三门峡黄土湿陷特性及其与结构强度的关系

针对黄土湿陷性对大型输电线路塔基稳定产生不良影响的问题,对河南三门峡地区原状黄土开展了基本物理特性及湿陷性试验,获取了其湿陷系数与湿陷等级,分析了竖向压力和初始含水率对黄土湿陷性的影响规律,着重从结构强度的角度解释了黄土湿陷特性。结果表明:竖向压力与湿陷系数之间并非只是简单的单调增函数关系,而存在湿陷增强区间和湿陷减弱区间;塑限(18.6%)是黄土湿陷性强弱的分界点,当初始含水率小于塑限时,湿陷性较强,而当初始含水率接近或者大于塑限时,则湿陷性减弱;初始含水率与湿陷系数之间也并非只是简单的单调减函数关系,而在结构强度为200 kPa时(含水率为10%)附近出现明显的转折。

Collapsibility of Sanmenxia Loess and Its Relation with Structural Strength

The collapsibility of loess has exerted adverse impact on the stability of tower base of electric power transmission line in Henan Province.In view of this,we conducted tests on the basic physical properties and collapsibility of loess in Sanmenxia area in Henan Province in order to obtain collapsibility coefficient and evaluate collapsibility grades.Moreover,by analyzing the effects of changing vertical pressure and initial water content on loess collapsibility,we examined the relationship between collapsibility and structural strength of loess.Test results show that the relationship between vertical pressure and collapsibility coefficient is not a simply and monotonically increasing function; instead,we found intervals of vertical pressure which induces the exacerbation or weakening of collapsibility.A plastic limit of 18.6% is the dividing point on collapsibility curve which means that collapsibility weakens when initial water content is close to or over the plastic limit,or exacerbates when initial water content is smaller than that plastic limit.In addition,the relationship between water content and collapsibility coefficient is also not a simple and monotonically decreasing function where the turning point on that function would appear when initial water content equals 10% and structural strength is 200 kPa at the same time.