膨胀土(岩)湿化性的影响因素及降低湿化性的途径和方法  

Factors Influencing the Slaking of Expansive Soil ( Rock) and Methods to Reduce Slaking

作　　者：王小军 方建生 

机构地区：[1]中铁西北科学研究院,甘肃兰州730000

出　　处：《铁道学报》2004年第6期100-105,共6页Journal of the China Railway Society

基　　金：铁道部科技发展计划项目(96G57)

摘　　要：通过对西南地区8种典型膨胀土(岩)的湿化性试验,研究了矿物成分、粒度成分和微观组构、裂隙性、胶结性和初始含水率对膨胀土(岩)湿化性的影响作用,讨论了重塑土样的湿化性受干密度的影响规律。亲水性粘土矿物和粘粒含量愈多,湿化后的颗粒愈细腻;裂隙密度Imf愈大,湿化速率υt愈快;但湿化速率υt却随胶结系数I的增大呈递减变化;初始含水率w与湿化率At的关系曲线呈降梯形分布,存在两个临界含水率w1、w2;干密度ρd与完全湿化时间t100的关系式为t100=AρBd,A、B为回归系数。最后总结了降低湿化性的途径和方法:①进行土质改良,降低湿化性,提高膨胀土(岩)强度;②对边坡进行合理的支挡防护,降低大气营力的作用程度,减少和控制湿化作用深度,提高边坡的整体和局部稳定性。The effects of the factors of water-affinity clay minerals, granular contents,micro-fabric,fissuration,cementation and initial water content on slaking of expansive soil (rock) are investigated on the basis of the slaking tests of eight types of expansive soil (rock) in southwest China. Besides,the effect of the dry density on the slaking of remoulded samples is also discussed . The more the water-affinity clay minerals and clay fraction contents, the finer the grain sizes after slaking.The more the micro-fissure frequency I_(mf), the more the slaking rate υ_t. The slaking rate υ_t decreases progressively with the increase of cementation coefficient I. The shape of the initial water content w -percentage of slaking A_t curve is a half of trapezium, which demonstrates two critical water contents w_1 and w_2. The relation between dry unit density ρ_d and time of complete slaking t_(100) is t_(100)=Aρ~B_d , where A and B are regressive coefficients. Finally the ways and methods are summarized in order to reduce slaking of expansive soil (rock): ① Improve the quality of soil, reduce the degree of slaking and heighten the strength of expansive soil (rock). ② Take appropriate support and retaining measures to protect expansive soil (rock) slopes, decrease weather effect and control slaking depths so as to attain better quality of slopes no matter in parts or in the entirety.

关 键 词：膨胀土(岩) 湿化性 影响因素 降低方法 

分 类 号：TU443[建筑科学—岩土工程]