膨胀土边坡自平衡预应力锚固方法研究

针对膨胀土吸水膨胀的特点,提出膨胀土边坡自平衡预应力锚杆加固方法。该方法结合黏结型锚杆和预应力锚杆的优点,使用预应力锚杆结构,但在锚杆施工时仅施加少量或不加预应力,利用膨胀土吸水膨胀特性在边坡中形成自平衡的预应力锚杆加固体系。根据锚杆与土体变形协调关系,推导自平衡预应力锚杆初始应力计算公式,并探讨该方法的有限元计算过程。理论分析、数值计算和工程应用结果表明,自平衡预应力锚固结构在保证边坡稳定和锚固结构安全的前提下,边坡变形较小,同时经济上较为合理,对于类似工程具有广泛的推广应用价值。

Reinforcement approach of self-balance pre-stressed bolts for expansive soil slope

Considering the characteristics of swelling soil,a new reinforcement approach,called self-balance pre-stressed bolts reinforcing technique,was developed.In this method,the merits of grout bolts were combined with those of pre-stressed ones,and the reinforced structures were constructed by pre-stressed equipment,which included anchorage section and free section,but the initial pretension was small or null.When the soil swelled with the increase of its saturation,the bolts would be stressed enough to make the slope stable,so the slope and bolts would form a self-balance system.Based on the compatibility condition of the deformation between bolts and soil,the equation of the initial pretension was derived.At the same time,how to analyze by use of finite element method was described.It was shown by theoretical and numerical analysis that the self-balance pre-stressed reinforcement approach could increase the stability and decrease the deformation of expansive soil slope effectively,and its cost was reasonable.So the reinforced technique was recommended.