红层地区高速公路滑坡破坏机制及处治

Damage Mechanism and Control Measures of a Highway Slope in Red Bed Area

本文介绍了十堰至天水国家高速公路甘肃段某滑坡的治理过程。该滑坡下伏基岩为第三系泥质砂岩等软弱岩,中间的软塑带构成坡体的软弱带。原设计为多级放坡的方式,但按该方案施工后坡体后缘产生拉张裂缝、局部滑塌,坡脚处开始滑动。后来变更设计在坡脚增加一桩板墙,按照变更设计桩板墙施工完成后,部分桩体发生较大倾斜,桩顶与土体脱离,挡土板下与岩土交接面处发生较大剪切裂缝。故再次变更设计,在已施工完毕的桩体上增设两排预应力锚杆,并采取格构加预应力锚索的方式加固桩顶第一级放坡,最终该滑坡的稳定性满足要求。基于有限元法对各设计方案的变形与稳定性进行了分析,为类似工程提供参考借鉴。

The process of a highway slope＇ s treatment in Gansu area of the national highway from Shiyan to Tianshui is introduced in this article, The underlying bedrock of the landslide is the third series of soft rocks, such as mudstone and sandstone, and the soft plastic zone in the middle is a weak zone of the slope body. The original design Of this slope adopted the style of multi sloping. But local sliding collapse, tensile crack emerged at the rear of slope and shear plane emerged at the foot of slope during construction according to the original design. Then a row of sheet pile wall added at the foot of slope according to the altered design. However, large horizontal displacement happened at some piles, and separation occurred at the top of the piles between piles and soil, and the shear cracks occurred in the soil between piles after piles constructed according to the altered design. Thus, two rows of pre-stressed anchor bolts are additional arranged on the pile body, and lattice and the pre-stressed anchor cable had been used to reinforce the first step of slope above pile top, according to the second altered design. The stability of the slope eventually meets the requirements. The stability and deformation of the slope according each design scheme are comparatively analyzed with FEM, which aim to provide reference for similar projects.