岩溶隧道基底微型桩处理技术与监测

On the Micro-Pile Treating Techniques for and Monitoring of Karst Caves at the Bottom of a Tunnel

西南地区修建高铁隧道存在岩溶发育程度高、溶腔形态各异、深度和填充复杂、涉及范围较大等特点;高铁线下工程对预防沉降变形要求严格,设计和施工难度大。某高铁岩溶隧道采用?300 mm微型桩处理基底岩溶,介绍了施工过程。监测数据表明,隧道基底溶洞处理后不仅满足承载力要求,并且具有足够的刚度,保证了工后轨道沉降满足规范要求。实践证明该处理方法具有简单、安全、经济、实用性强的特点,值得推广使用。

Building high-speed railway tunnels in Southwest China is often faced with the problem of high karst development, in which case the karst caves are different in shape and depth, and complex in filling circumstance, and the range involved is usually far and wide. As is known to all, the off-line projects of high-speed railways are much demanding in requirements in the prevention of settlement and deformation, owing to which the difficulty in both design and construction is great. Introduced in the present paper is the construction of a certain high-speed railway tunnel where micro-piles of 300 mm in diameter are adopted to treat the karst at the bottom of the tunnel, with the construction process presented. The monitored data show that the karst caves, after being treated, can not only meet the requirements in bearing capacity but also have sufficient rigidity to ensure meeting the requirements of the technical norm in post-construction settlement of the track. Practice shows that the construction method has the characteristics of being simple,safe, economical and widely applicable, and is thus worth popularizing.