| Due to the characteristics of uneven composition and high compressibility,filling is prone to uneven settlement,and the slope formed by filling has great security risks.At the same time,in geotechnical engineering,the water content has a unique relationship with the shear strength of soil,and the strength value has a great correlation with the slope stability.The difference of strength value is only 1–2°,and the slope stability changes sharply.Therefore,ascertaining the internal relationship between soil moisture content and slope stability is the primary task of slope stability calculation and engineering design.In this paper,three adjacent slopes of Zhenxiong Metropolis Project in Yunnan Province were taken as the research objects.By means of shear experiments,six basic physical properties indexes(moisture content,specific gravity,dry density,saturation,liquid limit and plastic limit)and two shear strength indexes(cohesion and internal friction angle)were carried out.Pearson correlation analysis were carried out by SPSS software,and the sensitivity multiple regression analysis of shear strength index and slope stability were carried out based on FLAC 3D.On this basis,combined with the results of laboratory experiments and the actual situation of slope deformation,the calculation parameters were continuously tracked and inverted by FLAC 3D strength reduction method,and the three-dimensional stability of the composite slope was calculated and analyzed after determining the parameters.Finally,according to the stability results,the slope reinforcement scheme was designed,and the three-dimensional overall analysis was carried out by FLAC 3D.At the same time,the GTS / NX software was used to demonstrate the stability of the three slopes one by one,and compared with the monitoring data.Based on the above research content,the following understandings were mainly obtained :(1)Indoor shear strength index was significantly correlated with moisture content and dry density(compactness).It was negatively correlated with water content and positively correlated with compaction degree,but the fitting degree was not high,R2 was less than 0.7.In the test data section,there was a significant negative correlation between water content and compaction degree at 0.01 level,and the ratio was 1 : 1,that was,when the water content increases by 1%,the compaction degree decreases by 1%.(2)The shear strength indexes(cohesion and internal friction angle)of slope stability were positively correlated.The sensitivity of each slope to the shear strength index of the surface filling soil was different.The sensitivity of 1# slope to the cohesion of the surface filling soil was the weakest.The safety factor can be increased by 0.014 when the cohesion increases by 1KPa,but the sensitivity to the friction angle was the strongest.The safety factor can be increased by 0.046 when the friction angle increases by 1°.2# and overall slope are similar to 1# slope;on the contrary,the 3 #slope had the strongest sensitivity to the cohesion of the surface soil layer,which was about 2.3 times that of the 1 # slope,but the sensitivity to the friction angle was the weakest,which was about 0.61 times that of the 1 # slope.The influence of cohesion and friction angle on slope safety factor was independent and can be superimposed on each other.(3)In the natural state,the safety factors of 1 # and 2 # fill slopes were 0.85 and0.92,which were in an unstable state;3 # natural slope safety factor 1.17,in the basic state;at this time,the overall safety factor of the slope was similar to that of the 1 #slope,which was 0.84;compared with natural conditions,the safety factor of each slope under rainfall conditions is reduced by about 10 %.(4)After reinforcement treatment,the safety factors of the composite slope reached 1.54,1.65 and 1.57,respectively,which were in a permanent stable state.The simulation value of horizontal displacement of anti-slide pile was consistent with the distribution law of monitoring value. |
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