基于二次掺灰法的改良膨胀土施工工艺与检测方法

Construction and Detecting Methods for Stabilized Expansive Soil Using Two-step Lime-cement Mixing

膨胀土一般天然含水率高,透水性差,原状土一般以较大的团块存在,黏性较大,不易粉碎。但室内和现场试验成果证明:膨胀土经过掺灰改性后,其体积胀缩性低于一般黏土,而强度很高、压缩性低,是很好的土建工程填料。而能否将石灰和土料拌合均匀是影响改良效果的主要因素。因此石灰改良膨胀土施工工艺中最重要的一环就是掺灰工艺,其次就是掺灰土中掺灰量和均匀性是否达到设计要求的检验方法和判定标准。在大量室内和现场模拟试验的基础上,提出了石灰改良膨胀土的施工工艺和质量检验、控制标准。

The expansive soil usually has high moisture content and low permeability,and it appears as conglomeration under the undisturbed conditions.Moreover,the expansive soil has high viscosity and it not easily to be destroyed.However,the laboratory and in-situ experiments showed that the swell-shrink characteristic of the expansive soil after mixing with lime and/or cement is lower than that of the general clay,and the stabilized expansive soil has high strength and low compression,thus it is a good filling material for engineering construction.The equality for mixing the lime-cement and the expansive soil is the primary factor for the stabilized effects.Therefore,the lime mixing technology is the most important technology for the construction methods of the stabilized lime-cement expansive soil.Besides that,the quantity and equality of the lime mixing soil are also important to check if they reach the designed criterion.In this paper,the construction method and the standard for quality inspection and control of stabilized expansive soil are presented based on numerous laboratory and in-situ model tests.