Experimental Study On The Lime Improvement Of Expansive Soil Embankment Of Nan-You Highway

A mass of expansive soil is distributed along the Nan-You Highway when it pass through the Lingming Basin in Guangxi province. The typical geological section plane show as: the first layer is ploughing-plant soil, and the second layer it is gray expansive soil under that it is gray-black expansive mud-rock, thereinto the gray expansive soil contains most water, swells and shrinks most strongly, and its strength is the lowest among the three kinds of soil. If the all expansive soil is abandoned, the project cost will be increased greatly and a great deal of environmental pollution will be brought out, and how to treat the expansive soil is the biggest engineering technology problem for the construction of Nan-You Highway. Therefore, combining the research of expansive soil task of Communication Ministry West Item, this paper takes the gray expansive soil as studying target and studies the improving technology of adding lime into the expansive soil.Firstly, based on finishing the terrene research of typical expansive soil section, after synthesizing and analyzing the merit and defect of the existing main judgment-grade methods for expansive soil indoors and outdoors, this paper presents the judgment-grade method of neural network which adopts three index of plasticity index, glue content and expanding rate of freedom for the first time. The method is used for classification of the expansive soil of Nan-You Highway successfully, and offers referrence for the treating project of Nan-You Highway expansive soil.In order to select an economical and feasible improvement project, three kinds of improvement project have been studied contrastively by experiments. Through effective contrast and economical analyse, this paper selects the project of lime improving expansive soil.For discussing the feasibility and effect of lime improving expansive soil, and in order to offer parameter for engineering practice, this paper takes a mass of improving laboratory tests. In view of the bad character of expansive soil filler, this paper designs physical property tests, strength-mechanics tests and swelling-shrinkage tests for improvement soil, especially the CBR test is studied by the numbers, and some significative fruit is obtained. The results of study indicate that adding lime into the expansive soil can reduce the content of clay gain obviously, reduce the plasticity notably, increase the strength greatly, control the property of swelling and shrinking...