General Evaluation In Geotechnical Engineering And Research On Soil Improvement With Construction Waste

As an all-round rising subject, geoenvironmental engineering, with its study work covering so many science fields, is now in the groping and developing phase. It aims at protecting environment by using the geotechnical theories, techniques and methods, highlights the importance between geo-environment and construction activities, and attempts to fulfil the optimization of three benefits, social, economic and environmental. Further, the ideas of geoenvironmental engineering embody sustainable development fully.Based on the practice of Guangzhou higher education mega center(GZHEMC), the thesis combines macroscopical study with microcosmical analysis, evaluates the engineering environment firstly, then put the main work on the attempt of making construction waste diminish and become resource. The elaborate work involves several aspects as follows:(1) On the engineering background of Xiaoguwei Island, the thesis analyzes its status quo in terrain, geologic structure, strata and hydro-geology. Give a macroscopical evaluation to the disasters and geoenvironmental problems possibly causing by construction. Put forward some measures to protect environment and prevent disasters.(2) The thesis discusses the adaptability of geo-environment towards the GZHEMC project, applies fuzzy mathematics theory to solve the problem that so many factors in the discussion of adaptability are difficult to be ascertained for ambiguity. Then a calculation with fuzzy theory is made to evaluate engineering environment during three phases, before construction, in construction and after construction. Result shows that the grade of adaptability for three phases is "C" , " D" and "B" respectively, in accordance with practice.(3) A mass of demolition waste will be produced. We must fully know its classification, composition and basic characters. Demolition waste has some resemblance with common soil, but it also has characteristics. Treat the waste as a special sort of soil and discuss its grain gradation, unit weight, water content, porosity, permeability, organic content and compressibility. It is necessary to pretreat demolition waste. In the thesis, several pretreatment means are discussed. At the same time, a simple and economical pretreatment flow is put forward.(4) The thesis combines waste treatment with soil improvement. When the waste is used in replacement method, it embodies diminution effect;when used as padding in piles, it embodies resourcing effect;Discuss these three methods of soil improvement, replacement method, waste pile and waste pedestal pile. Analyze their mechanism, applicability and main points in construction. Combining with an engineering example in Guangzhou science park, the thesis puts forward a perfect technique flow for waste pile. According to the data of oile test, the thesis explains the feasibility of soil improvement with construction waste.(5) Though there are successful examples of soil improvement with waste, the rate of success and popularization degree are still low in the whole. The reason is that people doubt about the characteristics of construction waste and feasibility in technique or cost. The thesis applies fuzzy mathematics theory again to analyze the general benefit of three methods, waste pile, cement mixing pile and dynamic compaction, providing with reference for practice.