Study On Unsaturated-Saturated Seepage Characteristics Of Soil Subjected Dynamic Load

During the mining area,the groundwater level is changed due to excavation,resulting in seepage changes.The water accumulation in the mining area not only affects the progress of the engineering,but also the dynamic load of blasting in the mining area is more frequent,and the influence on the seepage will be more intense.In this paper,combined with the Changde leigong Temple limestone mine,Through the study of Unsaturated-Saturated seepage characteristics of silty clay under dynamic load,the change of seepage under the influence of dynamic load is analyzed.Through the three methods of indoor test,model test and numerical simulation,the seepage of soil under dynamic load is studied.The following conclusions are obtained:(1)Through the laboratory test,the basic parameters of the test soil sample are obtained,and the penetration test is carried out on this basis.Based on the traditional osmosis test instrument,the live load permeability test device is improved,and the indoor model test is carried out through the penetration test device.Through the analysis of the test results,the effect of dynamic load increases the unsaturated-saturated seepage velocity of the soil.(2)By comparing the change of soil pressure in the test process,it is found that the effect of dynamic load makes soil pressure increase during unsaturated-saturated seepage process.Under the same condition,the change of soil water content in unsaturated saturated seepage process is found.It is found that the dynamic load makes the water content increase in the seepage process of the soil.The pressure change is measured by setting the pressure tube on the side of the model box,and found out the loss of water head in the seepage process is reduced by the analysis of the dynamic load.Through comprehensive analysis of the change of wetting front and seepage volume,it is found that the influence of dynamic load on unsaturated soil saturated seepage is delayed.That is,the influence of the dynamic load on unsaturated-saturated seepage of soil will not be immediately apparent,and will gradually emerge with the time of time.(3)By FLAC3D numerical simulation calculate and On the basis of verifying the feasibility of numerical simulation,the effect of dynamic load on pore water pressure in the seepage process of soil is analyzed by changing the size of dynamic load.Through the numerical calculation,it is found that the pore water pressure of soil increases gradually with the increasing of the dynamic load.The size of the pore water pressure is closely related to the distance to the dynamic load,and the closer the distance to the dynamic load is.The greater the pore water pressure increases,the more intense the response is,and vice versa.Through the change of pore water pressure and theoretical analysis,it can be concluded that the seepage of soil is more obvious with the increasing of dynamic load,which will also affect the stability of the basic structure of the soil.But,it is obtained under the premise that the basic internal structure of the soil has not been completely destroyed.