An Experimental Comparative Study on Improvement Technology of the Subgrade Filling Expansive Soil

Improvement of the expansive soil is one of the vital issues in the field of subgrade engineering. This paper is based on the test section of Xi’an-Nanjing double track engineering, respectively adopt quick lime and cement as expansive soil improvers, adopts quick lime and cement as expansive soil improvers ,conducts a study on the swell-shrinking property, strength characteristics and strength change law under drying and wetting cycles of NanYang expansive soils. The results show that the lime-improved expansive soil and cementimproved expansive soil can also effectively reduce the swell-shrinking property of expansive soils, which strength can reach the requirement of subgrade filling engineering. The lime-improved expansive soil has better effect in the shearing characteristics, compaction characteristics, permeation characteristics and the ability to lower expansibility than the cement-improved expansive soil. But the cement-improved expansive soil possesses better characteristic of strength reduction after drying and wetting cycles than the lime-improved one. The lime resource is more abundant and the price is cheaper than cement in NanYang city. So the lime-improved expansive soil is one of the most effective and economic method for improvement of the expansive soil.