Study On Mechanical Properties Of Fly Ash Reinforced Soil Retaining Wall

Fly ash is a coal thermal power plant burning solid waste to produce energy in the process of population density,rapid industrialization and the development of thermal power dominated country,fly ash production increasing resources for sustainable development of the environment and land pollution has become a major challenge.Mixed with a certain proportion of the quality of fly ash,the formation of new mixed soil backfill material,improve the mechanical properties of undisturbed soil,the increase of fly ash solid waste resource efficiency benefits,while taking advantage of the site of the original soil,to solve the problem area of earthworks,making improved mechanical properties of the soil is improved.In this paper,a large-scale triaxial test and a static load model test of indoor reinforcement wall with a certain mass ratio of fly ash soil mixture are made to carry out a series of research on fly ash reinforced soil.The main contents are as follows:(1)The CU test,CD test and UU test were carried out on the pulverized ash soil mixture with a certain mass ratio.Soil water stability and shear resistance of the fly ash mixture was studied.The results showed that as the deviator stress increases with the increase of axial strain,and gradually becomes stable after the axial deviator stress increases to the peak value,most of the axial direction.The peak value of the deviating stress is not easy to observe,and the stress-strain property is strain hardening.According to the Mohr-Columb strength criterion,the shear strength index cohesion(c)and the internal friction angle(?)are calculated by the function of the p-q curve to obtain the shear strength index.The c value of the UU shear is greater than that of the CU tests,and the c value of the CD tests is smaller.CD and UU tests have higher ? values than the CU tests.(2)Based on the large-scale triaxial test of fly ash and soil mixed filler.Laying single layer of different types of reinforced materials.Geocell,biaxial,triaxial geogrid,waste tires reinforcement and biaxial geogrid with different layers are used for reinforcement.The results show that the effect of laying the reinforcement on the shear strength is obvious in the mixture;the comprehensive reinforcement effect of the waste tires is better,and the geogrid is reinforced compared to the geogrid more superior,but the actual geogrid reinforcement effect is better than the geocell;the more the number of reinforcement layers laid in the sample,the higher the bearing capacity,but the material cost is multiplied when the multi-layer geogrid is reinforced.It is more suitable and more economical to raise the spacing of the laying layers to 20 cm.(3)Through studying the internal force and deformation form of the retaining wall structure under the surcharge load of the reinforced earth retaining wall,the reinforced earth retaining wall was carried out by changing the number of reinforced layers(layer spacing)and replacing the reinforced materials.Model tests for a variety of operating conditions.The earth pressure,horizontal lateral displacement and vertical settlement of the reinforced retaining wall soil under 9 model tests were compared.The experimental results suggest that the vertical earth pressure on the retaining wall increases rapidly and the maximum vertical earth pressure of each layer moves from the lower part of the loading point to the wall surface;the horizontal displacement of the wall surface of the retaining wall is larger,and the horizontal displacement of the wall is about the maximum.The height of the wall is 0.75H~0.9H;reducing the spacing of the retaining wall of the retaining wall effectively improves the performance of the retaining wall,but the effect of changing the type of reinforcing material is more obvious.The spacing of the reinforced layer 20 cm is more reasonable and economical.The use of waste tire three-dimensional reinforcement and biaxial geogrid combination reinforcement instead of the traditional uniaxial geogrid reinforcement can effectively improve the overall performance of the retaining wall,disperse the surcharge load to generate surcharge stress,effectively reduce the horizontal displacement of the wall and the vertical settlement of the wall.