膨胀土在不同约束状态下的试验研究  

Testing study on expansive soil in different restrained conditions

作　　者：罗冲[1] 殷坤龙[2] 周春梅[2] 姚林林[2] 

机构地区：[1]广西电力工业勘察设计研究院,南宁530023 [2]中国地质大学(武汉)工程学院,武汉430074

出　　处：《岩土力学》2007年第3期635-638,共4页Rock and Soil Mechanics

基　　金：高校博士点基金资助项目(No.20030491004)

摘　　要：用环刀取样,在不同约束压力下进行膨胀力和膨胀率试验,发现约束压力对膨胀土膨胀性有很大的影响,且压力越大,膨胀性越小。在此基础上,还设计了膨胀土的3种不同约束状态下的试验:(1)土样周围与上下端都有约束;(2)土样周围与下端约束而上端自由;(3)土样周围约束而两端自由。试验结果表明,不同的约束状态对膨胀土的含水率、密度、孔隙比和抗剪强度等物理力学性质指标有显著影响,且两端无约束的膨胀土吸水膨胀后,含水率接近其液限,膨胀土最容易沿无约束面发生膨胀变形。试验结果对膨胀土的治理具有重要的指导意义。By test of swelling pressure and expansion rate with cutting ring sample under different restrained pressures, it is shown that the restrained pressure has obvious influence on expansive soil＇s expansibility; the greater restrained pressure is, the smaller expansibility is. On this basis, experiments in three kinds of different restrained conditions of expansive soil are designed：（1） the lateral, upside and downside of the expansive soil are restrained.（2） the lateral and downside of the soil are restrained, while the upside is unrestrained.（3） the lateral of the soil is restrained, upside and downside unrestrained. The test results indicate that different restrained conditions have obvious influence on expansive soil＇s physical and mechanical characteristics such as moisture content, density, void ratio and shear strength. Furthermore, expansive soil is more easily deformed along unrestrained surface. Furthermore, when the upside and downside of expansive soil are unrestrained, the expansive soil＇s moisture content is close to its liquid limit after sopping water. The study will provide important basis for the control of the expansive soil.

关 键 词：膨胀土 约束状态 含水率 孔隙比 液限 

分 类 号：TU441[建筑科学—岩土工程]