全强风化岩高边坡破坏模式与加固效果分析

公路工程遇到的全强风化岩高边坡的情况很多。风化岩体的物理力学特性与未风化岩体物理力学性质有很大差异,特别是全强风化岩体,原岩的结构面已被风化改造,对边坡的稳定性已不起控制作用,其工程性质更接近于粗粒土,因此全强风化岩高边坡极易发生破坏。以贵州凯里~麻江高速公路鹅山冲全强风化岩高边坡为例,发现全强风化岩高边坡经常会出现从浅部到深部不同深度的破坏面,圆弧是滑动面的主要形式,并提出了可以采用浅层压力灌浆、中部锚固和下部支挡等措施,分别针对不同深度的破坏面进行加固。这一综合方案不仅有效加固了高达157 m的全强风化岩高边坡,而且防止了水土流失,保护了环境,是一种经济有效的加固方式。鹅山冲高边坡加固已完成5年,一直稳定,植被完好,从中积累的全强风化岩边坡加固模式具有非常典型的意义。

Analysis of Failure Modes and Reinforce Effect of High Slope with Entirely Weathered Rock Mass

Entirely weathered rock mass slopes are often encountered in the highway engineering.It is well known that there are big differences existing between physical and mechanical properties of weathered rock mass and fresh rock mass,especially entirely weathered rock mass.To entirely weathered rock mass,its joints are totally weathered and rebuilt and did not control the stability of the slope any more,and its property is close to coarse granule soil.Thus,the high slope with entirely weathered rock mass is easily failed.Taking the high slope of Eshanchong of Highway from Guizhou to Majiang for example,and it is found that there exist various possible circular sliding faces in different depth of the slope.Moreover,a systemic reinforce scheme is presented such as grouting in the superficial,anchor in the middle and propping at the foot of the slope.The scheme is proved to be successful,economical and effective in the reinforcement of the entirely weathered high slope of the Eshanchong.These are very meaningful in the treatment of other similar high slopes.