ISSN 1000-3665 CN 11-2202/P

    多级荷载下弱膨胀土的膨胀变形特性试验研究

    An experimental study of expansion deformation characteristics of weak expansive soil under multi-stage load

    • 摘要: 为研究压实弱膨胀土的膨胀变形特性,对取自高淳某边坡的弱膨胀土进行固结及浸水膨胀变形试验,研究了在300,200,150,100,75,50,25和12.5 kPa共8种上覆压力下不同初始干密度及初始含水率土体的固结及膨胀变形特征。试验结果表明:初始含水率及初始干密度对弱膨胀土的膨胀变形特性均存在一定的影响,在其余条件相同的情况下,膨胀土的膨胀变形量随着初始干密度的增大而增大,随着初始含水率的增大而减小。分析了膨胀土固结及膨胀变形过程的典型曲线特点,研究了不同初始干密度及初始含水率下土体固结与膨胀曲线膨胀区与压缩区分界点特征,得出在初始含水率相同时,分界点的上覆压力与分界点孔隙比及土体的初始干密度均呈正比关系。通过对土体试验数据的分析拟合,结合土体变形过程中的孔隙比与初始状态关系的推导,提出了弱膨胀土的膨胀变形量计算方法,结合工程包边法路堤填筑的荷载分布,采用分层总和法推导了工程包边法膨胀土路堤填筑的膨胀变形量计算方法,并用于路堤膨胀量的预估中。

       

      Abstract: In order to study the expansion deformation characteristics of compaction weak expansive soil, the tests of consolidation and expansive deformation characteristics of the weak expansive soil from a slope in Gaochun were conducted. The consolidation and expansive deformation characteristics under pressures of 300, 200, 150, 100, 75, 50, 25 and 12.5 kPa in different water content and different initial water content were analyzed. The test results show that the initial dry density and water content have certain influence on the weak soil's expansive deformation, under the same other conditions, expansion deformation increases with the increasing initial dry density, and decreases with the increasing initial water content. The typical curve characteristics of the process of consolidation and deformation of the expansive soil were also analyzed. The characteristics of the boundary point on the curve of the soil consolidation and expansive between expansive area and compression area under different initial dry density and water content are summarized, and the results are given that the overlying press of a boundary point has the linear relationship between the boundary point void ratio and the initial dry density under the two initial water content. Through the analysis and fitting of the soil tests data and combined with the derivation of the relationship between the void ratio and the initial state in the process of soil deformation, the calculation methods of the expansion deformation amount of the weak expansion soil is proposed. Combined with the load distribution in the engineer wrapper methods of embankment, the layered summation method is used to deduce the calculation methods of the expansive deformation amount in the embankment, to propose the prediction calculation methods in the expansive deformation value of embankment.

       

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