Study On Settlement And Deformation Characteristics Of High-fill Foundation In Mountain Area

With the increasing height and scale of filling soil,the settlement deformation of filling body has become one of the most concerned problems at present.And,there is relatively little research on foundation deformation caused by large area filling with gravel soil.The deformation mechanism of foundation formed by gravel soil filling is more complexed than that of single filling type.Based on theoretical analysis,indoor mechanical test,indoor model test,numerical analysis and field monitoring,the mechanical properties of the mixture,the optimization of reinforcement parameters,and the development of monitoring platform were studied in this paper.The main findings of this paper are as follows:(1)the mechanical properties of filling materials were investigated by laboratory test.The stress-strain relationship of gravel soil accords with hyperbolic relationship,and it is shear-shrinkage under low stress and shear-expansion under high stress.When the gravel content is about 70%,the density reaches the maximum value.Thus,the mass ratio of soil and rock with the maximum density was 2.5 to 7.5.Subsequently,it decreases with the increase of gravel content.When the aggregate content is more than 50%,the compressibility of the mixture is small.The compression index is minimal when it has the maximum density.The relationship between rheological deformation and time is logarithmic.(2)based on the indoor model test,the control variable method is used to design the test.Considering the characteristics of geogrid itself,the reinforcement effect of soil and the stress characteristics of geogrid under the combination of different geogrid embedded ratio,spacing and number of reinforced geogrids are studied by numerical analysis.Through range analysis and variance analysis,the comprehensive optimization combination is prosed.(3)the automatic monitoring and early warning platform have realized the functions of data monitoring and analysis,monitoring and early warning,etc.It has successfully solved the difficulties of manual monitoring,insufficient power supply and abnormal sensor work caused by the complex geological conditions of the site.(4)the monitoring results show that the surface settlement is not only influenced by the height of the filling soil,but also the thickness of the soft soil beneath the filling.According to the results of in-site monitoring,the settlement rate is decreasing,the settlement law is in accordance with the exponential decay mode,and the settlement is linear with the logarithm of the time,and finally,the settlement rate is convergent.The pre-stress loss and the prestress increase due to the change of filling height make up for each other,and the pre-stress of the anchor cable is stable in the early stage.