Probabilistic Analyses Of Soft Ground Treatment Schemes For Airport Runway And Decision-making

Civil Aviation is given more chance to develop rapidly by Economic development in our country. Especially in the eastern littoral province, there are much more airports and skyways. Along with the increasement of the transportation, More and more airports are confronted with the heavy assignments of expansion or rebuilding. But most of these airports located in the aggraded valley plain. There are deep soft soil distributed in these areas. Several airports in Zhejiang Province like Hangzhou, Ningbo, Wenzhou, Zhoushan Airport and so on are the types. The soft soil ground disposal is necessarily the geotechnical engineering problem for these airports'construction. Now the mostly used soft soil ground disposal methods include the soft foundation treatment of drainage consolidation (load prepressure with plastic drainage slab, Construction statement for PVC, Vacuum and Load-fill compression method), cement-mixed pile and Dynamic consolidation method and so on.How to conform the best ground disposal scheme satisfided with reliability and economy is the chief task for project planning and design. When we are making the decision, we should forecast and evaluate the uncertain factors which have an effect on the project's reliability. These uncertain factors include coefficient of compressibility , porosity, modulus of compressibility, coefficient of consolidation and thickness of soil layers, which inevitably make ground disposal projects go with the definite risk. The dissertation carries through the probability analysis of the uncertain factors and the sensibility analysis of the parameters, makes the reliability analysis of the calculated value of ground disposal settling using JC method, and also puts forward the risk analysis model based on the reliability .It also evaluates the engineering loss and makes the decision by the expected value which is the least.The text applies the reliability theoiy to the geotechnical engineering, and also makes trial of the Wenzhou Airport's geology reconnaissance report. It makes the reliability analysis of the settling calculated value of two different ground disposal methods. Through the analysis, we know that different design parameters have different effects on the project's reliability and the reliability of cement-mixed pile method is much more greater than the loading pre-pressing method's. The text also estimates the cost of different soft soil ground disposal schemes in airport engineering and evaluates the project loss and the economic benefit of project time limit. When confirming the scheme, it forecasts and evaluates the expected value of loss with the model of risk-decision tree. The text provides the foundation of the scientific decision-making for the soft soil ground disposal scheme of airport engineering. Being provided with the applicability and the universality, it can be used to instruct the engineering design.