Frame Shear Wall Structure-Pile Raft Foundation-Rock Slope Subgrade Interaction Analysis

Mountains are widely distributed in our country,exception for a few provinces and citys,most provinces,autonomous regions and municipality are mainly mountainous areas.In modern urban construction,it is common to build buildings on slopes.Therefore,the practical significance of the study on the interaction of superstructure-foundation-rock slope subgrade in geotechnical engineering practice gradually emerges.The traditional design method divides the superstructure,foundation and subgrade into three parts,imposes fixed constraints on the column bottom of the superstructure,analysis stress separately,and then acts the calculation results on the foundation.This design method is quite different from the actual situation.After referring to the relevant literature and summarizing the relevant theories at home and abroad,this paper uses ABAQUS finite element analysis software to analyze the interaction of frame shear wall structure,pile raft foundation and rock slope subgrade.Through finite element analysis,the main conclusions are obtained.:(1)By changing the building distance,the effect of the building distance on the interaction is obtained: when the building distance is big,the horizontal displacement of the superstructure,the maximum settlement and differential settlement of pile-raft foundation are small,which is beneficial to maintaining the stability of the slope.In addition,for the bottom frame force of superstructure,the axial force of the middle column decreases with the increase of the building distance,while the both side column is opposite;the larger the building distance,the smaller the maximum bending moment of the side axis beam and column top of the bottom frame of the superstructure is,and the opposite is the middle axis;For the bending moment of the foundation under the column,the larger the building distance,the larger the positive bending moment of the raft.For raft bending moment between columns,the greater the building distance,the greater the absolute value of negative bending moment of raft.The counterforce of the pile top near the slope decreases with the increase of building distance,while the counterforce of the pile top distribution tends to be uniform away from the slope,in addition,the load sharing coefficient of piles decreases with the increase of building distance.Under the action of earthquake load,the smaller the building distance,the greater the influence of horizontal earthquake load on the superstructure.(2)By changing the building stories,the effect of the stories of the superstructure on the interaction is obtained: when the stories is small,the displacement of the superstructure is smaller,the degree of safety is higher,and the overall settlement of the pile-raft foundation tends to be gentle;with the increase of the building stories,the axial force of the bottom column,the axial force difference between the middle column and the side column,the side column and the corner column both increases;the bending moment of foundation under the column and the absolute value of the negative bending moment of foundation between the columns increases with the increase of the layers of the superstructure;the larger the building stories,the greater the counterforce of the pile top of each pile,in addition,the load sharing coefficient of piles decreases with the increase of building stories.Under the action of earthquake load,the grater the building stories,the greater the influence of horizontal earthquake load on the superstructure.(3)By changing the deformation modulus of subgrade,the effect of deformation modulus on the interaction of superstructure-foundation-rock slope subgrade is analyzed.The results show that the larger the deformation modulus,the smaller the horizontal displacement of superstructure,the smaller the settlement and differential settlement of foundation;furthermore,the lower the deformation modulus is,the smaller the maximum bending moment of beam and column top of bottom frame of superstructure is;the bending moment of foundation under the column and the absolute value of the negative bending moment of foundation between the columns decreases with the increase of the deformation modulus of subgrade;with the increase of deformation modulus of foundation soil,the pile top reaction near the shear wall and the load sharing coefficient of the pile gradually increase,while the counterforce of the pile top of the middle pile is opposite.Under the action of earthquake load,the smaller the deformation modulus,the greater the influence of horizontal earthquake load on the superstructure.(4)By changing slope gradient,the effect of slope gradient on the interaction is analyzed.The results show that the horizontal displacement of superstructure,the maximum settlement and differential settlement of foundation are bigger when the slope gradient is larger.The axial force of middle column increases with the increase of slope gradient,while that of side column is just the opposite with the increase of slope gradient.The bigger the slope gradient is,the bigger the positive moment of raft at the bottom of column is,the smaller the absolute negative moment of raft between columns is,and the bigger the counterforce of the pile top and the load sharing coefficient of piles are.Under the action of earthquake load,the grater the slope gradient,the greater the influence of horizontal earthquake load on the superstructure.(5)The effect of raft thickness on the interaction is studied by changing raft thickness.The results show that when the raft thickness is large,the horizontal displacement and settlement difference of the superstructure are small,and the average settlement and maximum settlement of the foundation are large;The maximum bending moment at the top of beam and column in the bottom of superstructure decreases with the increase of raft thickness;for the moment of foundation under column,the moment of raft under each column increases with the increase of raft thickness.For the moment of raft between columns,the moment of raft changes from negative to positive,and increases continuously.In addition,with the increase of raft thickness,the counterforce of the pile top and the load sharing coefficient of piles decrease gradually.Under the action of earthquake load,the smaller the raft thickness,the greater the influence of horizontal earthquake load on the superstructure.