Study On The Basement Construction Process Of Existing Commercial Building By Numerical Simulation

With China’s rapid economic growth, the ratio of commercial construction area in the totalconstruction area is continuously increasing. Besides, people are becoming increasingly closewith shopping malls. However, most of the existing large commercial buildings are situated atthe core area of the city and occupy large building areas, where the land resources are veryscarce; thus, the effective use of underground space resources is of much significance for thecore areas of the city. Therefore, the implementation of the renovation project of theunderground additional floors for the existing commercial buildings can effectively solve thetraffic congestion and parking problem at the ground level.To reconstruct and renovate the existing buildings needs a set of feasible constructiontechnique process and a comprehensive understanding of the influence of the reconstructionand renovation process on the buildings themselves and their surrounding environment. In thispaper, the three-dimensional finite element numerical analysis method is used to conductfeasibility study of the construction techniques of the underground space on the existingbuildings, and the main research results are as follows.1) Combining with the existing specification requirements and the reconstruction andrenovation techniques at home and abroad, a set of feasible underground additional floorsrenovation techniques and the pile foundation bearing capacity calculation method for thepressured pile by anchor rod of the existing buildings are put forward2) Influence rule of the renovation and construction process of the undergroundadditional floors on the upper structure and the surrounding environment are studied, andresults show that: before the renovation of the existing buildings, the real settlement status ofthe upper structure appears as the rule of “basin-shaped settlement”. With the implementationof the construction process, the settlement value of the bottom of the upper structure graduallydevelops and stabilizes until the construction of the underground additional floors iscompleted. For the change of the settlement of the upper structure caused by the constructionof the foundation supporting, the settlement of the bottom stabilizes when the construction ofthe underground additional floors is completed. The maximum settlement value of the column of the existing building is21.339mm, and the difference of the settlement value of the adjacentcolumns is2.613mm, both of which meet the specification requirements. During the processof the construction and renovation of the underground additional floors, the maximumhorizontal displacement value of the underground continuous wall is5.265mm, and themaximum value of the ground settlement outside the pits is2.800mm, meeting the currentspecification requirements. The foundation pit itself and the surrounding environment is in asafe state in the whole stimulated construction process.3) Based on the analysis of the influence of the construction techniques parameters of theunderground space, the results show that the increase of soil elastic modulus can effectivelyreduce the influence of the construction process on the settlement of the upper structure.Comparing the influence of the three kinds of earthwork excavation construction methods onthe settlement of the upper structure, it can be seen that center island excavation method ismore suitable for underground additional floors project. It also can be known from thecomparison between the leading construction of the basement roof and the routineconstruction that the latter is more favorable for the control of the difference of the settlementvalues between adjacent columns of the upper structure.