Study On The Load Distribution Regularity Of Double-Row Drilled Anti-slide Piles

This paper relies on National Natural Science Foundation Project(ID: 51108488),in the model experiment,numerical simulation as a research tool,Research variation rockfall impact under the factors change of the cushion compactness,rockfall quality,rockfall drop height and cushion thickness,cushion obtained optimum thickness values,and on this basis to study the dynamic changes of soil pressure cushion when different types of reinforced and reinforced positions different,of reinforced cushion set is optimized,in order to provide the basis for the optimization of cushion cushion.The main research results are as follows:(1)Model test results show,influence of cushion compaction on the rockfall impact force significantly.The greater the density,the greater the rockfall impact force;Rock quality and falling height increase,rockfall impact force increase linear growth trend.When the density from the state of nature to slightly dense state of rockfall impact force increase 52.4%~70.6% when the density from slightly dense to dense state,rockfall impact force increase 10.2%~42.1%.Proved in setting the cushion,rolling on the cushion will increase the rockfall impact force,is not reasonable,it is recommended to take a survey of the state of nature in the cushion design,(2)Model test results show,With the increase of the thickness of cushion,rockfall impact force gradually decreases.When the cushion thickness increases to a certain value,rockfall impact force decrease amplitude less than to increase the cushion thickness due to the increase in weight,before a cushion thickness is in this case corresponds to the optimum thickness of cushion.The optimal thickness of different diameter corresponding rockfall cushion through this experiment,to provide reference for the engineering design of rockfall protection.(3)Model test results show,When the reinforcement is added in the cushion material,the impact resistance ability is improved obviously.Anti impact ability: EPS foam reinforced material > reinforced materials > river sand material.After the addition of EPS foam material,the maximum soil pressure is reduced by 58.8% compared to a single river sand;the maximum soil pressure is decreased by 5.4% compared with the single river sand after adding the earthwork grid material.(4)Model test results show,The reinforcement position is not the same as the buffer layer,and the anti interception ability is different.Anti impact ability with reinforced position different from large to small in turn: cushion upper > cushion middle > bottom cushion,namely in the reinforced cushion is arranged on the upper part of the shed hole in the top of dynamic soil pressure minimum than single sand layer decreases 58.7%,here reinforced anti intercept effect is the best.It is recommended that the project used.(5)The results of numerical simulation show that,The use of rubber instead of the thickness of sand cushion can effectively reduce the stress and deflection of the shed tunnel structure.When the cushion is 1m thick sand,the stress and deflection of the shed tunnel are the largest,and the stress and deflection of the shed tunnel are the smallest when the cushion is 1m thick rubber.When the cushion is 1m thick rubber,the structure stress of shed tunnel is 27.2%,and the maximum deflection is reduced by 23.5%.It is suggested that the stress and deflection of the shed tunnel should be in accordance with the requirements,and the rubber should be used instead of sand cushion in the view of safety and economy.