| The embankment project is an important component of our national defense flood-retaining system and water conservancy infrastructure.At present,about one-third of the embankments have hidden safety hazards and risks of accidents.In recent years,the gabion support and reinforcement technology that can consider both the stability of the embankment and the ecological function has been gradually applied in the design of river embankment engineering,and the application effect is remarkable.However,as the frequency of the change of the embankment protection water level increases,problems such as insufficient resistance of the gabion support in the embankment reinforcement project and the ambiguity of the safety factor calculation are caused.Especially the lack of knowledge of the temporal and spatial characteristics of the infiltration of the gabion slope and the whole process of stability under the change of water level.To cope with technical problems and better serve the practice,this paper uses the Qingshui River flood control embankment project in Jianhe,Guizhou Province as the backing project,and researches the slope of the reinforced gabion retaining wall,which is the form of the flood control embankment adopted by the project.This paper conducts research and analysis to summarize the seepage change,the deformation of the supporting structure,and the infiltration evolution process of the gabion embankment slope in the temporary stable state and the rising and falling state of the water level.By combining the model test data and the shape of the infiltration line,the overall state stability coefficient of the slope under the dynamic head(temporary stable state of the water level and change of the rising and falling water level)of the gabion embankment slope is simulated and calculated and expressed in a mathematical function relationship.The main research work and research results of this article are as follows:(1)The infiltration characteristics of the gabion embankment slope under static and dynamic water levels are clarified.When the static water level is infiltrated,it is infiltrated in a fan shape with the slope foot as the center of the circle.The specific morphology is that the infiltration response time of the gabion embankment slope is 1to 2 times longer than that of the plain soil slope,the average infiltration rate is reduced by 50 to 70%,the migration distance of the infiltration line slope is 65% of the plain soil slope,and the shape It is in a radial shape with the foot of the slope pointing to the inside of the slope.Compared with the grouted rubble retaining method,the coupling effect of the gabion retaining wall and the slope soil is better,and the slope deformation convergence time is short.The transition time from the saturated area to the unsaturated area in the slope is relatively stable,the pore water pressure increases nonlinearly with rising water,and the precipitation gradually decreases step by step,and there is no phenomenon of excess pore water pressure and basement flow.(2)The sensitivity factors that affect the slope stability of the gabion embankment slope during the rise and fall of water are analyzed,and the order of their influence is in the order of gabion support structure> rising and falling water level>bedrock surface layer.In the process of raising and lowering water,based on the test conditions of the slope,its sensitivity to the stability of the slope is analyzed,and its influence degree is gabion support structure> rising and falling water level> bedrock surface layer.The seepage field has a significant effect on slope stability.The key role is that the substantive influencing factor is the infiltration rate.The faster the infiltration rate,the greater the possibility of its instability,the greater its water level rises and falls,and the higher its potential instability risk.(3)It is clear that the gabion retaining structure can improve the slope stability under static and dynamic water levels,which can effectively reduce the slope displacement,settlement,and other factors,increase the slope’s shear strength,and significantly improve the slope stability.The specific performance is that the displacement and settlement in the X direction of the gabion embankment slope at a constant water level are about 1% of the plain soil slope,and the maximum tensile stress is about 5.8% of the plain soil slope;the gabion supports the slope when the dynamic water level changes.The horizontal displacement of the slope is about67.57% of the plain soil slope,and the tensile capacity is 15.58 times that of the plain soil slope.When the water level rises,the calculated safety factor of the gabion embankment slope is 1.88 times that of the plain soil slope on average.When it is11.86 times of plain soil slope,it is 13.04 times of plain soil slope when cyclically ascending.(4)The whole state function of the slope stability of the gabion embankment slope is established.The slope stability shows a sine-like function of strength attenuation after the second water level cycle.When the water level rises,the horizontal displacement,settlement,and effective tensile stress in the X direction of the slope decrease as the water level rises,which is more beneficial to the slope;when the water level drops,the horizontal displacement,settlement,and effective tensile stress in the X direction of the slope decrease with the increase in the water level.The water level decreases and increases,and the change in the internal slope of the slope lags behind the water level outside the slope,the X forward osmotic pressure increases,and the osmotic pressure directed outside the slope is formed in the slope,which is detrimental to the stability of the slope;when the water level circulates,the water level changes It will cause the change of the suction of the soil matrix,the water content of the slope soil will increase,and the pore water pressure will be larger than when there is no water,which is disadvantageous to the stability of the slope.When the water level is circulating,the horizontal displacement,settlement,and effective tensile stress in the X direction of the slope decrease as the water level rises.The values are larger than the initial value.The safety is relatively reduced compared to the initial cycle state.The overall slope working conditions of the test are similar.The gradually decaying sine-like function state.The stability of the increased gabion retaining wall is much greater than the slope without gabion support,and the safety factor increases when the water level rises,and the slope safety factor rises when the circulating water level rises,which is still smaller than the initial value,which is consistent with the actual engineering conditions G4(with gabion and bedrock)can effectively resist this stability attenuation trend,which is of guiding significance for the construction method of gabion embedded in bedrock.In this paper,relying on the practice project of gabion embankment,the study on the infiltration characteristics and stability of the slope of gabion embankment is carried out.Based on the indoor model test and numerical simulation,analyze the influencing factors of seepage field,stress field,and displacement field with or without gabion support and with or without bedrock slope.The infiltration law of the gabion dike slope and the support effect of the gabion retaining wall are summarized,the sensitive factors affecting the stability of the gabion embankment slope are explored,and the full state function of the slope stability is established.From model tests,numerical simulations,theoretical derivation,and comprehensive study of the infiltration evolution and all-state stability of the slope of the gabion embankment. |
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