The Foundation Pit Of The Optimization Design And Application Research

Pit excavation and retaining were begun in the80’s last century. As the development of high architectural, the depth of pit excavation is increasing, the deepest pits are about20to30meters. Pit excavation and retaining come down to rock and soil engineering, structure engineering and drain engineering, it is a colligating study. During the excavation of pits, many factors must be considerate, including the choosing of the retaining scheme, variety of forces and displacements of the retaining structure, drain of pit and the development of settlement of the construction along the pit. To solve there problems, it can insure the engineering safe, scientific and economic.With the excavation and retaining engineering of the SuZhou communication bank mansion, some study were done, for example, the chosen of the retaining schemes, the variety of the force and displacement of the retaining structure, the controlling of the ground water and so on. With there studies, some conclusion were gotten:1. In allusion to the parameters of soil and rock, depth of excavation and the construction along the pit, three feasible schemes of retaining were gotten.2. For the analysis of factors which can affect the chosen of the retaining schemes, the calculating method of the transform of evaluating parameters were gotten, and the multi-attribute decision-making model on selecting retaining scheme were established. For the calculation, the conclusion that the drain and hermetical purdah is the best scheme for the retaining schemes of the pit of the SuZhou communication bank mansion.3. Based on the theory of beam of elastic foundation, considering the influence of comparatively displacement between soil and piles, firstly, break up the foundation pit excavation for different processes based on the setting of horizontal supports, and then, combine with the method of initial parameter, the calculation formulas of the distribution of horizontal displacement, rotational displacement, moment and shear along piles under foundation pit excavation are derived.4. The resist of the gush and seepage were analyzed. With the parameters of soil and rock of the pit of the SuZhou communication bank mansion, two kinds of this problem were calculated.5. With the academic calculating method of the precipitation of the pit, the precipitation of the pie engineering of the SuZhou communication bank mansion was calculated. It can insure that the amount and caliber of the precipitation well of confined water and tiny confined water is enough.6. By academic analysis, the calculating formulas of water press with three instance were acquired, the instance include water and soil are calculated together, water and soil are calculated separated, the seepage of underground water is considered. And then the calculation formulas of the force and displacement with the considering of the seepage of underground water were analyzed. The validity of academic analysis was validated with the contrasted analysis of the calculated and practical horizontal displacement.7. The variety of displacement of deep soil inside the pit, settlement of nearly roads, axis force, settlements of pile, horizontal displacement of bank, settlement of injacent structure and the water table was monitored, and the variety of these parameters were analyzed during the excavation of the pit.