降雨入渗条件下预应力锚索加固边坡稳定性分析

Prestressed Cable Anchor Reinforced Slope Stability Analysis under Rainfall Penetration Condition

根据目前边坡失稳案例统计,导致边坡失稳破坏的原因多为降雨入渗,目前大多学者对自然边坡在降雨入渗条件下的失稳机理做了大量研究,但是对于不同降雨入渗条件下边坡加固结构及其稳定性是如何随降雨强度的变化而发生改变的研究却较少。以云南昆明某边坡为研究对象,考虑土体饱和-非饱和渗流理论及非饱和强度理论,通过有限元软件MIDAS-GTS分析研究降雨动态过程中边坡加固结构内力的变化规律及边坡的稳定性变化规律。研究发现:①当降雨时长一定时,降雨强度越大,非饱和区越小,负孔隙水压力降低越明显,安全系数越差;②随着降雨入渗的进行,边坡下滑力增大,抗滑力逐渐变小;③降雨入渗对原始边坡的稳定性影响较大,但是对加固后边坡的稳定性影响相对较小;④预应力锚索轴力随着降雨时长增大而增大,当降雨时长一定时,锚索轴力随降雨强度增大而增大。

According to the statistics of current slope unstable cases,the causation of most slope unstable failure is from rainfall penetration.At present,many research achievements have been made by most scholars on natural slope unstable mechanism under rainfall penetration condition,but less research on under different rainfall penetration conditions slope reinforced structure and its stability variation along with rainfall intensity variation.Taking a slope case in the Kunming,Yunnan as subject investigated,considering soil mass saturation-unsaturation seepage theory and unsaturation intensity theory,through finite element software Midas-GTS analytically studied slope reinforced structure force variation pattern and slope stability variation pattern.The study has shown:①When rainfall duration is certain,the larger the intensity,the smaller the saturation area and the more obvious negative pore water pressure drop,as well as the poorer safety factor;②Along with rainfall penetration carry on,slope gliding force increasing,antiskid force gradually lessening;③Impact from rainfall penetration on stability of original slope is rather large,but relatively less on stability of reinforced slope;④Prestressed cable anchor axial force increasing with rainfall duration increasing;when rainfall duration is certain,cable anchor axial force increasing with rainfall intensity increasing.