The Structural Deformation Of The Pile - Anchor Of The Single Point Calculation And Deformation Control Inversion Analysis

On the base of studying a great deal of Chinese and English research literature, a few problems have been solved by theoretically deducing and program calculating. These problems, such as: the calculation model of single fulcurm pile-anchor retaining structure in deep foundation pit excavating, the determine of model parameters, the research of deformation calculation of pile-anchor retaining structure, the analysis of deformation controlling, the inter-influence of every factors, have high theoretical value and are instructive for constructing. The effect of every factor to deformation is researched by counterdeducing. It can guide deformation predicting and controlling. The calculating method is founded theoretically to establish the pretensioned force of the anchor a little accurately.Firstly, lots of classical monographs and research literature are studied by consulting all kinds of periodicals. Secondly, the theoretical research achievements are presented in the exordium. Here is the example: the late theoretical achievements of the soil pressure in deep foundation pit engineering, the trait research of capacity and deformation about the pile-anchor retaining structure, the research about the soil anchor, the methods of design and calculation, the finite element analysis of pile-anchor retaining structure, together with its optimizing. Thirdly, after studying over eighty constructed projects, in accord with the region characteristic of geotectonic engineering, some typical actual projects are listed, which adopt the pile-anchor retaining structure, together with their similar region trait and soil parameters. At the same time, the trait of the pile-anchor retaining structure projects in each region is presented for theoretical research, including its deformation law, project datum sorting and constructed effect.In the second chapter, principium of pile-anchor retaining structure is firstly introduced, together with its trait, classification and calculating method in the current specification. Then, for the same excavating case of a pile-anchor retaining structure project, the time-effect regular pattern of soil pressure and deformation beneath the pit bottom is produced. Next, by comparing several theories for design and calculation, the proper rule of soil pressure on distributing and changing is also produced for the single fulcurm pile-anchor retaining structure.The calculation model of the single fulcurm pile-anchor retaining structure is established by theoretically analyseing in the third chapter: the retaining structure is identified as a successive beam with a free section. The prestress anchor beneath the topend of the pile is regarded as a spring bracing, and the constraint end of the pile is simplified as a flexible pivot that can rotate some degree. It is postulated that the soil pressure behind the pile consists of ultimate active soil pressure and uncertain soil pressure. With the next excavation, the uncertain soil pressure may fade away after the retaining structure deformation appeared. So the soil pressure to the retaining structure can be regarded closely as the active soil pressure in the next excavating cases.In the light of theory of elastic foundation beam, introducing the reactive force parameter of the foundation soil, the rigid parameter of flexible rotation is obtained. As a result, the pivot of the pile at the bottom end of foundation pit is simplified to a pin pivot. During the simplifying course, the concept of the short-dated stress history of the foundation soil is introduced, and the revising advise on the current technical specification for retaining and protection of building foundation excavations is produced.On the base of the assumption that the structure deformation consists of bending deformation and rigid rotation, the predicting and controlling about the deformation can be theoretically actualized.In the fourth chapter, using the theory on the Soil Mechanics and Mechanics of Material, together with the methods introduced by other research literature, the...