Analysis And Application Of Settlement Difference Of Main Podium On Shallow Rock Foundation

With the rapid development of the economy and society,the urban population is increasing day by day,and the urban land resources are becoming more and more precious.In order to make more efficient use of land resources,urban buildings tend to develop in the direction of ultra high and deep.For this reason,high-rise buildings often have 2-3 stories of basement and 3-6 floors of podium.Because of the difference of the height of the main skirt building,the load of the main skirt building is different greatly,which causes the uneven settlement of the foundation of the main building and the podium of the high-rise building.In order to solve the problem of uneven settlement of the foundation of the main skirt building,the post-pouring zone with a width of about 800 mm is usually set at the junction of the main skirt building.The settlement of post poured band has been adopted by many designers as a solution to the problem of uneven settlement of the main podium.However,the post-settlement pouring belt also brings many problems to the construction unit,such as increasing the construction cost,affecting the construction period,and it is difficult to guarantee the quality of concrete pouring at the location of the post-settlement pouring belt.There is no uniform technical standard for the problems related to the post-pouring zone in the relevant codes at home and abroad,and there is no comprehensive and systematic theory for the design and construction of the post-pouring zone.Based on the geological conditions in Qingdao area,this paper will do the following research work around the settlement difference and variation law of high-rise main skirt building on shallow soil foundation.Firstly,the research status of post-cast-in-situ settlement zone is summarized,and the settlement observation of a main skirt building project in Qingdao area is carried out in the whole construction process.Due to the constraints of construction site,construction schedule and observation conditions,the arrival time of settlement observation is relatively late,resulting in incomplete settlement observation data.Existing observation data,cumulative settlement curve and settlement theory calculation are used to calculate the pre-settlement and obtain the complete settlement data of the main skirt building during the construction process,which provides complete data support for the analysis of the variation law of the settlement and settlement difference of the main skirt building with the construction process.The method of calculation can provide guidance for similar projects to calculate the early settlement.Secondly,according to the existing settlement observation data,using BIM technology,this paper analyzes the variation law of settlement and settlement difference with the construction progress of the main skirt building in the construction process,and the location of the maximum settlement difference between the main skirt building in the construction process.In the area with abundant groundwater,the settlement of the main skirt building is greatly affected by the buoyancy of water.The influence mechanism of buoyancy on the settlement of the building is analyzed.Thirdly,taking the actual project as an example,the settlement of the main skirt building structure is calculated based on different settlement calculation methods,and the comparison between the different calculation results and the actual observation values is made to put forward the calculation method of shallow soil settlement and the relevant correction coefficient.The settlement differences under different conditions are analyzed,including different building heights,different geological conditions,different overlying soil thickness and so on.Finally,based on the PKPM design software,the integral model of the main skirt building is established,and the maximum bending moment at the position of the post-pouring zone is obtained by calculating the analysis results of the software.The maximum crack width at the position of the post-pouring zone is further obtained.When the maximum crack width meets the specification limit,the post-settlement between the main skirt buildings can be cancelled.Pouring belt.By changing the properties of overlying soil and analyzing the crack width at different building heights,it is proposed that the building height of shallow overlying soil foundation should be cancelled under different geological conditions...