Study Of Decision-Making Method For Pile Foundation Design Based On GIS Technology

In the engineering practice for pile foundation, following three aspects: design, construction, and quality inspection are conducted independentaly. Owing to this independentce, the information provided for the decision-making in the state of disorder and dispersing and this state makes it is difficult to control the quality. In this study, Database software (SQL Server 2000) and geography information system (GIS) software (MapObjects) are employed to manage large number of engineering practices of pile foundation in Fuzhou area and used to achieve the digital management of pile foundation in Fuzhou. Then the decision-making and consulting system of pile foundation is developed by MATLAB and Visual Basic. The system can provide reasonable suggestions on geological condition, pile-type, and vertical bearing capacity of single pile. The new findings of this study are as follows:(1) This study established a generalization and systematic pile foundation database in Fujian province. This makes it implementing in systematic management of a large number of pile foundation data and provided a good tool for inquiry and management. At meantime, the GIS software– MapObjects and Visual Basic 6.0 programming software are incorporative adopted in database management of pile foundation. It can provide inquiry and consulting interface based on geographical position for users, so that customers can use the engineering data more conveniently and visually. (2) Decision-making and consulting platform basing on GIS is eatablished. The GNN model of geological condition prediction and fuzzy synthetic analytic hierarchy process model are incorporated in this platform. Firstly, the GNN model can predict the geological condition of planned construction point. Then, the geological condition of planned construction point is analyzed by the ruled database of pile-type selection and suggestions of bearing strata on planned construction point are presented. Finally, the fuzzy synthetic analytic hierarchy process and ruled database are used to analyze the three influential factors in pile-type selection: bearing strata, numbers of stories and environment. It provided reasonable suggestions about pile-type selection and optimized the suggestions of pile-type by ruled database. The two proposed models are applied to a case history in Fuzhou area, the analytical results show that the prediction and selection based on the proposed theory agrees well with the engineering practice. Thus, the proposed decision-making and consulting system is a useful tool in pile foundation design.(3) GNN model was built yo predict of geological condition at design site. Geological condition usually achieved by geological investigation. Existing engineering data did not used sufficiently. However, the GNN model can use the existing engineering data sufficiently; it can build the relationship of BP neural network between geographical position and parameters of soil layers by nonlinear mapping of GNN. Thus it can avoid the wasting of existing information and difficulties in determining parameter relationship of others quantized methods.(4) Fuzzy synthetic AHP model was established for the optimal selection of pile-type. Selection of pile type is a difficult work in pile foundation design. There are many factors affecting the determination of pile type, which have the characteristic of uncertainty, In this paper, an evaluation approach combined fuzzy synthetic evaluation method with AHP (Analytic Hierarchy Process) is employed to analyzed the cross influence of all kinds of factors in pile-type selection, and the weights of restraint indexes are obtained by AHP, which can reduce the influence of subjective factors of just applying fuzzy synthetic evaluation method. Therefore, this method can achieved a better optimized result in pile-type selection.