石灰改性膨胀土路基变形特性仿真研究

Simulation Study on Deformation Characteristics of Roadbeds of Lime-modified Expansive Soil

掺石灰对膨胀土进行改性是膨胀土地区筑路常用方法之一。相关技术规范仅规定强膨胀土不能作为路基填料和中膨胀土经过改性处理后可作为高速公路路基填料,但并未阐述其具体配合比。选取某高速公路局部膨胀土地基路段作为研究对象,对已有的膨胀土地区公路路基的相关技术指标和运营情况进行调查,通过现场钻探取样,选取有代表性的膨胀土样,进行室内试验和仿真模型计算,研究石灰改性膨胀土路基的应力与应变特性。研究结果表明,掺加石灰对膨胀土路基进行改性是有效的,掺灰率控制在4%～6%时较为合适。

Modification of expansive soil with lime is one of common methods for road construction in the areas of expansive soil.The relevant technical specifications only stipulate that strong expansive soil cannot be used as roadbed filling and that medium expansive soil after modification treatment can be used as expressway roadbed filling,but do not state its specific mix ratio.This paper selects a section with local expansive soil foundation of some expressway as the object of study and investigates related technical indices and operating conditions of the existing highway roadbeds in expansive soil areas.By boring sampling on site,the paper chooses representative expansive soil samples to conduct indoor test and calculation of simulation model to study stress and strain characteristics of modified expansive soil roadbeds with lime.The result of study shows that addition of lime is effective for improvement of expansive soil roadbed,it is appropriate to control the ratio of added lime at 4% ～ 6%.