Study On The Displacement Of Adjacent Structures In Deep Foundation Excavation Engineering

As the exploitation of underground space and the construction of high-rise in urban, a large number of deep foundation excavations have appeared lately. Its scale and depth increase constantly. Urban deep foundation excavations are generally surrounded with dense buildings. So their working space is very narrow, especially when they are close to the foundations of adjacent buildings or structures. Applying the traditional design theory (strength-controlling design) and routine construction technology, there is an inevitable difficulty about protecting surrounding buildings or structures in construction. Many scholars, engineers and technicians have already worked a lot in the displacement-controlling design of deep foundation excavations recent years, however, difficulty remains to be solved in correlation among the deformation of the retaining structures, soil deformation around the excavations and the displacements of adjacent structures. Deep foundation excavations, bracing structures and adjacent structures are studied as an integrated system in this paper. The construction process of the typical deep foundation excavation which is under the typical geological conditions of Beijing area is simulated and analyzed with the aid of large-scale software-flac4. 0. So is the excavating process of the deep foundation excavation in different supports. Numerical simulation is carried under different conditions, including (a)the different distance between deep foundation excavations and theadjacent structures ; (b) different supports are used, such as cantilever piles, row piles with one-layer grouted soil anchor, row piles with two-layer grouted soil anchor, row piles with three-layer grouted soil anchor and soil nailings etc. This paper reveal the law of adjacent structures and bracing structures displacements and surrounding soil settlements. Anchor and soil nailing's impact on the displacements of adjacent structures is analyzed then. Further more, we find the law of displacements of bracing structures, surrounding soil settlements, differential settlement and absolute settlements of adjacent structures that may appear in the process of excavation by steps. Finally, the conclusions that are valuable for designing and construction of deep foundation engineering are found. Considering the absence of the study about the displacements of the adjacent structures during the excavating process of deep foundation excavations, the result can be used as reference for the relevant numerical simulation and other research.