Study On Mesoscopic Mutiscale Failure Evolution Mechanism Of Coal Gangue Stabilized Base In Seasonal Frozen Zone

Coal is the main energy source in China.China’s attention to energy consumption and the country’s economic development is growing.China’s economic construction,production and life are inseparable from the important support of coal energy.However,coal gangue,a kind of solid waste accompanied by coal resources,will have a great impact on people’s living environment.Based on the principle of"making the best use of local materials",this paper discusses the possibility of coal gangue powder replacing part of cement for cementing with aggregate in road base.This paper mainly studies the following aspects:（1）The chemical composition,bulk density,water content,liquid plastic limit,sand equivalent,expansion rate,water stability and other basic properties of coal gangue are tested and analyzed in detail,and the physical and chemical characteristics of coal gangue are discussed.The plastic limit w_land w_pof selected coal gangue liquid are 23.3 and 20.6,respectively.The plasticity index Ip is 2.7,and the expansion rateαis 7.35×10^-2,both of which are small.The sand equivalent of coal gangue used is 76.2%,and the water stability coefficient of coal gangue measured is about 0.9,which meets the relevant requirements of subgrade design.（2）Through orthogonal test,the ratio of cement-coal gangue polymerized inorganic mixture was designed,the best moisture content of each group of samples was tested by compaction test,and the ratio and curing were carried out according to the obtained results.The 7d unconfined compressive strength test and freeze-thaw cycle test were carried out on each group of samples after curing.Based on the comprehensive range and variance analysis,the optimum proportion experiment was determined for the eighth group of cement-coal gangue polymerized inorganic mixture samples with cement content of 5%,gangue content of 4%and aggregate content of 15%.（3）using the Python language containing cohesive element of three-dimensional random aggregate model is set up,with a cohesive element of cement-coal gangue aggregate and soil aggregate formation of interfacial transition zone（ITZ）between the simulation and probe into its constitutive relations after the compression,material to model according to the group of 8specimen,giving,and do the same as the experiment of the unconfined compressive strength test,through the observation of the sample after compression cloud image analysis the stress of specimen,and the damage range,and the 0 times and 10 times after freezing and thawing cycle stress strain curves are drawn,Then the strength formation mechanism of cement-coal gangue polymerized inorganic mixture was analyzed.（4）Build a road model with a length of 20m,a width of 4m and a height of 1.5m,and give various material parameters to it.Respectively using the subroutine Dload.For,qualities.For,DFLUX.For as well as the USDFLD.For the model to add moving load,ambient temperature changes over time,along with the time change of the surface heat flow and the field variables for the saturation of the meaning,respectively for single stress,temperature and seepage field model is established,and then single temperature field and stress field of the result file to import into single seepage field of prestress field definition,in order to simulate in three field coupling condition of pavement response,analysis of cement-the stress characteristics of gangue aggregate stabilized macadam layer Furthermore,the road service life can be estimated by the accumulated equivalent axis in the design years through the inversion of the bending and subsidence value of the road surface.