朔州隧道塌陷下沉侵限段支护处治施工技术

Construction Technology for Abnormal Phenomena Treatment of Shuozhou Tunnel including Collapse,Subsidence and Exceeding Clearance Limit

风积砂质黄土构造疏松，垂直节理发育，具大孔隙，具有中等～严重湿陷性，这种土质在隧道施工中易发生崩塌。针对准池铁路朔州隧道进口段风积砂质黄土段初支后出现塌陷、下沉、侵限，喷射混凝土剥落、开裂、下塌变形、初支钢拱架扭曲变形等现象，采用有限元差分软件FLAC^3D对风积砂质黄土隧道坍塌体进行分析，处治方法采用迈式锚杆管棚超前支护和径向迈式锚杆打设处治技术，对原初支进行有效拆挟，迈式锚杆具有钻进、锚固作业一体化施工特点，实现了塌陷、下沉、侵限段支护处治有效施工。该施工技术方便、快捷，适合隧道狭窄空间作业和抢险施工等特点。

Aeolian sandy loess is characterized by loose structure, vertical joint development, large pores, moderate or severe collapsibility, and easy to collapse during tunnel construction. The aim of this paper was to illustrate how to treat the abnormal phenomena appeared after initial supporting at the aeolian sandy loess section of Shuozhou Tunnel on Zhun-Chi Railway, such as the collapse, subsidence, exceeding clearance limit, shotcrete＇s peeling off and cracking or sinking down, and the distortion of steel arch frame of initial supporting, etc. The finite difference software FLAC3D was utilized to analyze the collapsed section of the aeolian sand loess tunnel. And then, by using advance support of Michael bolt pile-roof and using Michael bolts in radial direction, the initial support was removed and replaced effectively. As a result, by virtue of the Michael bolt＇s advantage in drilling-anchoring integration operation, the construction was able to be effectively implemented for treating the abnormal phenomena of collapse, subsidence and exceeding clearance limit. Then this paper comes to the conclusion： this construction technology is convenient, fast, suitable for working in narrow tunnel space and suitable for emergency construction.