Interaction Analysis Between A Building And Its One-sided Underground Structure

With the rapid development of China’s economy,more and more multi-story(high-rise)buildings are equipped with underground structures to meet people’s living needs.When the underground structure is installed on one side of the building,there will be obvious differential settlement between the main building and the underground structure due to the large difference weight,which lead to the main building inclining to the side without underground structure and cause the internal force of the frame structure changed.The settlement post-pouring strap can reduce the differential settlement between the main building and the underground structure effectively,and the position selection of settlement post-pouring strap is also of great significance to the internal force and deformation of the main building.In order to study the interaction of internal force and deformation between main building and its unilateral underground structure,and find the influence of the settlement post-pouring strap on the internal force and settlement of the main building,the numerical models include the main building and its unilateral underground structure was established by MIDAS/Gen based on the actual project.The settlement of building and its unilateral underground structure,internal force of frame structure,interaction law of base reaction and settlement post-pouring strap position were studied in this paper.The results were as follows:(1)When the main building is equipped with underground structure,the load difference between the main building and the underground structure is large.The part of the load of the main building is transmitted to the underground structure,resulting in the reduction of the base reaction on the side of the main building with underground structure and the increase of the other side,which is the reason of the main building inclining away from the underground structure.(2)The underground structure has the greatest influence on the internal force of the main building first floor,and the influence decreases with the increase of the number of floors.When the main building is equipped with one side underground structure,the negative bending moment at the end of the frame beam on the side without underground structure increases,while the positive bending moment at the middle of the beam decreases,and The bending moment of the main building on the side with underground structure changes in opposite way.The axial force of the frame column in the main building without underground structure increases,while the axial force of the frame column on the other side decreases.The part of main building load will be transferred to the underground structure,resulting in the settlement,base reaction,frame beam bending moment,frame column axial force of underground structure near the main building are significantly increased.And the influence scope is only in the first two spans of the underground structure.(3)With the decrease of foundation soil modulus,the inclination of the main building increases.And the frame beam end negative bending moment near the underground structure on the first floor of the main building increases obviously,and the axial force of the frame column increases gradually.The foundation stiffness in soft soil area is small,so the influence of one side underground structure on the main building should be paid attention to in order to avoid engineering quality problems.(4)With the increase of the number of floors of underground structure,the inclination of the main building increases gradually,and the difference between the two sides of the basement reaction increases gradually.When the number of floors of the underground structure is more than two,the main building frame beam bending moment and the frame column axial force near the underground structure increase obviously,and the main building is greatly affected by the underground structure(5)When settlement post-pouring strap of underground structure is set the first span near the main building,the difference of settlement,base reaction,bending moment of frame beam and axial force of frame column on both sides of the main building is small,which is approximately symmetrical.When settlement post-pouring strap of underground structure is set in the second or third span,the effect of settlement post-pouring strap is less.Therefore,the best position for setting the settlement post-pouring strap is in the first span.