysis of Fellnius and simplified Bishop method of horizontally-sliced slope,considering the two failure modes of tensile reinforcement and pull-out,the local and overall stability of the bilaterally wrapped geosynthetic-reinforcement embankment was established.And the formula for calculating the stability coefficient is derived.The example analysis shows that the local stability coefficient deviations of the limit analysis method and the Fellenius method,simplified Bishop method,and numerical simulation are 6.6%,2.9%,and 3.3%,respectively;Simplified Bishop method,Fellenius method,numerical simulation of embankment-foundation stability coefficient deviations are 6.1% and 2.7% respectively;the potentially most dangerous slip surface of the local slip of the embankment passes the slope foot;the overall stability of the Fellenius method sliding surface shear outlet is about8% more than the simplified Bishop method.(3)The influence of the fill strength parameters,the properties of the reinforcement,the height of the embankment,and the size of the pavement load on the stability of the reinforced embankment slope is discussed.The analysis results show that increasing the internal friction angle and cohesion of the fill,reducing the embankment height and load size can effectively improve the stability of the embankment;increasing the ultimate tensile force of the reinforcement within a certain range and reducing the reinforcement distance can also significantly enhance the stability of the embankment.(4)A calculation method for determining the quasi-cohesive force of reinforced soil embankment based on the stability of embankment slopes is proposed,and the suitability of the traditional quasi-cohesive principle is given in conjunction with examples.Within a certain range,the ultimate tensile force of the reinforcement,the reinforcement spacing,and the friction angle and the cohesive within the fill have a significant effect on the cohesive force;beyond this range,increasing the ultimate tension of the reinforcement and reducing the reinforcement spacing cannot effectively improve the embankment stability;embankment height and load size have little effect on cohesion.This article can provide theoretical guidance and reference for the actual engineering design of the research results of the mechanism and stability analysis of the bilaterally wrapped geosynthetic-reinforcement embankment.