Study On The Effect Of Side Loading On The Properties Of Long And Short Pile Composite Foundation

With the acceleration of modernization,the city land resources are becoming more and more scarce,in the limited space of land,the buildings are characterized by high and dense.The stress state under the original building will inevitably be disturbed by a new building or a temporary pile of heavy weight.Composite foundation is an efficient and economical way of foundation treatment.Under such a disturbance,the change of its properties will also have a series of effects on the overlying buildings.Therefore,the effect of side load on the composite foundation must be considered when building or loading heavy objects around a building.In the composite foundation near the position of the new high-rise buildings,heavy pressure,temporary pile foundation excavation,composite foundation under the original stress field near symmetry,a new stress field changes the stress field of the composite foundation,it will inevitably lead to the change of the properties of the pile and soil in the composite foundation.,the difference settlement is formed,and the difference settlement of the composite foundation is more than a certain degree,which will directly lead to the problems of overlying and cracking.pressure concentration.It also leads to the change in the position of the overlying load on the pile lead to the piles pressure concentration,causing potential safety problems for buildings.Therefore,studying the relationship between the surrounding load and the characteristics of adjacent composite foundation has always been a concern in the field of building safety,and has certain practical value.At present,many scholars have done a lot of work on the research of composite foundation,but the research on the characteristics of composite pile composite foundation under side load is very few,and the characteristic change of composite pile composite foundation under side load condition is not very obvious.Based on the study and draw lessons from the existing research results on the study of composite pile foundation characteristics,analyzes the combination of unilateral load on pile composite foundation uneven settlement and pile stress changes,and analyzes the effect of underground continuous wall to change the characteristics of composite ground control boundary load conditions.The main contents and results of this paper are the following aspects:1)Elaborated the composite foundation system theory and the selection of the constitutive model of experimental materials are selected,and established the indoor scale model test and FLAC3 D simulation test.2)The control variable method,by controlling the side load grade,side loading distance,loading depth,pile length of composite foundation to analyze the impact of changes in side load of long short pile composite foundation characteristics,and the relationship between the settlement and stress of the composite foundation is analyzed in depth.3)Introduced the finite difference software FLAC3 D,which is suitable for the Rock and soil simulation analysis.Based on the software simulation,the characteristic changes of the composite foundation under the condition of unilateral side load are analyzed.It is analyzed that the uneven settlement of the composite foundation,the prone position of the composite foundation and the failure mechanism of the composite foundation under different influence factors.4)The influence of the underground continuous wall on the characteristics of the long and short pile composite foundation under the side load condition is selected through the analysis of the results of the test,Setting up a FLAC3 D simulation test,Analysis the composite foundation uneven settlement,pile stress by changing the length and depth of underground continuous wall,and summarize the rules for future similar projects in the selection of appropriate preventive measures to provide reference.