砂层隧道预加固咬合桩施工技术与费用分析

Construction Techniques for and Cost Analysis of Secant Piles for the Pre-Reinforcement of Tunnels in Sand Strata

大西铁路客运专线上白隧道全长1 717 m,全隧洞身范围均穿越不同厚度的干燥粉细砂层,存在涌砂、突砂风险。通过研究干燥粉细砂层的物理力学特性并经过方案比选,最终确定了以预加固咬合桩为核心技术的施工工艺。鉴于相关行业对此工艺无明确定额标准,文章对预加固咬合桩的施工工艺流程、施工难点等问题进行了阐述并重点对施工费用进行了单价分析,可供类似工程借鉴使用。

Considering that the Shangbai tunnel on the Datong-Xi′an passenger dedicated railway line, 1717 m in total length, is at risk of sand gushing caused by construction in the dry, fine siltstone strata of different thicknesses,the construction technique of using a secant pile for tunnel pre-reinforcement is proposed based on research per-formed on the physical and mechanical properties of this strata. A relevant scheme comparison and some relevant is-sues, such as the construction technology process and construction difficulties regarding the secant pile for pre-rein-forcement, are discussed in light of the absence of a clear professional quota standard for this technique, especiallyregarding the unit price of its construction cost.