大潮高速公路路堑边坡灾变机理及防治

Mechanism and Prevention of Slope Disaster in Cut Slopes of Dachao Expressway

随着高速公路逐渐向复杂艰险的山区延伸,公路建设和运营过程中面临着边(滑)坡等地质灾害的严重威胁。以大潮高速公路K49+460~+995段右侧路堑边坡出现多次滑动为研究对象,结合现场详细勘察和调查结果,基于传递系数法理论推导以及数值模拟分析计算方法,分析该滑坡的稳定性与滑坡演变过程、边坡滑动机理,提出了快速有效的新型防治技术。结果表明:(1)该边坡变形的破坏模式为人工开挖诱发地下水改变的牵引式滑坡;(2)提出了多次分段控制注浆“竖向钢花管微型桩群+斜向预应力钢锚管锚索”组合框架加固新技术;通过劈裂注浆锚固技术能对滑带岩土体的空隙进行砂浆充填、挤密,提高了滑带岩土体强度指标,明显提升了滑带抗滑力和边坡的稳定性;(3)通过模拟滑坡演变过程,在滑坡蠕动阶段,滑动面塑性应变区主要出现在主滑段,此外后缘牵引段存在轻微的塑性变形;在滑坡挤压阶段,塑性区显著增大,并不断向牵引段发展,主滑段塑性区域也逐渐增大;当再次对滑动面土体力学参数折减后,抗滑段也出现塑性区域,此时整个滑动面接近贯通,坡体处于不稳定状态。

With gradually extending ofexpresswaysto the complicated and difficult mountainous areas, construction and operation of highwayshave been faced with serious threat of geological disasters such as sideslopesliding. Taking the cut slope on the right side of K49+460~K49+995 section of Dachao Expressway as an example, where several side slope sliding occurred. Being combined with detailed survey and on-site investigation, the stability, sliding developing and sliding mechanism of the slopeshave been comprehensively analyzed by means of transfer coefficient method and numerical simulation, withrapid and effective prevention and control countermeasures being proposed. The analysis results have shown that:(1)The failure mode of the slope sliding belongs to the landslide disaster caused by manual excavation;(2) A new technology of multi-section control grouting “vertical steel flower tube micro pile group cooperating with oblique prestressed steel anchor pipe anchor cable” for slope reinforcement is proposed, with forming a similar “anchor cable anti-slide pile structure”, the anti-slide pile is equivalent to the vertical steel tube micro-pile group, and the pre-stressed anchor cable is equivalent to the pre-stressed steel anchor pipe anchor cable structure;(3) Being found through numerical simulation calculations, the treatment of landslides should be done as early as possible, at this time the landslide support effect is better, and the engineering budget of the support measures will also be reduced.