Numerical Simulation On Several Support Patterns Of Foundation Under The Condition Of Adjacent Buildings

The excavation of foundation pit in the city, we should not only consider the safetyof foundation and the supporting structures, but also consider the uneven settlement ofadjacent buildings. Today, as the urbanization process accelerated in China, theconstruction of houses and subway is facing the problem that how to excavatefoundation in densely built areas. Due to various reasons, the foundation pit may beunstable or the deformation is too larger. It not only will bring economic loss, but alsobring personnel casualties. Now the foundation excavation area and depth increased, inaddition, there may be one or several great high-rise buildings around which is burieddeeply. In this case, the internal bracing can’t guarantee the safety of foundation. Theanchor can’t deep into the soil when using the pile-anchor system. The distance betweenthe foundation pit edge and adjacent building cannot meet the requirements of rowdistance when using row pile support system. It is even more difficult for the commoncantilever pile to support this kind of foundation pit. So, how can we can excavate thefoundation pit better in the condition that it is surrounded by buildings is worthystudying.In order to study the effect of these kinds of support patterns on the deep and hugefoundation pit which is close to buildings. This paper use ABAQUS to simulate andcalculate different pre-stressed pile-anchor systems, different row distance of row pilesupporting structure and abnormity pile supporting structure. Abnormity pile isproposed as a new support form, which is used to meet the huge and deep foundation pitthat cannot be supported safely when using common supporting form. Compared to thesame section area of the other sheet pile form, it has a greater resistance moment andinertia, so it can effectively support the deep foundation pit. In order to compare thedifference between other cross sectional pile with the same section area, this paper alsocalculated the square pile supporting structure.In this paper, through the simulation on the example that is one foundation pit inZhengzhou city, Henan Province, The effect calculated on the settlement of adjacentbuilding with the above supporting patterns. Some conclusions are drawn: Usingpre-stress anchor to support structure can reduce the building uneven settlement; Row pile supporting need a distance to produce synergistic effect; When the row distance isbetween four times and six times of pile diameter, it can support the foundation pit evenbetter. The greater the row spacing, the smaller the settlement of building; Thesupporting effect of abnormity pile is better than the square pile which has the samesection area with the abnormity pile.To further study the supporting effect of abnormity pile. In this paper, a deep andhuge foundation pit in Changsha city is simulated. The excavation area of thisfoundation pit is more than140acres, and the excavation depth is32m. There is a20-floor building close to foundation pit. The distance between building and the edge offoundation pit is6.5m, and the buried depth of the building is22m. Using othercommon supporting form cannot guarantee the safety of foundation pit, or need a lot ofmoney. In this paper, the abnormity pile is used. The calculation results show that: theabnormity pile can effectively support foundation pit excavation. The settlement andhorizontal displacement of adjacent buildings are within bounds.