Interactive Effects Of Excavation Of Foundation Pit And Nearby Buildings In Soil-rock Mixed Strata

With the increase of foundation pit with adjacent buildings, Some of referenceshave investigated the influence on deformation of the foundation pit due to adjacentbuildings, but most of them regard the adjacent building as a kind of uniform loaddirectly instead of the model of the building, and ignore the overload depth. therefore,the paper has complete the following work：First of all，taking an example based on practical deep foundation and usingPLAXIS finite element calculation software, Comparison of different buildingoverloading pressure effect on the deformation of foundation pit, and verify theapplicability of model building instead of the adjacent buildings in numericalsimulation.Following, taking Qingdao soil-rock mixed strata a typical foundation pitsupported by pile-inner bracing structures as a prototype, considering model of theadjacent building located in one side of the pit and both side of the pit, characteristicsof the pit deformation have been analyzed due to variation of the overload depth ofthe building. at the same time, Characteristics of the near side deformation due tovariation of the distance between the building and the pit for different overload depthare analyzed. Furthermore, mechanism of the pit deformation under different overloaddepth of adjacent buildings is discussed.Finally, studying foundation settlement changes caused by the distance betweenthe building and the pit for different overload depth change.by data fitting analysis ofexpression of foundation settlement, and verified the expression has certainapplicability combination of specific conditions in rock under the settlement ofbuilding foundation.Through the above study, some conclusions can be drawn.(1) Using the framework model building simulate building overload has betterapplicability.(2) The pit from one side of a building deformation is favorable when it has thepresence of asymmetric buildings, the curve looks like a spoon shaped; and maximum value of the horizontal displacement of the pile and the ground displacement are alsorelatively stable, is about0.45.(3) There is a critical effect depth in the side of recent overload, when thebuilding depth is less than the critical depth, the lateral deformation of foundation pitis unfavorable; and when the building loading depth is less than or equal to the criticaleffect depth, with the distance from foundation to building increased, the lateralhorizontal displacement of pile and ground displacement decreased, The maximumposition of ground displacement contorted by the building position-the distance to thefoundation pit occurs at the latest in buildings; otherwise, it presents a trend ofincreasing, the maximum surface subsidence occurred at0.3h-0.5h distance.(4) There are some differences between both sides of the foundation pitdeformation under the condition of asymmetric, this difference with increasing depthincreases first and then decreases, reaches a minimum at the critical effect depth. Inthe foundation pit support design should be considered when the difference value.(5) Formula in the building function range and depth in the scope of0.3~0.6h isapplicable to the settlement of building foundation.