| The reinforcement of soft base under overload is attached much importance by engineering field in the long run. As for different reinforcement schemes in special situation, a qualitative and quantitative evaluation is crucial for the last decision. An engineering example, which is the soft road base reinforcement in the area of Hongjiang power station upstream reservoir, is taken in this paper. Then the technology for reinforcing the clay base under overload is researched and the optimization is selected. The main study is as follows:First, different kinds of theories and methods in the world are introduced and their characteristics and applicability are also analyzed. As for this project three methods are chosen as primary schemes: riprapping and rolling, soil-cement pile, cement-flyash-crushed stone pile.Second, a fuzzy mathematical evaluation model, which is set up for the selection of base reinforcement structures in this project, is used in the comparing between different schemes. The first level integrated evaluation in technique, safety and economy aspects is applied before the second level integrated evaluation. By the assistance of the expert system, the reinforcement scheme choosing is carried out according to the principle of two levels fuzzy integrated evaluation method. The choosing is more dependable because the subjective evaluation is turned into numeric form to embody the importance degree of every factor.Third, the general formulas of the band method in the limit analysis theory is deduced, Bishop method and sliding wedge method are introduced at the same time, whose precisions are also compared. Analysis shows that as for the stable analysis Bishop method is accurate in most situations.Fourthly, elastic-plasticity finite element method (FEM) computation is applied to the composite base with cement-flyash-crushed stone pile. The variety rule of displacement and plastic zone resulted from FEM, which shows the difference between before and after the reinforcement, is studied profoundly. The research shows that the non-deformability of base is greatly improved by reinforcement because ofthe decrease of vertical deformation in the reinforcement layer. Although the vertical deformation in the subjacent bed increased, the total vertical deformation is reduced much because the decrease of vertical deformation in the reinforcement layer is greatly more than the increase in the subjacent bed, which improves the stability of road base.Research Achievements:1.Huang Haijun,Discussion on the Construction Quality Supervision of Cement Deep Mixing Pile,Science and Technology lnformation,2006(4).2.Huang Haijun,Application of CFG Pile in the Soft Clay Foundation,Knowledgae and Innovation,2006(2). |
