Study On Characteristics Of Earth Pressure On Balance Weight Retaining Wall Based On Centrifugal Model Test

With the rapidly development of national infrastructure,continuous breakthroughs in the construction of railways and highways,the rapid development of support technology in my country,and the continuous innovation of support structures.The balance weight retaining wall is developed from the traditional broken line gravity retaining wall.Compared with the gravity retaining wall,the balance weight retaining wall has an additional platform at the junction of the upper wall and the lower wall,with the help of this platform,the retaining wall can effectively balance the overturning moment of the soil mass behind the wall,so the platform is called the counterweight platform.The appearance of counterweight platform in retaining wall can stabilize the wall more effectively and enhance the stability and safety of embankment slope.On the other hand,the counterweight platform also causes the separation of the upper wall and the lower wall of the retaining wall,and at the same time,the second fracture surface appears in the soil,which makes the stress and deformation characteristics of the balance weight retaining wall different from the traditional gravity retaining wall.For the balance embankment retaining wall,although the calculation method of the relevant codes and design manuals is the same as that of the shoulder wall,the actual force of the retaining wall may be very different from the theoretical calculation because of the influence of the construction quality on the compaction degree of the filling and the top slope ratio of the wall.In particular,it is not appropriate to calculate the upper wall section of the retaining wall based on the actual active earth pressure on the back of the wall.The active earth pressure value used in the shear check calculation at the counterweight is obviously too small.The uncertainty of factors such as slope height,slope rate and packing compactness has a great safety hazard.On the basis of summarizing and analyzing the existing research on the earth pressure action characteristics of balance weight retaining wall,in order to explore the variation law of earth pressure on the back of retaining wall in the process of lateral displacement under different working conditions,the development process of filling sliding body behind the wall and the influencing factors of fracture surface,technology mainly by means of centrifugal model test,design through the use of a set of precise control in geotechnical centrifuge operation environment the size of the retaining wall displacement control device,designed the four groups of centrifugal model test,analyzed the different retaining wall in the embankment height or wall filling strength under the action of different factors,such as back earth pressure of wall,and further compared with the theoretical calculation results,and draws the following conclusions:(1)The total earth pressure of the upper wall shows a trend of nonlinear increase with the increase of the displacement of the retaining wall.The higher the height of the embankment or the greater the shear strength of the soil,the increase range of earth pressure with retaining wall displacement also increases.The total earth pressure of the equilibrator shows a trend of nonlinear increase with the increase of the displacement of the retaining wall.The higher the height of the embankment or the greater the shear strength of the soil,the degree of increase becomes more obvious.In the lower part of the wall,the earth pressure on the back of the wall generally decreases first and then gradually increases.(2)In the translation mode,the lower wall reaches the active limit state before the upper wall.With the decrease of embankment height or the increase of soil shear strength,the displacement required by soil to reach the ultimate displacement decreases gradually.(3)As the height of the embankment decreases,the inclination angle of the soil fracture surface behind the balance-weight retaining wall shows a trend of first decreasing and then increasing.When the shear strength of the embankment filling decreases,the inclination angle of the upper wall’s fracture surface gradually decreases to the opposite of the inclination of the upper wall’s back,while the lower wall’s fracture surface inclination increases.(4)Through the comparison between the centrifugal model test and the theoretical calculation,it is found that the earth pressure of the upper and lower walls in the theoretical calculation result is larger than that of the centrifugal test result.But as a result of the theoretical calculation does not take into account in the process of weighing retaining wall and the connection between the upper and lower wall,will be calculated separately from the upper and lower wall,lead to the theoretical calculation upper middle wall in the wall back up and down the total earth pressure is less than the proportion of centrifugal test results.