Study On Stability Of Soil Subgrade Slope Under Synergetic Action Of Blast Vibration Load And Groundwater

During the construction period of highway slope,the influence of blasting vibration is frequent,and it is also often affected by rainfall and changes of water level.The current slope codes in which it often independently considers the effect of the blast vibration and groundwater on the slope for the design of engineering,and it is also one of the reasons for the destruction of some new or under construction roadbed slopes.The soil slope is as the research object,the dynamic response and disaster form and characteristics of the highway slope are revealed by considering the influence of dual factors of blasting vibration and groundwater,and the definition of slope stability and failure criterion is discussed.Thus,using field monitoring,theoretical analysis,numerical simulation and indoor test,Study on stability of soil embankment slope under synergistic effect of blasting vibration load and groundwater.The research of the project is based on actual slope engineering,on the basis of the test of its physical mechanical parameters,the model is generalized,and the model is established by using Geostudio and Plaxis software.The stability and deformation mechanism of the slope under the combined action of blasting vibration and groundwater are studied.By pseudo-static analysis of slope under different underground water levels,influence laws of stress,safety factor of slope and displacement are obtained.The research results show that the maximum deformation appears at the slope toe.The position of slope slip surface depth and the maximum horizontal displacement are different with the underground water level rising,and the reduction of stability of the slope will appear mutations after reaching a certain height,and it shows different instability mode under different ground water level.Finally,the main control factors(cohesion,internal friction angle,gravity,blasting vibration peak acceleration and groundwater level height)affecting the slope stability are analyzed in orthogonal,and the internal friction is the worst factor,then blasting vibration peak acceleration,gravity,groundwater level height and cohesion.The theoretical work is mainly that based on the rotational balance theory,the calculation formula of the critical groundwater level of the slope is derived,and a simple calculation method of the critical groundwater level of the slope considering the influence of blasting vibration load is proposed,which avoid the solution of complex nonlinear equation and greatly simplifies the computational effort.Finally,the critical groundwater levels of the different height slopes are calculated by finite element method,and verified the accuracy of the proposed simple calculation method by comparing to the values calculated by the simple calculation method.Vibration response of the soil roadbed slope under different groundwater levels in site is monitored,and horizontal vibration displacement,horizontal vibration acceleration and horizontal vibration velocity of the slope in different positions are monitored.Based on the data analysis of slope vibration velocity,multiple linear regressive analysis of the horizontal vibration distance and vertical vibration distance of the slope is performed and the vibration velocity attenuation relation of the slope is determined.Using dynamic elastic-plastic time history analysis of the soil roadbed slope,dynamic response of the roadbed slope under the coupling of the blasting and groundwater is studied.The results show that the blasting vibration acceleration decreases with the increasing of the groundwater levels,and the displacement increases when the velocity decrease.Displacement and velocity decrease along the height of the slope under the conditions of the same water level and blast vibration.A test model whose geometric similarity coefficient is 1:10 was established using simulating model test,and blasting monitoring of the several models are carried out with similar small-scale explosive,and indoor model experimentation of the slope affected by blasting vibration under different underground water levels is developed.The progressive failure mechanism of the slope with the groundwater and no groundwater is revealed.The research results show that when the slope has no groundwater,then the slope top is destroyed.Finally,the slope top and slope foot destruction are most serious,which shows that the slope produced the amplification effect to the blasting vibration wave.When the slope has the groundwater,the slope foot is first tensile crack when the slope foot is detonated,however,the slope top is no destroyed,which show that groundwater accelerated the blasting vibration wave attenuation,and made the slope top destruction reduction.Conducting quasi-static analysis,critical water level calculation,field test of blasting vibration,similar simulation test data and using the former people's achievements for reference,a new idea of blast vibration stability evaluation of slope is developed and the evaluation procedure of the blast vibration stability of the slope is put forward,and a simple calculation method of permanent displacement considering the influence of the coupling of the blast vibration load and groundwater is proposed.By this method the influence of dynamic pore water pressure could be considered,which could provide the reference for slope stability assessment.