The Study On Bearing Capacity Of Geogrid Reinforced Building Slag Cushion

Geosynthetics reinforced cushion is a soil treatment method with convenience and economy.Geogrid is widely used in reinforced cushion because of its light weight,high strength,good toughness and corrosion resistance.In recent years,with the continuous promotion of urban transformation and the continuous development of new rural construction,a large amount of construction waste is produced,of which the construction waste accounts for a high proportion.If the construction waste is directly piled up without any treatment,it will not only occupy a large number of sites,but also cause serious damage to the environment,at the same time,it is also a waste of resources.Therefore,how to effectively deal with and use the construction residue has become an urgent problem.If the construction residue can be applied to the reinforcement technology,and the reinforced slag cushion can be used in engineering practice,it will obtain good economic and environmental benefits.In this paper,four grids with different tensile strengths and grid sizes,and three building slag with different particle sizes and gradations are selected to carry out 14 groups of plate load tests construction slag cushions,including 3 groups of unreinforced slag cushion and 11 groups of reinforced slag cushion.By comparing the bearing capacity values,earth pressure distribution,fundamental laws of the cushion bearing capacity and stress diffusion are discussed and summaried.The results show that:(1)There is no steep drop in the load settlement curve of the unreinforced and reinforced slag cushion.The load settlement curve of the unreinforced slag cushion is steeper than that of the reinforced slag cushion.The ultimate bearing capacity of the reinforced cushion is greater than that of the unreinforced cushion,and the settlement of the reinforced cushion is less than that of the unreinforced cushion under the same load.(2)When the cushion materials used in the cushion is the same,the biaxial geogrid with higher tensile strength has the best reinforcement effect,followed by three-way geogrid and four-way geogrid,and the biaxial geogrid with lower tensile strength is the worst;when the reinforcement conditions are the same,the bearing capacity of the well graded slag cushion is the greatest,and the bearing capacity of the poorly graded slag with the smallest particle is the lowest.(3)The distribution of earth pressure of unreinforced cushion is parabolic at all depths,while that of reinforced cushion is saddle at both the bottom of cushion and 500 mm depth,but that of reinforced cushion is parabolic at 1000 mm depth.(4)Grid type,particle size distribution,load and vertical depth all have influence on the distribution of earth pressure under the cushion.The results show that the reinforcement of cushion changes the shape of earth pressure distribution curve from parabola to saddle;the change of slag type has no effect on the shape of earth pressure distribution,but it will change the value of earth pressure;the load value will also affect the earth pressure,and the value of earth pressure at the same horizontal position increases with the increase of the load;the increase of vertical depth will not change the earth pressure under the unreinforced cushion In addition,with the increase of vertical depth,the earth pressure distribution curve under the reinforced cushion changes from saddle distribution to parabolic distribution.