MODEL TESTS ON MASS CARBONATION STABILIZATION OF MUCKY SOIL

Based on the existing studies of the MgO-carbonated soft soils, model tests of mucky soils are conducted through the carbonation stabilization technology. The mucky soil taken from Chang-Yi highway(from Yixing to Changzhou) is used for the reactive MgO-mass carbonation and stabilization experiments. Some parameters including temperature, moisture content and pH are measured to analyze the degree of carbonization. Laboratory micro penetration test(MPT) and compression tests are conducted to evaluate the bearing capacity and compressibility of carbonated mucky soil. The results indicate that(1) the mucky soil can achieve the better treatment effect after MgO carbonation when its initial moisture content is 35%, its state is hard plastic state transformed from its soft plastic state, and its bearing capacity reaches 300 kPa. (2) When the initial water content of mucky soil is 46%, the migration distance of carbon dioxide is restricted, resulting in that its carbonization degree and bearing capacity improvement are limited and the soil state is still the plastic state except that the limited areas near the surface and vents can be effectively improved. (3) Carbonation can obviously reduce compression of mucky soil even only through simple compaction measures. Comparing with other treatment methods of mucky soil, it is considered that the air permeability of mucky soil can be increased by some auxiliary measures, e.g., adding water reducer or fine sand under the conditions of low construction requirements and inconvenient drainage, the better treatment effect may be obtained by magnesium oxide carbonation method.