The Research Of Displacement-Controlling Design Of Piles And Anchors In Deep Foundation Pits

Recently high-rises and civil engineering appear fast with the development of national economy and improving of people’s living. The construction of basement and garage underground and subway brings deep excavation. As one of retaining structure, piles and anchors are widely used because of exact design theory, power of controlling displacement and convenient construction. Presently, for the room of construction becomes smaller, some lifeline engineering, road, bridge and house are affected by close deep excavation. Therefore, according to engineering geology and environment, the design of retaining structure aimed at displacement on the basis of stability is the trend.The content of this dissertation included:1. The principle, content, progress and confusion of piles and anchors design are concluded. The significance of design of retaining structure aimed at displacement is emphasized.2. The theory of soil pressure relative to design of retaining structure is introduced, which include Rankine soil pressure, Coulomb soil pressure and other experienced soil pressure. Then, their applicability is discussed.3. On condition of controlling displacement, the design of a case with traditional method is given.The conclusion of this dissertation included:1. Elastic ground beam method can’t calculate ground settlement, so the design of retaining structure aimed at displacement with elastic ground beam method is incomplete.2. In the process of analyzing displacement, the procedure of excavation need be considered because structure stress and displacement is changed with excavation. In advance of setting anchor, pile has moved. Thus there is different between calculate result and fact if the status of completing excavation is used to design. In this dissertation calculate result is matched with the fact because excavation is considered.3. The lateral displacement of pile in retaining structure of piles and multilayer anchors is arched. Therefore, only monitoring the displacement of the top of pile is not enough. The displacement of pile from top to bottom should be monitored in order that the largest lateral displacement is under the control level.4. The setting of anchors in retaining structure of piles and multilayer anchors has great effect on the lateral displacement of pile. If the first layer is nearer to the top of pile, the lateral displacement of the top of pile is smaller, but the largest moment of pile becomes bigger. Hence, the setting of anchors should be optimizing according to actual condition.