黄山高速滑移弯曲边坡变形机理分析及应急治理对策

黄山高速公路穿行于皖南山区,公路建设过程中,汤口互通A匝道高边坡产生了大范围变形,严重威胁已有构筑物和施工安全。为保证边坡稳定,成立“应急指挥小组”,建立快速反应机制,并采用工程地质测绘、勘探、监测等手段,快速查明边坡结构特征,分析边坡变形机理和稳定性,提出应急治理方案。分析表明,该边坡为层间软弱夹层JP2]发育的砂泥岩互层型顺向边坡,地质历史上边坡曾发生滑移—弯曲变形,公路施工时对弯曲隆起部位岩体进行开挖,引起坡体产生快速变形,在降雨、开挖等条件下,边坡产生整体失稳的可能性极大。在分析边坡变形机制基础上,应用变形控制理论,确定对边坡采取桩锚结合、综合排水的应急治理措施,并根据变形特点提出了应急治理施工步骤。应急治理措施实施后,边坡变形得到了有效控制,稳定性达到了高速公路的安全要求

Analysis of Deformation Mechanism of Sliding to Bending Slope and Study of Deformation Emergency Control at Huangshan Expressway

Huangshan expressway is located at mountain area in southern Anhui Province. The Tangkou ramp slope generated deformation during the expressway construction, which affected the safety of constructed building and workers. The construction organization organized "Emergency Commander Group", which adopt quick reaction mechanism to assure the slope safety. Engineering geological survey, exploration, and monitoring were adopt to study the slope structure quickly. Then, the mechanism and stability of the slope were analyzed aimed to design emergency control scheme. The studied result indicated that the slope is bedding slope interbedded by sandrock and argillaceous sandrock, which exists weak layers between bedding planes. Slipping to curving deformation happened during the slope formed, and the curved rock mass were excavated during construction of expressway roadbed, which induced rapid deformation of the slope.According to analysis mentioned above, the ramp slope may be destabilized during rainfall or excavation. Based on analysis of slope deformation mechanism, the emergency control scheme including friction piles, prestressed anchors and drain was designed by deformation control theory, and support steps were put forward according to the slope deformation characteristics. The large deformation was controlled which reached safety request of expressway when the emergency controlling measures were implemented indicated by displacement monitoring curves.